1) The document analyzes the surface integrity of En31 steel after grinding with different abrasives. Temperature measurements showed that tensile residual stresses formed before visible damage like oxidation or phase transformations.
2) High efficiency deep grinding was shown to reduce thermal damage potential under optimal conditions by using an inclined heat source with circular contact.
3) The choice of grinding abrasive was found to be important for controlling thermal effects on surface integrity. Controlling grinding temperature is key to preventing different types of damage.
This study analyzed intergranular tempered martensite embrittlement (TME) in commercial 4340 and 4140 steels. TME was observed through decreasing impact toughness with increasing tempering time and temperature. The 4340 steel, which contains nickel to enhance intrinsic toughness, exhibited slower TME than the 4140 steel. This is because the higher toughness of the 4340 steel matrix requires coarser carbides to form at grain boundaries to initiate brittle intergranular cracking. Additionally, nickel may slow the rate of carbide coarsening in the 4340 steel. The study suggests intrinsic toughness influences TME by affecting the relaxation of stresses at grain boundaries and the formation of coarse boundary carbides required
safety regulations, competing materials, customer demand for high quality, and the high cost of capital have
led to a need for changes across the industry. Refractories for all unit processes are selected on the basis of their
longevity and the cleanliness of the steel. The various types of refractories influence the safe operation, energy
consumption and product quality; therefore, selecting refractories to each application is of great importance. This
study discusses the types, characteristics and properties of various refractories suitable for steel plant ladle.
The document discusses the Jominy end quench test for determining the hardenability of steels. It describes how a standardized test sample is austenitized and then quenched at one end with water. Hardness measurements along the length provide a hardenability curve, with greater hardness penetration indicating higher hardenability. The cooling rate decreases with distance from the quenched end, allowing simulation of a range of cooling rates. Comparison of curves for different steels establishes their relative hardenability.
The document discusses the Jominy end quench test, which is used to measure the hardenability of steels. In the test, a cylindrical steel sample is uniformly heated, then quenched at one end with water to rapidly cool it. Hardness measurements are then taken at intervals along the sample's length from the quenched end. The results show decreasing hardness further from the quenched end, indicating how deep within the material the heat treatment can harden it. Alloying elements like chromium, molybdenum, and manganese can shift the hardness "nose" deeper, improving hardenability by slowing the transformation of austenite. The test provides critical information for selecting ste
Research Inventy : International Journal of Engineering and Scienceresearchinventy
This document reviews the effects of hot extrusion on metal matrix composites (MMCs). It finds that hot extrusion improves many properties compared to cold extrusion due to recrystallization and reduced porosity. Specifically, hot extrusion leads to higher hardness, impact strength, tensile properties and texture strength, and lower residual stresses and porosity compared to cold extrusion. Micrographs show hot extrusion minimizes porosity and improves reinforcement distribution. In conclusion, hot extrusion is an effective secondary process for fabricating MMCs that enhances mechanical properties.
Investigation on the Rate of Solidification and Mould Heating in the Casting ...IOSR Journals
Abstract: The quality of casting in the foundry can be measured by the rate at which solidification of the
molten metal takes place, which is consequent upon the rate the mould, is able to dissipate the heat of
solidification to the surroundings. The faster or slower the heat removal process during solidification the
structure of the grains formed by the casting is either finer of coarser. An experimental investigation was
carried out to compare the rate of solidification of commercially pure aluminium in metallic moulds. The rate at
which solidification occurred was compared with the rate at which the mould absorbed and dissipates heat. The
experiments conducted recorded the temperature fields at different casting location and that of the moulds
respectively. The results showed that there is a direct relation of the rate of heat absorption by the mould and
the rate of solidification in metallic moulds.
Keywords – Aluminium, casting, heat, mould, solidification, temperature.
Report and Analysis: Resulting Microstructures of Cooled Carbon SteelDeAndria Hardy
Report and Analysis of experiment which tested the mechanical properties and resulting microconstituents of carbon steel under various cooling conditions
This study analyzed intergranular tempered martensite embrittlement (TME) in commercial 4340 and 4140 steels. TME was observed through decreasing impact toughness with increasing tempering time and temperature. The 4340 steel, which contains nickel to enhance intrinsic toughness, exhibited slower TME than the 4140 steel. This is because the higher toughness of the 4340 steel matrix requires coarser carbides to form at grain boundaries to initiate brittle intergranular cracking. Additionally, nickel may slow the rate of carbide coarsening in the 4340 steel. The study suggests intrinsic toughness influences TME by affecting the relaxation of stresses at grain boundaries and the formation of coarse boundary carbides required
safety regulations, competing materials, customer demand for high quality, and the high cost of capital have
led to a need for changes across the industry. Refractories for all unit processes are selected on the basis of their
longevity and the cleanliness of the steel. The various types of refractories influence the safe operation, energy
consumption and product quality; therefore, selecting refractories to each application is of great importance. This
study discusses the types, characteristics and properties of various refractories suitable for steel plant ladle.
The document discusses the Jominy end quench test for determining the hardenability of steels. It describes how a standardized test sample is austenitized and then quenched at one end with water. Hardness measurements along the length provide a hardenability curve, with greater hardness penetration indicating higher hardenability. The cooling rate decreases with distance from the quenched end, allowing simulation of a range of cooling rates. Comparison of curves for different steels establishes their relative hardenability.
The document discusses the Jominy end quench test, which is used to measure the hardenability of steels. In the test, a cylindrical steel sample is uniformly heated, then quenched at one end with water to rapidly cool it. Hardness measurements are then taken at intervals along the sample's length from the quenched end. The results show decreasing hardness further from the quenched end, indicating how deep within the material the heat treatment can harden it. Alloying elements like chromium, molybdenum, and manganese can shift the hardness "nose" deeper, improving hardenability by slowing the transformation of austenite. The test provides critical information for selecting ste
Research Inventy : International Journal of Engineering and Scienceresearchinventy
This document reviews the effects of hot extrusion on metal matrix composites (MMCs). It finds that hot extrusion improves many properties compared to cold extrusion due to recrystallization and reduced porosity. Specifically, hot extrusion leads to higher hardness, impact strength, tensile properties and texture strength, and lower residual stresses and porosity compared to cold extrusion. Micrographs show hot extrusion minimizes porosity and improves reinforcement distribution. In conclusion, hot extrusion is an effective secondary process for fabricating MMCs that enhances mechanical properties.
Investigation on the Rate of Solidification and Mould Heating in the Casting ...IOSR Journals
Abstract: The quality of casting in the foundry can be measured by the rate at which solidification of the
molten metal takes place, which is consequent upon the rate the mould, is able to dissipate the heat of
solidification to the surroundings. The faster or slower the heat removal process during solidification the
structure of the grains formed by the casting is either finer of coarser. An experimental investigation was
carried out to compare the rate of solidification of commercially pure aluminium in metallic moulds. The rate at
which solidification occurred was compared with the rate at which the mould absorbed and dissipates heat. The
experiments conducted recorded the temperature fields at different casting location and that of the moulds
respectively. The results showed that there is a direct relation of the rate of heat absorption by the mould and
the rate of solidification in metallic moulds.
Keywords – Aluminium, casting, heat, mould, solidification, temperature.
Report and Analysis: Resulting Microstructures of Cooled Carbon SteelDeAndria Hardy
Report and Analysis of experiment which tested the mechanical properties and resulting microconstituents of carbon steel under various cooling conditions
Overview on Thermal Barrier Coatings Application and DevelopmentIJRES Journal
This paper mainly summary the application and development of thermal barrier coatings (TBC) in last decades. TBCs have been widely used in automotive, gas turbine, solid oxide fuel cell and other fields. It can protect substrate materials from high temperature oxidation and corrosion meanwhile increasing lifetime of parts and improving the work efficiency. At last, the development trend of TBC was referred on the TBCs materials and structures.
This document analyzes the formation of central cracks in the continuous casting of 49MnVS3 microalloy steel blooms. Thermodynamic calculations show that the solidus temperature is lower than expected due to non-equilibrium solidification, leading to increased solute segregation of elements like C and S toward the center. Microscopy reveals central cracks perpendicular to the outer arc that form in the mushy zone late in solidification. Hot ductility tests indicate a high temperature brittle zone just below the solidus where failure occurs via brittle fracture with little ductility. Precipitates like MnS and Ti(C,N) are found to form near the solidus, which can decrease the temperature and promote crack propagation. Controlling center
Cutting of hardened steel is a topic of high interest for toda 's industrial production and scientific research.
Machine parts consisting of hardened steel are high peiormance components which are often loaded
near their physical limits. The functional behavior of machined parts is decisively influenced by the fine
finishing process which represents the last step in the process chain and can as well be undertaken by
cutting as grinding. An overview of the mechanisms of chip removal in hard cutting and the thermomechanical
influence of the work area is presented. Furthermore, several models of chip removal in hard
turning are introduced and discussed summarizing the metallurgical fundamentals and giving an overview
on stress and temperature distributions in the work area. Boundary conditions for hard cutting as e.g.
machine tools, cutting materials and others are subject to discussion to determine the achievable
workpiece quality and economic efficiency of hard cutting processes in comparison with grinding.
Super plastic forming is a metalworking process that uses high temperatures and controlled strain rates to form sheet metal. Materials like titanium alloys and aluminum alloys can elongate several times their original length through this process. Explosive forming also shapes metals through high pressure, using an explosive charge to form sheet metal against a die in either a standoff or contact method. Both processes allow for complex shapes but super plastic forming is slower while explosive forming supports larger parts and shorter production runs.
This document summarizes a presentation on heat treatment processes. It defines heat treatment as heating a material to a particular temperature, holding it for a period of time, and cooling it to achieve desired properties. The document then classifies and describes common heat treatment processes like annealing, normalizing, hardening, and tempering. It explains how each process affects the microstructure and properties of metals. The document also discusses principles of heat treatment, factors that influence hardness, and surface hardening techniques like induction hardening and flame hardening.
Chapter 3: Metal Works, Casting & Heat Treatmentsyar 2604
This topic explains the processes of metal works and casting. It also describes the types and purpose of heat treatment for steels and the effects of heat treatment on mechanical properties of steels.
Material Engineering,
Heat treating (or heat treatment) is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching
The document discusses quality control procedures for analyzing the composition, microstructure, and properties of refractory materials. It describes testing the chemical composition, solid phase composition, microstructure, densification properties, mechanical properties, thermal properties, and abrasion resistance of refractory samples according to Egyptian and ISO standards. Key tests and properties discussed include bulk density, apparent porosity, thermal expansion, thermal shock resistance, and thermal conductivity.
Thermal Barrier Coatings (TBCs) are coatings applied to gas turbine engine components to increase their high-temperature capability. TBCs typically have four layers: a superalloy substrate, bond coat, thermally grown oxide layer, and yttria-stabilized zirconia ceramic topcoat. TBCs allow gas turbine blades to operate at temperatures up to 1500°C, significantly increasing engine efficiency. However, TBCs can fail over time due to thermal expansion mismatches and oxidation of the bond coat, reducing the operating life of coated components.
Conventional heat treatment of low carbon steelAyush Chaurasia
Heat treatment of Low Carbon Steel via heat treatment processes of annealing, quenching and normalising and observing the structural changes affecting the hardness property of material.
Mumbai University
Mechanical engineering
SEM III
Material Technology
Module 1.4
Strain Hardening:
Definition importance of strain hardening, Dislocation theory of strain hardening, Effect of strain hardening on engineering behaviour of materials, Recrystallization Annealing: stages of recrystallization annealing and factors affecting it
Effect of Hardness and Wear Resistance on En 353 Steel by Heat Treatment IJMER
En 353 steel is an easily available and cheap material that is acceptable for heavy duty
applications. Heat treatment on En 353 steel is improved the ductility, toughness, strength, hardness and
relive internal stress in the material. Spectrographic method is used to analyze the composition of the
alloy material. The experimental results of hardness and dry wear testing on pin-on-disc are done to get
idea about heat treated En 353 steel. It is found that the hardness and wear resistance of the En 353 steel
is improved after the heat treatment and the microstructure is changed from ferrite to martensite.
Heat treatment involves heating and cooling metals and alloys to obtain desirable properties or conditions. It includes processes like annealing, normalizing, hardening, and tempering. Heat treatment can relieve stresses, improve machinability and ductility, and make structures more homogeneous.
Effect of Subzero Treatment on Microstructure and Material Properties of EN...IJMER
Cryogenic treatment of steels has been widely used for enhancing mechanical properties
like hardness, toughness and stable metallurgical structure. Application such as gears, kicker rods,
bolts are made of medium carbon alloy steels like EN-24 steel. In these applications, percentage of
retained austenite has considerable effects on the life of the material. A comparative study on
conventionally heat-treated (CHT) and shallow cryogenic treated (SCT) EN-24 steel was done to
evaluate the effect of shallow cryogenic treatment (SCT) on hardness, toughness and the amount of
retained austenite present in the structure of EN24 steel. The microscopic structure of cryogenic
treated EN24 steel revealed the formation of carbides, both primary and secondary carbides. An
estimated amount of 15% retained austenite after CHT tempered condition was less than 2% after SCT
tempered condition. Tensile test fractography of subzero treated (SCT) specimen revealed ductile
fracture. The maximum hardness observed in case of SCT tempered samples was 415BHN, 15%
increase from CHT tempered samples. The maximum impact strength observed in case of SCT
tempered samples was 240kJ/m2, 11% increase from CHT tempered samples. Further SCT tempered
samples, tempered at 650°C resulted in ductility increase by 55% as compared to CHT tempered
samples without sacrificing hardness.
Recrystallization is the process in which deformed grains of the crystal structure are replaced by a new set of stress-free grains that nucleate and grow until all the original grains have been consumed. The process is accomplished by heating the material to temperatures above that of crystallization.
This document provides an overview of metallurgy and material properties. It discusses the main classes of steels including carbon steels, alloy steels, and stainless steels. It also covers alloying elements, heat treatment processes, mechanical properties testing, and non-destructive testing methods. The key information presented includes the classifications of steels based on chemistry, the effects of common alloying elements, and standard tests used to evaluate material properties and integrity.
This document discusses heat treatment of steel, including:
- The iron-carbon phase diagram which shows the different phases of steel at various temperatures and carbon levels.
- Common constituents in steel like ferrite, austenite, cementite, and pearlite.
- Heat treatment processes like hardening, quenching, and tempering which are used to change the microstructure and properties of steel.
- Quenching involves rapidly cooling steel from high temperatures to form martensite and involves considerations like quenching media and cooling rates.
- Tempering is used after quenching to reduce brittleness and relieve stresses by reheating steel to lower temperatures.
- Furnaces like batch and
Wear Properties of Thixoformed Al-5.7Si-2Cu-0.3Mg Aluminium AlloyDr. Manal Abdullatif
Earlier work has shown that Al-5.7Si-2Cu-0.3Mg aluminium alloy is suitable for
thixoforming process. Here, the dry sliding wear behaviour of the alloy, in the as-cast and
thixoformed conditions were investigated. The cooling slope technique was used to produce the alloy
with globular microstructure for the thixoforming process. Both the thixoformed and cast samples
were subjected to T6 heat treatments prior to the wear tests. The tests were carried out using a
pin-on-disc tribometer, against a hardened M2 tool steel disc of 62 HRC at different loads, under dry
sliding conditions at fixed sliding speed and sliding distance of 1 m.s–1 and 5 km respectively. The
microstructural response, worn surfaces was thoroughly and carefully examined using various
methods such as scanning electron microscopy, energy dispersive spectroscopy, and differential
scanning calorimetry. The density of the heat treated thixoformed alloys showed significant increase
in the hardness property, among others, due to its reduced porosity. Their wear test results also
observed that the weight loss of materials increase with an increase in the input load and the sliding
distance for all samples. However, the as-cast alloy displayed higher wear rate compared with the
thixoformed alloys. In general, the wear mechanisms showed a mixture of abrasive, oxidative and
delamination wear (mild wear) at low applied loads and mainly an adhesive (severe wear) at high
applied loads.
The document provides an overview of various surface heat treatment processes for metals. It discusses techniques like surface hardening, case hardening, and nitriding that involve diffusing elements like carbon or nitrogen into the surface of the metal to create a hard case while leaving the core soft. Induction hardening, carburizing, and nitriding are described as common methods for surface hardening. The document also covers other surface hardening techniques like flame hardening, vapor deposition methods, and plasma nitriding.
Overview on Thermal Barrier Coatings Application and DevelopmentIJRES Journal
This paper mainly summary the application and development of thermal barrier coatings (TBC) in last decades. TBCs have been widely used in automotive, gas turbine, solid oxide fuel cell and other fields. It can protect substrate materials from high temperature oxidation and corrosion meanwhile increasing lifetime of parts and improving the work efficiency. At last, the development trend of TBC was referred on the TBCs materials and structures.
This document analyzes the formation of central cracks in the continuous casting of 49MnVS3 microalloy steel blooms. Thermodynamic calculations show that the solidus temperature is lower than expected due to non-equilibrium solidification, leading to increased solute segregation of elements like C and S toward the center. Microscopy reveals central cracks perpendicular to the outer arc that form in the mushy zone late in solidification. Hot ductility tests indicate a high temperature brittle zone just below the solidus where failure occurs via brittle fracture with little ductility. Precipitates like MnS and Ti(C,N) are found to form near the solidus, which can decrease the temperature and promote crack propagation. Controlling center
Cutting of hardened steel is a topic of high interest for toda 's industrial production and scientific research.
Machine parts consisting of hardened steel are high peiormance components which are often loaded
near their physical limits. The functional behavior of machined parts is decisively influenced by the fine
finishing process which represents the last step in the process chain and can as well be undertaken by
cutting as grinding. An overview of the mechanisms of chip removal in hard cutting and the thermomechanical
influence of the work area is presented. Furthermore, several models of chip removal in hard
turning are introduced and discussed summarizing the metallurgical fundamentals and giving an overview
on stress and temperature distributions in the work area. Boundary conditions for hard cutting as e.g.
machine tools, cutting materials and others are subject to discussion to determine the achievable
workpiece quality and economic efficiency of hard cutting processes in comparison with grinding.
Super plastic forming is a metalworking process that uses high temperatures and controlled strain rates to form sheet metal. Materials like titanium alloys and aluminum alloys can elongate several times their original length through this process. Explosive forming also shapes metals through high pressure, using an explosive charge to form sheet metal against a die in either a standoff or contact method. Both processes allow for complex shapes but super plastic forming is slower while explosive forming supports larger parts and shorter production runs.
This document summarizes a presentation on heat treatment processes. It defines heat treatment as heating a material to a particular temperature, holding it for a period of time, and cooling it to achieve desired properties. The document then classifies and describes common heat treatment processes like annealing, normalizing, hardening, and tempering. It explains how each process affects the microstructure and properties of metals. The document also discusses principles of heat treatment, factors that influence hardness, and surface hardening techniques like induction hardening and flame hardening.
Chapter 3: Metal Works, Casting & Heat Treatmentsyar 2604
This topic explains the processes of metal works and casting. It also describes the types and purpose of heat treatment for steels and the effects of heat treatment on mechanical properties of steels.
Material Engineering,
Heat treating (or heat treatment) is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching
The document discusses quality control procedures for analyzing the composition, microstructure, and properties of refractory materials. It describes testing the chemical composition, solid phase composition, microstructure, densification properties, mechanical properties, thermal properties, and abrasion resistance of refractory samples according to Egyptian and ISO standards. Key tests and properties discussed include bulk density, apparent porosity, thermal expansion, thermal shock resistance, and thermal conductivity.
Thermal Barrier Coatings (TBCs) are coatings applied to gas turbine engine components to increase their high-temperature capability. TBCs typically have four layers: a superalloy substrate, bond coat, thermally grown oxide layer, and yttria-stabilized zirconia ceramic topcoat. TBCs allow gas turbine blades to operate at temperatures up to 1500°C, significantly increasing engine efficiency. However, TBCs can fail over time due to thermal expansion mismatches and oxidation of the bond coat, reducing the operating life of coated components.
Conventional heat treatment of low carbon steelAyush Chaurasia
Heat treatment of Low Carbon Steel via heat treatment processes of annealing, quenching and normalising and observing the structural changes affecting the hardness property of material.
Mumbai University
Mechanical engineering
SEM III
Material Technology
Module 1.4
Strain Hardening:
Definition importance of strain hardening, Dislocation theory of strain hardening, Effect of strain hardening on engineering behaviour of materials, Recrystallization Annealing: stages of recrystallization annealing and factors affecting it
Effect of Hardness and Wear Resistance on En 353 Steel by Heat Treatment IJMER
En 353 steel is an easily available and cheap material that is acceptable for heavy duty
applications. Heat treatment on En 353 steel is improved the ductility, toughness, strength, hardness and
relive internal stress in the material. Spectrographic method is used to analyze the composition of the
alloy material. The experimental results of hardness and dry wear testing on pin-on-disc are done to get
idea about heat treated En 353 steel. It is found that the hardness and wear resistance of the En 353 steel
is improved after the heat treatment and the microstructure is changed from ferrite to martensite.
Heat treatment involves heating and cooling metals and alloys to obtain desirable properties or conditions. It includes processes like annealing, normalizing, hardening, and tempering. Heat treatment can relieve stresses, improve machinability and ductility, and make structures more homogeneous.
Effect of Subzero Treatment on Microstructure and Material Properties of EN...IJMER
Cryogenic treatment of steels has been widely used for enhancing mechanical properties
like hardness, toughness and stable metallurgical structure. Application such as gears, kicker rods,
bolts are made of medium carbon alloy steels like EN-24 steel. In these applications, percentage of
retained austenite has considerable effects on the life of the material. A comparative study on
conventionally heat-treated (CHT) and shallow cryogenic treated (SCT) EN-24 steel was done to
evaluate the effect of shallow cryogenic treatment (SCT) on hardness, toughness and the amount of
retained austenite present in the structure of EN24 steel. The microscopic structure of cryogenic
treated EN24 steel revealed the formation of carbides, both primary and secondary carbides. An
estimated amount of 15% retained austenite after CHT tempered condition was less than 2% after SCT
tempered condition. Tensile test fractography of subzero treated (SCT) specimen revealed ductile
fracture. The maximum hardness observed in case of SCT tempered samples was 415BHN, 15%
increase from CHT tempered samples. The maximum impact strength observed in case of SCT
tempered samples was 240kJ/m2, 11% increase from CHT tempered samples. Further SCT tempered
samples, tempered at 650°C resulted in ductility increase by 55% as compared to CHT tempered
samples without sacrificing hardness.
Recrystallization is the process in which deformed grains of the crystal structure are replaced by a new set of stress-free grains that nucleate and grow until all the original grains have been consumed. The process is accomplished by heating the material to temperatures above that of crystallization.
This document provides an overview of metallurgy and material properties. It discusses the main classes of steels including carbon steels, alloy steels, and stainless steels. It also covers alloying elements, heat treatment processes, mechanical properties testing, and non-destructive testing methods. The key information presented includes the classifications of steels based on chemistry, the effects of common alloying elements, and standard tests used to evaluate material properties and integrity.
This document discusses heat treatment of steel, including:
- The iron-carbon phase diagram which shows the different phases of steel at various temperatures and carbon levels.
- Common constituents in steel like ferrite, austenite, cementite, and pearlite.
- Heat treatment processes like hardening, quenching, and tempering which are used to change the microstructure and properties of steel.
- Quenching involves rapidly cooling steel from high temperatures to form martensite and involves considerations like quenching media and cooling rates.
- Tempering is used after quenching to reduce brittleness and relieve stresses by reheating steel to lower temperatures.
- Furnaces like batch and
Wear Properties of Thixoformed Al-5.7Si-2Cu-0.3Mg Aluminium AlloyDr. Manal Abdullatif
Earlier work has shown that Al-5.7Si-2Cu-0.3Mg aluminium alloy is suitable for
thixoforming process. Here, the dry sliding wear behaviour of the alloy, in the as-cast and
thixoformed conditions were investigated. The cooling slope technique was used to produce the alloy
with globular microstructure for the thixoforming process. Both the thixoformed and cast samples
were subjected to T6 heat treatments prior to the wear tests. The tests were carried out using a
pin-on-disc tribometer, against a hardened M2 tool steel disc of 62 HRC at different loads, under dry
sliding conditions at fixed sliding speed and sliding distance of 1 m.s–1 and 5 km respectively. The
microstructural response, worn surfaces was thoroughly and carefully examined using various
methods such as scanning electron microscopy, energy dispersive spectroscopy, and differential
scanning calorimetry. The density of the heat treated thixoformed alloys showed significant increase
in the hardness property, among others, due to its reduced porosity. Their wear test results also
observed that the weight loss of materials increase with an increase in the input load and the sliding
distance for all samples. However, the as-cast alloy displayed higher wear rate compared with the
thixoformed alloys. In general, the wear mechanisms showed a mixture of abrasive, oxidative and
delamination wear (mild wear) at low applied loads and mainly an adhesive (severe wear) at high
applied loads.
The document provides an overview of various surface heat treatment processes for metals. It discusses techniques like surface hardening, case hardening, and nitriding that involve diffusing elements like carbon or nitrogen into the surface of the metal to create a hard case while leaving the core soft. Induction hardening, carburizing, and nitriding are described as common methods for surface hardening. The document also covers other surface hardening techniques like flame hardening, vapor deposition methods, and plasma nitriding.
Welding is a process that joins metals by heating them to melting point and allowing them to merge together. There are two main types: plastic welding applies pressure and fusion welding fully melts the materials. Oxy-fuel welding uses a heated gas flame, such as oxy-acetylene, to melt the metals. It is inexpensive but has a lower temperature than other methods. The equipment includes welding torches, cylinders of gas, regulators to control pressure, and filler rods. Precise flame adjustment is required to protect the metal and achieve the necessary temperature.
Diffusion bonding is a solid-state welding technique that joins materials together through atomic diffusion without melting. It involves applying high pressure and moderate heat to join carefully cleaned and mated surfaces. Diffusion occurs in two stages - initial metal-to-metal contact formation followed by atomic diffusion and grain growth across the interface to form a complete bond. Various factors like temperature, pressure, time and surface preparation influence the diffusion rate. Common diffusion bonding methods include gas pressure bonding, vacuum fusion bonding and eutectic bonding. Diffusion bonding finds applications in the fabrication of components for industries like aerospace, nuclear and others.
This document provides information on various heat treatment processes including annealing, normalizing, hardening, and tempering. It defines heat treatment as any process of heating and cooling metals to alter their properties. Annealing aims to relieve stresses and refine grains, while normalizing also improves properties. Hardening involves heating steel to form austenite and then quenching to form martensite. Tempering reduces brittleness caused by hardening. Specific methods like flame hardening and induction hardening selectively harden surfaces. Case hardening diffuses carbon or nitrogen into surfaces to create a hard case over a tough core.
The document discusses various heat treatment techniques for steels, including annealing, normalizing, hardening, and tempering. It provides an overview of the basic principles and purposes of different heat treatments, such as using annealing to produce high ductility, normalizing to refine grain structure, and hardening followed by tempering to achieve good strength and toughness. The document also describes how properties can be tailored through surface treatments versus bulk treatments, and how alloying can increase the hardenability of steels.
Design &Analysis of Pure Iron Casting with Different MouldsIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Electron beam welding uses a focused beam of high-velocity electrons to join materials. It allows for deep penetration and precise control of the weld. Resistance welding uses electrical resistance to heat and join materials. Common types are spot welding, seam welding, and projection welding. Solid state welding occurs below the melting point using pressure to join materials, such as forge welding, friction welding, and explosive welding.
Heat treatment is used to alter the physical and mechanical properties of metals through controlled heating and cooling without changing the shape. It involves phase transformations during heating and cooling to modify the microstructure. Common heat treatments include annealing, which involves slowly cooling a heated metal to reduce hardness and increase ductility after cold working, and normalizing, which heats metal to above the critical temperature to dissolve carbides before air cooling. Recrystallization is an important annealing process where new strain-free grains nucleate and grow to replace the deformed microstructure.
The desired to reach higher efficiencies, lower specific fuel consumption and reduced emission in modern engines has becomes the primary focus of engine researches and manufactures over the past three decades. Ceramic coating is a solution to such problem as they provide good thermal barrier properties for designers. In the design of adiabatic engines, reducing in cylinder heat rejection requires very special thermal barrier coatings on the engine combustion chamber. Partial Thermal barrier coatings (TBC) on the top surface of the piston is considered as a solution for reduction of unburned Hydrocarbon (HC) emission produce by incomplete combustion with respect to crevice volume when engines start. The TBC on the top piston surface decreases the thermal conductivity and increases the unburned charged oxidation, so that the metallic substrates will be exposed to lower peak temperature thereby reducing the thermal stress in engines components. Also thermal barrier coatings on other elements of combustion chamber of internal combustion engine offer advantages including fuel efficiency, multi fuel capacity and high power density. Therefore, thermal barrier coating (TBC) technology is successfully applied to the internal combustion engines, in particular to the combustion chamber.
The document provides an outline on heat treatment processes. It defines heat treatment and its purposes, discusses heat treatment theory and the stages of heat treatment including heating, soaking, and cooling. It describes various heat treatment processes like annealing, normalizing, hardening, and tempering. It also discusses case hardening techniques like carburizing, cyaniding, and nitriding. Finally, it introduces the TTT diagram and the microstructures obtained from different cooling rates.
The document discusses various heat treatment processes including annealing, normalizing, quenching, and martensitic transformation. It provides details on the purposes, methods, and applications of each process. Annealing involves heating and slow cooling to relieve stresses and modify properties. Normalizing heats above the transformation temperature and air cools to produce a fine grain structure. Quenching rapidly cools steel above the transformation temperature to form very hard martensite. Martensitic transformation is the formation of acicular needlelike structures during rapid cooling of austenite.
This document discusses welding metallurgy and the structure of fusion welds. It describes the different zones that make up a typical fusion welded joint, including the fusion zone, weld interface, heat affected zone, and base material. It explains how the microstructure varies across these zones due to melting and solidification processes during welding. Factors like welding parameters, heat input, and joint geometry are described as influencing weld pool shape and grain structure. The concept of thermal severity number is introduced as a way to assess cracking susceptibility based on total plate thickness.
This document discusses welding metallurgy and the structure of fusion welds. It describes the different zones that make up a typical fusion welded joint, including the fusion zone, weld interface, heat affected zone, and base material. It explains how the microstructure varies across these zones due to melting and solidification processes during welding. Factors like welding parameters, heat input, and joint geometry are described as influencing weld pool shape and grain structure. The concept of thermal severity number is introduced as a way to assess cracking susceptibility based on total plate thickness.
Heat treatment processes involve heating and cooling metals to change their mechanical properties. There are several types of heat treatment processes, including softening processes like annealing which involves slowly cooling metals, hardening processes like quenching which rapidly cool metals, and tempering which heats quenched metals to reduce brittleness. Other processes include case hardening to harden surfaces, austempering to improve properties without distortion, and martempering to reduce cracking during hardening. Each process produces different microstructures and properties in metals to make them suitable for various applications.
Duplex 2209 Weld Overlay by ESSC ProcessIJERA Editor
In the modern world of industrialization the wear is eating metal assets worth millions of dollars per year. The wear is in the form of corrosion, erosion, abrasion etc. which occur in the process industries like oil & gas, refineries, cement plants, steel plants, shipping and offshore working structures. The equipments like pressure vessels, heat exchangers, hydro processing reactors which very often work at elevated temperatures face corrosion in the internal diameter. Duplex 2209 weld overlay on ferrous material is developed for high corrosion resistance properties and having high productivity by Electroslag strip cladding process due to its less dilution ~10% as compared to SMAW , GTAW or FCAW process. Because of Low Dilution ~10% undiluted chemistry can be achieved with single layer as compared to other weld overlay processes. The facility was developed inhouse to carry out weld overlay by ESSC and Testing.
The document discusses the heat treatment process of annealing. It begins by defining heat treatment as heating a metal to a specified temperature, keeping it at that temperature for a period of time, then cooling at a specified rate. Annealing is described as a heat treatment that involves heating metal above its recrystallization temperature, holding for some time, then slowly cooling to develop an equilibrium structure with increased ductility. The document outlines the stages of annealing as recovery, recrystallization, and grain growth.
Surface treatment techniques play an important role in improving properties like hardness, wear and corrosion resistance. The document discusses 8 techniques:
1) Mechanical hardening uses impacts to work-harden surfaces and improve fatigue strength. Shot peening is commonly used.
2) Different coating techniques add thin layers, like case hardening which diffuses alternate elements into steel to harden surfaces.
3) Phosphate conversion coatings chemically react phosphoric acid with metal surfaces to form insoluble phosphate layers for corrosion resistance.
4) Chromate conversion coatings provide highly corrosion-resistant surfaces for aluminum.
Heat treatment 2 by
P.SENTHAMARAI KANNAN,
ASSISTANT PROFESSOR ,
DEPARTMENT OF MECHANICAL ENGINEERING,
KAMARAJ COLLEGE OF ENGINEERING AND TECHNOLOGY,
VIRUDHUNAGAR, TAMILNADU.
INDIA.
Centrifugal Iso-Finishing is a high-speed, high-quality and hands-free method for deburring, smoothing, surface-0finishing, burnishing and polishing of work-pieces and parts. Contact Dave Davidson for additional technical information and assistance with getting your parts sample finished. Contact me at ddavidson@deburring-tech-group.com See also dryfinish.wordpress.com
Technical article reprint on the high-speed and high-intensity and high-quality Centrifugal iso-Finishing method.. The methods used widely on aerospace, motorsports, automotive, medical, dental, orthodontic and jewelry manufactured parts. For additional information contact Dave Davidson at ddavidson@deburring-tech-group.com. Ask about the free sample part finishing program.
See also the technical blog at https://dryfinish.wordpress.com
Modern machine-shop-apr-18 centrifugal isofinishing crnakshaftsDave Davidson
See the technical article on Centrifugal Iso-Finishing on surface finish and it's effect on engine components in the Motorsports Industry terms of performance improvement.
Contact D. A. (Dave) Davidson at ddavidson@deburring-tech-group.com for additional information or help with free sample finishing.
Centrifugal Iso-Finishing Technical article as seen in Products Finishing mag...Dave Davidson
Centrifugal iso-finishing is a high-speed mass finishing method that can produce very refined surface finishes on parts in short cycle times. It can be used for deburring, contouring edges, and developing surface finishes that improve part performance, integrity, and lifespan. Centrifugal iso-finishing involves processing parts with abrasives or polishing materials under high surface pressure to truncate peaks and create uniformly compressed stresses in the surface. This improves part wear resistance, fatigue resistance, and ability to withstand repeated stresses compared to surfaces finished by conventional methods.
Iso-Finishing sample part finishing application formDave Davidson
Free sample part processing and quotations for deburring, finishing or polishing of your production parts.
(1) Download the Word document form into your computer.
(2) Complete the form and include a paper copy with your sample parts to being shipped to the Isofinishing address shown on the form
MFI full finishing product catalog with technical assistance infoDave Davidson
Mass Finishing Equipment and Supply Catalog includes equipment, finishing media, supplies and accessories. Features Centrifugal Iso-Finishing equipment for high-speed and hands-free deburring, finishing and polishing. For technical assistance and help with arranging for free sample finishing of your parts contact Dave Dagvidson at ddavidson@deburring-tech-group.com
It's the Finish that Counts. Technical Magazine article reprint.Dave Davidson
A conventionally produced surface (turned, milled,
ground, EDM) is typically Gaussian in nature, that is,
the peak and valley distribution is pretty much equal
in height. This type of surface can be very unstable and
unpredictable when wear and load bearing are considered. The images in Figure 1 demonstrate this type of
surface.
There are many ways to produce plateaued surfaces.
They are varied in approach but all have the ability to
control the surface peak characteristics separately for
the valley characteristics. Methods that are used to improve surfaces for performance and increased service life include centrifugal barrel finishing, turbo-abrasive machining (aka Turbo-Finish) and isotropic micro-finishing with vibratory finishing equipment. For additional technical information and/or elp with free sample part processing contact Dave Davidson at ddavidson@deburring-tech-group.om
Modern machine shop interviews Dave Davidson about Gear finishing processes. For additional technical information and assistance with sample part finishing contact Dave Davidson | ddavidson@deburring-tech-group.com # #machining #polishing #finish #cnc #manufacturingengineering #automotiveindustry #finishing #deburring #leanmanufacturing #aerospace #massfinishing #grinding #automotive #leanmaufacturing #gears
BV PRODUCTS - Bowl and Tub Vibratory Finishing SystemsDave Davidson
Vibratory finishing machines designed, engineered and built-in Australia that out-perform and out-last vibratory finishing machines costing much more.
Robust design with direct-drive motor and integrated parts/media separation for economical vibratory finishing of metal parts. BV Products has been perfecting its unique all cast polyurethane vibratory finishing machines with direct-drive motion generators for almost 40 years to make them the most innovative and most cost-effective surface finishing solution in the industry. Contact Dave Davidson: ddavidson@deburring-tech-group.com
BV PRODUCTS VIBRATORY FINISHING SYSTEMS FOR DEBURRING AND FINISHINGDave Davidson
Vibratory finishing machines designed, engineered and built-in Australia that out-perform and out-last vibratory finishing machines costing much more.
Robust design with direct-drive motor and integrated parts/media separation for economical vibratory finishing of metal parts. BV Products has been perfecting its unique all cast polyurethane vibratory finishing machines with direct-drive motion generators for almost 40 years to make them the most innovative and most cost-effective surface finishing solution in the industry. Contact Dave Davidson: ddavidson@deburring-tech-group.com
BV Products - Vibratory Finishing machinery for deburring and polishingDave Davidson
Vibratory finishing machines designed, engineered and built-in Australia that out-perform and out-last vibratory finishing machines costing much more.
Robust design with direct-drive motor and integrated parts/media separation for economical vibratory finishing of metal parts. BV Products has been perfecting its unique all cast polyurethane vibratory finishing machines with direct-drive motion generators for almost 40 years to make them the most innovative and most cost-effective surface finishing solution in the industry. Contact Dave Davidson: ddavidson@deburring-tech-group.com
Vibratory finishing machines designed, engineered and built in Australia that out-perform and out-last vibratory finishing machines costing much more. Robust design with direct-drive motor and integrated parts/media separation for economical vibratory finishing of metal parts. BV Products has been perfecting its unique all cast polyurethane vibratory finishing machines with direct-drive motion generators for almost 40 years to make them the most innovative and most cost-effective surface finishing solution in the industry. Contact Dave Davidson: ddavidson@deburring-tech-group.com
Centrifugal Iso-Finishing for Additive Manufactured PartsDave Davidson
Centrifugal Iso-Finishing Technology is used on 3D Printed and conventional CNC precision machined components for deburring, finishing and polishing. It is a high-speed, high-quality hands-free finishing method that produces highly refined surface finishes in a fraction of the time required by other equipment (10 times faster, in many cases) Free sample finishing of your parts is available, contact Dave Davidson at ddavidson@deburring-tech-group.com
Centrifugal iso finishing sample processingDave Davidson
High-Speed, Hands-free deburring, iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish https://lnkd.in/gFjetZk
Centrifugal iso finishing contract services Dave Davidson
High-Speed, Hands-free deburring, iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish https://lnkd.in/gFjetZk
This document discusses high-speed post-processing of 3D printed parts using centrifugal iso-finishing to speed up workflows and reduce bottlenecks. It invites contacting the sender to arrange running sample parts through their free surface finishing program to see how it improves the process.
Centrifugal iso finishing - part dividersDave Davidson
High-Speed, Hands-free deburring, iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish https://lnkd.in/gFjetZk
Final vibratory iso-finishing processesDave Davidson
High-Speed iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish https://lnkd.in/gFjetZk
High-Speed, Hands-free deburring, iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish https://lnkd.in/gFjetZk
Centrifugal iso finishing - Equipment descriptionDave Davidson
High-Speed, Hands-free deburring, iso-finishing and polishing of manufactured and 3D printed parts. Contact Dave Davidson for free sample finishing, technical assistance and contract deburring and iso-finish polishing at dryfinish@gmail.com | https://dryfinish.wixsite.com/iso-finish
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CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
1. MROI -236
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Society of
Manufacturing
Engineers
2001
Controlling the Surface Integrity
of Ground Components
author(s)
DAVID F. McCORMACK Senior Project Engineer
W. BRIAN ROWE Director of AMTTREL
TAN JIN Researcher
Liverpool John Moores University
Liverpool, Merseyside, UK
abstract
The surface integrity of En31 was assessed after grinding with CBN and alumina
abrasive and different types of materials damage were described. Temperature
measurements were carried out for different grinding processes, these
temperatures were compared with different types of material damage including
burn and the formation of tensile residual stresses. It was found that the onset of
tensile residual stress occurred independently of, and before, any visible
damage such as oxidation, burn or phase transformations. High efficiency deep
grinding (HEDG) was analyzed, using an inclined heat-source with a circular arc
of contact, and was shown to give reduced potential for thermal damage under
optimum conditions. The choice of grinding abrasive was shown to be an
important factor for control of thermal effects on surface integrity.
conference
4th INTERNATIONAL MACHINING & GRINDING
May 7-10, 2001
Troy, Michigan
terms
Grinding Surface Integrity
Residual Stress HEDG
Sponsored by the
Composites Manufacturing Association
of the Society of Manufacturing Engineers
One SME Drive
P.O. Box 930
Dearborn, MI 48121
Phone (313) 271-1500
www.sme.org
2. D F McCormack, W B Rowe and T Jin
AMTTREL, School of Engineering, Liverpool John Moores University, UK
d.f.mccormack@livim.ac.uk
ABSTRACT
The surface integrity of En31 is assessed after grinding with CBN and alumina abrasive
and different types of materials damage are described. Temperature measurements
were carried out for different grinding processes, these temperatures were compared
with different types of material damage including burn and the formation of tensile
residual stresses. It was found that the onset of tensile residual stress occurred
independently of, and before, any visible damage such as oxidation, burn or phase
transformations. High efficiency deep grinding (HEDG) is analyzed, using an inclined
heat-source with a circular arc of contact, and is shown to give reduced potential for
thermal damage under optimum conditions. The choice of grinding abrasive is shown to
be an important factor for control of thermal effects on surface integrity.
KEYWORDS: Grinding, Surface Integrity, Residual Stress, HEDG
INTRODUCTION
Elevated temperatures in grinding can critically influence the surface integrity and life of
a component.
Thermal damage of a component includes burn and the formation of tensile residual
stresses. Burn is a general term used to indicate that the surface of a ground
component has been damaged by surface heating. The term can be used to describe
several types of damage caused by high temperatures including, the formation of
surface oxidation and sub-surface metallurgical changes. The nature of the material
changes associated with burn depends upon the material properties and the
temperature-time history to which the material has been exposed.
The influence of grinding heat source and choice of grinding abrasive are important
factors in maintaining surface integrity of a ground component.
SURFACE OXIDATION
Oxidation of the material surface occurs with exposure to high temperatures during
grinding and is seen as a discoloration of the workpiece surface. The discoloration is
analogous to the temper colours produced during conventional heat treatment, however,
the oxidation colours produced during grinding do not occur at the same temperatures
as for conventional heat treatment. The oxidation of the material surface is an Arrhenius
rate controlled process. The thickness and colour of the oxide layer is dependent on
time and temperature. The temperatures at which oxidation occurs during grinding, at
3. normal workspeeds, are high compared with conventional heat treatment. This is
because the duration of the thermal pulses are very short in grinding, typically less than
20ms. During conventional heat treatment, oxidation arises from lower temperatures
applied for longer periods of time. It has been found that the onset of light straw colours
for a range of ground ferrous materials occurs mainly in a range between 450 and 500°C
[Rowe, 19951. Severely burned ferrous workpieces are easily recognised and may be
brown or even blue/black on the surface. An example of a severely burned workpiece is
shown in figure 1. Dark bands are clearly visible on the surface of the workpiece. The
banding is not only evidence of burn but of vibration, also associated with the onset of
burn.
Figure I. Surface oxidation
Slight oxidation of the surface of a non-critical component may not in itself be considered
detrimental to the reliable operation of that component. The oxidation can be polished
off and the surface appearance restored. Oxidation of the surface of a critical
component is unacceptable, due to the associated risk of sub-surface metallurgical
damage and tensile residual stress formation.
RE-HARDENING BURN
During the grinding process, the action of the heat source moving across the workpiece
surface causes rapid heating and cooling of the surface layer to take place. Re-
hardening burn is the term given to the damage which occurs when the surface layer of
a previously hardened and tempered ferrous component is ground so abusively that the
temperature of the surface layer rises to a point necessary for the formation of austenite.
When the grinding heat source has passed, the surface layer is cooled at a rate which is
greater than the critical cooling rate for the material. Bulk cooling from the workpiece is
rapid and causes re-hardening. Re-hardening may lead to the formation of untempered
martensite (UTM), and may also give rise to the presence of small amounts of retained
austenite, particularly in high alloy steels.
4. Hardening involves the non-equilibrium transformation of austenite. Face-centred cubic
(fee) austenite will be formed within the surface layer of a workpiece, which has been
subject to grinding surface temperatures in excess of the austenitizing temperature for
that material. As a result of rapid cooling there is insufficient time for the fee, carbon-
rich, austenite to transform back to body-centred cubic (bee) ferrite and cementite. As
the temperature drops below approximately 3OO”C, a distorted lattice structure is
produced known as martensite. Martensite forms by a sudden shear process in the
austenite lattice, not normally accompanied by atomic diffusion, giving rise to a
characteristic lenticular microstructure [Honeycombe, 19811. In grinding, this
transformation takes place in less than lus because the movement of carbon atoms
does not rely solely on diffusion, as in conventional heat treatment, but also on transport
within the plastically deformed surface material [Shaw, 19941. Martensite is a body-
centred tetragonal (bet) structure which is of increased volume compared with bee ferrite
and cementite, causing an increase in lattice distortion. The increase in lattice volume
with transformation to martensite causes the formation of tensile residual stresses and
hardening within the surface and sub-surface layer, increasing the likelihood of crack
formation. The formation of UTM may lead to premature failure of a component due to
fatigue.
An example of a re-hardened surface can be seen in figure 2. The material is En31
bearing steel. The material was originally hardened by oil quenching from 84O”C,
followed by a sub-zero cooling process to -73°C for 2 hours, in order to transform any
remaining austenite to martensite. The material was then tempered at 150°C for 2 hours
to give a hardness of 850 HV. Three distinct zones can be seen in the microstructure, (i)
a UTM layer at the surface, of thickness approximately 20um, (ii) an over-tempered dark
layer beneath the surface, of thickness approximately 300um, (iii) a lighter coloured sub-
structure, comprised of the original tempered martensite.
Figure 2.Figure 2. Re-hardening burnRe-Gydening burn *
5. martensite111 ] q
T&w , , , , . ,
0 100 200 300 400
depth (vm)
Figure 3. Re-hardening burn - microhardness
Figure 3 shows microhardness readings taken below the surface of the sample shown in
figure 2. The readings confirm the presence of UTM in the surface layer. The
microhardness of the sub-surface layer has reduced to below that of the original
tempered martensite, indicating a layer of temper burn or over-tempered martensite.
OVERTEMPERING I TEMPER BURN
Tempering gives time for atoms of carbon to begin to diffuse back to their original
structure, giving rise to a relaxation of the distorted martensite lattice. If the temperature
of a previously hardened workpiece is raised above the original tempering temperature,
but below its transformation temperature, then overtempering or “temper burn” will
occur. The surface layer of the workpiece will be softened, resulting in a drop in wear
resistance of the component. Figure 4 is an example of an overtempered En31 bearing
steel. A dark layer beneath the surface, of thickness approximately lOOurn, indicates
the presence of over-tempering.
Figure 4. Temper burn
6. Figure 5 shows microhardness readings taken across the area shown in figure 4,
demonstrating the drop in hardness with over-tempering.
H,
I
RR
kg/mm3 Q
00
0 0
700
R
600 ]
0
t I
100 200
depth hm)
Figure 5. Temper burn - microhardness
RESIDUAL STRESSES
Grinding can be a major cause of surface residual stress in engineering components
and can therefore critically influence service life. Depending on their sign and
magnitude, surface residual stresses can either increase or decrease component
lifetimes.
In terms of the three factors influencing surface residual stresses due to grinding it was
found: -
(1) There is a direct relationship between tensile residual stress and temperature,
showing that it is thermal expansion/contraction, which is responsible for generating
tensile residual stresses in grinding.
(2) Compressive stresses, caused by mechanical effects, dominate at low
temperatures but are eliminated when thermal effects reach a critical level.
(3) Phase transformations, although capable of changing the residual stress-state,
are not relevant to the onset of tensile residual stress.
The onset of tensile residual stress is caused by exceeding a critical transition
temperature, as shown in figure 6. It was found that the transition temperature is
dependent on; the type of material being ground; the heat treatment history; the value of
yield stress and its relationship with temperature. The effects of the process parameters
such as workspeed were also shown to vary the onset temperature for tensile residual
stress. Using a critical transition temperature reduces the problem of controlling residual
stress into the easier problem of controlling grinding temperature.
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0 0
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250 300 350
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Temperature rise (“C)
Figure 6. Experimental results showing residual stress versus temperature rise in En31
MEASUREMENT OF GRINDING TEMPERATURES
Temperatures were measured experimentally using embedded ‘grindable’ constantan-
iron thermocouples to record the temperature as the wheel passed over the junction. A
single constantan pole was used, insulated by two adjacent layers of mica, located
inside a pre-machined slot. The average junction width was <25pm for both the foil and
wire thermocouples. Typical thermocouple assemblies are shown in figures 7 and 8.
Figure 7. Foil thermocouple assembly
8. Figure 8. Wire thermocouple assembly.Figure 8. Wire thermocouple assembly.
ANALYSIS AND EVALUATION OF RESIDUAL STRESS PROFILES
Near-surface residual stress profiles were analysed using X-ray diffraction (XRD) and
neutron diffraction. The XRD depth results were validated using neutron diffraction,
requiring development of the neutron diffraction method. The XRD measurements were
carried out by The Open University, UK, Department of Materials Engineering. The
Neutron measurements were performed at the ISIS facility of the Rutherford Appleton
Laboratory, UK using the ENGIN instrument.
For the XRD measurements a Brucker-Siemens 05005 diffractometer was used.
Residual stresses were obtained by analysing the displacement of the diffracted peaks,
and qualitative information about the plastic deformation on the surface was obtained by
analysing the change of the integral peak widths (IPW) [Maeder, 19811. Several
methods were investigated in order to determine the peak location accurately for
different peak shapes. Traditionally for simple materials such as En9, where the
diffracted peak is well defined, a standard procedure for XRD peak analysis is used.
The peak profile above 85% of the maximum intensity is fitted with a parabola, and the
peak centre 28 taken as the maximum of this parabola, as shown in figure 9. Analysis of
En31 was more complicated, owing to the much broader peaks obtained. The peak
broadening is a result of the lattice strain induced by the high martensite and carbide
content of these materials. For En31 the sliding gravity method was used to obtain peak
centre location [Convert, 1984; Pfeiffer, 19941, where the position of the peak centroid
was evaluated using progressively greater proportions of the peak data, as shown in
figure IO. Measurements at each point analysed were taken by tilting along two
orthogonal axes perpendicular to the beam, allowing the full stress tensor (assuming
os=O) to be determined. The reproducibility of the measurements was found to be
extremely good, making it possible to successfully analyse the data from this
microstructurally complex material.
For the in-depth stress measurements, surface removal by local electrochemical
polishing was performed. The surface removal was performed on an area of 0.5cm2 in
steps between IO and 50ym, making any stress relaxation negligible (Moore, 1958;
Castex, 1984).
9. Neutron diffraction surface stress measurements were used to validate, non-
destructively, the XRD stress profiles. A novel surface scanning geometry was used,
which proved capable of achieving near surface measurement (400pm) pang, 1998;
McCormack, 20001. Beyond an initial surface measurement, where the average stress
over 5pm is measured, XRD depth measurements are destructive, as surface removal
by local electrochemical polishing is required.
Figure IO. En31 X-ray peak
It was found that the stress in the grinding direction was always more tensile or less
compressive than in the perpendicular direction. From the depth analyses it was
observed that the maximum stress for the majority of the samples was present on the
top surface. The residual stress affected layer varied from IOum to 300um depending on
the process parameters and the abrasive type used. The affected layer depth was
determined by profiles of both stress and IPW. It was found that the IPW were
proportional to the density of plastic deformation in the material. Two different types of
curve shapes relating to the surface stress-state were obtained from the En31 samples
studied; tensile profile with maximum stress on the surface and compressive profile with
maximum stress on the surface.
Figure 11 shows an example of the profiles measured on En31, using both XRD and
neutron diffraction. There is excellent agreement between the XRD and neutron
measurements, taking into account the fact that the neutron results are the average
values within the penetration depth. With the neutron technique it is almost impossible
to measure the top surface point, however, the stress over the first 5pm can be obtained
non-destructively using XRD.
10. t
100 200
Depth (pm{
-250 1
0
Figure 11. Comparison of XRD and neutron measurements on En31
CRITICAL DAMAGE TEMPERATURE
Prevention of material damage during grinding requires the maximum temperature to be
kept below the critical damage temperature for the material. The critical damage
temperature must be specified for the particular type of damage, which it is desired to
avoid. When grinding En31: -
0) In order to prevent the formation of tensile residual stresses the maximum surface
temperature should be kept below 250°C figure 6. The transition temperature is
dependent on; the type of material being ground; the heat treatment history; the value of
yield stress and its relationship with temperature. The effects of process parameters,
such as workspeed, can also vary the onset temperature for tensile residual stress.
(ii) The critical damage temperature for the onset of temper burn is approximately
450°C [Rowe, 19951. When temper burn occurs, tensile residual stresses are already in
evidence.
(iii) The temperature at which phase transformation takes place under equilibrium
conditions is known to be 723°C for plain carbon steels. This temperature may be
further lowered by the addition of alloying elements. There is a danger of re-hardening
burn occurring where measured grinding temperatures approach 650°C. Severe
workpiece damage may be encountered due to higher than expected grinding
temperatures resulting from the process becoming unstable.
Table 1
Material
En31
Critical Damage Temperatures
Residual Stress Temper Burn
Transition
250°C 450°C
Re-hardening Burn
650-723°C
11. 10
EFFECT OF HEAT SOURCE ON TEMPERATURE
Whilst increasing material removal rates give rise to increasing grinding temperatures in
shallow-cut and creep grinding, reduced grinding temperatures can be achieved with
increased material removal rates using HEDG (High Efficiency Deep Grinding)
technology. Whilst HEDG can yield lower temperatures under optimum conditions it can
also give disastrous results if these conditions are not optimised. Current research is
limited and further investigation of the process is required to optimise reduced values of
specific energy with increasing workspeed, increasing depths of cut and effective fluid
delivery.
HEDG uses a combination of deep grinding at high workspeeds and very high removal
rates to give values of specific energy which, are lower than those obtained in shallow-
cut and creep grinding [Rowe, 20011. Experiments were carried-out to demonstrate the
high removal rates achievable and to measure the resulting contact temperatures.
Experiments were conducted on an Abwood 6 kW surface grinding machine using an
alumina wheel. The process conditions are detailed in Table 2. The workpieces used
were made from two 0.6 mm steel blades, sandwiching a constantan wire thermocouple,
as in figure 8. The samples were 38-55 mm long and 1.2 mm wide. Power was
monitored during up-grinding along the length of the samples. The samples were offset
at an angle of I” to the grinding direction, to give a more reliable thermocouple junction.
Increased wheel wear, due to the high removal rates, was offset by the reduced specific
energy and by increasing wheelspeed.
A jump in temperature was observed in the transition region between boiling and burn-
out of the grinding fluid, figure 12. Measured contact temperatures are compared with
theoretical temperatures in figure 13. The theoretical temperatures
previously published work [Rowe and Jin, 20011, using a model based
heat source with a circular arc of surface. Values of specific energy are
removal rate in figure 14.
Table 2 HEDG Test Conditions
are based on
on an inclined
shown against
12. 11
+ vf =0.32 m/s
1000 j 0
Burn out
00 0
800 1 0
600
0
400
i
Up to boiling Up to boiling
200 d w
n
o vf =0.3 m/s
-Calculated
mean
” rQ;, ( mm% )
220 240 260 280 300 320
Figure 12. Measured maximum contact
temperatures in near-transitional
conditions
e, (J/mm3)
24
Tmax (Deg.C) A vf =0.2 m/s
1500 i
A A
13001 -
L
i A 4 .
-Calculated
mean
1100 i +A
63
0 vf =0.25 m/s
900 I
1700 /
- /
. Calculated
V, =0.25 m/s
500 I
60 100 140 180
*i. Q,’ (mm%.)
Figure 13. Measured maximum contact
temperatures in burn-out conditions
I /
70 120 170 220 270
Figure 14. Specific energy versus removal rate in HEDG
EFFECT OF ABRASIVE TYPE ON TEMPERATURE
The best method of achieving cool grinding is to reduce the grinding energy entering the
workpiece surface, by ensuring that the partition ratio, &,, is kept to a minimum.
The rise of the surface temperature of a workpiece during grinding depends upon how
much of the total energy generated during grinding enters the workpiece. The thermal
characteristics of the grinding wheel play an important role in energy partitioning. Due to
their greater grain conductivity, CBN abrasives carry more energy away from the
grinding zone than do alumina abrasives, giving a lower R, and leading to cooler
grinding. Grinding with CBN leads to cooler grinding, giving decreased likelihood of
either workpiece burn or the formation of thermally induced tensile residual stresses in a
component surface.
The effect of grinding with CBN can be seen in figure 15 for the cylindrical grinding of
En31. Use of CBN abrasive has led to high magnitude compressive residual stresses
being generated in the workpiece at temperatures below the critical transition
13. 12
temperature for En31, for removal rates between 14-57mm*/s. This is in contrast to the
results obtained with alumina abrasive where extremely high temperatures and, thus,
tensile residual stresses have been generated, for removal rates of only 19 mm*/s.
Workpiece: En31I-Rc 54-68
Wheel: CBN (B91)
1000 T
800
t
Alumina
Alumina (73A601J8V)
Q'w= 19mm'/s : Machine: Jonesand Shipman
Series 10
CBN
Q'w= 14-57 mrr?/s
-800 -
Temperature rise (“C)
Figure 15. Experimental results showing the effect of abrasive-type on temperature and
residual stress during cylindrical grinding of En31
CONCLUSIONS
Temperatures were measured during grinding and related to the onset of different types
of damage, including burn and the formation of tensile residual stresses, in the form of
critical damage temperatures.
The combination of XRD surface stress measurement and neutron diffraction sub-
surface measurement has produced a technique for non-destructively mapping the
residual stress profile within a ground surface. This offers significant advantages,
particularly for the evaluation of the residual stress-state of expensive ‘in-service’
components within the aerospace industry.
HEDG has the potential to reduce the transmission of heat to a ground finished surface
due to the combined effects of large inclination angle and high workspeeds. It was
shown that very efficient grinding can be achieved using HEDG under optimum
conditions, with values of specific energy lower than those achieved in shallow-cut or
creep grinding. The transition from boiling to burn-out of the coolant has a strong
influence on contact temperatures.
Grinding with CBN abrasives leads to cooler grinding and a decreased likelihood of
imparting a tensile residual stress-state to the ground component surface.
14. 13
ACKNOWLEDGEMENTS
Acknowledgements are due to Corus, EPSRC, Jones and Shipman, Timken, TRW and
Unicorn Van Moppes for funding of the work on residual stresses. Acknowledgements
are also due to Dr Lyndon Edwards, Dr Michael Fitzpatrick and Dr Ahmed Bouzina of
The Open University, UK, Department of Materials Engineering, for their contribution to
the work involved with the analysis and evaluation of the residual stress profiles.
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