G18NiMoCr3-6铸钢焊接接头低温冲击性能不合格原因  

Reasons for unqualified low temperature impact performance of G18NiMoCr3-6 cast steel welded joints

作　　者：李明 李金红 李辉 刘月 LI Ming;LI Jinhong;LI Hui;LIU Yue(Testing Center,Jinzhou Jietong Railway Machinery Co.,Ltd.,Jinzhou 121116,China)

机构地区：[1]锦州捷通铁路机械股份有限公司检测中心,锦州121116

出　　处：《理化检验（物理分册）》2024年第3期41-44,48,共5页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：某G18NiMoCr3-6铸钢焊接接头的低温(-40℃)冲击性能不合格。采用力学性能测试、宏观观察、化学成分分析、扫描电镜及能谱分析、金相检验、回火工艺试验等方法分析了焊接接头低温冲击性能不合格的原因。结果表明:焊缝金属在560℃回火时,在原奥氏体晶界处析出了Fe3C薄壳,降低了晶界结合力,使材料产生高温回火脆性,材料的韧-脆转变温度升高,最终造成材料发生低温脆断。The low temperature(-40℃)impact performance of a G18NiMoCr3-6 cast steel welded joint was unqualified.The reasons for the unqualified low temperature impact performance of welded joints were analyzed using methods such as mechanical performance testing,macroscopic observation,chemical composition analysis,scanning electron microscopy and energy spectrum analysis,metallographic examination and tempering process test.The results show that when the weld metal was tempered at 560℃,Fe3C thin shells precipitated at the original austenite grain boundaries,reducing the grain boundary bonding force,resulting in high-temperature tempering brittleness of the material.The ductile-brittle transition temperature of the material increased,ultimately led to low temperature brittle fracture of the material.

关 键 词：G18NiMoCr3-6铸钢 焊接接头 低温冲击性能 回火脆性 

分 类 号：TB31[一般工业技术—材料科学与工程] TG115.5[金属学及工艺—物理冶金]