Dry-sand molds of sand casting processes

Dry-sand molds actually performed with molding sand in green condition. Sand mix is ​​modified slightly to favor good strength and other properties after the drying model.

Can dry-sand molding to do the same way with green-sand molding sizes smaller castings. Typically, the mold-cavity surface coated or sprayed with a mixture which, on drying taste, hardness more or refractoriness to the model. The entire model is then dried in an oven at 300-650 F or by circulating heated air through the mold. The time-consuming drying operation inherent disadvantage one of the dry-sand mold.

Advantages

Dry sand molds are generally stronger than green sand molds and thus can withstand extra long handle. Dimension control better than if they were molded in green sand. Can better the quality of the mixture of sand due to the elimination of moisture leads to a much smoother finish of the castings than if done in green sand molds. Where models properly washed and sprayed with refractory coatings, the end is further improved solutions.

Disadvantages

- This type of shape are much more expensive than green sand molding and is not highproduction process. Right baking (drying) required times.

● Skin-drying models: the effect can be dry-sand mold to get involved by drying the mold surface with some depth, 1/4 to 1 in Skin drying may be performed by torches or electric heating elements focused on the surface mold. . Skin models must-dried to pour shortly after drying, so moisture will not penetrate the sand undried the dried skin.

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