顿亚鹏 杨伟 刘建永 盛晓菲

摘  要：通过惯性摩擦焊机对30CrMnSi/37CrMnMo进行摩擦焊接，通过金相显微镜（OM）和扫描电子显微镜（SEM）对焊接接头进行组织观察，利用能谱仪（EDS）检测了焊接界面的元素扩散，通过硬度计测定了焊接界面两侧的硬度变化。实验结果表明，焊接界面紧密结合呈现凹凸状“咬合”，完全塑性变形区发生了元素扩散实现了良好的冶金结合，Si和Mo发生短程扩散，其余元素在界面处均匀化;焊接接头感应热处理后塑变区组织转变成回火索氏体和少量贝氏体。部分塑性变形区内的组织为回火索氏体夹杂小块状的铁素体，30CrMnSi管体侧Zud末端的硬度最低，随着与焊缝距离的减小硬度值有上升的趋势，在焊缝处可达29.4HRC。

关键词：惯性摩擦焊;扩散;回火索氏体;硬度

中图分类号：TG453.9         文献标志码：A         文章编号：2095-2945（2019）26-0033-04

Abstract： The friction welding of 30CrMnSi/37CrMnMo was carried out by inertial friction welding machine， the microstructure of welded joint was observed by optical microscope （OM） and scanning electron microscope （SEM）， and the element diffusion of welding interface was detected by energy dispersive spectrometer （EDS）. The hardness changes on both sides of the welding interface were measured by hardness tester. The experimental results show that the tight bonding of the welding interface shows a concave and convex "occlusal"， the element diffusion occurs in the complete plastic deformation zone to realize a good metallurgical bonding， the short range diffusion occurs in Si and Mo， and the other elements are homogenized at the interface. After induction heat treatment of welded joints， the microstructure of plastic zone is transformed into tempered sorbite and a small amount of bainite. The microstructure in part of the plastic deformation zone is tempered sorbite inclusion small block ferrite， and the hardness of the Zud end of the 30CrMnSi tube is the lowest， which tends to increase with the decrease of the distance from the weld， and can reach 29.4HRC at the weld seam.

Keywords： inertial friction welding; diffusion; tempered sorbite; hardness

1 實验材料及方法

实验材料为37CrMnMo钢和30CrMnSi，其成分如表1所示，经过调质处理工艺的端部加厚管体其钢级为G105，工具接头为NC50 成品接头。

应用320BX惯性摩擦焊机对管体和工具接头进行摩擦焊接，焊接工艺参数有：顶锻压力1950psi，旋转速度有745rpm。摩擦焊接后的飞边采取退火后进行切削加工，焊缝处通过XG-40型中频加热装置进行局部感应热处理。

通过OM、SEM和EDS对惯性摩擦焊接头进行显微组织形貌观察、金属流线观察、焊接接头界面合金元素分布及扩散测定，通过硬度计测定焊接接头附近硬度值，揭示焊接接头的形成过程和接头性能。

2 实验结果与分析

2.1 焊接接头的金属塑性流动特性

在摩擦焊接初始阶段，工具接头和管体环形区域摩擦产生大量热，同时摩擦扭矩急剧增大，界面处金属发生破碎、剪切行为。……