Low speed vacuum squeeze casting technology

Abstract

The invention provides a low speed vacuum extruding casting technique which comprises the steps of: (1) the design of dies, a vacuum system and a hot runner; (2) the installation, the preheating and the coating of the hot runner and the dies; (3) the pouring of molten metal into the hot runner, die matching and vacuum pumping; (4) low speed and vacuum filling; (5) extruding and solidifying; (6) the opening of the dies to take finished products. The technical effects of the technique are the improvement of a temperature field during the casting process and the realization of the casting method of injection at low speed, solidification under high pressure and hole shrinkage without vacuum. The low speed vacuum extruding casting technique can effectively reduce the probability of containing pores and shrinkage and loose defects, heat treatment can be carried out to die casts, and both the tensile strength and the percentage elongation of the die casts after the heat treatment are increased by 25 percent, thereby greatly improving the quality of the die casts.

Description

technical field [0001] The invention relates to a casting process, in particular to a full vertical die-casting process. Background technique [0002] Die casting - the most important and advanced technology in the modern foundry industry. However, in the die-casting process, due to the high-speed filling, it is difficult to discharge the gas in the cavity; in addition, the liquid metal cools quickly in the cavity, and it is actually difficult to feed the shrinkage, so that the die-casting often has pores and shrinkage defects. The larger the thickness value, the more serious this defect is; because the gas expansion in the pores at high temperature will cause the surface of the die-casting to bubble, so the die-casting cannot be heat-treated; these will seriously affect the quality of the die-casting, and the expansion and use of die-casting production The scope is limited. Vacuum die-casting once flourished for a while, but it is not widely used now. The main reason is t...

AI Technical Summary

Problems solved by technology

The precision, speed and precision die-casting method can play a greater role in eliminating pores and shrinkage defects, but this method has strict requirements on the heat balance and temperature field of the mold, and there are no effective measures. Casting, coupled with the difficulty in maintenance of double punches, the scope of its promotion and application is not large

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