How to ensure that the material and quality are qualified when casting gray iron castings

Many casting materials will choose gray iron castings when designing, such as common mechanical parts, machine tool castings are made of gray iron castings, the reason is that the mechanical properties are good, the casting production cost is lower than other materials of castings, common gray iron casting materials are HT200, HT250, HT300 and other materials, so how to configure the material and ensure that the material meets the requirements of the grade in casting production? The detailed steps are as follows:

1. Laboratory analysis of pig iron composition of main raw materials for casting; The specific content of the five elements of pig iron is grasped in detail, so that the batching operation can be accurately carried out during casting.

2. the accurate grasp of the melting temperature of different materials, the standard temperature must be reached when the furnace is released, and only when the sufficient temperature is reached can the metal elements be evenly dissolved in the molten iron.

3. Even if the ingredients are made in strict accordance with the specific content during smelting, the specific content data should be tested before the furnace is tested using the pre-furnace analyzer.

4. The addition of inoculant should strictly control the amount of addition and inoculation time, generally after inoculation, it should be completed within 3-7 minutes, because the inoculation effect in this time period is a more reasonable time. It can improve the stability of the microstructure of gray iron castings, keep the mechanical properties in excellent condition, and avoid the appearance of white mouth phenomenon and supercooled structure.

5. The gray iron castings should be insulated and placed after the casting, and the sand should not be unpacked and cleaned too early to avoid the surface of the molding castings being cooled, and the internal structure is uneven and the skin is hard, which brings difficulties to the later processing. Only when it has cooled to a suitable temperature can it be unpacked and cleaned.