铸造C12A耐热钢焊接接头的金相组织分析

对铸造C12A高强耐热钢焊接接头的金相组织变化及硬度特点等方面进行了研究分析．试验结果表明：铸造C12A高强耐热钢经过焊接，基体组织没有明显发生变化，过热区的金相组织为板条马氏体 奥氏体组织，其硬度有所降低；熔化区的金相组织为针状马氏体 奥氏体 板条马氏体，硬度很高；焊后经过回火处理的基体金相组织与性能没有变化，过热区的金相组织为保留板条马氏体形态的回火索氏体组织，较基体组织要粗大，其硬度要比基体有所下降；熔化区的金相组织转变为保留板条马氏体的回火索氏体，但组织较为基体组织要细小，表现为硬度要比基体的有所升高．铸造C12A焊接后再经回火处理，可使焊接后的组织差别消除；性能变化趋于平缓，有利于材料的使用．

The Analysis of Welding Microstructure of Cast C12A Heat Resistant Steel

The analysis of microstructure and hardness cast C12A was carried out. The results show that its matrix has no significant changed after being welded. The microstructure of heat affected zone is composed of blocky martensite and austesite. The hardness of welding zone is slightly decreased. The meting zone is composed of needle martensite and blocky martensite plus austesite. Its hardness is very high. Both microstructure and hardness of welded change little after temper treatment. The microstructure of heat affected zone after tempering is sorbite maintained blocky martensite and is bigger than that of matrix. , and its hardness is decreased slightly. The microstructure of melt zone changes to the tempered sorbite maintained blocky martensite with fine matrix microstructure, and its hardness is slightly increased compared with that of the matrix. After tempering of welded cast C12A, the difference of welded microstructure is vanished and its properties are tended to the same, resulting in increase in application.