【Summary】In the processing of wear resistance castings, the extrusion process is currently the casting process with highest efficiency. The die casting machine is divided into hot chamber die casting machine and cold chamber die casting machine.
Using the hot chamber die casting machine to process wear resistance castings, its degree of automation is higher, the material loss is less, and the production efficiency is higher than the cold chamber die casting machine. However, in this regard, it will be restrict to the heat resistance of the machine. At present, it can only be used in the production of low melting point materials such as zinc alloy or magnesium alloy.
Today, the widely used wear resistance castings, because of the high melting point, can only be produced in the cold chamber die casting machine. The main characteristic of die casting is that the metal liquid is filling cavity under high pressure or high speed, and forming and solidifying under high pressure.
However, for the wear resistance castings of die casting, the defects are that the metal liquid is in the process of high pressure or high speed filling cavity, and the air clips in the cavity will inevitably be wrapped inside the casting. In this way, the hypodermal pores will be formed. Therefore, the die casting is not suitable for heat treatment.
When the internal porosity of the wear resistance casting is heated above, pay attention to the deformation of wear resistance casting caused by deformation or bubbling. In addition, the mechanical cutting finish allowance of the wear resistance casting is less than 0.5 mm, which will not only reduce the casting weight, but also reduce the cutting processing and the cost.