气门座圈粉末锻造工艺的数值模拟与实验

Numerical Simulation and Experiment on Powder Forging Process of Valve Retainer

目的研究气门座圈的粉末锻造工艺,提高产品的致密度。方法通过建立气门座圈粉末锻造数值模型,分析锻造过程中相对密度的变化过程,研究预制毛坯初始相对密度、锻造加热温度和成形速度对致密化的影响。在此基础上进行粉末锻造实验,并与模拟结果比较。结果随着预制毛坯初始致密度、加热温度的增加以及成形速度的降低,粉末锻造致密度化所需的成形力降低;预制坯初始密度对锻件密度均匀性影响最为显著。经过粉末锻造后的气门座圈,密度从6.6 g/cm^3提高到7.46 g/cm^3,致密度达到96.4%。结论相比传统压制-烧结工艺,粉末锻造可以大幅度提高气门座圈的致密度。

The paper aims to study the powder forging process of valve retainer to improve the density of product. The relative density of powder sintered blanks, the effects of forging heating temperature and forming speed on the densification were studied by establishing a numerical model for forging the valve retainer and analyzing the changing process of relative density in the forging process. On this basis, the powder forging experiment was carried out and compared with the simulation results. The forming force required for the density of the forging of the powder reduced with the decrease of initial density of the preform blank, the increase of forging heating temperature and the decrease of the forging speed. The initial density of powder sintered blanks had the most significant effect on the density uniformity of forgings. The density of valve retainer after powder forging increased from 6.6 g/cm3 to 7.46 g/cm3, and its relative density reached 96.4%. Compared with the traditional P/M process, powder forging can improve the density of valve retainer greatly.