挤压铸造ZA27合金大高径比铸件

ZA27 Alloy Castings with High Height-diameters Ratio in Squeezing Casting

通常挤压铸造仅适用于高径比小于3.5的铸件,研究大高径比铸件的挤压铸造将扩大这种先进铸造技术的应用范围。用试验和计算机模拟的方法,研究了高径比为7的ZA27合金铸件的力学性能、凝固过程中铸件内的温度、压力以及缩松的分布。结果表明,增加挤压铸造的压力不能有效地减少大高径比铸件的缩松缺陷;合理控制浇注温度和铸型预热温度能有效地消除大高径比铸件内的缩松,获得力学性能高且均匀的铸件。

Generally,the squeezing casting is only employed for the castings whose height-diameter ratio is less than 3.5.Researching the castings with high height-diameter ratio in squeezing casting can extend the applicable scopes of the advanced casting technology.The mechanical properties of the ZA27 alloy with the high height-diameter ratio of 7 and distribution of temperature,pressure and shrinkage porosity during solidification process were investigated by experiment and numerical simulation.It is revealed that the shrinkage porosity in the castings with high height-diameter ratio can be obviously reduced with the increase of the pressure.Through rationally controlling pouring temperature,preheated temperature for mould and temperature distribution of the cast mould,the shrinkage porosity in the castings can be eliminated to obtain the castings with high and even mechanical properties.