The first is the design process of castings. When designing, in addition to determining the geometry and size of the casting according to the working conditions and the properties of the metal material, the rationality of the design must also be considered from the perspective of the casting alloy and casting process characteristics, that is, the obvious size effect and solidification and shrinkage. , Stress and other issues to avoid or reduce the occurrence of defects such as segregation, deformation, and cracking of castings.
Second, there must be a reasonable casting process. That is, according to the casting structure, weight and size, casting alloy characteristics and production conditions, select the appropriate parting surface and shape, core making method, and reasonably set the casting rib, cold iron, riser and gating system. To ensure high-quality castings.
The third is the quality of raw materials for casting. The quality of metal furnace charge, refractory materials, fuel, flux, modifier, foundry sand, sand binder, coating and other materials is substandard, which will cause the castings to produce pores, pinholes, slag inclusions, sand sticking and other defects, which affect the appearance quality of the castings And internal quality, if serious, the casting will be scrapped. The fourth is process operation. It is necessary to formulate reasonable process operation procedures to improve the technical level of workers so that the process regulations can be implemented correctly.
In casting production, the quality of castings must be controlled and inspected. First of all, we must formulate process rules and technical conditions from raw materials and auxiliary materials to the control and inspection of each specific product. Each process is strictly controlled and inspected in accordance with the process rules and technical conditions. Finally, the quality of the finished castings is inspected. To be equipped with reasonable testing methods and appropriate testing personnel. Generally, for the appearance quality of castings, comparison samples can be used to judge the surface roughness of castings; fine cracks on the surface can be inspected by coloring method and magnetic powder method. The internal quality of castings can be inspected and judged by audio frequency, ultrasound, eddy current, X-ray and γ-ray methods.