Die-casting mold casting method and inner gate of die-casting mold

Abstract

Disclosed is a die-casting mould casting method. The flowing speed of a punch is 0.4 meter per second to 0.8 meter per second in a die-casting process; and the cross section of a flow gate (1) has a polygonal structure. Compared with the prior art, the die-casting mould casting method has the advantages that because the cross section of the flow gate has the polygonal structure, the cooling speed of the center of the flow gate is lower than that of the center of a thick and big portion of a cast, a pressure-maintaining and feeding channel for the cast is formed, the thick and big portion of the cast can be fed in the process of cooling the center of the thick and big portion, shrinkage and loosing can be effectively eliminated, the yield can be greatly improved, and the production cost is reduced. The die-casting mould casting method has the advantages of high yield and low production cost.

Description

technical field [0001] The invention belongs to the technical field of metal die-casting, and in particular relates to a die-casting method for casting thick and large castings and an inner gate of the die-casting die. Background technique [0002] At present, in the die-casting production, some die-casting parts with holes are often encountered in the thick part of the casting. In view of the large cavity volume of the die-casting part with thick body, the gate speed is initially reduced through the large cross-sectional area during injection filling. ; At the same time, because there is more molten metal accumulated in the thick and large parts after filling, the accumulated heat is also relatively large, so the cooling and solidification of the molten metal in the casting is relatively slow; when the die-casting machine is in the pressure-holding stage after filling and boosting The molten metal near the mold around the casting solidifies rapidly, and only the central mol...

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Problems solved by technology

[0002] At present, in the die-casting production, some die-casting parts with holes are often encountered in the thick part of the casting. In view of the large cavity volume of the die-casting part with thick body, the gate speed is initially reduced through the large cross-sectional area during injection filling. ; At the same time, because there is more molten metal accumulated in the thick and large parts after filling, the accumulated heat is also relatively large, so the cooling and solidification of the molten metal in the casting is relatively slow; when the die-casting machine is in the pressure-holding stage after filling and boosting The molten metal near the mold around the casting solidifies rapidly, and only the central molten aluminum is still in a liquid or semi-solid state, forming a closed small molten pool. When this part of the metal is solidified, it cannot be supplemented by the surrounding molten metal, so it is also It is easy to form shrinkage cavities and porosity; so that the castings obtained after casting are prone to large shrinkage cavities in the interior of the castings during X-ray machine flaw detection. Casting defects such as air holes and shrinkage cavities, especially when these holes are processed into threaded holes, serious rotten teeth phenomenon will occur, causing a large number of products to be scrapped; Improve the mold gate size, gate position, reduce machining allowance and select reasonable process parameters, etc., but there is still the problem of low yield

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