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采用金相、扫描电镜(SEM)和焊接热模拟方法,研究了不同峰值温度和焊接线能量对ASTM4130钢焊接热影响区(HAZ)显微组织、冲击韧性和断口形貌的影响。结果表明,ASTM4130钢热影响区除回火软化区外均发生脆化现象。当峰值温度为1200℃和1350℃时,由于晶粒粗大,且产生了贝氏体、未回火马氏体和M-A组元等非平衡组织,其冲击韧性损失达母材的94.5%,脆化现象最严重。当峰值温度为950℃,冲击韧性较低的原因是该区产生了未回火马氏体和块状铁素体。当峰值温度为800℃时,晶界附近碳化物聚集和不均匀分布,以及块状铁素体的存在,造成该区发生脆化。焊态下焊接线能量对ASTM4130钢粗晶区的冲击韧性影响较小。
The effects of different peak temperature and welding line energy on the microstructure, impact toughness and fracture morphology of the heat affected zone (HAZ) of ASTM4130 steel were studied by means of metallographic examination, scanning electron microscopy (SEM) and thermal simulation. The results show that, except for the tempering softening zone, the brittleness occurs in the heat affected zone of ASTM4130 steel. When the peak temperature is 1200 ℃ and 1350 ℃, the impact toughness loss reaches 94.5% of the base metal due to the coarse grains and the bainite, untempered martensite and MA component, The most serious phenomenon. The reason for the lower impact toughness when the peak temperature is 950 ° C is that untempered martensite and massive ferrite are produced in this zone. When the peak temperature is 800 ℃, the carbides near the grain boundary are aggregated and unevenly distributed, and the presence of massive ferrite causes embrittlement in the zone. Weld line welding energy of ASTM4130 steel coarse grain impact toughness less affected.