Pressure casting method for multi-section uniform accelerated injection of liquid metal

Abstract

The invention discloses a pressure casting method for multi-stage uniform accelerated injection of liquid metal, which comprises three stages of low-speed injection, high-speed injection and pressurization and pressure maintaining, and comprises the following step: determining the initial injection speed, critical speed and critical acceleration of the liquid metal according to the parameters of apressure chamber and the fullness of molten metal after the low-speed injection stage and before the high-speed injection stage. A low-speed injection stage is divided into 3-9 acceleration stages, an injection punch performs uniform acceleration advancing according to the speeds of the 3-9 acceleration stages to reach the critical speed, so that liquid metal is prevented from splashing out of asprue gate to seal the sprue gate of a chamber, and thus, stable laminar flow motion of molten metal in the pressure chamber is achieved, turbulence and vortexes are avoided, air in the pressure chamber can be exhausted through a pouring gate system and a die; and the whole pressure chamber is filled with molten metal, so that the phenomena of air entrapment and oxide inclusion are avoided, air holes and oxide inclusion of castings are reduced, and the performance of the castings is improved.

Description

technical field [0001] The invention relates to a liquid metal die-casting forming method, in particular to a pressure casting method for multi-stage uniformly accelerated injection of liquid metal. Background technique [0002] Die casting is a kind of filling liquid or semi-solid metal or alloy, or liquid metal or alloy containing reinforced phase, into the cavity of die-casting mold at a high speed under high pressure, and make the metal or alloy under pressure A casting method that solidifies to form a casting. [0003] Die casting has two characteristics of high pressure and high speed. Due to its very high injection speed, there are serious gas entrainment and oxidation inclusions in the molten metal during the injection process, resulting in a large number of pores and oxidation inclusions in the casting, which reduces performance and limits range of use. In order to reduce gas entrainment and oxidation inclusions, the movement of molten metal in the pressure chambe...

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Problems solved by technology

[0004] The invention provides a pressure casting method for multi-stage uniformly accelerated injection of liquid metal, the purpose of which is to solve the phenomenon of gas entrainment and oxidation inclusion of liquid metal during the movement process in the pressure chamber after the low-speed injection stage and before the high-speed filling of the mold cavity The resulting castings have a large number of pores and oxidation inclusions, which reduce performance. That is, after the low-speed injection stage, before the high-speed filling of the cavity, the smooth laminar movement of the molten metal in the pressure chamber is achieved to avoid turbulent flow and vortex. The air in the room can be discharged through the runner system and the mold, without entrainment and oxidation inclusions, thereby reducing the pores and oxidation inclusions of the casting and improving the performance of the casting

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