熔敷金属膨胀系数对YG20硬质合金与45^(#)钢激光焊的影响  

Deposited Metals’ Expansion Coefficient on Laser Welding of YG20 Cemented Carbide and Steel 45^(#)

作　　者：张一鸣 陈春焕[1] 赵秀娟[1] Zhang Yiming;Chen Chunhuan;Zhao Xiujuan(School of Material Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《稀有金属》2023年第2期245-251,共7页Chinese Journal of Rare Metals

基　　金：辽宁省自然科学基金项目(2014028023)资助。

摘　　要：选取ENi102焊条,Z408焊条和Fe55NiC焊丝,以电弧焊的方式在45^(#)钢表面堆焊过渡层,再与YG20进行激光焊接,对激光焊接头进行了扫描电镜(SEM)观察、硬度测试,弯曲力学性能试验,并对母材和过渡层材料进行了膨胀系数测试,研究了过渡层材料熔敷金属膨胀系数对硬质合金与钢激光焊的影响。研究结果表明:YG20硬质合金与45^(#)钢无过渡层直接激光焊时,在焊缝与硬质合金界面位置生成了有害脆性η相和鱼骨状共晶碳化物,且硬质合金侧形成宽15μm左右的WC疏松区,导致接头性能较弱;45^(#)钢表面堆焊铁镍合金和纯镍都可以抑制界面脆性η相的生成,碳化物呈点状弥散分布,界面碳化物的量与焊缝Ni元素浓度有关,Ni元素浓度越高,形成的点状碳化物越少;过渡层金属的膨胀系数是影响接头力学性能的主要因素,改变过渡层中的Ni含量可以调整膨胀系数的大小,当过渡层的膨胀系数介于45^(#)钢与硬质金之间,并且接近硬质合金时,缓解应力作用最强,对接头力学性能提高最有利。In practical applications,cemented carbide often needs to be joined with steel,however,their fusion welding faces great challenges.The most important problems lie in the harmful phases formed along with the bonding interface because of metallurgical reaction during the welding process and the cracking induced by high residual stress under mismatch of linear expansion coefficient.In recent years,the laser welding technique has been widely used in the manufacturing field with the development of high-tech industries due to its high energy density and precise position control.The laser joining between cemented carbide and steel has received extensive attention.In order to avoid above problems,pre-setting interlayers between the two dissimilar metals is one of the feasible options.Thus,the influence mechanism of the interlayers on the welding process and the properties of the joint is worthy of study.In this paper,the transition layers were pre-overlayed on the surface of steel 45^(#)using Ni102 (ENi102) electrode,Z408 (ENiFe-C1) electrode and Fe55NiC wire respectively,and then laser welded with YG20 (WC-20Co) cemented carbide.Through scanning electron microscopy (SEM),X-ray energy dispersive spectrum (EDS) analysis,hardness test,bending test and expansion coefficient examination,the influence of the transition layer on the laser welding of cemented carbide and steel was systematically studied.The optimal parameters of the laser welding process were obtained as well.The results showed that a higher heat input than that with transition layer was required when YG20 cemented carbide was directly laser welded with steel 45^(#)to ensur the through-welding and the defect-free welding surface of the joint.The welding process was more sensitive to the laser beam offset in the situation of without-than with-transition layer,and deviating laser beam to steel by 0.25 mm could achieve a good bonding surface while welded without transition layer.Harmful brittle phases formed near the weld metal/cemented carbide interface and narro

关 键 词：过渡层 硬质合金 激光焊 弯曲强度 

分 类 号：TG406[金属学及工艺—焊接]