多道次环焊焊缝组织变化规律与冲击韧性的关系研究  

Research on Relation between the Change Rule of Multiple Passes Circumferential Weld Microstructure and Impact Toughness

作　　者：李学达[1] 范玉然[2] 陈亮[1] 尚成嘉[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]中国石油天然气管道科学研究院,廊坊065001

出　　处：《焊管》2015年第1期11-16,共6页Welded Pipe and Tube

基　　金：新一代高钢级含铌管线钢及钢管的焊接性和应用技术联合项目(2011-D056-1)

摘　　要：采用力学性能试验、断口及其金相组织的原位分析等方法,研究了环焊缝韧性下降的原因。结果表明,在多道次环焊焊接过程中,焊缝组织由于受到后一道次热输入的影响,其组织会产生连续变化。多道焊焊缝中的组织按二次热循环的温度从高到低按柱状晶组织、粗晶区组织、细晶区组织、粗晶区与M/A混合组织、亚临界粗晶区组织的顺序呈规律性重复变化。其中粗晶区与回转奥氏体冷却形成的晶界链状M/A组元是焊缝韧性下降的主要原因。In this article, it studied the reason caused the circumferential weld toughness decrease, through analyzing mechanical properties, fracture and metallographic structure etc. The results showed during multiple passes welding process,the weld structure generates continuous variations due to heat inputting from the later pass welding. The structure sequence of multiple passes weld is regularly repeated change according to the temperature of the secondary thermal cycle from high to low, the columnar crystal, coarse crystal area organizations, fine grain zone, combination structure of coarse grain zone and M/A hybrid organization, subcritical coarse grain zone. The grain boundary chain M/A component caused by coarse grain area and rotary austenite cooling is the main reason for weld toughness decrease.

关 键 词：焊接 环焊缝金属 临界再热粗晶区 链状M/A 冲击韧性 

分 类 号：TG407[金属学及工艺—焊接]