Microstructural Investigation on Simulated Heat Affected Zone of SA533 B2 Steel

• Main Authors: Ru-Chao Wei, 魏汝超
• Other Authors: 楊哲人
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/47571645496203571858

博士 === 國立臺灣大學 === 材料科學與工程學研究所 === 95 === To investigate the phase transformation and the microstructural evolution of SA533 B2 steel plates during the SMAW (Shielding Gas Metal-Arc Welding) welding processes, simulations of the coarse grained region of heat affected zone (with heat inputs of 10, 20 and 30 kJ/cm) followed by inter-pass heating at 300℃ and post-weld heat treatments at 590℃ were carried out. The microstructural evolution and the toughness of the simulated specimens were studied after different soak time of heat treatments. With heat inputs of 10 and 20 kJ/cm, both of the simulated microstructures contain large amount of lower bainite with significant amounts of auto-tempered martensite. With the heat input of 30 kJ/cm, the simulated microstructure is composed mainly of lower bainite structure. Thus, the higher hardness of the specimens would be got under the smaller heat input condtions. Besides, the Charpy impact toughness property has been measured for the specimens treated by 20 kJ cm-1 heat input, followed by inter-pass heating at 300℃ and post-weld treatment at 590℃. The resaults of impact tests show that the impact energies would be meliorated after inter-pass heating and further improved by post-weld heat treatments. The highest impact energy was got in the specimen after 60 minutes of post-weld heat treatment following 30 minutes of inter-pass heating.