X100抗大变形管线钢焊接热影响区的显微组织与冲击功

摘要

The X100 pipeline steel with high deformation resistance was obtained by the critical region accelerated cooling method.The impact energy and microstructures of the heat affected zone (HAZ)specimens prepared by means of welding thermal simulation technology were investigated.The results show that the ultimate strain capability of the X100 pipeline steel with high deformation resistance was strong and the microstructure was composed of bainite and ferrite.The impact energy of the HAZ specimens prepared by weld simulation decreased with the rise of the thermal cycle peak temperature.When the peak temperature was 1 300 ℃,the impact energy reached the lowest value of 247.9 J,which was reduced by 1 7.3% comparing to that of base material,and then the fracture mode changed from ductile fracture to cleavage fracture.The rise of the thermal cycle peak temperature resulted in the recrystallization and grain coarseness in HAZ microstructure,and then decreased the toughness.%采用部分再结晶区加速冷却的方法获得了 X100抗大变形管线钢,利用焊接热模拟技术制备了不同热影响区试样并研究了其冲击功和显微组织.结果表明：X100抗大变形管线钢具有较强的极限应变能力,其组织为粒状贝氏体和多边形铁素体；模拟热影响区试样的冲击功随热循环峰值温度的升高而下降,当峰值温度为1300℃时,冲击功为247．9 J,比母材的降低了17．3％,冲击断裂方式也从韧性断裂转为解理断裂；热循环峰值温度升高使热影响区组织发生再结晶,并且晶粒粗化,降低了其韧性.