Casting process of stainless steel castings

In the casting process of machine bed castings, the principle of high-temperature oven and low-temperature casting should be followed. Because raising the temperature of molten metal is beneficial to the complete melting of inclusions, slag floating, easy to remove slag and degassing, reduce the slag inclusion and porosity defects of machine tool castings; The lower casting temperature is beneficial to reduce the gas solubility of liquid metal, liquid shrinkage and the baking of high temperature liquid metal on the surface of the cavity, so as to avoid defects such as porosity, sand sticking and shrinkage cavity. Therefore, on the premise of filling the mold cavity, a lower pouring temperature should be used as far as possible. The operation of pouring liquid metal from the ladle into the mold is called pouring. Improper pouring operation will cause defects of machine tool castings such as insufficient pouring, cold insulation, porosity, shrinkage and slag inclusion, and cause personal injury.

Casting quality

Mainly include appearance quality, immanent quality and use quality. Appearance quality refers to casting surface roughness, surface defects, size deviation, shape deviation and weight deviation; The internal quality mainly refers to the chemical composition, physical properties, mechanical properties, metallographic structure and holes, cracks, inclusions and segregation in the casting. Service quality refers to the durability of castings under different conditions, including wear resistance, corrosion resistance, cold and heat resistance, fatigue, shock absorption and other properties, as well as the machinability, weldability and other technological properties.

Casting quality has a great influence on the properties of mechanical products. For example, the wear resistance and dimensional stability of machine tool castings directly affect the accuracy retention life of machine tools; The size, profile accuracy and surface roughness of impeller, shell and inner cavity of hydraulic parts of all kinds of pumps directly affect the working efficiency of pump and hydraulic system, energy consumption and the development of gas erosion, etc. The strength and heat resistance of cylinder block, cylinder head, cylinder liner, piston ring and exhaust pipe directly affect the working life of engine.