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一、前 言 当前生产的发动机铸造叶片,一般在叶身的单面留有0.5～0.8毫米的加工余量,由于叶型的变形,甚至把加工余量加大到1.2毫米以上,这样不但增加叶型的加工工时,而且加工后的叶片常常出现粗大晶粒和柱状晶,致使叶片大量报废。日前国外已采用叶身不留加工余量的铸造叶片,保留致密的细晶层,使叶片的疲劳强度和持久性能都得到改善。
First, the foreword The current production of engine casting leaves, usually leaves a single side left 0.5 to 0.8 mm allowance, due to the deformation of the leaves, and even the machining allowance increased to 1.2 mm or more, so not only increase the leaves Type of working hours, and processing of the leaves often appear coarse grains and columnar crystals, resulting in a large number of scrapping leaves. A few days ago, foreign countries have adopted leaves without casting allowance casting leaves, retaining dense fine grain layer, the blade fatigue strength and long-lasting performance have been improved.