Precise Size Of Castings

- Oct 20, 2017 -

Basic features of castings:

1 from the angle of casting process, the dimension precision and surface roughness of castings depend mainly on the properties of casting. To change the manufacturing process of mold and the special casting method of the material. Investment casting: Thin shell mold, high fire resistance. Metal mould casting: Metal mold.

EPC: Dry sand mold without binder.

Also: Gypsum casting, ceramic mold casting, graphite casting and so on.

2 The mechanical properties of castings under the same chemical composition are mainly dependent on the cooling speed. Change the liquid metal filling and cooling conditions.

Centrifugal casting: solidification under the action of centrifugal force. Pressure casting: Filling and solidification under high pressure. Metal Mold Casting: The cooling speed is faster than the sand type. Also: low-pressure casting, differential pressure casting, Casting Parts vacuum suction casting.

The significance of casting production:

1 Casting size precision (die casting ct4-7, EPC ct6-9, Pressure casting ct4-8), low surface roughness (investment casting: RA1.6-6.3, EPC Ra6. 3-20, Pressure casting: Ra1.6-6.3). can achieve less cutting or no cutting processing.

2 castings have good internal quality and high mechanical properties. Casting wall thickness can be reduced (minimum wall thickness: melting die casting 0.5, EPC: 2-3, Pressure casting: 0.3).

3 Reduce metal consumption and casting scrap rate (process yield: Melt casting $number, EPC 40-75%, Pressure casting $number).

4 Simplified casting process (excluding investment casting), Casting Parts easy to achieve mechanization and automation.

5 improve labor conditions and increase labour productivity.

Process characteristics of casting structure

If the castings are of good quality, they should have the characteristics of clear outline, precise size, compact microstructure and fine grain.

The casting performance of the alloy is required for the structure of castings: the wall thickness of castings should be reasonable first to ensure the requirement of alloy fluidity. Then consider as far as possible not to make the casting wall thickness is too large, the casting thick wall should consider the shrinkage is convenient, avoid the casting shrinkage when blocked; the wall thickness of castings should be as homogeneous as possible to form shrinkage, shrinkage, coarse grains and other defects The castings should avoid large horizontal surfaces as far as possible.

Casting process to the requirements of the casting structure: avoid the shape of the living block, Casting Parts simplify the casting structure, reduce the type of surface, as far as possible to reduce or not use the core, consider the core of the fixed, venting and cleaning, to make the fractal plane straight;