药芯焊丝Cr含量对低合金钢焊缝金属性能的影响

Influence of Cr content in flux cored wire on mechanical properties of low alloy steel weld metal

通过在金红石型药芯焊丝中加入不同含量的金属Cr,研究了Cr对低合金钢焊缝金属组织及力学性能的影响。利用金相显微镜和透射电镜对组织进行观察,结合热力学软件Thermal Calc对组织变化进行分析。结果表明：焊缝金属中每增加0.1%的Cr,抗拉强度提升约10 MPa;随元素Cr的加入,碳化物体积分数增加,部分碳化物沿晶界条链状分布,使焊缝金属冲击性能离散性增大且冲击吸收能量均值下降。随Cr含量的不断增加,组织中产生粗大的M-A组元,在提升强度的同时使冲击性能显著恶化。

The influence of Cr on the microstructure and mechanical properties of low alloy steel weld metal was studied by adding different amount of chromiumin the rutile-type flux cored wires. The microstructure of the weld metals was observed with metallurgical microscope and transmission electron microscope,and the differences were analyzed as well with thermodynamics software Thermal Calc. The results show that the strength of the weld metal increases about 10 MPa for every 0. 1% increase of Cr in the weld metal. The volume fraction of carbides increases when chromium is promoted into the weld and some of the carbides are in strips or chains distributed along the grain boundary resulting in greater cattering of the impact absorbing energy and lower average value. With the Cr content increasing,coarse M-A constituent is formed,which can strengthen the weld metal but be deteriorated to the impact toughness significantly.