CrMoV与NiCrMoV异种钢焊接接头的高周疲劳性能及寿命模型

打开文本图片集

中图分类号：TG407

High cycle fatigue property and lifetime modeling of CrMoV and NiCrMoV dissimilar steel welded joint

WANG Zhipeng，ZHU Mingliang，XUAN Fuzhen （School of Mechanical and Power Engineering，East China University of Science and Technology，Shanghai，200237，China）

Abstract： CrMoVand NiCrMoV dissmilar steel welded joints were subjected to high cycle fatigue tests at room temperature and 400 C ，fracture analysis was carried out on the failed specimens to study the high cycle fatigue failure mechanism of dissimilar steel welded joints. The results show that the S-N curves showed a continuous decrease，and there is no fatigue limit plateau observed during high cycle fatigue，whileallthe failure locations were located in the weld metal region，which was definedas the structurally weak zone with lower micro-hardness；with the increase of the high fatigue lifetime，the crack initiation mode was changed from the competition betweensurfaceand interal initiation tothe dominated internal micro-defectinitiation，the internal weld porosity micro-defects were themain source of crack initiation；The fatigue limits obtained by the Murakami model were dispersive and there was no apparent law between high cycle fatigue life. By introducing the Z parameter model，it was pointedout thatthe high cycle fatigue lifetime of welded joint was determined bythe stress level， effective size and relative depth of micro-defects，and the Z parameter had a good linear relationship with the high cycle fatigue lifetime.

Key words：welded joint；high cycle fatigue；crack initiation;porosity defects ; Z parameter model

0前言

焊接是制造压力容器等设备的重要技术[1-2]。（剩余8467字）