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Nonferrous metal precision castings processing characteristics
- May 15, 2018 -

Non-ferrous metal precision castings have higher mechanical properties than their cast irons during use, and to a certain extent are investment castings or precision castings. The non-ferrous metal precision castings have higher melting points, the molten steel is easily oxidized, the flowability of the molten steel is poor, and the shrinkage is large. The stainless steel precision casting is applicable not only to the casting of various types and various alloys.

Nonferrous metal precision castings process characteristics

1. The non-ferrous metal precision castings will greatly exceed the cast iron's shrinkage during the operation process. In order to prevent the shrinkage and shrinkage defects of the castings during the use, the riser and the cold iron are mostly used in the casting process. And subsidies and other measures, so that you can achieve a certain degree of sequential solidification.

In order to prevent holes and cracks in non-ferrous metal precision castings, uniform wall thicknesses, sharp corners and right angle structures, sawdust in mold sands, coke in cores, hollow cores and oil sands should be used. Cores, etc. to improve the sand type or core concession and permeability.

2. During the manufacturing process of non-ferrous metal precision castings, due to the poor fluidity of the molten steel, the wall thickness of the steel castings shall not be less than 8mm in order to prevent the steel castings from producing cold separation and insufficient pouring. The dry casting or heat is used. Casting, appropriately increase the pouring temperature, generally 1520 ° ~ 1600 °C, because the pouring temperature is high, the superheat of the molten steel, to maintain a long liquid state, fluidity can be improved.

Nonferrous metal precision castings, but the temperature is too high, can cause coarse grains, hot cracks, pores and sticky sand and other defects. Therefore, generally small-sized, thin-walled and complex-shaped precision castings, the pouring temperature is about the melting temperature of the steel +150 °C, the structure of the pouring system is simple, and the cross-sectional size is larger than that of cast iron; the pouring temperature of large-scale, thick-walled castings It is about 100°C higher than its melting point.

Improve surface quality of non-ferrous metal precision castings

1. Starting from the mold, clean the surface of the mold, that is, clean the surface with a sandpaper and brush the nitro paint. Use a metal or plastic mold for the high-precision stainless steel casting to improve the surface finish of the mold.

2. Starting with raw materials, modeling and core making use of zircon sand resin sand, mesh number 75-150, the use of thermosetting resin, sand mixed sand grinding high, smooth surface, good collapsibility, falling sand easy.

3. Strictly control the process, ensure that the shape and the sand core are in a warm state before the box is filled, and ensure the liquidity of the molten steel during pouring. Use the Fosco ISOMOL 300 alcohol-based zirconium powder coating for brushing at places where the surface is rough and damaged. After ignition and baking, the stainless steel casting surface is smooth.