焊后热处理对P92钢焊接接头显微组织和力学性能的影响

Effect of postweld heat treatment on microstructure and mechanical properties of P92 steel welded joint

通过试验研究了不同热处理方式下P92钢焊接接头的组织性能变化。结果表明:所有试样的拉伸断口均位于非焊缝区,焊缝处的拉伸性能好于母材区域。在低于700℃温度下保温60 min后,焊缝硬度高于母材,焊缝硬度值在35~45 HRC,母材硬度约为20 HRC,对焊缝区硬度无改善;760℃保温90 min焊后热处理后焊缝组织接近原始母材组织,为回火屈氏体,组织均匀细小,焊接硬度明显下降且接近母材,为最佳焊后热处理工艺。

The weld,heat affected zone and microstructure and properties of P92 steel under different heat treatment were studied.The results show that the tensile fractures of all the specimens are located in the non-weld zone,and the tensile properties at the weld are better than those in the parent metal zone.After the sample being kept warm below 700℃for 60 min,the hardness of the weld is higher than t hat of the parent metal,where the hardness of the weld is between 35~45 HRC and the hardness of the parent metal is around 20 HRC.This postweld heat treatment does not improve the hardness of the weld zone.After the postweld heat treatment with heat preservation at 760℃for 90 min,the weld microstructure is close to the original parent material micro-structure,which is tempered tortoise,the microstructure is uniform and small,the hardness of weld microstructure decreases and is close to that of the base metal,which is the best postweld heat treatment process in the test.