高镍壳类产品皮下气孔的产生原因及解决措施

Causes and Solutions of Subsurface Blowholes in High Nickel Shell Products

高镍球铁因其优良的耐高温、耐磨损、抗腐蚀以及良好的力学性能而被广泛应用于汽车相关零部件。目前对高镍材质的性能、工艺特点等相关研究较多,但针对高镍材质壳类产品的生产过程中出现问题的研究较少,尤其是针状的皮下气孔。皮下气孔形成的原因有很多,覆膜砂的特性、型腔内铁液温度以及砂芯等均会对皮下气孔的形成有重大影响。本文结合实际开发的某款产品分析了覆膜砂特性对皮下气孔的影响机理;利用Magma模拟软件研究分析了型腔内铁液温度对皮下气孔的影响,提出了提高型腔铁液温度的措施;并根据实际生产经验总结了砂芯处理方法。

High nickel ductile iron is widely used in automobile parts because of its excellent high temperature resistance, wear resistance, corrosion resistance and good mechanical properties. At present, there are many researches on the properties and process characteristics of high nickel materials, but few researches are focused on these problems arising in the production process of shell products made of high nickel material, especially needlelike subsurface blowholes. There are many reasons for the formation of subsurface blowholes, such as the characteristics of coated sand, the temperature of molten iron in the mold cavity and sand core, etc. In this study, the influence mechanism of the characteristics of coated sand on the subsurface blowhole was analyzed based on a product developed in practice. The influence of molten iron temperature in the mold cavity on the subsurface blowholes was studied and analyzed by using the Magma simulation software. Then, several measures to increase the temperature of the molten iron in the mold cavity were adopted. According to the actual production experience, the sand core treatment methods are given.