Weldox960低合金超强精细钢焊接热影响区韧性和组织分析

Ductility and Microstructure of HAZ of Fine Weldox960 Low-alloying High-strength Steel

选用ED-FK1000实心焊丝对Weldox960低合金超强精细钢进行混合气体保护焊,并利用光学显微镜,扫描电镜和透射电镜等对焊接热影响区的组织和冲击断裂形貌进行了详细分析。结果表明,尽管受焊接热循环的影响,焊接热影响区粗晶区出现了局部晶粒长大现象,但其回火板条马氏体中大量位错和碳化物的形成成为该区域良好韧性的根本保证;同时,在焊接过程中严格控制焊接线能量,避免形成更粗大的板条马氏体和上贝氏体,可以保证热影响区尤其是粗晶区的韧性。

ED-FK1000 solid wire was selected as filler materials for the welding of fine weldox960 low-alloying high-strength steel by mixture-gas shielded welding procedure. The microstructure and tincture face of HAZ were observed by optical microscope, SEM and TEM. The results indicate that the exist of great deal of dislocation and carbide in low-carbon matensite in HAZ improve the ductility of HAZ greatly, in spite that coarse grain was observed in local part under the effect of weld thermal cycle. So, it was one of the key factors to get excellent ductility of HAZ to control the heat input accurately and avoid the formation of coarser matensite and upper bainite.