In the process and production of the precision casting, the temperature ensures that the solution will have good fluidity during the injection process. The precision casting temperature should be determined according to the injection distance and the cooling conditions, specifications, alloy, flow and other factors. The precision casting temperature is 50 to 110 ℃ higher than the liquidus temperature of the alloy.
The crack tendency of precision casting round ingot is low, so the alloy has good exhaust complement ability. Create sequential crystallization conditions, increase the density and the general casting temperature is high. The casting temperature of the ingot with diameter more than 350 mm is generally 730 ~ 750 ℃. Small diameter ingot, because of its small size, good mechanical properties, generally to meet the liquidity and do not form bright crystal, the general temperature is 715 ~ 740 ℃.
The application of precision casting in the process
In the production of precision castings, about 60 - 70 % of the precision casting parts are produced by sand mold, and then 70 % are produced by clay sand mold. The reason why sand mold casting accounted for most of the reason is because of low gas cost and simple process. Therefore, the precision casting parts of auto parts belong to the sand mold precision casting parts. In general, for some large and medium-sized precision castings, iron castings can be produced with resin self-hardening sand mold, stainless steel precision castings can be produced with water glass sand mold. And castings with accurate size and smooth surface can be obtained.
Advantages of dewaxing precision casting
The use characteristics of dewaxing precision casting is that it can make thin-wall parts, pattern fine parts, net parts, and several parts in one forming. The dimensional accuracy and surface brightness are good. In particular, the complex parts with strange shapes which are difficult to use the traditional sand casting process, forging method or cutting machining method to make, using the dewaxing die casting can achieve the purpose of short construction period and low cost.