Precision castingThe company's metal materials mainly come from purchased materials, the company's waste castings, and pouring risers. The purchased metal materials are often in bulk, rarely pressed into a cylindrical shape, and materials of different materials are easy to mix together, such as 316 materials mixed with 304 or 430 materials. Therefore, precision casting companies should choose to purchase materials that are pressed into a cylindrical shape as much as possible. The chemical composition of each batch of purchased materials is analyzed with a spectrum analyzer. If possible, the supplier should conduct on-site inspections to evaluate whether the materials are labeled, protected, and stored in isolation.

The scrap steel (waste castings, pouring risers) of the enterprise shall be treated with rust removal, degreasing, sand removal and cleaning and drying, and the S and P components shall be controlled. In addition, scrap steel of different materials must be marked, protected, and stored separately, and cannot be confused.

Due to the different purposes of precision castings, there are many heat treatments, which can basically be divided into two categories. The first is that the structure of the heat treatment will not change or should not change, and the second is that the basic structure changes. The first heat treatment procedure is mainly used to eliminate internal stress, which is caused by different cooling conditions and conditions during the stainless steel 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 stainless steel casting.

3. Quenching treatment: 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.