回火工艺对9Ni钢焊接接头显微组织的影响

Effect of Tempering Process on Microstructures of 9NI Steel Welded Joints

采用Ni基焊条对9Ni钢进行手工电弧焊,焊后对焊接接头分别进行不同回火温度和回火时间处理,对不同回火条件下母材、热影响区的组织和硬度进行了分析比较。结果表明:9Ni钢焊接接头回火处理后,其主要组织为铁素体、回火马氏体和回转奥氏体,随着回火温度的升高和回火时间的增加,粗晶区组织由粗大板条马氏体转变为细小的板条马氏体;热影响区硬度随着回火温度和回火时间的增加而降低;粗晶区在580℃回火时马氏体板条边界明显析出回转奥氏体,随着回火时间的延长回转奥氏体的量增加,当回火时间大于4 h以后,回转奥氏体的量变化不大。

The manual arc welding on 9Ni Steel by using Ni-based electrodes was carried out, and different tempering temperature ＆ tempering time treatments after welding on welded joint were also carried out. The organization and hardness of the base metal and heat affect zone were compared and analysed under different tempering conditions.The results show that after tempering, the main organization of the 9Ni steel welded joint is ferrite, tempered martensite and rotary austenitic. With the increasing of tempering temperature and time, The thick lath martensite turns to fine shape of the coarse-grained texture;With the increasing of tempering temperature and time, the hardness of heat affect zone reduces. When tempering temperature is 580℃,there is rotary austenitic separated out from martensite laths boundary. The increasing of tempering time makes the amount of rotary austenitic increase.When the tempering time is more than 4 hours, the amounts of rotary austenitic remain unchanged.