高强度细晶粒碳素钢焊接接头熔合区附近的显微组织及精细结构

Microstructure and Fine Structure in Fusion Zone of Welded Joint for High Strength Fine Grain Steel

研究了高强度细晶粒碳素钢焊接接头熔合区附近的显微组织及精细结构。结果表明,在熔化极混合气体保护焊接条件下,该钢材的熔合区宽度为20～40μm。随着焊接线能量的减小,熔合区的整体硬度提高。熔合区焊缝侧针状铁素体的形态与焊接线能量有关。氧化物夹杂大多位于针状铁素体边界。在熔合区母材侧,下贝氏体中的碳化物呈多种形态,并受焊接规范的影响。

The microstructure and fine structure of weld fusion zone for high strength fine grain steel were studied. The results indicate that the width of the fusion zone is only 20-40 μm under PCMAG welding with different welding parameters. The microhardness is increased with the decreasing of heat input. The acicular ferrite morphology at the weld side is affected by welding parameter, and the inclusions are located at the boundaries of ferrite. There are different morphologies of carbide in low bainite, and the distribution of carbide is affected by welding parameter.