Research on mechanical properties and microstructure of the ultra-narrow gap laser wire filler welding joint for the S355J2N steel

LI Tao; ZHU Zhongyin; XING Yanshuang; LI Junmin; ZHANG Haoru

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Research on mechanical properties and microstructure of the ultra-narrow gap laser wire filler welding joint for the S355J2N steel
Vol. 48, Issue 12, Pages: 98-103(2018)
Published：2018
DOI：
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DOI：

LI Tao, ZHU Zhongyin, XING Yanshuang, et al. Research on mechanical properties and microstructure of the ultra-narrow gap laser wire filler welding joint for the S355J2N steel[J]. Eletric Welding Machine2018, 48(12): 98-103. DOI：

摘要

以S355J2N钢为研究对象

采用窄间隙激光焊进行焊接工艺试验

研究焊接接头的拉伸强度、弯曲性能、冲击强度、显微硬度以及微观组织。结果表明:焊接接头的拉伸强度、弯曲性能、冲击性能、显微硬度均符合标准要求。母材组织为铁素体和珠光体;焊缝区组织为先共析铁素体沿柱状晶分布

无碳贝氏体沿晶界向晶内平行生长

晶内有针状铁素体、粒状贝氏体和珠光体;热影响区网状晶界明显

其组织特征为板条马氏体及白色小块区域的M-A组织。观察多层焊层的层间区微观组织形貌发现

白色铁素体沿原奥氏体晶界析出

晶内为针状铁素体+粒状贝氏体+珠光体。由此可见

超窄间隙激光填丝焊技术焊接S355J2N材料具有较好的工程应用价值。

Abstract

Taking S355 J2 N steel as the research object

the ultra-narrow gap laser welding is used for welding technology test to study the tensile strength

bending property

impact strength

microhardness and microstructure of welded joints. The results show that the all these properties of welded joints meet standard requirements. The microstructure of the base metal is composed of ferrite and pearlite. The microstructure of the weld zone is composed of first eutectoid ferrite which distributes along columnar crystals

the carbon-free bainite grows into the crystal parallel to the boundary and the acicular ferrite

granular bainite and pearlite distribute in the crystal. The reticular crystal boundary of the HAZ is obvious and its microstructure is lath martensite and M-A microstructure.The microstructure of the interlayer of multilayer are observed to find that white ferrite is precipitated along the grain boundary of primary austenite and the acicular ferrite

granular bainite and pearlite distribute in the crystal. So the ultra-narrow gap wire filler welding has good application value for the S355 J2 N steel welding.