用插销法研究焊接再热裂缝-对14MnMoNbB、BHW38、15MnVNCu三种压力容器用钢再热裂缝敏感性的评定

A STUDY OF REHEAT CRACKING WITH THE IMPLANT METHOD-ASSESSED THE REHEAT CRACKING SUSCEPTIBILITY OF 14MnMoNbB,BHW38,AND 15MnVNCu PRESSURE VESSEL STEELS

摘要: 文中提出了一种插销再热裂缝应力释放试验法,并对14MnMoNbB、BHW38、15MnVNCu三种压力容器用钢的再热裂缝敏感性进行了评定。可以采用:1.最低临界初应力;2.再热裂缝"C"形曲线上的最短断裂时间;作为两种判裂准则,来评定钢材的再热裂缝的敏感性。试验表明,14MnMoNbB 钢的过热粗晶区具有较强的再热脆化倾向,BHW38钢次之。而15MnVNCu钢具有很小的再热脆化倾向,实际上很少会出现再热裂缝。

Abstract: In this paper an implant reheat cracking test by stress relaxation was introduced and a comparison of the reheat cracking susceptibility of three pressure vessel steels, namely 14MnMoNbB,BHW38,and 15MnVNCu,was made.The study of suscep tibility was based on two rupture criterions:the minimum initial critical stress and the minimum rupture time shown on the "C"-shaped curve of reheat cracking.The test results revealed that the coarse grained overheated region of 14MnMoNbB steel was more susceptible to reheat embrittlement than that of BHW38 steel,while 15MnVNCu steel,being practically free from reheat cracking,was the one least susceptible.