Mainly including the appearance quality, the inherent quality and use quality. Appearance quality of casting surface roughness, surface defect, dimensions, shape, weight deviation deviation deviation; internal quality mainly refers to the chemical composition of casting, physical properties, mechanical properties, microstructure and exists in the casting holes, cracks, inclusions, segregation condition; the use of quality of castings in different working conditions endurance, including wear resistance, corrosion resistance, cold shock thermal shock, fatigue, shock absorption properties and machinability, welding process performance.
Casting of mechanical properties of product quality has a great influence on. For example, machine tool castings wear resistance and dimensional stability, directly affect the accuracy of machine tool to maintain life; all kinds of pump impeller, shell and a hydraulic cavity size, contour accuracy and surface roughness, directly affect the pump and the hydraulic system working efficiency, energy consumption and cavitation development; an engine block, cylinder head, cylinder liner, piston ring, the exhaust pipe casting strength and resistance to cold shock thermal shock resistance, directly influence the working life of the engine.
Influence of casting quality of many factors, the first is the design of cast process. Design, in addition to according to the working conditions and material properties to determine the geometry of castings, size, also must from casting alloy and casting characteristics point of view to consider the rationality of the design, the apparent size effect and solidification, shrinkage, stress and other issues, in order to avoid or reduce the casting composition segregation, deformation, cracks and other defects. Second must have the reasonable casting process. According to the casting structure, weight and size, casting alloy properties and production conditions, select the appropriate type and modeling, core making method, setting reasonable casting bars, cold iron, riser and gating system. In order to guarantee the quality of castings. Third is the raw materials for casting quality. Metal materials, refractory materials, fuel, flux, modifier and foundry sand, sand binder, coating materials such as quality standard, make casting blowholes, pinholes, slag, sand casting defects, influence the appearance quality and interior quality, serious when can make the casting scrap. Fourth is the process operation, it is necessary to formulate a reasonable craft operating rules, improve the technical level of workers, so that the process to obtain the correct implementation.
Casting production, to casting quality control and inspection. First of all to develop from raw materials, auxiliary materials to each specific product control and inspection technical codes and technical conditions. For each procedure are strictly according to technical codes and technical condition control and inspection. At the end of the finished casting for quality inspection. Be equipped with sound detection method and appropriate testing personnel. On the quality of castings, available comparison specimens to determine the surface roughness; surface fine cracks available coloring method, magnetic particle inspection. On the internal quality of castings, available audio, ultrasonic, eddy current, X rays, and gamma rays and other methods to examine and judge.
