Investment casting system and method for U-shaped magnesium alloy parts

Abstract

The invention discloses an investment casting system and method for U-shaped magnesium alloy parts. The investment casting system comprises a U-shaped cavity with two arms facing upwards. The upper end opening of a sprue cup is connected with S-shaped variable cross-section main and auxiliary cross gates. The S-shaped variable cross-section cross gates both have circular cross sections and the sectional area of the S-shaped variable cross-section cross gates is gradually increased in the flowing direction. The rear end of the main cross gate is connected with a main gate sprue, and the upper end of the main gate sprue is connected with the bottom center of the same end of the U-shaped cavity. The two auxiliary cross gates are connected with transition gate sprues correspondingly, and the upper portions of the two transition gate sprues are connected with the thinnest positions of the two arms of the U-shaped cavity through gap sprues separately. The bottoms of the gate sprues are all connected with S-shaped slag collecting buffers. The investment casting method sequentially includes the steps of manufacturing an appearance mold and a core box mold, manufacturing a soluble mold core, conducting mold assembly and mold material injection, taking out a mold, dissolving the mold core, performing mold assembly, conducting degreasing and brushing, carrying out dewaxing, roasting, modelling, mold filling, pressure rising, pressure maintaining and pressure relieving, and obtaining the U-shaped magnesium alloy parts by means of cooling. By adoption of the casting system and method, the rate of certified products is high.

Description

technical field [0001] The invention relates to a casting of a magnesium alloy part, in particular to an investment casting system of a U-shaped magnesium alloy part. The invention also relates to an investment casting method for a U-shaped magnesium alloy piece, which belongs to the technical field of metal casting. Background technique [0002] The investment casting process refers to making a model with wax, wrapping multiple layers of refractory materials such as clay and binder on the outside, heating the wax to melt and flow out, so as to obtain an empty shell formed by refractory materials, and then melting the metal and filling it. After the metal is cooled, the refractory material is crushed to obtain metal parts. This process of processing metal is called investment casting, also known as investment casting or lost wax casting. [0003] The common ends of the U-shaped magnesium alloy parts are connected, and the two arms extend downward or upward. Due to the low ...

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Problems solved by technology

Due to the low density of magnesium alloy, small dissolved heat capacity and high thermal conductivity, the temperature of the alloy liquid drops rapidly during the flow process, and it is very easy to oxidize and absorb gas, and the specific gravity of the oxide is similar to that of the light alloy liquid, so that the mixed alloy The oxides in the liquid are difficult to skim off. After the alloy liquid solidifies, the volume shrinks greatly, and defects such as shrinkage cavities, shrinkage porosity, and slag inclusions are prone to occur. The thin-walled parts of the two arms of the U-shaped magnesium alloy parts are prone to insufficient pouring.

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