二次焊接热循环对超高强度钢过热区冲击性能的影响

Effect of Secondary Welding Thermal Cycles on Microstructure and Toughness of Over-heated Zone of Ultrahigh Strength Steel

采用热模拟技术研究了900MPa级超高强度钢过热区经历二次热循环后组织与韧性的变化规律。结果表明,900MPa级超高强度钢过热区经历二次热循环后,冲击韧性均有所下降,其中过热区经历了850℃的二次热循环后韧性最差,沿原奥氏体晶界形成的链状分布的小晶粒是造成韧性下降的主要原因。

In this paper,thermal simulation technique is adopted to investigate the microstructure and toughness of over-heated zone of 900MPa yield strength steel exposed secondary thermal cycle,The results show that the toughness of the steel after the thermal cycles decreased,specially at the temperature of 850℃,It may be caused by the small grains distributed continuously on the border of grain which led to disability of border.