This document summarizes a computational weld mechanics simulation of hot crack nucleation conducted by Ahmed Nasser. The simulation used computational weld mechanics software to predict the risk of ductility dip cracking and solidification cracking in nickel-based alloys. For ductility dip cracking, the simulation varied welding speed and found a higher risk of cracking with slower speed. For solidification cracking, the simulation identified risk areas based on the evolution of stress-strain-temperature states determined from the simulation. The objective was to demonstrate using a mechanical approach to predict hot cracking risk.
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.
Investigation on Effect of Heat Input on Cooling Rate and Mechanical Property...IJMER
The effect of heat input in MMAW arc welding on cooling rate and hardness of weld
joint is investigated in this paper. The parameter affects the heat input are welding current, arc voltage
and welding speed. Mild steel weldments were welded under varying current 80, 90 and 100 ampere
and keeping arc voltage and travel speed constant. Other mild steel specimens were welded under
varying arc voltage 21V, 23V and 25V and keeping welding current and welding speed constant. Other
mild steel specimens were welded by varying welding travel speed 1.52 mm/sec, 1.67 mm/sec and 1.82
mm/sec and keeping arc voltage and welding current constant. Heat input was calculated for each
weldment. Rockwell hardness testing of all specimens was done. It was observed that with increase in
arc current hardness of mild steel weld joint was increased up to optimum level and then decreased.
Cooling rate was decreased with increased in arc current. With increase in welding arc voltage
hardness of weld joint decreased and cooling rate was decreased also. With increase in welding travel
speed hardness of weld joint increased and cooling rate was increased also.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
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.
Investigation on Effect of Heat Input on Cooling Rate and Mechanical Property...IJMER
The effect of heat input in MMAW arc welding on cooling rate and hardness of weld
joint is investigated in this paper. The parameter affects the heat input are welding current, arc voltage
and welding speed. Mild steel weldments were welded under varying current 80, 90 and 100 ampere
and keeping arc voltage and travel speed constant. Other mild steel specimens were welded under
varying arc voltage 21V, 23V and 25V and keeping welding current and welding speed constant. Other
mild steel specimens were welded by varying welding travel speed 1.52 mm/sec, 1.67 mm/sec and 1.82
mm/sec and keeping arc voltage and welding current constant. Heat input was calculated for each
weldment. Rockwell hardness testing of all specimens was done. It was observed that with increase in
arc current hardness of mild steel weld joint was increased up to optimum level and then decreased.
Cooling rate was decreased with increased in arc current. With increase in welding arc voltage
hardness of weld joint decreased and cooling rate was decreased also. With increase in welding travel
speed hardness of weld joint increased and cooling rate was increased also.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Effects of cryogenic treatment on tool steel aisi d6eSAT Journals
Abstract
In present technological modern age. All the manufacturers adopt that process which governs to higher productivity that has been achieved by the various treatment of tool steel. These conventional processes improve no of characteristics to fulfill desired purpose. But all these process does not provided fully satisfaction from conventional heat treatment process. Thus a new process is being additionally employed for improving mechanical properties called cryogenic treatment process or sub-zero treatment of tool steels. During this process tool steel is proceed below Atmospheric tem. That is in minus about (-1960 C or 3100 F). Due to cooling, steel alter their mechanical properties like wear resistance, Hardness, toughness, fatigue life micro-structure alteration etc. Cryo-treatment not only improve its mechanical properties but also improve thermal properties, electrical properties & easier machining etc. in this paper cryogenic treatment of tool steel AISI-D6 is perform and study is made for wear-resistance, Hardness, toughness, with respect to untreated test specimen of same, we have got improved wear-resistance capacity improve hardness as well as toughness.
Keywords – AISI-D6 tool steel, cryogenic process, wear resistance, Hardness, Toughness.
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
Microstructure design of steel for high creep resistanceRajdeep Mondal
In modern world the material has to be high creep resistance and high fatigue resistance. So, Design the material in such a way that material has to be high creep resistance and high fatigue resistance.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Microstructure and Abrasive Wear Properties of Chrome Alloy Steel IDES Editor
En 31 steel is widely used for applications like ball bearings and grinding media balls. The sliding wear properties of En 31 steel has been studied in the past, however the data on abrasive wear properties of En 31 steel is limited. En 31 steel was quenched and tempered at different tempering temperatures. Metallographic and hardness studies were carried out on heat treated samples. The hardened and tempered samples were tested using two body abrasive wear testing apparatus. The abrasive medium used in the present investigation was silicon carbide paper. The effect of normal load and sliding distance on wear loss of as received and heat treated specimens tempered at different tempering temperatures was investigated. The abrasive wear resistance of EN 31 steel with different hardness was compared under different test conditions. The worn out samples were observed by Scanning Electron Microscope to study morphology of worn surfaces. The abrasive wear resistance exhibited an increasing trend with increase in hardness and it was rationalized in terms of microstructure and the hardness.
MICROSTRUCTURAL CHARACTERIZATION AND HOT EROSION BEHAVIOR OF CRC-NICR COATED ...IAEME Publication
Erosion behavior of the High Velocity Oxygen Fuel (HVOF) deposited CrC - NiCr coating on stainless steel was evaluated. Th e solid particle erosion stu dy was conducted using an air jet erosion test rig at a velocity 60m/sec and impingement angle 60 ° , 75 ° and 90 ° , on HVOF spray coated steel at 600 ° C. Microstructure, chemical composition, phases present in the coating on the steel substrate was studied by using Scanning Electron Microscope (SEM) and X - Ray Diffraction method. The Hardness is gradually increasing with increasing content of Cr 3 C 2 particles in all three samples. The erosion mechanism of coatings was also discussed and erosion rate is maximum at impingement angle 75 °
Corrosion resistance performance of fly ash blended cement concreteseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Study on Influence of heat treatment on Tribological properties of mild steeldbpublications
A study was made on the effect of heat treatment upon the mild steel. Total six samples were prepared for each test (hardness test, tensile test, microstructure test and wear test) from those two was tested as received and rest four were subjected to different heat treatment that are annealing and normalizing (heated on a temperature of 850 degree Celsius). The hardness of all sample was measured by Rockwell hardness testing machine. Wear measurement was done on pin-on disc wear machine. Tensometer was used to find out the ultimate stress and strain of the sample. The result of tensile test showed that the strength is decreased by heat treating and the surface hardness is also decreased by heat treatment. Microstructure of the mild steel specimens shows the grain boundary of the particles and the content of % of carbon present. It justifies the experimental results of tensile test and hardness test. Surface Hardness is the measure of resistance that any material applies. As the specimen gets soft on treating the hardness also gets decreased. Tensile strength of any specimen is specified as how much stress the material can withstand before breaking. As the metal gets soft after heat treatment the load required for breaking goes on decreasing. Wear test is carried out to see the variation in wear measurement and coefficient of friction as the mesh size of paper are varied. More soft the surface of material is more wear is seen and vice-versa.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
A Review on Mechanical and Wear Properties of Heat Treated SteelIJSRD
This Review Paper describes effects of heat treatment on various material by varying process parameters and by using different types of heat treatment process. The heat treatment includes heating & cooling operations or the sequence of two or more such operations applied to any material in order to modify metallurgical structure and alter its physical, mechanical and chemical properties. This Review paper shows progress and research in the field of heat treatment process. Different types of heat treatment processes such as annealing, normalising, nitriding, hardening, tempering carburising used & available in recent time. This paper deals with important progress work on heat treatment and its process parameters.
Prediction of Weld Pool Geometry in Pulsed Current Micro Plasma Arc Welding o...drboon
Pulsed Micro Plasma Arc Welding (MPAW) is a metal joining technique widely used in manufacturing of thin sheet components due to its inherent properties. The weld quality and productivity are controlled by the process parameters. The paper discuses about development of mathematical models for weld pool geometry of stainless steel 304L sheets. Design of experiments based on full factorial design is employed for the development of a mathematical model correlating the important controlled pulsed MPAW process parameters like peak current, background current, pulse and pulse width with front width, back width, front height and back height. The developed mode has been checked for adequacy based on ANOVA analysis. Weld bead parameters obtained by the models are found to confirm actual values with high accuracy. Using these models effect of pulsed MPAW process parameters on weld pool geometry are studied.
Experimental and Finite Element Analysis of Single-V Groove Butt Weld on Weld...IJSRD
Gas Tungsten Arc Welding Process (GTAW) is widely used in fabrication of Aluminium and Aluminium Alloy material when precision is considered as a prime importance. Deformations in the object undergoing welding are one of the foremost problems encountered in the welding industry. Thus it is often required to study the factors which affect the deformations produced during welding to avoid errors in the geometry. Present investigation highlights Experimental and Finite Element Analysis of a Single-V Groove Butt Weld on Weld Pool Geometry of Aluminium Alloy Plate under Different Joint Parameters.Finite Element Method (FEM) has been employed to do the transient thermal and structural analysis of the assembly. The Finite Element Analysis has been done on ANSYS 14.5 Workbench. Number of factors is liable to produce effects in the job during the welding operation. Aim of this paper is the effect of welding parameters like as welding current, shielding gas flow rate and welding speed with mechanical Properties like tensile strength and hardness. After that finite element analysis for temperature distribution and distribution of the stresses in the welded Aluminium alloy plate. The results show that the larger the Welding current and smaller welding speed will lead to the maximum residual tensile stress. Therefore a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at different temperature. The higher yield strength at different temperature has higher material residual stress. Because of its higher thermal conductivity, aluminium alloy test specimens have small temperature differential.
Effects of cryogenic treatment on tool steel aisi d6eSAT Journals
Abstract
In present technological modern age. All the manufacturers adopt that process which governs to higher productivity that has been achieved by the various treatment of tool steel. These conventional processes improve no of characteristics to fulfill desired purpose. But all these process does not provided fully satisfaction from conventional heat treatment process. Thus a new process is being additionally employed for improving mechanical properties called cryogenic treatment process or sub-zero treatment of tool steels. During this process tool steel is proceed below Atmospheric tem. That is in minus about (-1960 C or 3100 F). Due to cooling, steel alter their mechanical properties like wear resistance, Hardness, toughness, fatigue life micro-structure alteration etc. Cryo-treatment not only improve its mechanical properties but also improve thermal properties, electrical properties & easier machining etc. in this paper cryogenic treatment of tool steel AISI-D6 is perform and study is made for wear-resistance, Hardness, toughness, with respect to untreated test specimen of same, we have got improved wear-resistance capacity improve hardness as well as toughness.
Keywords – AISI-D6 tool steel, cryogenic process, wear resistance, Hardness, Toughness.
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
Microstructure design of steel for high creep resistanceRajdeep Mondal
In modern world the material has to be high creep resistance and high fatigue resistance. So, Design the material in such a way that material has to be high creep resistance and high fatigue resistance.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Microstructure and Abrasive Wear Properties of Chrome Alloy Steel IDES Editor
En 31 steel is widely used for applications like ball bearings and grinding media balls. The sliding wear properties of En 31 steel has been studied in the past, however the data on abrasive wear properties of En 31 steel is limited. En 31 steel was quenched and tempered at different tempering temperatures. Metallographic and hardness studies were carried out on heat treated samples. The hardened and tempered samples were tested using two body abrasive wear testing apparatus. The abrasive medium used in the present investigation was silicon carbide paper. The effect of normal load and sliding distance on wear loss of as received and heat treated specimens tempered at different tempering temperatures was investigated. The abrasive wear resistance of EN 31 steel with different hardness was compared under different test conditions. The worn out samples were observed by Scanning Electron Microscope to study morphology of worn surfaces. The abrasive wear resistance exhibited an increasing trend with increase in hardness and it was rationalized in terms of microstructure and the hardness.
MICROSTRUCTURAL CHARACTERIZATION AND HOT EROSION BEHAVIOR OF CRC-NICR COATED ...IAEME Publication
Erosion behavior of the High Velocity Oxygen Fuel (HVOF) deposited CrC - NiCr coating on stainless steel was evaluated. Th e solid particle erosion stu dy was conducted using an air jet erosion test rig at a velocity 60m/sec and impingement angle 60 ° , 75 ° and 90 ° , on HVOF spray coated steel at 600 ° C. Microstructure, chemical composition, phases present in the coating on the steel substrate was studied by using Scanning Electron Microscope (SEM) and X - Ray Diffraction method. The Hardness is gradually increasing with increasing content of Cr 3 C 2 particles in all three samples. The erosion mechanism of coatings was also discussed and erosion rate is maximum at impingement angle 75 °
Corrosion resistance performance of fly ash blended cement concreteseSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Study on Influence of heat treatment on Tribological properties of mild steeldbpublications
A study was made on the effect of heat treatment upon the mild steel. Total six samples were prepared for each test (hardness test, tensile test, microstructure test and wear test) from those two was tested as received and rest four were subjected to different heat treatment that are annealing and normalizing (heated on a temperature of 850 degree Celsius). The hardness of all sample was measured by Rockwell hardness testing machine. Wear measurement was done on pin-on disc wear machine. Tensometer was used to find out the ultimate stress and strain of the sample. The result of tensile test showed that the strength is decreased by heat treating and the surface hardness is also decreased by heat treatment. Microstructure of the mild steel specimens shows the grain boundary of the particles and the content of % of carbon present. It justifies the experimental results of tensile test and hardness test. Surface Hardness is the measure of resistance that any material applies. As the specimen gets soft on treating the hardness also gets decreased. Tensile strength of any specimen is specified as how much stress the material can withstand before breaking. As the metal gets soft after heat treatment the load required for breaking goes on decreasing. Wear test is carried out to see the variation in wear measurement and coefficient of friction as the mesh size of paper are varied. More soft the surface of material is more wear is seen and vice-versa.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
A Review on Mechanical and Wear Properties of Heat Treated SteelIJSRD
This Review Paper describes effects of heat treatment on various material by varying process parameters and by using different types of heat treatment process. The heat treatment includes heating & cooling operations or the sequence of two or more such operations applied to any material in order to modify metallurgical structure and alter its physical, mechanical and chemical properties. This Review paper shows progress and research in the field of heat treatment process. Different types of heat treatment processes such as annealing, normalising, nitriding, hardening, tempering carburising used & available in recent time. This paper deals with important progress work on heat treatment and its process parameters.
Prediction of Weld Pool Geometry in Pulsed Current Micro Plasma Arc Welding o...drboon
Pulsed Micro Plasma Arc Welding (MPAW) is a metal joining technique widely used in manufacturing of thin sheet components due to its inherent properties. The weld quality and productivity are controlled by the process parameters. The paper discuses about development of mathematical models for weld pool geometry of stainless steel 304L sheets. Design of experiments based on full factorial design is employed for the development of a mathematical model correlating the important controlled pulsed MPAW process parameters like peak current, background current, pulse and pulse width with front width, back width, front height and back height. The developed mode has been checked for adequacy based on ANOVA analysis. Weld bead parameters obtained by the models are found to confirm actual values with high accuracy. Using these models effect of pulsed MPAW process parameters on weld pool geometry are studied.
Experimental and Finite Element Analysis of Single-V Groove Butt Weld on Weld...IJSRD
Gas Tungsten Arc Welding Process (GTAW) is widely used in fabrication of Aluminium and Aluminium Alloy material when precision is considered as a prime importance. Deformations in the object undergoing welding are one of the foremost problems encountered in the welding industry. Thus it is often required to study the factors which affect the deformations produced during welding to avoid errors in the geometry. Present investigation highlights Experimental and Finite Element Analysis of a Single-V Groove Butt Weld on Weld Pool Geometry of Aluminium Alloy Plate under Different Joint Parameters.Finite Element Method (FEM) has been employed to do the transient thermal and structural analysis of the assembly. The Finite Element Analysis has been done on ANSYS 14.5 Workbench. Number of factors is liable to produce effects in the job during the welding operation. Aim of this paper is the effect of welding parameters like as welding current, shielding gas flow rate and welding speed with mechanical Properties like tensile strength and hardness. After that finite element analysis for temperature distribution and distribution of the stresses in the welded Aluminium alloy plate. The results show that the larger the Welding current and smaller welding speed will lead to the maximum residual tensile stress. Therefore a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at different temperature. The higher yield strength at different temperature has higher material residual stress. Because of its higher thermal conductivity, aluminium alloy test specimens have small temperature differential.
Verification of johnson cook material model constants of aa2024-t3 for use in...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
"Fracture Toughness I" is the first half of a 2-hour presentation on Fracture Mechanics by metallurgical expert Carl Ziegler of Stork Testing and Metallurgical Consulting , Houston, Texas. In this webinar, Mr. Ziegler will cover many aspects of Fracture Toughness, including theory, applications, specifications, testing methods, and the effects of various stresses, strains and environmental conditions on your materials.
Orientation Effects of Stress Concentrators on the Material Deformation Beha...IJMER
Present investigation pertains to carry out to experimental work to generate data in order to
establish the mode of material deformation and fracture in AISI 316 stainless steel strips of 1.70mm thickness in
the presence of elliptical notches at the center of the specimen whose major axis were designed to incline to the
tensile axis at an angle of 0o
, 45o
and 90o
and the same happens to be the axis of rolling. An elliptical hole of
8.00mm (major axis) with 5.0mm (minor axis) were machined in each specimen so as to correspond to the above
angles of 0o
45o
and90o
and one specimen without any elliptical hole as a notch for comparative analysis of the experimental data. These flat specimens with and without stress concentrators were tested under tension using Hounsfield Tcnsomctcr and the changes in notch geometry have been recorded at various loadings. Further, the visual appearance of the cracks initiation have been continuously observed and recorded. The effect of stress ratio factors and the strain ratio parameters on the mode of fracture on material deformation in and around the stress concentrator has been thoroughly analyzed and it has been established that the crack initiation began either at the inner tips of the minor or the major axis of the elliptical stress concentrator, but, always perpendicular to the direction of loading irrespective of the rolling direction and the orientations of the stress concentrators. However, the changes in the rotation of the major and the minor axis of the elliptical stress concentrators were found to alter, and, this alteration in fact assisted in estimating the strains along the major as well as the minor axis of the stress concentrators. Relation between a plastic strain ratio with respect to the ratio between the major and the minor strains was observed to be of extremely complex nature. The overall observation in the present investigation has indicated that thin strips or sheet specimens containing a single or multiple or a combined type of stress concentrators will create a keen interest in the research approach of the investigators and make them aware of the seriousness of the presence of the stress concentrators and caution them to incorporate any possible design notifications in order to avoid any catastrophic failure (s).
Reducing Corrosion Rate by Welding DesignIJERD Editor
The paper addresses the importance of welding design to prevent corrosion at steel. Welding is
used to join pipe, profiles at bridges, spindle, and a lot more part of engineering construction. The
problems happened associated with welding are common issues in these fields, especially corrosion.
Corrosion can be reduced with many methods, they are painting, controlling humidity, and also good
welding design. In the research, it can be found that reducing residual stress on the welding can be
solved in corrosion rate reduction problem.
Preheating on 500oC and 600oC give better condition to reduce corosion rate than condition after
preheating 400oC. For all welding groove type, material with 500oC and 600oC preheating after 14 days
corrosion test is 0,5%-0,69% lost. Material with 400oC preheating after 14 days corrosion test is 0,57%-0,76%
lost.
Welding groove also influence corrosion rate. X and V type welding groove give better condition to reduce
corrosion rate than use 1/2V and 1/2 X welding groove. After 14 days corrosion test, the samples with
X welding groove type is 0,5%-0,57% lost. The samples with V welding groove after 14 days corrosion test is
0,51%-0,59% lost. The samples with 1/2V and 1/2X welding groove after 14 days corrosion test is 0,58%-
0,71% lost.
REVIEW ON EFFECT OF HEAT INPUT ON TENSILE STRENGTH OF BUTT WELD JOINT USING M...ijiert bestjournal
Present work investigates the effect of heat input (controlled by welding current,welding voltage and welding speed) on tensile strength,micro-hardness and microstructure elements produced by shielded metal arc welding (SMAW). From the experimental res ults it was found that the increase in heat input affects the micro-constituents of base metal,and h eat affected zone (HAZ). Tensile strength decreases with increase in heat input and from scanning elect ron microscopy of tensile test fractured surfaces exhibited ductile & brittle failure. From micro har dness data values it was observed that hardness of material increases with increase in heat input in w eld pool and decreases in HAZ zone. Optical microscopy shows that smaller dendrite sizes and le sser inter-dendritic spacing were observed in the fusion zone at low heat input. And long dendrite si zes and large inter-dendritic spacing were observed in the fusion zone of the joint welded at high heat in put. Further it was observed from the optical micrographs that the extent of grain coarsening in the HAZ increases with increase in heat input. The welding heat input has a great influence on the wel dments properties. This paper describes the influen ce of welding heat input on the weld metal toughness of h igh-carbon steel surface welded joint .
Correlation between the Interface Width and the Adhesion Strength of Copper F...IOSRJAP
The present study has been conducted in order to determine the influence of negative bias voltage applied to substrate on adhesion of copper films deposited on carbon steel substrates. The adhesion strength has been evaluated by the scratch test. Coatings were deposited by a DC magnetron sputtering system. The substrates were firstly mechanically polished and then ion-etched by argon ions prior to deposition. Adhesion was found to increase with the bias voltage. The critical load had a value of 9.5 g for an unbiased substrate and reached 18.5 g for a bias voltage of 600 V. Equally important, the interface width, measured using Auger electron spectroscopy, increased as a function of the bias voltage. The width of the interface is related to the time of ion milling in the Auger spectrometer. The size of this width is obtained from the Auger elemental depth profiles through measuring the depth of the interface coating/substrate. The width had a value of 335 min with a bias of 600 V whereas it didn't exceed 180 min when the substrate was unbiased. Therefore, the effect of the bias voltage was to expand the interface because of the diffusion phenomenon and physical mixing of materials at the interface. Moreover, the critical load increased with the increase of the interface width.
Correlation between the Interface Width and the Adhesion Strength of Copper F...
16March2012
1. 1
Computational Weld
Mechanics Simulation
of
Hot Crack Nucleation
Ahmed Nasser
under the supervision of
Prof. John Goldak
Starting off we already knew the capability of CWM to determine
the evolution of stress-strain-temperature state.
And we knew that hot cracking is often observed during welding.
2. 2
Why predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk ofWhy predict the risk of
hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?hot crack nucleation?
C.J. Huang, C.M. Cheng, C.P. Chou and F.H. Chen. Hot Cracking in AZ31 and AZ61 Magnesium
Alloy. J. Mater. Sci. Technol., 27(7):633-640, 2011.
Predicting the risk of hot cracking during welding is of the utmost
importance, in order to minimize the risk of occurrence.
The purpose is to reduce the risks associated with welding and
facilitate the use corrosion resistant materials that maintain
strength/stiffness at high temperatures, which can also be
susceptible to hot cracking.
This was driven by the increasing demand from the energy,
aerospace, and other industries.
Eliminating the risk hot cracking may be an impossible task, but
understanding the causes of hot cracking should clarify the options
available to reduce the risk of hot cracking.
3. 3
Hot
Cracking
Ductility
Dip
SolidificationLiquation
C.M.Cheng, C.P.Chou, I.K.Lee and I.C.Kuo. Susceptibility to Hot Cracking and Weldment
Heat Treatment of Haynes 230 Superalloy. J. Mater. Sci. Technol., (5):685-690, 2006.
One point of view is that the cause is a combination of both a tensile
strain and reduced material resistance to cracking.
The reduced material resistance means deformation cannot
compensate for a localized tensile strain.
This reduced material resistance is only experienced within certain
temperature ranges.
There are different reasons for the reduction in material resistance
and accordingly hot cracking can be classified.
Types:
DDC in heat affected zone
LC in partially melted zone
SC in fusion zone
4. 4
Ductility Dip Cracking
`
Matt Collins, Nathan Nissley and Antonio Ramirez. Ductility-Dip Cracking in Ni-base Alloys. March 2012.
· http://www.matsceng.ohio-state.edu/wjmg/ductilityDip.htmlx
DDC occurs in a completely solid phase.
e.g. For austentic alloys DDC is observed at 1/2 the absolute
solidus temperature.
The cause of reduced material resistance is not agreed upon, but
some research has attributed this to:
-segregation of elements to grain boundaries
-an accumulation of voids at the grain boundaries
-the size, shape, and orientation of grains
-a combination
Material resistance to DDC is improved:
-below that temperature range, due to hardening
-above the temperature range, due to recrystallization
5. 5
Liquation Cracking
S. Kou. "Solidication and liquation cracking issues in welding." JOM Journal of the Minerals, Metals and Materials
Society 55, 37-42 (2003).
At a higher temp range, some metallic materials are at risk of
liquation cracking.
This type of cracking occurs in a solid-liquid coexistent region.
Resistance to LC drops, because above the local solidus
temperature the GB melt, but the grain centre remains solid.
For Inconel 600
Maximum 1655 K
Minimum 1557 K
6. 6
Solidification Cracking
S. Kou. "Solidication and liquation cracking issues in
welding." JOM Journal of the Minerals, Metals and
Materials Society 55, 37-42 (2003).
Ploshikhin, V., Prikhodovsky, A., Makhutin, M., Ilin, A.
and Zoch, H.-W.. Integrated Mechanical-Metallurgical
Approach to Modeling of Solidification Cracking in
Welds. 2005.
Like liquation, solidification cracking occurs in the solid-liquid
coexistent region.
Resistance drops because below local liquidus, dendrites growing in
completely liquid phase surrounded by a liquid film.
For Inconel 600
Maximum 1655 K
Minimum 1557 K
7. 7
Material Resistance to
Cracking
Morgan Leo Gallagher. An Investigation of the Elevated
Temperature Cracking Susceptibility of Alloy C-22 Weld-
Metal . PhD thesis, The Ohio State University, 2008.
Strain to
Fracture
Decreasing
Henry Tan. MACE 61058: Plasticity – Lab. March 2012. ·
http://www.abdn.ac.uk/~eng907/teaching/plasticity/lab.htm
Vast majority of research on the subject of hot cracking is based on a
metallurgical approach.
But Limited research has been done using a mechanical approach
such as that conducted here.
The concept of mechanical approach was greatly assisted by the
work of Prokhorov in the 1950's. He quantified resistance to hot
cracking by measuring the strain to fracture within material specific
temperature.
But measurements taken by Prokhorov were not localized.
And hot cracking nucleates at a point, as a direct result of evolution
of state in the immediate neighbourhood.
In the 1980's, Matsuda improved the technique to measure localized
resistance by developing the MISO technique.
Material resistance to DDC is measured using a tensile test
conducted at various temperature within the susceptible
temperature range.
8. 8
Measuring Material
Resistance
MISO technique
Fukuhisa Matsuda, Hiroji Nakagawa, Kazuhiro Nakata, Hiroaki Kohmoto and Yoshiaki Honda. Quantitative Evaluation of
Solidification Brittleness of Weld Metal during Solidification by Means of In-Stu Observation and Measurement (Report I).
Transaction of JWRI, 12:65-72, April 1983.
On the other hand, resistance to solidification cracking is accurately
measured using the Measurement by means of In-Situ
Observation (MISO) technique.
The MISO technique measures the local strain and strain rate across
cracks behind the weld pool, where the material is a combination
of liquid and solid phase, using high-speed photography. Strain is
determined by visually measuring the distance between any two
surface marks in the desired direction. The surface marks used,
naturally appear, as a result of the welding process.
9. 9
Driving Force versus
Resistance
Yanhong H. Wei, Zhibo B. Dong, R. P. Liu and Z. J. Dong. Three-Dimensional Numerical Simulation of Weld Solidification
Cracking. Modelling and Simulation in Materials Science and Engineering, 13:437-454, 2005.
The risk of hot crack nucleation in any situation can be predicted,
using the experimentally determined resistance.
This is based on a competition between resistance and driving force.
The driving force is the tensile strain increment in the susceptible
temperature range.
10. 10
Motivation
demonstrate the potential of CWM as
an effective design tool for the
prediction of the risk of hot crack
nucleation in a welded structure
This concept is based on the work of:
-Chihoski (1972) - effect of deformation pattern on weld cracking
-Feng (1993) - CWM to determine driving force
We wanted to enhance the limited research conducted using a
mechanical approach.
Since 2004, 3 international workshops, dedicated to hot cracking,
have been held and the overwhelming majority of the presented
research on the topic has been based on a metallurgical approach
11. 11
Objective
estimate risk of hot crack based on a
mechanical approach, using the evolution
of the stress-strain-temperature state
A mechanical approach to compliment the metallurgical approach.
The evolution of the temperature-stress-strain state determined the
driving force.
We wanted to identify whether a certain area is at risk of hot cracking
nucleation.
--------------------------------------------------------------------------------------------
In contrast, the metallurgical approach explains hot cracking by:
-conditions of solidification
-grain size
-presence of low-melting eutectic films
12. 12
Method
VrWeld software
transient 3-D CWM analysis
Ductility Dip
Cracking
Solidification
Cracking
The evolution of state was based on transient 3-D analysis
conducted using a CWM software called VrWeld.
We conducted two tests. Both were bead on plate welds, but for two
different nickel-based alloys.
One of the tests was only for DDC and the other test was only for
solidification cracking.
The design of the tests used data from the literature.
In both tests, we identified the risk of hot cracking nucleation at
specific locations.
13. 13
Ductility Dip CrackingTest
Variable:
welding speed
sub-model
fine
mesh
coarse
mesh
The first test was for ductility dip cracking.
Welding speed is varied to observe its effect on the risk of DDC.
(localized strain and strain rate)
Material: Filler metal 82 (used to weld Inconel alloys)
Dimensions:100x100x2mm plate (test coupon)
Boundary conditions: Free body motion restraint
Mesh: 8-node brick
Refined along weld path because of high thermal gradients
Sub-model
The entire model was solved with a coarse mesh, then the results
were mapped onto the boundary of small section with a finer
mesh. This is the sub-model feature. This way we can get higher
accuracy, while maintaining low computational time.
14. 14
Ductility Dip CrackingTest –Temperature Results
2 mm/s
5 mm/s
Here we have a visualization of the thermal results for the two
welding speeds at the instant the heat source reaches halfway
across the weld path.
The size of the weld pool is same, but the area susceptible to DDC is
larger with the higher welding speed.
15. 15
`
Ductility Dip CrackingTest – Strain Results
2 mm/s
5 mm/s
However, the tensile stain increment is smaller with a higher welding
speed. Therefore, the likelihood of DDC nucleation is less with a
higher welding speed. According to the results, hot cracking is not
likely to occur with both welding speeds. However, there is a
relatively higher risk of DDC nucleation at distance of 4 mm from
the centre-line on the top surface of the plate, with a welding
speed of 2 mm/s.
Measurements for temperature and plastic strain increment is
computed for all principal directions at Gauss points that are in
between the markers. Shown is their location, behind the weld
pool and relative to the temperature distribution, in the sub-model
with a 2 mm/s welding speed, at t= 32.5 s.
The plots are for the maximum tensile principal plastic component,
which are almost parallel to the welding direction. The tensile
plastic strain increment is thought to be responsible for the
irreversible damage that leads to ductility dip cracking
In `ddc_pps_gp' video, the arrows show directions of the eigen
vectors for the principal plastic strains and their relative
magnitudes at a Gauss point 3 mm from weld centre.
16. 16
Ductility Dip CrackingTest -Validation
5 mm/s
2 mm/s
Jingqing Chen and Hao Lu. Investigation on ductility dip cracking susceptibility of filler metal 82 in welding.
Transaction of JWRI, 39(2):91-93, 2010.
The results obtained by the DDC test for the equivalent plastic strain
increment versus temperature are not similar to the results of
Chen and Lu.
The point with the maximum plastic strain increment was at 4 mm
from the centre line, rather than the 3 mm observed by Chen and
Lu.
The most probable cause for the apparent discrepancies is the lack
of detail in Chen and Lu's paper.
The locations, at which strain and temperature were
recorded, were not clearly identified.
In addition, the restraints applied to welded plate were not
specified. The lack of values for arc efficiency and the size of
the weld pool or heat source are also a concern.
17. 17
Solidification CrackingTest
Variable: cross head speed
sub-model
coarse
mesh
fine
mesh
The second test was for solidification cracking.
Cross-head speed is varied to observe its effect on the risk of DDC
(localized strain and strain rate) - 20, 2, 0.2, and 0.1 mm/s
Welding speed: 2mm/s
Material: Inconel 600
Dimensions: 300x50x2mm plate
Boundary conditions: Free body motion restraint
Cross head speed – a displacement rate is
applied at opposite end of the plate once the
heat source reaches halfway across the weld
path
Mesh: 8-node brick
Refined along weld path
Sub-model
18. 18
Solidification CrackingTest –Temperature Results
Here we have the visualization of the temperature results, when the
arc is halfway across the weld path
The transient temperature results are shown in video `ddc_temp'.
The video is for the sub-model, located at the centre of the plate
19. 19
Solidification CrackingTest – Strain Results
`
The total strain increment behind the weld pool is measured using a
virtual gauge of 1 mm length to measure, perpendicular to the
welding direction.
Plastic strain is not used, only to best reproduce the experiment from
literature on which this test is based.
The risk of solidification cracking can be greatly reduced, with a
lower localized strain rate rather than the magnitude of the strain
alone. The localized strain strain was controlled by the CHS.
According to the results, an applied CHS of 0.2 or 0.1 mm/s will most
likely not cause solidification cracking.
A CHS of 2 mm/s will likely lead to solidification cracking with the
lowest magnitude of strain, also referred to as minimum ductility,
which is at 1.2% and the temperature of 1645 K. Solidification
cracking will likely nucleate with a CHS of 2% with an applied CHS
of 20 mm/s.
Determining the risk of hot cracking for all points is a tedious
process. The solution is automation.
20. 20
Solidification CrackingTest
Hot Cracking
Post-Processor xy
z
Automation of the process of determining the risk of hot cracking was
made possible by the post processor developed by Goldak
technologies inc.
The risk of hot cracking is determined at all Gauss points. This is
based on the criteria that the principal plastic strain increment, in
the susceptible temperature range, exceeds critical values and the
rate of the principal plastic strain increment exceeds a critical
value, as well.
These critical values are obtained from experimentation that was
available in literature. These are an input to the library for material
properties.
The relative risk of hot cracking at the Gauss points depends on the
magnitude of the principal plastic strain increment.
The arrows show directions of the eigen vectors for the principal
plastic strains and their relative magnitudes at a single Gauss
point, after applying the CHS. The largest tensile component is
near the direction of the CHS (x-axis).
22. 22
review state of the art
meshing / sub-model
Challenges
The main challenges faced to reach our objective included:
Studying and Understanding prior work and state of the art techniques used in
predicating hot cracking (Kuo for an overview, Nishimoto for state of the art,
Zhilli Feng and Zacharia for prior CWM.)
Another challenge was the meshing process - Refining to determine localized
strain maintaining low computational time.
We also use the Sub-model feature, to get higher accuracy, while maintaining
low computational time. This is achieved by solving the entire mesh with a
coarse mesh, then mapping the results onto the boundary of small section
with a finer mesh.
This is particularly useful for the stress analysis, which takes a longer CPU
time compared to the thermal analysis.
23. 23
Challenges
lack of detail in literature
– optimize welding parameters
– stress Dirichlet boundary conditions
validation
Since we attempted to emulate tests from literature, the main
problem is that people rarely provide sufficient information, to
accurately reproduce an experiment.
This was particularly a problem as we tried to optimize welding
parameters and stress Dirichlet boundary conditions, to best
represent experimental set up.
Validation / Interpreting results – we studied and compared our
results to those from literature, understanding the cause of any
discrepancy.
24. 24
Recommended
Future Work
couple micro to macro
– microstructure evolution
– composition gradient across grains
– shape and flow of liquid film
In the analysis we conducted, the macroscopic analysis alone is an
adequate approximation for the nickel-based alloys. Because
nickel alloys largely stay in the face-centred cubic (FCC) crystal
structure in the solid state.
However, in the future, a possible improvement to the CWM
simulation would be coupling a microscopic analysis to the
macroscopic constitutive equations, used in the CWM analysis.
The microscopic analysis should take into account:
the evolution of the microstructure
the composition gradient across grains(segregation)
the shape and flow of the liquid film on solidifying grains