Papers by Author: Prachya Peasura

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Authors: Prachya Peasura
Abstract: ASTM A36 carbon steel is the most commonly available of the hot-rolled steels. This specification covers carbon steel shapes, plates, and bars of structural quality for use in riveted, bolted, or welded construction of bridges and buildings, and for general structural purposes. The research was to study the in effected of gas tungsten arc welding parameters which effects the hardness and physical characteristics of welding for carbon steel ASTM A36. The specimen was carbon steel sheet metal 6 mm thick. The 23 factors experiment was used polarity direct current electrode negative (DCEN) and alternating current (AC), welding current at 90 and100 amperes with tungsten electrode angles at 30 and 60degree. The weld sample was test by hardness and penetration. The result showed that polarity, welding current and tungsten electrode angle had on interaction on hardness and penetration at 95% confidence (p-value < 0.05).The factors made maximum hardness was polarity AC, welding current 100 amp. and tungsten angle 60๐of 803.16 HV. The factors made maximum penetration was polarity DCEN, welding current 100 amp. and tungsten angle 60๐ of 2.71mm. The research data can be used to determine the appropriate gas tungsten arc welding process of carbon steel weld.
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Authors: Prachya Peasura, Narasak Duangsrikaew, Santirat Nansaarng
Abstract: In this research, the post weld heat treatment (PWHT) of duplex stainless steel (DSS) was study. The PWHT process can be affected by differing parameters. The specimen was duplex stainless steel UNS31803 grade sheet of 10 mm thickness. The PWHT parameters were analyzed by application of full factorial design. The factors used in this study were PWHT temperature of 650, 750, and 850 C with PWA time of 1, 2, 4 and 8 hours. The welded specimens were tested with micro vickers hardness and ferrite content testing according to ASTM E3-11 code. The result showed that both of PWHT temperature and PWHT time interaction on hardness and ferrite content for 95% confidential (P value < 0.05). The factor in most effect of hardness was the PWHT temperature of 850C and PWHT time for 4 hour at the hardness of 277.73 HV. The ferrite was the most ferrite content for 77.39% resulted in corrosion resistance due to suitable of PWHT temperature 750 C and PWHT time for 8 hour. Finally, form PWHT process with the information was used choosing the appropriate for PWHT parameters to duplex stainless steel welds.
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Authors: Prachya Peasura, Bovornchok Poopat
Abstract: Alloy X-750 also has excellent properties down to cryogenic temperatures high stability and strength at high temperatures. This reason the alloy is used in manufacturing of gas turbine hot components. The research was study the effect of post weld heat treatment (PWHT) parameter on hardness and microstructure. The specimen was Inconel X-750 grade sheet of 2.8 mm thickness. This 23 factorial design was used in experimental various post weld heat treatment at 705 and 845°C for 20 and 24 hour including solution temperature at 1,000 and 1,150°C. The welded specimens were tested by hardness testing in fusion zone (FZ) and heat affected zone (HAZ). The result showed that both of solution temperature, PWHT temperature and PWHT time interaction on hardness of FZ and HAZ at 95% confidential (P value < 0.05). The PWHT temperature and PWHT time interaction effect was the largest. The factor showed in the hardness increase with the low level (-1) of PWHT temperature and PWHT time for the hardness while it trended decrease for the solution temperature. The microstructure was the γ amount and small size would result in high hardness. Experimental results showed that the solution temperature at 1,150°C, PWHT temperature 705°C PWHT time of 20 hours provided intensity of gamma prime (γ) and MC carbide resulting in higher hardness both in FZ and HAZ.
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Authors: Prachya Peasura
Abstract: This research was to effect of electrode force on the tensile shear and nugget size of the resistance spot welding. The specimen was austenitic stainless steel 304 grade sheet metal 1.2 mm thickness. The electrode force are 1, 1.5, 2.0, 2.5, and 3.0 kN apply to the specimen. The replications in each treatment are 20 follow JIS Z 3136:1999 and JIS Z 3139:1978. Factor control, welding current 7 kA., time current flow 7 cycle and electrode tip diameter 6 mm. The welded specimens were tested by tensile shear testing according to JIS Z 3136: 1999, macro structure testing according to JIS Z 3139: 1978 and analysis results by using One-way ANOVA .The result showed that electrode force had affected on tensile shear and nugget size at 95% confidential (P value > 0.05). The low force induced the gab between specimen increasing then the current flow difficult to pass and both of gab between specimen and nugget seize had increase (Q=I2Rt). When the resistance increased so that fusion zone will have a high heating. It had affected to nugget size, heat affected zone and mechanical properties decreasing. The electrode forces are complete 2.5 kN. tensile shear 9.21 kN and nugget size 5.82 mm. The data can be applied to be used as process monitoring of resistance spot weld quality
2176
Authors: Mongkol Chaisri, Prachya Peasura
Abstract: The research was study the effect of gas metal arc welding process parameters on mechanical property. The specimen was carbon steel ASTM A285 grade A which thickness of 6 mm. The experiments with full factorial design. The factors used in this study are shielding gas and voltage. The welded specimens were tested by tensile strength testing and hardness testing according to ASME boiler and pressure vessel code section IX 2007. The result showed that both of shielding gas and voltage had interaction on tensile strength and hardness at 95% confidential (P value < 0.05). Factors affecting the tensile strength are the most carbon dioxide and 27 voltage were tensile strength 213.43 MPa. And hardness maximum of 170.60 HV can be used carbon dioxide and 24 voltage. This research can be used as data in the following appropriate parameters to gas metal arc welding process.
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Authors: Prachya Peasura, Lersak Sumarn
Abstract: The research was study the effect of post weld heat treatment parameters on microstructure and hardness in heat affected zone. The specimen was carbon steel AISI 1050 which thickness of 6 mm. The experiments with full factorial design. The factors used in this study were post weld heat treatment(PWHT) temperature of 500, 550, 600, 650 and post weld heat treatment time of 10 and 15 hour. The welded specimens were tested by tensile strength testing and hardness testing according to ASTM code. The result showed that both of post welds heat treatment temperature and post weld heat treatment time had interaction on hardness at 95% confidential (P value < 0.05). A factor affecting the hardness was the most PWHT temperature 550 ๐C and PWHT time 10 hr. of 279 HV. Microstructure can be concluded that low PWHT temperature and time effect on temper martensite with a coarse grain and martensite scattered throughout. Martensite was a smaller and greater fine grain, the ferrite and the volume decrease due to a higher temperature.This research can be used as data in the following appropriate PWHT parameters to carbon steel weld.
612
Authors: Prachya Peasura, Bovornchok Poopat
Abstract: The Inconel X-750 indicates good hot corrosion resistance, high stability and strength at high temperatures and for this reason the alloy is used in manufacturing of gas turbine hot components. The objective of this research was study the effect of post weld heat treatment (PWHT) on fusion zone and heat affected zone microstructure and mechanical properties of Inconel X-750 weld. After welding, samples were solutionized at 1500 0C. Various aging temperature and times were studied. The results show that aging temperature and time during PWHT can greatly affect microstructure and hardness in fusion zone and heat affected zone. As high aging temperature was used, the grain size also increased and M23C6 at the grain boundary decreased. This can result in decreased of hardness. Moreover excessive aging temperature can result in increasing MC carbide intensity in parent phase (austenite). It can also be observed that M23C6 at the grain boundary decreased due to high aging temperature. This resulted in decreasing of hardness of weld metal and heat affected zone. Experimental results showed that the aging temperature 705 0C aging time of 24 hours provided smaller grain size, suitable size and intensity of MC carbide resulting in higher hardness both in weld metal and HAZ.
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Authors: Prachya Peasura
Abstract: This research was study the effect of resistance spot welding process on physical properties. The specimen was austenitic stainless steel sheet of 1 mm. The experiments with 23 factorial design. The factors used in this study are welding current at 8,000 and 12,000 Amp, welding time at 8 and 12 cycle and electrode force were set at 1.5 and 2.5 kN. The welded specimens were tested by tensile shear testing according to JIS Z 3136: 1999 and macro structure testing according to JIS Z 3139: 1978. The result showed that the welding current, welding time and electrode force had interaction on tensile shear and nugget size at 95% confidential (P value < 0.05). Factors affecting the tensile shear are the most welding current of 12,000 amp., welding time of 8 cycle and electrode force of 2.5 kN. were tensile shear of 9.83 kN. The nugget size was maximum at 7.15 mm. on welding current of 12,000 amp., welding time of 12 cycle and electrode force of 1.5 kN This research can bring information to the foundation in choosing the appropriate parameters to resistance spot welding process.
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Authors: Prachya Peasura
Abstract: This research was to study of gas tungsten arc welding (GTAW) welding parameters that affects to the mechanical properties of aluminum alloy AA5083 welding with GTAW. The full factorial design was experiment. The factors was study in type of polarity on alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), levels of welding current for 180,200,220 and 240 amp. The specimen to analyses the physical properties has microstructure and hardness of weld metal and heat affected zone. The result showed that type of welding current and levels of welding current interaction hardness at the level of confidence 95% (P-value<0.05). The factor hardness maximum of weld metal was alternating current at level of current 240 amp. and hardness of 136.53 HV. The factor hardness maximum of HAZ value was alternating current at level of welding 220 amp. and hardness of 169.43 HV. The welding parameters can result in increasing Mg2Si intensity in parent phase. It can also be observed that Mg2Si at the parent phase decreased due to high welding current in HAZ.This research can be used as information in choosing how to welding parameter for gas tungsten arc welding of aluminum alloy.
183
Authors: Santirat Nansa-Arng, Prachya Peasura
Abstract: Duplex stainless steel (DSS) offers an alternative to the austenitic stainless steels especially at temperatures between –50 and 300°C and is suitable for structural applications. The research was study the effect of post weld aging (PWA) parameters on microstructure in heat affected zone. The specimen was duplex stainless steel (DSS) UNS31803 which thickness of 10 mm. The PWA sample were tested the microstructure and phase analysis. The factors used in this study were PWA temperature of 650, 750, and 850 C with PWA time of 1, 2, 4 and 8 hours. The welded specimens were tested by microstructure and phase analysis testing according to ASTM E3-11 code. The result showed that both of PWA temperature and PWA time can greatly affect microstructure and phase analysis in heat affected zone (HAZ). The ferrite that was austenite with a grain and an austenite scattered throughout. The microstructures of PWA 650 °C with PWA 1, 2, 4 and 8 hours in ferrite phase which ferrite phase was not different. The widmanstätten structures were observed high PWA temperatures were also distributed at grain. At high PWA temperature, ferrite at the grain boundary tended to decrease. Moreover excessive aging temperature can result in increasing austenite intensity and size in parent phase. Definitely, at high PWA temperature and time, over-aging of HAZ resulted in corrosion resistance reduce.
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