碳迁移对9%Cr和2.25%Cr异种钢焊接接头高温韧性的影响

发布时间：2018-04-10 11:11

本文选题：异种钢接头 + 碳迁移　；参考：《机械工程学报》2015年16期

【摘要】：异种钢的焊接连接在发电设备中制造中扮演着重要角色,其中碳迁移是影响异种钢焊接接头服役性能的一个重要因素。研究9%Cr+2.25%Cr异种钢焊接接头的碳迁移现象及其对接头高温韧性的影响,发现该接头在9%Cr母材侧热影响区(Heat affected zone,HAZ)中形成富碳区,在紧邻的2.25%Cr焊缝一侧形成贫碳区,富碳区和贫碳区存在较大的硬度差异。在对接头HAZ的高温(500℃)准静态断裂韧度测试中,发现位于焊缝的贫碳区裂纹容易扩展。富碳区断口形貌以准解理为主,贫碳区断口形貌以浅韧窝为主。有限元计算结果表明,在贫碳区中有塑性应变集中现象,导致其损伤加剧,成为裂纹扩展过程中的较弱环节。结合断口形貌以及有限元计算结果,对控制该接头断裂过程的机理进行分析,认为弹性能与塑性能储备能力的不同是导致断口形貌差异的主要原因。
[Abstract]:The welding connection of dissimilar steel plays an important role in the manufacture of power generation equipment, in which carbon transfer is an important factor affecting the service performance of dissimilar steel welded joint.The carbon transfer phenomenon of 9%Cr 2.25%Cr dissimilar steel welded joint and its effect on the high temperature toughness of the joint were studied. It was found that the joints formed a carbon-rich zone in the heat affected zonehal zone of the 9%Cr base metal side and a carbon-poor zone on the adjacent side of the 2.25%Cr weld.There is a great difference in hardness between carbon rich region and low carbon area.In the quasi static fracture toughness test of HAZ at high temperature, it is found that the crack in the carbon-poor zone is easy to propagate.The fracture morphology of carbon-rich zone is mainly quasi-cleavage, and that of carbon-poor zone is shallow dimple.The finite element calculation results show that there is a plastic strain concentration phenomenon in the carbon-poor region, which leads to the increase of damage and becomes a weak link in the process of crack growth.According to the fracture morphology and the finite element calculation results, the mechanism of controlling the fracture process of the joint is analyzed. It is considered that the difference of elastic energy and plastic property reserve ability is the main reason for the difference of fracture morphology.
【作者单位】：清华大学机械工程系;
【分类号】：TG457.11

【共引文献】