柴油机排气门摩擦焊试验及校直工艺改进

Friction Welding Test and Improvement of Straightening Technology on Exhaust Valve of Diesel Engine

对某型柴油机排气门异种钢摩擦焊工艺进行试验,对焊接接头进行了硬度测试、金相组织观察及拉伸试验,对排气门的校直工艺进行了分析和改进。结果表明:摩擦焊后焊缝、热影响区及基体硬度不一致,焊缝组织为马氏体,经时效处理后硬度基本相同,焊缝组织转变为回火索氏体;摩擦焊接接头的力学性能满足气门的工艺要求;采用先校直后时效的冷校直工艺可行。

The dissimilar steel friction weldings on the exhaust valve of a certain type of diesel engine were studied. The hardness ,microstrueture and tensile strength of the welded joints were studied. The straightening technology of exhaust valve were improved. The results show that the microhardness of the welded joint, heat affected zone and matrix is inconsistent. The microstructure of the welded joint is martensite after friction welding. The microhardness becomes same and the microstmcture of the welded joint turns into tempered sorbite after ageing .The mechanical property of the welded joint can meet the technological requirement of exhaust valve. The straightening technology of ageing after straightening is feasible.