When designing, in addition to determining the geometry […]
When designing, in addition to determining the geometry and size of the casting according to working conditions and metal material properties, the rationality of the design must be considered from the perspective of casting alloy and casting process characteristics, namely obvious dimensional effect and solidification and shrinkage. Problems such as stress, to avoid or reduce the occurrence of defects such as segregation, deformation, cracking of the casting.
The heat treatment of copper castings generally includes quenching, annealing, normalizing, as-casting and quenching, artificial aging (see aging treatment), stress relief, softening and graphitization. For example, high manganese steel castings require high wear resistance and sufficient toughness, and the internal structure should be austenite. To this end, the casting needs to be quenched, that is, after the casting is heated to the austenite region to be completely austenitized, it is rapidly quenched and quenched, so that the austenite can not be changed and maintained. This process is also called water toughness treatment or solution treatment.
In general, the coloring of copper art castings consists of three stages: pretreatment, coloring and post-processing. Pretreatment is to achieve a smooth, smooth surface of the crafts by polishing, degreasing, pickling, etc., which is beneficial to the coloring reaction. The coloring treatment should control the concentration of the coloring liquid, as well as the processing conditions such as the temperature of the coloring, time, etc., to facilitate obtaining a uniform colored film.
Therefore, the industry still uses a lot of tin-free Wuxi bronze, they are not only cheap, but also have the special properties required. Electronic springs, switches, electrical connectors, lead frames, vibrating plates and terminals are mainly used as wear parts and elastic components. Pure copper plus nickel can significantly improve strength, corrosion resistance, electrical resistance and pyroelectricity. Industrial white copper is divided into two types: white copper for structure and white copper for electrician according to its performance characteristics and uses. It satisfies various corrosion resistance and special electrical and thermal properties.