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Fathallah Karimzadeh - One of the best experts on this subject based on the ideXlab platform.
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Artificial neural network modeling for evaluating of epitaxial growth of Ti6Al4V Weldment
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Fathallah Karimzadeh, Abbas Ebnonnasir, A. ForoughiAbstract:Abstract The effect of epitaxial growth on microstructure of Ti–6Al–4V alloy Weldment was examined by artificial neural networks (ANNs). The microplasma arc Welding (MPAW) procedure was performed at different currents, Welding speeds and flow rates of shielding and plasma gas. Microstructural characterizations were studied by optical and scanning electron microscopy (SEM). Finally, an artificial neural network was developed to predict grain size of fusion zone (FZ) at different currents and Welding speeds. The results showed that a coarse primary β phase develops in the fusion zone as a result of epitaxial nucleation on coarsened β grains near the heat affected zone (NHAZ) which grow competitively into the Molten Weld Pool. Based on ANNs analyses, a map of current and Welding speed for α → β transformation in the HAZ can be constructed. For a lower energy input, grain growth of β phase in the HAZ could be restricted by α phase. The presence of small quantities of this phase at high peak temperatures in the Weld cycle is sufficient to prevent the grain growth of β phase in HAZ and FZ.
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EFFECT OF MICROPLASMA ARC WeldING PROCESS PARAMETERS ON GRAIN GROWTH AND POROSITY DISTRIBUTION OF THIN SHEET Ti6AL4V ALLOY WeldMENT
Materials and Manufacturing Processes, 2005Co-Authors: Fathallah Karimzadeh, Mehdi Salehi, A. Saatchi, Mahmood MeratianAbstract:ABSTRACT In the present investigation, the effect of microplasma arc Welding (MPAW) process parameters on grain growth and porosity distribution of thin sheet Ti6Al4V alloy Weldment has been examined. The MPAW procedure was performed at different current, Welding speed, and flow rates of shielding and plasma gas. Metallographic characterization was carried out by light microscopy and scanning electron microscopy (SEM). The results have shown that beyond a threshold energy, burn of the metal in Ti6Al4V thin sheet alloy can occur. This case should be considered for any selection of Welding process parameters. Furthermore, in MPAW there are a number of threshold parameters that can control Weldment size. Metallographic characterization has shown that coarse primary beta grains exist in the fusion zone. This is due to the fact that these grains have nucleated epitaxially upon coarsened beta grains in the near heat affected zone (NHAZ) and grown competitively into the Molten Weld Pool. Evaluation of grain size...
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Control of burning and grain growth during microplasma arc Welding of thin sheet Ti6Al4v alloy
2003Co-Authors: Fathallah Karimzadeh, A. Saatchi, Mehdi SalehiAbstract:In the present investigation, the effect of microplasma arc Welding (MPAW) process parameters on grain growth of thin sheet Ti6Al4V alloy Weldment has been examined. The MPAW procedure was performed at different current, Welding speed and flow rates of shielding and plasma gas. Metallographic characterization was carried out by light microscopy and scanning electron microscopy (SEM).The results have shown that beyond threshold energy, burn of the metal in Ti6Al4V thin sheet alloy can be occurred. This case should be considered for any selection of Welding process parameters. Furthermore in MPAW there are a number of threshold parameters which can be control Weldment size on different scale. Metallographic characterization has shown that a coarse primary β grain exist in the fusion zone. This is due to the fact that these grains have nucleated epitaxially upon coarsened β grain in near heat affected zone (NHAZ) and growth competively in to the Molten Weld Pool. Evaluation of grain size indicates that there is a threshold energy input for phase transformation of alfa in HAZ. In the case of lower energy input, the grain growth of â phase in HAZ could be restricted by alfa phase. The presence of small quantities of this phase at high peak temperatures in the Weld cycle is sufficient to prevent β grain growth of HAZ and FZ.
G Guaytima - One of the best experts on this subject based on the ideXlab platform.
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development of a chromium free consumable for austenitic stainless steels part 1 monel alloy 400 filler metal
Corrosion, 2006Co-Authors: G S Frankel, John C Lippold, G GuaytimaAbstract:Abstract During fusion Welding of stainless steels and other high-Cr alloys, evaporation and oxidation of Cr from the Molten Weld Pool result in the generation of carcinogenic hexavalent chromium (Cr[VI]) in the Welding fume. Stringent new exposure limits from the Occupational Safety and Health Administration (OSHA) might limit the environment in which the Welding of stainless steel will be possible in the future. Therefore, a Cr-free filler metal is needed to reduce the release of Cr(VI) during the Welding of stainless steel. From the galvanic series, the corrosion potential of the Ni-Cu alloy K400 (UNS N04400) is located in the same potential range as Type 304 (UNS S30400) and Type 316 (UNS S31600) stainless steels. In this study, the applicability of the Monel-type filler metals for the Welding of austenitic stainless steel is examined. Type 304L (UNS S30403) stainless steel plate was successfully Welded with Monel filler wire, resulting in high-quality Welds with no cracks. The Welds survived long-ter...
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Development of a Chromium-Free Consumable for Austenitic Stainless Steels—Part 1: Monel (Alloy 400) Filler Metal
CORROSION, 2006Co-Authors: Yeong Ho Kim, G S Frankel, John C Lippold, G GuaytimaAbstract:Abstract During fusion Welding of stainless steels and other high-Cr alloys, evaporation and oxidation of Cr from the Molten Weld Pool result in the generation of carcinogenic hexavalent chromium (Cr[VI]) in the Welding fume. Stringent new exposure limits from the Occupational Safety and Health Administration (OSHA) might limit the environment in which the Welding of stainless steel will be possible in the future. Therefore, a Cr-free filler metal is needed to reduce the release of Cr(VI) during the Welding of stainless steel. From the galvanic series, the corrosion potential of the Ni-Cu alloy K400 (UNS N04400) is located in the same potential range as Type 304 (UNS S30400) and Type 316 (UNS S31600) stainless steels. In this study, the applicability of the Monel-type filler metals for the Welding of austenitic stainless steel is examined. Type 304L (UNS S30403) stainless steel plate was successfully Welded with Monel filler wire, resulting in high-quality Welds with no cracks. The Welds survived long-ter...
G S Frankel - One of the best experts on this subject based on the ideXlab platform.
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development of a chromium free consumable for austenitic stainless steels part 1 monel alloy 400 filler metal
Corrosion, 2006Co-Authors: G S Frankel, John C Lippold, G GuaytimaAbstract:Abstract During fusion Welding of stainless steels and other high-Cr alloys, evaporation and oxidation of Cr from the Molten Weld Pool result in the generation of carcinogenic hexavalent chromium (Cr[VI]) in the Welding fume. Stringent new exposure limits from the Occupational Safety and Health Administration (OSHA) might limit the environment in which the Welding of stainless steel will be possible in the future. Therefore, a Cr-free filler metal is needed to reduce the release of Cr(VI) during the Welding of stainless steel. From the galvanic series, the corrosion potential of the Ni-Cu alloy K400 (UNS N04400) is located in the same potential range as Type 304 (UNS S30400) and Type 316 (UNS S31600) stainless steels. In this study, the applicability of the Monel-type filler metals for the Welding of austenitic stainless steel is examined. Type 304L (UNS S30403) stainless steel plate was successfully Welded with Monel filler wire, resulting in high-quality Welds with no cracks. The Welds survived long-ter...
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Development of a Chromium-Free Consumable for Austenitic Stainless Steels—Part 1: Monel (Alloy 400) Filler Metal
CORROSION, 2006Co-Authors: Yeong Ho Kim, G S Frankel, John C Lippold, G GuaytimaAbstract:Abstract During fusion Welding of stainless steels and other high-Cr alloys, evaporation and oxidation of Cr from the Molten Weld Pool result in the generation of carcinogenic hexavalent chromium (Cr[VI]) in the Welding fume. Stringent new exposure limits from the Occupational Safety and Health Administration (OSHA) might limit the environment in which the Welding of stainless steel will be possible in the future. Therefore, a Cr-free filler metal is needed to reduce the release of Cr(VI) during the Welding of stainless steel. From the galvanic series, the corrosion potential of the Ni-Cu alloy K400 (UNS N04400) is located in the same potential range as Type 304 (UNS S30400) and Type 316 (UNS S31600) stainless steels. In this study, the applicability of the Monel-type filler metals for the Welding of austenitic stainless steel is examined. Type 304L (UNS S30403) stainless steel plate was successfully Welded with Monel filler wire, resulting in high-quality Welds with no cracks. The Welds survived long-ter...
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novel approach for Welding stainless steel using cr free Welding consumables
2004Co-Authors: John C Lippold, G S FrankelAbstract:Abstract : This project was a SERDP seed grant that was extended from the normal one year duration to a total of two years. The goal of the project was to demonstrate the feasibility of a new approach for Welding stainless steel using Cr-free consumables. Stainless steels are usually selected as a material of construction for their corrosion resistance. When they are fabricated into structures, stainless steel components are often joined by Welding. In order to ensure that the Welds exhibit sufficient corrosion resistance, filler metals matching or exceeding the chromium (Cr) content of the base metal must be used. The Cr content of Types 304 and 308 stainless steels, the most commonly used stainless steel and the filler metal used to Weld, respectively, it is 18-20 wt%. Evaporation and oxidation of Cr from the Molten Weld Pool results in emission of carcinogenic hexavalent Cr (Cr+6 or chromate) in the fumes. This is a significant health hazard for the Welders and necessitates considerable expense for ventilation systems. In some conditions relevant to DOD interests, such as cramped ship interiors, it is extremely difficult to ventilate effectively. Furthermore, any future reduction in the Permissible Exposure Limit (PEL) for chromate in Welding fume, which is under consideration by OSHA, will exacerbate the situation. It is the objective of this proposal to develop a Cr-free consumable for Welding austenitic stainless steel that provides mechanical properties and corrosion resistance comparable to the Cr-bearing consumable that are currently used. The approach to solving this problem considers that, if stainless steel (SS) is to be Welded with a filler metal that is different in composition than the base metal, then the corrosion of the Welded structure will be controlled by the phenomenon of galvanic corrosion. Furthermore, passive metals such as stainless steels usually corrode in a localized nature.
Mehdi Salehi - One of the best experts on this subject based on the ideXlab platform.
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EFFECT OF MICROPLASMA ARC WeldING PROCESS PARAMETERS ON GRAIN GROWTH AND POROSITY DISTRIBUTION OF THIN SHEET Ti6AL4V ALLOY WeldMENT
Materials and Manufacturing Processes, 2005Co-Authors: Fathallah Karimzadeh, Mehdi Salehi, A. Saatchi, Mahmood MeratianAbstract:ABSTRACT In the present investigation, the effect of microplasma arc Welding (MPAW) process parameters on grain growth and porosity distribution of thin sheet Ti6Al4V alloy Weldment has been examined. The MPAW procedure was performed at different current, Welding speed, and flow rates of shielding and plasma gas. Metallographic characterization was carried out by light microscopy and scanning electron microscopy (SEM). The results have shown that beyond a threshold energy, burn of the metal in Ti6Al4V thin sheet alloy can occur. This case should be considered for any selection of Welding process parameters. Furthermore, in MPAW there are a number of threshold parameters that can control Weldment size. Metallographic characterization has shown that coarse primary beta grains exist in the fusion zone. This is due to the fact that these grains have nucleated epitaxially upon coarsened beta grains in the near heat affected zone (NHAZ) and grown competitively into the Molten Weld Pool. Evaluation of grain size...
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Control of burning and grain growth during microplasma arc Welding of thin sheet Ti6Al4v alloy
2003Co-Authors: Fathallah Karimzadeh, A. Saatchi, Mehdi SalehiAbstract:In the present investigation, the effect of microplasma arc Welding (MPAW) process parameters on grain growth of thin sheet Ti6Al4V alloy Weldment has been examined. The MPAW procedure was performed at different current, Welding speed and flow rates of shielding and plasma gas. Metallographic characterization was carried out by light microscopy and scanning electron microscopy (SEM).The results have shown that beyond threshold energy, burn of the metal in Ti6Al4V thin sheet alloy can be occurred. This case should be considered for any selection of Welding process parameters. Furthermore in MPAW there are a number of threshold parameters which can be control Weldment size on different scale. Metallographic characterization has shown that a coarse primary β grain exist in the fusion zone. This is due to the fact that these grains have nucleated epitaxially upon coarsened β grain in near heat affected zone (NHAZ) and growth competively in to the Molten Weld Pool. Evaluation of grain size indicates that there is a threshold energy input for phase transformation of alfa in HAZ. In the case of lower energy input, the grain growth of â phase in HAZ could be restricted by alfa phase. The presence of small quantities of this phase at high peak temperatures in the Weld cycle is sufficient to prevent β grain growth of HAZ and FZ.
Shashi Bhushan Prasad - One of the best experts on this subject based on the ideXlab platform.
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Optimization of vibratory Welding process parameters using response surface methodology
Journal of Mechanical Science and Technology, 2017Co-Authors: Pravin Kumar Singh, D Patel, S. Deepak Kumar, Shashi Bhushan PrasadAbstract:The current investigation was carried out to study the effect of vibratory Welding technique on mechanical properties of 6 mm thick butt Welded mild steel plates. A new concept of vibratory Welding technique has been designed and developed which is capable to transfer vibrations, having resonance frequency of 300 Hz, into the Molten Weld Pool before it solidifies during the Shielded metal arc Welding (SMAW) process. The important process parameters of vibratory Welding technique namely Welding current, Welding speed and frequency of the vibrations induced in Molten Weld Pool were optimized using Taguchi’s analysis and Response surface methodology (RSM). The effect of process parameters on tensile strength and hardness were evaluated using optimization techniques. Applying RSM, the effect of vibratory Welding parameters on tensile strength and hardness were obtained through two separate regression equations. Results showed that, the most influencing factor for the desired tensile strength and hardness is frequency at its resonance value, i.e. 300 Hz. The micro-hardness and microstructures of the vibratory Welded joints were studied in detail and compared with those of conventional SMAW joints. Comparatively, uniform and fine grain structure has been found in vibratory Welded joints.
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optimization of process parameters during vibratory Welding technique using taguchi s analysis
Perspectives on Science, 2016Co-Authors: Pravin Kumar Singh, D Patel, Shashi Bhushan PrasadAbstract:Summary With an aim to improve the mechanical properties of a Weld joint, a new concept of vibratory setup has been designed which is capable to stir the Molten Weld Pool before it solidifies during shielded metal arc Welding (SMAW) operation. Mechanical vibration having resonance frequency of 300 Hz and amplitude of 0.5 mm was transferred to the Molten Weld Pool of 6 mm thick mild steel butt-Welded joints during the Welding operation. The experimental work was conducted at various ranges of frequencies, Welding current and Welding speed. Taguchi's analysis technique has been applied to optimize the process parameters; the response values for analysis are yield strength and micro-hardness. The test results showed that with the application of the vibratory treatment the values of hardness and tensile properties increased. The auxiliary vibrations induced into the Weld Pool resulted in increased micro-hardness of the Weld metal which indicates the orientation of the crystal and refinement of grains took place. This study shows that vibration applied into the Weld Pool can be successfully improved the mechanical properties of Welded joints. Thus this research attempt provided an alternative Welding technique for grain refinement of Weldments.