熔模精密铸造无切削齿轮

Precision Investment Casting Gear Without Cutting

以硅溶胶为粘结剂,进行了3Cr13齿轮的熔模精密铸造,而齿形不切削加工,铸造毛坯经高频淬火后使用。要求齿形表面无任何铸造缺陷,不得用焊补修磨方法修复齿面。在试制生产过程中曾出现了尺寸超差、凹角金属豆、表面麻坑等缺陷。通过严格控制蜡模工艺参数,控制环境温度,脱蜡前型壳低温处理,控制型壳熔烧温度和浇注温度使尺寸稳定在了公差要求范围内。采取一遍浆吹气二遍浆预润湿消除了金属豆缺陷。采用浇注后点燃木屑盖铁皮桶,使铸件在还原气氛中凝固,解决了铸件表面麻坑缺陷。

Taking silica sol as a binder, precision investment casting of 3Crl 3 gear was carried out, and the tooth shape was not cut, casting blank was used after the high frequency quenching. Requirements of tooth surface were without any defect, and the tooth surface was repaired by not using the welding grinding method. In the trial production process there were the size out-of-tolerances, beans of concave angle, concave pitting defects on the surface. Through the strict control of the investment casting process parameters, the control of the environment temperature, the low temperature treatment of shell befler dewaxing, controlling shell melting and pouring temperature, the sizes were steadied in the tolerance range. The defects of beans were eliminated by blowing in one time slurry and pre-wetting in two time slurry. Becouse of casting solidification in a reducing atmosphere, the pit defects on the casting surface were eliminated by lighting wood and then covering tin bucket after pouring.