Low pressure casting method for magnesium alloy casting parts

Abstract

The invention discloses a low-pressure casting method for a magnesium alloy casting, which comprises the following technological steps: firstly, continuously adding magnesium alloy materials into a sealed furnace which is protected by inert gas for heating, and making the temperature of the furnace maintain between 680 and 730 DEG C; secondly, preheating a die to a temperature of between 220 and 240 DEG C, using the inert gas to sweep a die cavity, exhausting oxygen, and preparing casting; and thirdly, performing pressurization, making a magnesium alloy liquid introduced into and filled into the die cavity from the lower side of the die by controlling the pressure, maintaining the pressure for 1 to 3 minutes, and completing casting of the casting after the liquid in the die cavity is subjected to cooling forming. The invention adopts the low-pressure casting method, and can realize control of the die filling pressure and the die abandoning speed by controlling the pressure, and guarantee that no oxidized slag inclusion enters the casting. Moreover, the magnesium alloy liquid is introduced into the die cavity from the lower side of the die, so that the casting can effectively overcome the defects of cavity shrinkage, dispersed shrinkage and the like, and improve the tissue density, thereby the performance and the quality of products are improved.

Description

technical field [0001] The invention relates to a casting method of magnesium alloy castings, in particular to a low-pressure casting method of magnesium alloy castings. Background technique [0002] At present, magnesium alloy castings, as a new material, have been widely used in the fields of aviation, automobiles and military industry, because magnesium alloys have excellent physical and chemical properties such as shock absorption, radiation protection, specific stiffness, and high specific strength, and are more and more popular among the people. . At present, the casting process of magnesium alloy castings mainly includes gravity casting method and die-casting extrusion method. Since magnesium alloy is a light metal, it has small hot melt and poor fluidity, so the traditional gravity casting method is easy to burn, the density is not enough, and the performance of castings is difficult to guarantee. , and defects such as shrinkage porosity and shrinkage cavity are pro...

AI Technical Summary

Problems solved by technology

At present, the casting process of magnesium alloy castings mainly includes gravity casting method and die-casting extrusion method. Since magnesium alloy is a light metal, it has small hot melt and poor fluidity, so the traditional gravity casting method is easy to burn, the density is not enough, and the performance of castings is difficult to guarantee. , and defects such as shrinkage porosity and shrinkage cavity are prone to occur during the casting process; the pressure required by the die-casting extrusion method is large, and there are two forms of die-casting: hot chamber and cold chamber. The injection specific pressure of the hot chamber machine is about 40MPa, and the cold chamber The injection specific pressure of the machine is 40-70MPa, which is not suitable for the manufacture of large wall thickness, large parts and complex cavity parts. Both methods are difficult to cast large castings with complex structures.