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
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 summary provides the key information from the document in 3 sentences:
The document discusses a study on the austempering behavior of engineering grade ductile iron castings. Various factors were examined including heat treatment parameters, chemical composition, and nodular characteristics. The results showed that austempering temperature and time had the greatest effect on impact toughness, while higher austempering rates were achieved with additions of nickel, molybdenum, and copper to the alloy composition.
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
This document discusses metallurgical concepts related to welding, including:
1) Welding affects the mechanical properties of metals through metallurgical transformations in the heat-affected zone. Finer microstructures improve properties like strength and toughness.
2) Alloying and heat treatments can change microstructures and properties. Quenching produces martensite to increase hardness and strength. Tempering relieves stresses in martensite.
3) Preheating and controlling cooling rates in welding prevents cracking by allowing formation of microstructures besides martensite like ferrite and pearlite.
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
EFFECT OF SCANDIUM ON THE SOFTENING BEHAVIOUR OF DIFFERENT DEGREE OF COLD ROL...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher
annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
Dispersion Hardening:
Hard particles:
Mixed with matrix powder
Consolidated
Processed by powder metallurgy techniques
Second phase – Very little solubility (Even at elevated temp.)
No coherency
So thermally Stable at very high temp.
Resists :
Grain growth
Over aging
Recrystallization
Mobility of dislocation
Different from particle Metallic Composites (Volume Fraction is 3 to 4% max.) (Does not affect stiffness)
Examples : Al2O3 in Al or Cu, ThO2 in Ni
In the material testing laboratory, a Charpy impact test was performed on three different types (hot,cold,and steel alloy)of steels testing each variety at four different temperatures (32°C(RT), 100°C,0°C and -22°C ). From results (shown below), we determined that the a transition is from ductile failures to brittle failures
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 summary provides the key information from the document in 3 sentences:
The document discusses a study on the austempering behavior of engineering grade ductile iron castings. Various factors were examined including heat treatment parameters, chemical composition, and nodular characteristics. The results showed that austempering temperature and time had the greatest effect on impact toughness, while higher austempering rates were achieved with additions of nickel, molybdenum, and copper to the alloy composition.
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
This document discusses metallurgical concepts related to welding, including:
1) Welding affects the mechanical properties of metals through metallurgical transformations in the heat-affected zone. Finer microstructures improve properties like strength and toughness.
2) Alloying and heat treatments can change microstructures and properties. Quenching produces martensite to increase hardness and strength. Tempering relieves stresses in martensite.
3) Preheating and controlling cooling rates in welding prevents cracking by allowing formation of microstructures besides martensite like ferrite and pearlite.
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
EFFECT OF SCANDIUM ON THE SOFTENING BEHAVIOUR OF DIFFERENT DEGREE OF COLD ROL...msejjournal
The softening behavior of different cold rolled Al-6Mg alloys containing scandium 0.2 wt% and 0.6 wt% have been investigated by means of microscopy, hardness and electrical conductivity measurements. It is found that the scandium added alloys attend the higher hardness at every state of cold rolling at higher
annealed temperature due to the precipitation of scandium aluminides. Electrical resistivity of the scandium added alloys show higher than base alloy due to grain refining. It is seen from the microstructure that scandium refine the grain structure and inhibit recrystallization.
Dispersion Hardening:
Hard particles:
Mixed with matrix powder
Consolidated
Processed by powder metallurgy techniques
Second phase – Very little solubility (Even at elevated temp.)
No coherency
So thermally Stable at very high temp.
Resists :
Grain growth
Over aging
Recrystallization
Mobility of dislocation
Different from particle Metallic Composites (Volume Fraction is 3 to 4% max.) (Does not affect stiffness)
Examples : Al2O3 in Al or Cu, ThO2 in Ni
In the material testing laboratory, a Charpy impact test was performed on three different types (hot,cold,and steel alloy)of steels testing each variety at four different temperatures (32°C(RT), 100°C,0°C and -22°C ). From results (shown below), we determined that the a transition is from ductile failures to brittle failures
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 various classification systems used for iron and steel based on composition, manufacturing method, product form, microstructure, required strength level, and other factors. It focuses on the classification of carbon steels and alloy steels according to standards set by organizations like ASTM, SAE, and AISI. Key classification aspects covered include carbon content, alloying elements, manufacturing processes, product types, and material properties.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
The document discusses heat treatment processes for engineering materials. It describes how heating and cooling can be used to alter the structure and properties of materials, primarily metals. Key points include:
1) Heat treatment involves controlled heating and cooling to change a material's microstructure and properties in a way that does not alter its overall shape.
2) Common heat treatments include hardening, annealing, normalizing and tempering. All involve heating, holding, and cooling, which can result in phase transformations.
3) Phase transformations in steel depend on the alloy's carbon content and the heating/cooling rates. Rapid cooling can form martensite to increase hardness, while slower cooling forms pearlite or ferrite/
The document discusses hardenability, which is the ability of an alloy to form martensite and harden during heat treatment. It can be tested using the Jominy end-quench test, where a bar is heated and quenched at one end in water, causing a gradient of cooling rates and hardness levels along its length. Alloying elements like chromium, molybdenum, and nickel increase hardenability by shifting the CCT diagram to allow more martensite formation at a given cooling rate. The quenching medium, sample size, and alloy composition all impact the hardness profile achieved.
This document summarizes a student's report on impact testing. Impact testing is used to determine the strength and weaknesses of materials under sudden loading conditions. It can indicate how brittle or ductile a material is. Two common impact tests are the Charpy and Izod tests. In the Charpy test, a notched beam specimen is supported at both ends and struck in the middle. In the Izod test, a notched cantilever specimen is fixed upright and struck at the top. The tests measure the energy absorbed during fracture. The student's report provided an overview of impact testing, described the Charpy and Izod methods, and concluded that impact testing is important for determining appropriate materials for factories and ensuring safety.
Strain hardening occurs when dislocations in a deformed metal interact, increasing the material's strength. Deforming a metal increases the number of dislocations, further strengthening the material. Strain hardening is measured by properties like yield strength and tensile strength increasing while ductility decreases. The material becomes harder but more brittle. Annealing can be used to "undo" strain hardening by allowing dislocations to rearrange or new grains to form, restoring ductility at the cost of strength. The annealing process involves recovery, recrystallization and sometimes grain growth, and depends on temperature and time.
The document discusses the different types of strength in concrete including compressive, tensile, shear, and bond strength. It provides details on testing procedures used to determine compressive strength, such as cube and cylinder tests. The compressive strength of concrete is the most important property and is affected by numerous factors like the type of cement, aggregates, water-cement ratio, compaction, curing temperature, and age of the concrete. Higher strengths are obtained with low water-cement ratios, well-graded aggregates, and proper compaction and curing.
The document discusses different hardness testing methods. It describes Brinell hardness testing which uses a 10mm steel ball indenter under a load of 3000kg to test hardness. Vickers hardness testing uses a diamond pyramid indenter under loads ranging from 1-120kg. Rockwell hardness testing utilizes indentation depth under constant load to measure hardness using diamond cone or steel ball indenters under major loads of 60, 100, or 150kg. Microhardness testing uses Knoop indenters and low loads down to 25g to test small areas. Hardness is a measure of resistance to plastic deformation from indentation or abrasion.
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.
This document defines and provides examples of various mechanical properties of materials including elasticity, plasticity, ductility, malleability, brittleness, hardness, toughness, stiffness, resilience, creep, and strength. It also discusses deformation of metals through elastic deformation, plastic deformation, slip and twinning. Finally, it covers different types of material failure including brittle fracture, ductile fracture, fatigue fracture and creep fracture as well as theories related to these failures.
This document investigates the tribological behavior of stainless steel 304 and grey cast iron rotating against EN32 steel using a pin-on-disc apparatus. Testing was conducted at varying sliding speeds and normal loads while measuring weight loss over time. Stainless steel 304 exhibited higher wear rates that increased with speed and load. Grey cast iron showed lower wear due to the presence of graphite, which acts as a lubricant. Scanning electron microscopy revealed adhesive and abrasive wear on stainless steel along with cracks. Grey cast iron samples showed graphite structure breakdown with increasing load and speed.
Metallurgy P R O P E R T I E S And DefinitionsMoiz Barry
Engineering concepts of metals document discusses various hardness testing methods like Brinell and Rockwell. It explains that hardness is the resistance to deformation and depends on factors like grain size and work hardening. The document also covers tensile stress, shear stress, heat treatment processes to alter material properties like hardening and softening, and concepts like modulus of rigidity and stiffness.
The document discusses various methods for increasing the strength of metals, including hardening, quenching, annealing, tempering, normalizing, and austempering. It provides details on the processes involved and the microstructural and property changes that result from each method. Solid solution strengthening, strain hardening, grain size refinement, precipitation hardening, dispersion hardening, and phase transformations are also summarized as six major mechanisms for increasing metal strength.
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
TMT steel bars compliments “Reinforced Cement Concrete” (RCC) which has become an integral part of every structure, be it a multi-storied building, a tunnel, a flyover, a TV tower etc.
Here are some of the most frequently asked questions about TMT bars answered
1) A low carbon steel sample with dispersed cementite particles was subjected to warm torsion tests at 685°C to induce deformation in the ferrite phase.
2) The deformation generated defects that acted as nucleation sites for ultrafine ferrite grains less than 1 μm in size, through continuous dynamic recrystallization.
3) Electron backscatter diffraction analysis revealed the final microstructure consisted of ultrafine grains separated by high angle boundaries, showing cementite precipitation and ferrite recrystallization led to intense grain refinement during subcritical deformation.
Effects of Continuous Cooling On Impact and Micro Structural Properties of Lo...IJMER
Some mechanical properties and microstructural analysis were conducted on shielded
metal arc weldments of low carbon steels in some simulated environments. Specimens were prepared
and subjected to welding and continuous cooling at the same time at various positions. Results obtained
for impact strength using Charpy impact testing machine showed that impact strength of water cooled
samples were higher compared to salty water cooled samples. This is due to the increased formation of
martensitic structure and finer pearlite grains. The microstructure of the samples was studied using
photographic visual metallurgical microscope. For low cooling rate as in the air cooled sample, the
austenite was observed to transform into ferrite and pearlite. Ferrite is a body-centred cubic crystal
structure of iron alloys. For higher cooling rates of water and salt water cooled samples, low
temperature transformation products like bainite (an acicular microstructure which is not a phase) or
martensite (a very hard form of steel crystalline structure) were formed. The salt water cooled samples
had more martensite regions because of the increased cooling rate
Maraging Steels (Properties, Microstructure & Applications)MANICKAVASAHAM G
Maraging steel is used in aircraft, with applications including landing gear, helicopter undercarriages, slat tracks and rocket motor cases – applications which require high strength-to-weight material.
Maraging steel offers an unusual combination of high tensile strength and high fracture toughness.
Most high-strength steels have low toughness, and the higher their strength the lower their toughness.
The rare combination of high strength and toughness found with maraging steel makes it well suited for safety-critical aircraft structures that require high strength and damage tolerance.
Warm rolling of an interstitial-free steel was studied between 500-800°C. Microstructures showed elongated grains with microbands forming at higher strains. Microbands initially formed parallel to the rolling plane but some became curved within grains. At higher strains, microbands formed in two distinct directions within individual grains. The textures developed by warm rolling were similar to cold rolling textures, with comparable intensities. The microstructure contained many shear banded grains, which were quantified.
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 various classification systems used for iron and steel based on composition, manufacturing method, product form, microstructure, required strength level, and other factors. It focuses on the classification of carbon steels and alloy steels according to standards set by organizations like ASTM, SAE, and AISI. Key classification aspects covered include carbon content, alloying elements, manufacturing processes, product types, and material properties.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
The document discusses heat treatment processes for engineering materials. It describes how heating and cooling can be used to alter the structure and properties of materials, primarily metals. Key points include:
1) Heat treatment involves controlled heating and cooling to change a material's microstructure and properties in a way that does not alter its overall shape.
2) Common heat treatments include hardening, annealing, normalizing and tempering. All involve heating, holding, and cooling, which can result in phase transformations.
3) Phase transformations in steel depend on the alloy's carbon content and the heating/cooling rates. Rapid cooling can form martensite to increase hardness, while slower cooling forms pearlite or ferrite/
The document discusses hardenability, which is the ability of an alloy to form martensite and harden during heat treatment. It can be tested using the Jominy end-quench test, where a bar is heated and quenched at one end in water, causing a gradient of cooling rates and hardness levels along its length. Alloying elements like chromium, molybdenum, and nickel increase hardenability by shifting the CCT diagram to allow more martensite formation at a given cooling rate. The quenching medium, sample size, and alloy composition all impact the hardness profile achieved.
This document summarizes a student's report on impact testing. Impact testing is used to determine the strength and weaknesses of materials under sudden loading conditions. It can indicate how brittle or ductile a material is. Two common impact tests are the Charpy and Izod tests. In the Charpy test, a notched beam specimen is supported at both ends and struck in the middle. In the Izod test, a notched cantilever specimen is fixed upright and struck at the top. The tests measure the energy absorbed during fracture. The student's report provided an overview of impact testing, described the Charpy and Izod methods, and concluded that impact testing is important for determining appropriate materials for factories and ensuring safety.
Strain hardening occurs when dislocations in a deformed metal interact, increasing the material's strength. Deforming a metal increases the number of dislocations, further strengthening the material. Strain hardening is measured by properties like yield strength and tensile strength increasing while ductility decreases. The material becomes harder but more brittle. Annealing can be used to "undo" strain hardening by allowing dislocations to rearrange or new grains to form, restoring ductility at the cost of strength. The annealing process involves recovery, recrystallization and sometimes grain growth, and depends on temperature and time.
The document discusses the different types of strength in concrete including compressive, tensile, shear, and bond strength. It provides details on testing procedures used to determine compressive strength, such as cube and cylinder tests. The compressive strength of concrete is the most important property and is affected by numerous factors like the type of cement, aggregates, water-cement ratio, compaction, curing temperature, and age of the concrete. Higher strengths are obtained with low water-cement ratios, well-graded aggregates, and proper compaction and curing.
The document discusses different hardness testing methods. It describes Brinell hardness testing which uses a 10mm steel ball indenter under a load of 3000kg to test hardness. Vickers hardness testing uses a diamond pyramid indenter under loads ranging from 1-120kg. Rockwell hardness testing utilizes indentation depth under constant load to measure hardness using diamond cone or steel ball indenters under major loads of 60, 100, or 150kg. Microhardness testing uses Knoop indenters and low loads down to 25g to test small areas. Hardness is a measure of resistance to plastic deformation from indentation or abrasion.
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.
This document defines and provides examples of various mechanical properties of materials including elasticity, plasticity, ductility, malleability, brittleness, hardness, toughness, stiffness, resilience, creep, and strength. It also discusses deformation of metals through elastic deformation, plastic deformation, slip and twinning. Finally, it covers different types of material failure including brittle fracture, ductile fracture, fatigue fracture and creep fracture as well as theories related to these failures.
This document investigates the tribological behavior of stainless steel 304 and grey cast iron rotating against EN32 steel using a pin-on-disc apparatus. Testing was conducted at varying sliding speeds and normal loads while measuring weight loss over time. Stainless steel 304 exhibited higher wear rates that increased with speed and load. Grey cast iron showed lower wear due to the presence of graphite, which acts as a lubricant. Scanning electron microscopy revealed adhesive and abrasive wear on stainless steel along with cracks. Grey cast iron samples showed graphite structure breakdown with increasing load and speed.
Metallurgy P R O P E R T I E S And DefinitionsMoiz Barry
Engineering concepts of metals document discusses various hardness testing methods like Brinell and Rockwell. It explains that hardness is the resistance to deformation and depends on factors like grain size and work hardening. The document also covers tensile stress, shear stress, heat treatment processes to alter material properties like hardening and softening, and concepts like modulus of rigidity and stiffness.
The document discusses various methods for increasing the strength of metals, including hardening, quenching, annealing, tempering, normalizing, and austempering. It provides details on the processes involved and the microstructural and property changes that result from each method. Solid solution strengthening, strain hardening, grain size refinement, precipitation hardening, dispersion hardening, and phase transformations are also summarized as six major mechanisms for increasing metal strength.
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
TMT steel bars compliments “Reinforced Cement Concrete” (RCC) which has become an integral part of every structure, be it a multi-storied building, a tunnel, a flyover, a TV tower etc.
Here are some of the most frequently asked questions about TMT bars answered
1) A low carbon steel sample with dispersed cementite particles was subjected to warm torsion tests at 685°C to induce deformation in the ferrite phase.
2) The deformation generated defects that acted as nucleation sites for ultrafine ferrite grains less than 1 μm in size, through continuous dynamic recrystallization.
3) Electron backscatter diffraction analysis revealed the final microstructure consisted of ultrafine grains separated by high angle boundaries, showing cementite precipitation and ferrite recrystallization led to intense grain refinement during subcritical deformation.
Effects of Continuous Cooling On Impact and Micro Structural Properties of Lo...IJMER
Some mechanical properties and microstructural analysis were conducted on shielded
metal arc weldments of low carbon steels in some simulated environments. Specimens were prepared
and subjected to welding and continuous cooling at the same time at various positions. Results obtained
for impact strength using Charpy impact testing machine showed that impact strength of water cooled
samples were higher compared to salty water cooled samples. This is due to the increased formation of
martensitic structure and finer pearlite grains. The microstructure of the samples was studied using
photographic visual metallurgical microscope. For low cooling rate as in the air cooled sample, the
austenite was observed to transform into ferrite and pearlite. Ferrite is a body-centred cubic crystal
structure of iron alloys. For higher cooling rates of water and salt water cooled samples, low
temperature transformation products like bainite (an acicular microstructure which is not a phase) or
martensite (a very hard form of steel crystalline structure) were formed. The salt water cooled samples
had more martensite regions because of the increased cooling rate
Maraging Steels (Properties, Microstructure & Applications)MANICKAVASAHAM G
Maraging steel is used in aircraft, with applications including landing gear, helicopter undercarriages, slat tracks and rocket motor cases – applications which require high strength-to-weight material.
Maraging steel offers an unusual combination of high tensile strength and high fracture toughness.
Most high-strength steels have low toughness, and the higher their strength the lower their toughness.
The rare combination of high strength and toughness found with maraging steel makes it well suited for safety-critical aircraft structures that require high strength and damage tolerance.
Warm rolling of an interstitial-free steel was studied between 500-800°C. Microstructures showed elongated grains with microbands forming at higher strains. Microbands initially formed parallel to the rolling plane but some became curved within grains. At higher strains, microbands formed in two distinct directions within individual grains. The textures developed by warm rolling were similar to cold rolling textures, with comparable intensities. The microstructure contained many shear banded grains, which were quantified.
MECHANICAL PROPERTY ASSESSMENT OF AUSTEMPERED AND CONVENTIONALLY HARDENED AIS...IAEME Publication
The chemical composition and mechanical properties of steel decide its applicability for manufacturing various components in different areas of engineering interests. Heat treatment processes are commonly used to enhance the required properties of steel with or without change in chemical composition. The present work aims to perform conventional hardening and Austempering treatment with experimental investigation of the effect of austempering and conventional hardening (quenching) on AISI 4340 steel. Different tests like tensile, torsion, hardness, impact and microstructure analysis are carried out in as bought and heat treated conditions
Microstructure and chemical compositions of ferritic stainless steelGyanendra Awasthi
This document discusses the microstructure and chemical compositions of ferritic stainless steel. It begins by defining ferrite as the body-centered cubic crystal structure of pure iron that gives steel and cast iron their magnetic properties. It then discusses how adding nickel changes the crystal structure from body-centered cubic to face-centered cubic. The document also examines the different groups of ferritic stainless steels based on their chromium content, from 10-14% chromium to those with over 18% chromium. It notes that ferritic stainless steels have lower strength at temperatures over 600°C but greater resistance to thermal shocks than austenitic stainless steels.
Anirban sadhu Project Report on AustemperingAnirban Sadhu
This document discusses austempering heat treatment of carbon alloy steels. Austempering involves heating steel to the austenite phase and then quenching into a molten salt bath at a temperature between 230-330°C to form bainite instead of martensite. This improves strength, toughness and reduces distortion compared to quenching. The document reviews literature on austempering various steel grades and examines microstructure and properties of austempered steels. It also provides theoretical background on phase transformations involved in austempering and equations to estimate transformation temperatures.
This document summarizes research on the hot deformation behavior of a twinning induced plasticity (TWIP) steel containing 20% manganese. Hot compression tests were performed at temperatures from 800-1200°C and strain rates from 0.001-0.1 s-1. The steel exhibited high strength over 1000 MPa and ductility over 55% at room temperature due to twinning. Flow curves showed stress increased with lower temperatures and higher strain rates. Microstructures indicated dynamic recrystallization was slow. Double hit compression tests at 900°C showed static recrystallization kinetics were also relatively slow, with over 70% recrystallization after 50-100 seconds. The results provide important insights for controlling hot working
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
A study on the application of modern corrosion resistant alloys in the upstre...Kukuh Wanengkirtyo
This document summarizes a study on using modern corrosion resistant alloys (CRAs) in the oil and gas industry to optimize costs. It discusses various CRA materials like duplex, super duplex, and hyper duplex stainless steels that offer higher corrosion resistance and strength compared to austenitic grades, allowing for thinner wall thicknesses and weight savings. A case study shows how duplex and super duplex materials can meet pressure requirements while reducing material costs for a drilling riser hydraulic line compared to austenitic grade 316L stainless steel.
Stainles Steel Soldering and welding ....pptxDrSureshKumarK
This document provides information on stainless steel soldering and welding for orthodontic applications. It discusses the history, composition, properties and classifications of stainless steel. It also covers heat treatment processes, corrosion resistance, and appropriate uses of different stainless steel types in orthodontics. Soldering and welding of stainless steel is described, including definitions, required materials, techniques and examples of applications in orthodontics.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
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.
Effect Of Tempering Process On Hydrogen Delayed Fracture Susceptibility Of 41...IRJET Journal
The document summarizes a study on the effect of tempering process on the hydrogen delayed fracture susceptibility of 4140 steel fasteners. Specimens were tempered at temperatures ranging from 350°C to 520°C. Testing showed that increasing the tempering temperature decreased the tensile strength, yield strength, and hardness of the steel. Delayed fracture testing found that specimens tempered at 450°C and 520°C had the longest fracture times. Scanning electron microscopy revealed that specimens tempered at lower temperatures exhibited more brittle, intergranular fractures while those at higher temperatures showed more ductile fractures. Overall, tempering between 450°C to 480°C produced optimum mechanical properties and lowest susceptibility to hydrogen embrit
Influence of Heat Treatment on Mechanical Properties of Aisi1040 SteelIOSR Journals
This investigation is concerned to evaluate the influence of heat treatment on mechanical behavior of AISI1040 steel; it is one of the grades of medium carbon steel of American standard containing 0.40% carbon in its composition. Specimen of quenched/hardened AISI1040 steel was tempered at temperature (650,450&250℃) for 60, 90&120 minutes to modify desired properties. The mechanical behavior, particularly, ultimate tensile strength, yield strength and elongation were investigated using universal testing machine; while the hardness measurement was done on Rockwell hardness testing machine of heat treated specimens. Result shows that the ultimate tensile strength and the yield strength decrease while the elongation increases with an increase in tempering temperature and tempering time of different tempered specimen. The hardness of quenched/hardened specimen decreases with an increase in tempering temperature and tempering time. Furthermore, increasing temperature and lowering time produces approximately same result as decreasing temperature and increasing time.
Effect of Minor Change in Composition on the Toughness of Weldmetal for Repai...RAMASUBBU VELAYUTHAM
1. The document describes the development of a repair welding procedure for cracked turbine blades made of 13Cr-2.6Ni-1.1Mo martensitic stainless steel.
2. Two twin-wire filler metals were tested (TW-1 and TW-2) that consisted of ER 16-8-2 and ER 410 wires. TW-2 filler metal composition more closely matched the turbine blade material.
3. A two-stage post-weld heat treatment at 675°C for 2 hours followed by 615°C for 4 hours was found to produce good mechanical properties for the weldments, with strength and toughness similar to the turbine blade material.
1. Warm rolling of pure iron involves rolling the material in the ferritic phase region between room temperature and the austenite transformation temperature. This results in a two-phase microstructure of ferrite and austenite during deformation.
2. Solute carbon interacts strongly with dislocations during warm rolling, resulting in high strain rate sensitivity and reduced in-grain shear band formation compared to hot or cold rolling. This significantly impacts the development of texture and recrystallization.
3. Warm rolling can produce deep drawing {111} textures traditionally obtained through cold rolling and annealing. Process parameters in warm rolling therefore have a strong influence on recrystallization texture development.
Effect of martensite start and finish terhadap hasil pengelasan cr nihengkiirawan2008
This document discusses the effect of martensite start and finish temperatures on residual stress development in structural steel welds. Low martensite start and finish temperatures can generate compressive residual stresses by allowing expansion from martensitic transformation to compensate for thermal contraction during welding. The study developed new low-transformation-temperature welding wires and investigated their effect on martensite temperatures, microstructure, hardness, and residual stresses in single- and multi-pass welds.
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.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
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.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Recycled Concrete Aggregate in Construction Part II
Lee1995
1. ScriptaMetallurgica et Materialia Vol. 32. No. 8, pp.1197-1201.1995
Copyright 0 1995 Elsevier Science Ltd
Printedin the USA. All rights reserved
0956-716XP35 $9.50 + .OO
0956-716X(95)0012=
ON 1NTE:RGRANULAR TEMPERED MARTENSITE EMBRITTLEMENT
K. B. Lee, S. 1% Yoon, S. I. Hong and H. Kwon
Department of Metallurgy and Materials Engineering
College of Engineering, Kookmin University
Seoul 136-702, Korea
(Received June 27, 1994)
(Revised November 8, 1994)
Tempering of martensitic alloy steels is generally required to impart adequately high toughness
instead of brittleness in the as-quenched state. When hardened steels are tempered in the range
of 250 - 400 “C. however. a loss in toughness can occur in suite of the decrease in strennth with
increasing temgerin
f
temperature. Tiis phenomenon is referred to as tempered muartensite
embrittlement (TME
TME can be classified into two types according to fracture mode: intergranular and
transrrranular TME. Transeranular TME was observed generally at test temueratures near the
duct&-brittle transition temperature. It was suggested to- be ca;sed by the f&nation of coarse
carbides at martensite lath boundaries, following Ihe decomposition of retained austenite (l-7).
However, there were studies indicating that ‘I‘ME would be correlated closely with the carbide
coarsening rather than the decomposition of retained austenite G-10). On the other hand, the
intergranular type of TME has been observed generally at test temperatures below the critical
temperature (e.g., transition temperature). It has been associated with the combined action of
coarse carbides .and impurities at the prior austenite grain boundaries (11-16).
In addition, it was suggested that the intrinsic toughness of the matrix, compositionally
modified by the alloying addition, affects the fracture behavior (17-22). The microstructures
combined with intrinsic toughness play a fundamental role detennining the intragranular toughness
(i.e., the resistance to transgranular brittle fracture), whereas, the impurity segregation acts as a
significant determiner of intergranular toughness (i.e., the resistance to intergranular fracture). The
fracture type of TME can be influenced by the intrinsic toughness as well as by the impurity
segregation since it is determined by the competition between the intergranular and intragranular
toughness.
In this study, the intergranular type of TME has been analyzed in terms of impact toughness
and fracture behavior on isothermal and isochronal tempering. The alloy systems chosen are the
commercial 4140 and 4340 steels. The 4340 steel contains the alloying element Ni which enhances
the intrinsic toughness.
The 4340 and 4140 steels as-received were made by air-melting and hot-forging. The 4340
steel had a coarse-grained structure, probably due to the relatively higher melting and/or forging
temperatures, compared with the 4140 steel. The chemical compositions of alloys are listed in
Table 1. Charpy V-notch impact specimens of the standard size were machined from the forgings.
The impact :,pecimens were austenitized in a flowing argon atmosphere at 1200 “C for 1 h, and
then oil-quenched. The different initial structures resulted in a variation in prior austenite grain
size, about 200 and 50 ,umin the 4340 and 4140 steels, respectively. Austenitized specimens were
1197
2. 1198 TEMPEREDMARTFNSITE EMBRITTLEMENT Vol. 32, No. 8
tempered in a neutral salt bath at 200 to 450 ‘C for 1 to 400 h and water-quenched.
The fracture surfaces were examined in a Jeol scanning electron microscope, operated at 25 kV.
The fractographs were taken from the vicinity of notch since the crack initiation may become the
primary stage in the fracture of the impact specimens of the relatively low toughness.
ExDerimental He_s&
The hardness values of both steels were similar and decreased from HRC 53 to 43 with
increasing tempering temperature in the range of 200 to 450 “C. The hardness decrement with
tempering time at a given temperature was slight, as compared to tempering temperature.
Fig. 1 shows the impact toughness variations with tempering time. In the 4340 steel, at 200 “C,
the impact toughness increased in the 1 h tempered condition, but decreased down through a
medium value of 13 J in the 10 h tempred condition to a low value of 5 J in the 400 h tempered
condition. At 250 ‘C, the impact toughness increased in the 1 h tempered condition, but rapidly
decreased to a low value of 6 J already in the 10 h tempered condition, and showed no recovery
even in the 400 h tempered condition. The impact toughness level of the 4140 steel was lower
than that of the 4340 steel. At 200 “C, it increased in the 1 h tempered condition, but continuously
decreased and already reached a low value of 4 J in the 100 h tempered condition, earlier than 400
h in the 4340 steel. At 250 “C, the impact toughness already exhibited a low value of 5 J with
little increase even in the 1 h tempered condition, earlier than 10 h in the 4340 steel, and a slight
decrease was retained without any recovery even in the 400 h tempered condition.
The impact toughness variations with tempering temperature in the 1 h tempered condition
were compared in Fig. 2. The 4340 steel showed the maximum at 200 “C, the rapid decrease at
300 “C, the minimum at 350 “C, the slight increase at 400 “C, and the rapid increase at 450 “C. In
the 4140 steel, there was a maximum at 200 “C, a rapid decrease at 250 “C, a minimum at 300 “C,
and a relatively rapid increase at 400 “C. In the 4140 steel with prior austenite grains of about
100 pm, austenitized at 1250 “C, an increase in grain size gave little influence on impact toughness
variation with tempering temperature, despite the lowering of impact toughness (23).
Fracture surfaces are shown in Figs. 3 and 4. In both steels, the intergranular area increased
with decreasing impact toughness (i.e., increasing tempering time and temperature), and dominated
the specimens with the low impact toughness of about 5 J, consistent with the impact toughness
results. Hence, more tempering time and the higher temperature are required for extensive
intergranular fracture to occur in the 4340 steel, as compared to the 4140 steel.
Discussion and Summary____
TME on isothermal tempering was detected by the continuous decreases in impact toughness
with increasing time in the range of l-400 h conducted in this study at 200 and 250 ‘C. The 4340
steel exhibited the slower decrease in impact toughness to the low value of about 5 J, which was
associated with the occurrence of the mostly intergranular fracture, as compared to the 4140 steel.
In addition, during isochronal tempering for 1 h, there were the TME troughs with the minimum
at 300 and 350 ‘C, in the 4140 and 4340 steels, respectively. Thus, it is seen that TME of the 4340
steel proceeds at a slower rate, as compared to the 4140 steel.
The intergranular type of TME has been associated with the combined action of coarse
carbides and impurities at the prior austenite grain boundaries (11-16). Almost all segregation of
impurities occurs during austenitizing, but the coarse boundary-carbides are formed during
tempering, as a result of the decomposition of retained austenite and/or of the independent
precipitation at all types of boundaries containing the martensite lath and packet boundaries and
the prior austenite grain boundaries, irrespective of the fracture type of TME. This means that the
toughness (or strength) of the grain boundaries, which is dependent upon the impurity segregation
before tempering, may determine the fracture type of TME. On the other hand, in recent years,
Kwon and his coworkers (17-22) suggested that the intrinsic toughness of the matrix
compositionally modified by the alloying addition affect the fracture behavior. If the grain
boundaries act as the slip barriers, the blocked slip bands can induce the crack nucleation at the
grain boundaries. Dislocation pile-ups at the grain boundaries needed for intergranular cracking
also may be affected by the relaxation process at the grain boundaries which is associated with
the inherent slip behavior. This means that the intergranular fracture can be influenced by the
intrinsic toughness which is dependent upon the inherent dislocation motion, as well as the
transgranular fracture.
3. Vol. 32. No. 8 TEMF’EREDMARTENSITEEMEJ~ 1199
Even though the higher impurity content, of course, lowers the impact toughness overall
tempering temperature range, it has little influence on variation in fracture mode with tempering
temperature (4,i!4), or extends the TME temperature range, that is, the embrittlement initiates at
lower tempering temperature and ends at higher temperature (12). In contrast, the 4140 steel
having more S, and similar P compared with the 4340 steel, exhibited the TME minimum at lower
temperature than the 4340 steel. However, the impact toughness presented a recovery at lower
temperature and the TME range was not widened. Hence, the impurity effect, by itself, cannot
reasonably account for the impact toughness variations in the TME region, that is, both the rapid
decrease and increase in impact toughness with tempering in the 4140 steel and the slow decrease
and increase in the 4340 steel.
Here, let us consider the TME process in view of intrinsic toughness. The relatively high
intrinsic toughness due to the Ni-addition in the 4340 steel can cause the relaxation of stresses
concentrated at the grain b0undarie.s to be easier (e.g., by means of the relatively easy cross slip),
in comparison with the 4140 steel. Since the coarser carbides at the grain boundaries are required
to establish the stress concentration for the occurrence of intergranular fracture in the 4340 steel,
the TME slowly proceeds. Furthermore, the coarsening rate of carbides of the 4340 steel, in
which the alloying element Ni has low solubility within cementite and high activity of carbon in
the matrix (25), may be somewhat slower. In order to clearly elucidate the effects of Ni-addition
on intrinsic toughness and microstructures (the retained austenite and the interlath and intralath
carbides), the 41.30+(0-6wt%)Ni system, which may indicate the various fracture modes containing
ductile fracture due to a relatively low carbon content, will be systematically analyzed, using the
instrumented im:pact testing machine.
Thus, the tendency of intergranular TME to slowly proceed in the 4340 steel can be understood
by the following two factors: 1) the delay of the formation of coarse boundary-carbides, and/or 2)
the high intrinsic toughness requiring the coarser boundary-carbides for the activation of brittle
intergranular fracture.
This study was supported by the Non-Directed Research Fund, Korea Research Foundation,
1992.
1.
32.
4:
5.
6.
::
190:
:;:
13.
14.
15.
16.
::.
19:
20.
21.
22.
23.
24.
25.
References_____
J. McMahon and G. Thomas, Proc 3rd Int. Conf on Strength and Metals and Alloys, Inst. of
Metals, London, Vol. 1, (1973) 180.
G. Thomas, Metall. Trans. A, 9, 439 (1978).
R. Clark and G. Thomas, Metall. Trans. A, 6, 969 (1975).
J.P. Materkowski and G. Krauss, Metall. Trans. A, 10, 1643 (1979)
D.L. Williamson, R.G. Schupmann, J.P. Materkowski, and G. Krauss, Metall. Trans. A, 10, 379
(1979)
G. Krauss, Steels: Heat Treatment and Processing Principles, ASM International, (1990) 231.
H. Kwon and C. H. Kim, Metall. Trans. A, 14, 1389 (1983).
J.E. King, RF. Smith, and J.F. Knott, Fracture 1977 ICF4, ed. D.M.R. Taplin, Univ. of
Waterloo, Vol. 2 (1977) 279.
H.K.D.H. Bhadeshia and D.V. Edmonds, Met. Sci., 13, 325 (1979).
J.A. Peters,, J.V. Bee, 8. Kolk and G.G. Garrett, Acta Metall., 37, 675 (1989).
S.K. Banerji, C.J. McMahon, Jr., and H.C. Feng, Metall. Trans. A, 9, 237 (1979).
C.L. Briant and S.K. Banerji, Metall. Trans. ii, 10, 1729 (1979).
C.L. Briant and S.K. Banerji, Metall. Trans. A, 10, 1151 (1979).
CL. Briant and S.K. Banerji, Metall. Trans. A, 13, 827 (1982).
H. Kwon and C.H. Kim, J. Mater. Sci., 18, 3671 (1983).
H. Kwon and C.H. Kim, Metall. Trans. A, 15, 393 (1984).
H. Kwon and! C.H. Kim, Metall. Trans. A, 15, 745 (1986).
H. Kwon and CM. Kim, Metall. Trans. A, 15, 1173 (1986).
J.C. Cha, H. Kwon and C.H. Kim, Mater. Sci. Eng. 100, 121 (1988).
H. Kwon and J.W. Hong, Metall. Trans. A, 20, 560 (1989).
J.S. Song and H. Kwon, Mater. Sci. Eng. A, 117, 133 (1989).
K.B. Lee, S.H. Yoon and H. Kwon, Scripta Metall. Mater., 30, 1111 (1994).
SW. Yoon, K.B. Lee, S.I. Hong and H. Kwon, J. Korean Inst. Met. Mater., in press.
F. Zia-Ebrahimi and G. Krauss, Acta Metall., 32, 1767 (1984).
B.V.N. Rao and G. Thomas, Metall. Trans. A, 11, 441 (1980).
4. 1200 TEMF’ERFB MARTENSITE EMBRIlTLEMENT Vol. 32, No. 8
TABLE 1. Chemical Composilion of Experimental Alloys. (wt%)
25
=;‘
- 20
z
g 15
ti
I TEMPERING TEMP
~200°c-4J40
EEE1250°c-4340
~200°c-4140
B25O"C-4140
AQ 1 10 100 1000
TEMPERING TIME (h)
25 , 1
FIG. 1 - Impact toughness
variations with tempering time.
FIG. 2 - Impact toughness
variations with tempering
temperature in the specimens
tempered for 1 h.
TEMPERING TEMP(“C)
5. Vol. 32, No. 8 TEMPEREDMARTENSlTE EMBRITIZEMENT 1201
FIG. 3 - Fractographs of the 4340 steel:
(a) 200 “C, 100 h; (b) 200 “C, 400 hi
(c) 250 “C, 10 h
ITIc. 4 - Fractographs of the 4140 steel:
(a) 200 ‘C, 1 hi (b) 200 “C, 100 11:
(c) 250 “C, 1 b.