钼粉末合金与模具钢摩擦焊接组织特征分析

On Exploring Better Friction Welding Joint of TZM Mo-Base Powder Alloy and H11 Mold Steel

采用微观组织分析、硬度测试以及电子探针线分析等方法 ,对复合热顶头材料 TZM钼基粉末合金与 H1 1模具钢的摩擦焊接性进行了研究 ,探讨了焊接规范对接头组织、硬度以及扩散层厚度的影响。结果表明 ,这两种材料在摩擦焊接过程中存在着摩擦面向 H1 1模具钢侧转移的现象 ,这主要与两摩擦副在耐磨性和高温强度方面的差异有关 ;且摩擦焊接过程中的热力耦合作用有利于近缝区晶粒细化 ,以及 TZM粉末合金中孔隙的闭合 ;此外 ,采用强焊接规范可获得良好、无缺陷的摩擦焊接头。

Good and durable hot top is very important for quick production of high quality seamless steel tubes. In order to improve the quality and to develop new kind of hot top in China, we explore experimentally the characteristics of friction welding joint of TZM Mo-base powder alloy and H11 mold steel. Table 2 lists the friction welding parameters of TZM Mo-base powder alloy and H11 mold steel used in our experiments. We performed microstructure analysis of the joints tested (subsection 2.2), determined distributions of chemical elements in friction welding joints with electronic probe (subsection 2.3), and determined hardness distributions of joints as given in Fig.5. As expected, the difference of wear resistances and that of thermal strengths of the two materials cause the initial friction surface, which joins TZM Mo-base powder alloy with H11 steel, to shift to the final friction surface well within the interior of H11 steel (Fig.2). Also, as expected, the coupled thermo-mechanical action favors grain refinement and the closure of holes in Mo-Base TZM alloy at and near the weld. We emphasize that using hard friction welding parameters is conducive to obtaining high-quality friction welding joint.