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一、前言 12V300EDZ型柴油机排气阀所用的材料是4Cr14Ni14W2Mo高合金奥氏体耐热钢(成份见表1),其锻造区域窄(1130～900℃),热处理抗力大,热塑性较差,在锻造过程中易开裂。而且高温性能和金相组织要求较高,锻造和切削加工都存在一定的困难。在使用中,排气阀的盘部常因高温变形而过早失效(约3000h),使用寿命达不到技术要求(约18000h)。同时,常规热处理工艺工序多,工时长,劳动强度高。
I. Introduction 12V300EDZ diesel exhaust valve material used is 4Cr14Ni14W2Mo high-alloy austenitic heat-resistant steel (ingredients see Table 1), forging narrow (1130 ~ 900 ℃), heat treatment resistance, poor thermoplasticity, forging Easy to crack in the process. And high temperature performance and high requirements of the microstructure, forging and cutting there are some difficulties. In use, the exhaust valve plate often premature failure due to high temperature deformation (about 3000h), the service life of less than technical requirements (about 18000h). At the same time, conventional heat treatment process and more long working hours, labor-intensive.