G50超高强度钢机器人MIG焊接试验分析

The testing and analysis of G50 high strength steel welding with robotic MIG welding

为使G50焊接后的力学性能满足设计要求,通过机器人自动MIG焊对G50进行焊接试验,并对焊缝区域的硬度、力学性能和金相组织进行了测试和分析。结果表明,焊接工艺参数对焊缝内部质量和焊缝区域的金相组织影响较大,当焊接热输入量较高时,HAZ区域晶粒粗大,拉伸断裂位置出现在该区域;当焊接热输入量较低时,则容易产生未熔合等缺陷,影响焊缝强度。焊后通过淬火、回火处理可以一定程度上减少残余奥氏体的含量,使之转变为回火马氏体,提高焊缝的综合力学性能。

The research of G50 steel weld is investigated in detail by means of the automatic robotic MIG welding.It is the emphasis that how post-heat treatment affects the weld properties of G50 steel,and the hardness,mechanical properties and microstructure of weld are also tested and analyzed.The results show that welding parameters have significant effects on the inner quality and micro structure of G50 steel welding seam.When the heat input of weld is high,the crystal grain of HAZ is very large,and the tensile rupture is often located in the HAZ.When the heat input is low,some weld defects such as unfusion are prone to appear,and the tensile strength decreases sharply.The integrative mechanical properties of G50 steel welding seam are improved by the method of quenching＋ tempering after welding because the remain austenite is transformed into tempering martensite to some extent.