W6高速钢/16Mn钢电子束焊接接头组织及性能分析

Study on microstructure and properties of W6 high speed steel/16Mn electron beam welded joint

高速钢作为一种高硬度、高耐磨性和高耐热性特殊工具钢,应用于刀具、模具及特殊结构件上时,往往需要结合异种钢使用.但高速钢焊接工艺研究仍不成熟,焊接中产生的裂纹与碳化物缺陷是制约高速钢应用的主要因素.文中通过对W6Mo5Cr4V2高速钢与16Mn钢预置镍填充层后进行电子束焊接.结果表明,镍中间层的引入有效的抑制了高速钢侧热影响区的开裂,接头呈不对称"漏斗形".焊缝组织主要由镍基固溶体与少量M2C碳化物构成,焊缝中无马氏体组织,其焊缝平均硬度为185 HV;接头抗拉强度达到378 MPa,为16Mn侧母材抗拉强度的75%.拉伸断口断裂于距W6侧熔合线0.8 mm处的热影响区,为准解理断裂.

As a tool steel with high hardness, high wear resistance and high heat resistance, high speed steel often needs to be combined with dissimilar steel when applied to cutting tools, dies and special structural parts. However, the research on the welding process of high speed steel is still immature and the cracks and carbide defects in the welding are the main restrict factors of the application of high speed steel. In this paper, the electron beam welding of W6 Mo5 Cr4 V2 high speed steel and 16 Mn steel preplaced Ni intermediate layer effectively restrained the cracking of the heat affected zone of high speed steel side. The results showed that the joint was asymmetrical "funnel shape". The microstructure of the weld zone was mainly composed of nickel based solid solution and a small amount of M2 C carbide. The plastic deformation ability of the weld was increased and the hardness of the weld reduced, which was 185 HV. The tensile strength with no defect joint was 378 MPa, which was 75% of the tensile strength of the 16 Mn side. The tensile fracture occureed at the heat affected zone at 0.8 mm of the fusion line at the W6 side,and the fracture form was a quasi cleavage fracture with a certain plastic deformation.