一、前言 近年来随着内燃机强化指标的提高,对排气门密封锥面的耐磨、耐蚀性提出了更高的要求,气门专用钢难以兼顾热强性和耐磨蚀的工作条件。因此在锥面堆焊合金成为提高排气门寿命的有效手段。目前国内除火焰喷焊及等离子喷焊以外,还有真空熔烧和真空感应堆焊。真空熔烧采用合金粉末作为填充材科,在真空条件下利用钼丝进行局部辐 I. Introduction In recent years, with the improvement of the intensified index of internal combustion engines, the wear resistance and corrosion resistance of the exhaust valve sealing conicals have put forward higher requirements. The valve special steel can hardly meet the requirements of the heat-resistant and abrasion-resistant working conditions. Therefore, surfacing alloy cone to become an effective means to improve exhaust valve life. In addition to domestic flame spray and plasma spray welding, there are vacuum melting and vacuum induction surfacing. Vacuum melting alloy powder as a filler material, the use of molybdenum wire in vacuum under the conditions of local radiation