Casting is a relatively economical method of forming blanks, and it can show its economy more for parts with complex shapes. Such as the cylinder block and cylinder head of automobile engine, ship propeller and exquisite artwork. Some parts that are difficult to cut, such as nickel-based alloy parts of gas turbines, cannot be formed without casting.
For foundry engineers and mechanical structure design engineers, heat treatment is a very meaningful and valuable method to improve the quality of materials. Heat treatment can change or affect the structure and properties of cast iron, while achieving higher Strength, hardness, and improve its abrasion resistance and so on.
Due to different purposes, there are many types of heat treatment, which can be basically divided into two categories. The first type is the structure that does not change through heat treatment or should not change, and the second is the basic structure that changes. . The first heat treatment procedure is mainly used to eliminate internal stress, which is caused by different cooling conditions and conditions during the casting process. The structure, strength and other mechanical properties will not change significantly due to heat treatment.
For the second type of heat treatment, al Qaeda has undergone significant changes, which can be roughly divided into five categories:
- (1) Softening annealing: Its purpose is mainly to decompose carbides, reduce their hardness, and improve processing performance. For ductile iron, its purpose is to obtain more ferrite structure.
- (2) Normalizing treatment: The main purpose is to obtain pearlite and sorbite structure to improve the mechanical properties of the casting.
- (3) Quenching: mainly to obtain higher hardness or abrasion strength, and at the same time to very high surface wear resistance.
- (4) Surface hardening treatment: mainly to obtain a hardened surface layer and at the same time obtain a very high surface wear resistance.
- (5) Precipitation hardening treatment: mainly to obtain high strength without drastic changes in elongation.
- (6) Defect treatment of surface casting: But sometimes we don’t have many defects, and it is unnecessary to invest alarge cost. We can repair it with some repairing agent, which is convenient and simple. For example, for iron materials, we can use ( Jin Sucheng) JS902 can be repaired, and it can be used later if it is used up. This can save costs for our manufacturers and allow our casting manufacturers to invest more money in improving the quality of the product itself, so that it can be used. Those who create more wealth.