【摘要】 本文用缓进磨削、铣削、普通磨削三种不同工艺方法加工M17镍基铸造合金疲劳试件,进行对比疲劳试验,分析了表面粗糙度,冷作硬化,残余应力等疲劳寿命的影响。常温疲劳试验表明,试件表面残余压应力越大,疲劳寿命越长,冷作硬化有利于提高常温疲劳寿命,粗糙度对疲劳寿命影响不显著,缓精磨工艺加工的试件疲劳寿命最长。在高温疲劳试验中,冷作硬化层小的疲劳缓进寿命长,因此应采用缓进给精磨作为最后工序。本文是首次对M17材料在国内进行磨削表面完整性试验。更多还原

【Abstract】 M17 nickel-based cast alloy is a superalloy developed in China and used asturbojet-engine blade material. It is difficult to machine M17. The surface alte-ration layer created by CFG (Creep-Feed Grinding) of M17 has been studiedby the authors since 1985. In this paper, the authors present the results of theirresearch on the effect of method of machining on fatigue strength of M17, forboth room temperature and high temperature. The authors carricd out cantilever-beam fatigue tests of M17 cast alloyspecimens with surface layer created by CFG and conventional grinding respe-ctively. At room temperature, fatigue life is longer with higher compressive residualstress as is to be expected. The influence of surface roughness on fatigue stre-ngth is not significant. The fatigue life of specimen with surface layer createdby CFG is the longest. In order to ensure that the fatigue strength of M17 blade tenons is adequateat high temperature, there exists an urgent need to specify technical require-ments on its machining. Of course, this paper is intended to meet only a verysmall part of such a need. In the authors’ tests at 900℃, longer fatigue life of M17 specimen is obtai-ned when the altered layer contains least strain hardening. In order to reducethe amount of strain hardening, the authors’ research results indicate that thespecimen should be machined in two steps, first by rough CFG and then byfinish CFG, so that the strain hardening layer is less than 15μm and the de-gree of strain hardening is less than 5%.更多还原