热力透平2024，Vol.53Issue(4)：276-283,8.DOI:10.13707/j.cnki.31-1922/th.2024.04.011
异质接头宏观偏析及其对持久性能的影响
Macro-Segregation Structure in Dissimilar Metal Welds and Its Impact on Creep Resistance
摘要
Abstract
For dissimilar metal welded joint between 617B nickel-based alloy and 10%Cr martensitic heat-resistant steel filled with 617 nickel-based filler metal,analysis was carried on its high-temperature creep resistance,failure mechanism and interfacial microstructure evolution behavior.The high-temperature creep tests were conducted at 600℃with stress levels of 100,120 and 140 MPa.The test results showed that fractures mainly occurred at the interface between the nickel-based weld metal and the 10%Cr martensitic heat-resistant steel,and the proportion of fractures at the interface increased as the stress level decreased.Further research found that fractures at the interface were primarily related to the macro-segregation zone near the interface.The microstructure within the macro-segregation zone was mainly high-Ni martensite,which would undergo local austenization under high-temperature creep conditions,leading to a multi-directional tensile stress state at the interface between the macro-segregation zone and the 10%Cr martensitic heat-resistant steel.Thus,creep voids and fractures at this interface were formed.Additionally,exploration was carried out for the solid-state phase transformation process of the macro-segregation zone during the welding cooling process,and a model of sequential formation of austenite was proposed,by which the phenomenon could be explained that the crystal orientation of the columnar grain at the root could"transmit"through the macro-segregation zone to the columnar grain on the other side.The research findings can provide a reference for welding and creep performance evaluation of iron-nickel-based dissimilar metal welds.关键词
异种金属焊接接头/高温持久/界面失效/宏观偏析/高镍马氏体Key words
dissimilar metal welded joint/high temperature creep/interface failure/macro-segregation/high-Ni martensite分类
矿业与冶金引用本文复制引用
范曼杰,李松林,李克俭..异质接头宏观偏析及其对持久性能的影响[J].热力透平,2024,53(4):276-283,8.基金项目
上海市科学技术委员会科技创新行动计划项目(20dzl205101) （20dzl205101）
