Low-pressure casting hole porosity defect calculation method

Abstract

The invention relates to the technical field related to hole porosity defects in the low-pressure casting process, in particular to a low-pressure casting hole porosity defect calculation method whichcomprises the following steps: S1, constructing a three-dimensional model of a pouring system, and initializing the pouring system at the beginning of solidification; S2, obtaining an inlet pressurevalue at the current moment according to the set inlet pressure curve, calculating a critical solid phase rate corresponding to the inlet pressure according to the inlet pressure value, and searchingan isolated liquid phase region according to the critical solid phase rate corresponding to the inlet pressure; The method is designed for a low-pressure casting shrinkage cavity calculation method; The three situations that the critical solid fraction of flowing of molten metal is increased due to the pressure feeding effect and the inlet pressure, and the liquid phase connected with an inlet flows back in the pressure relief stage are comprehensively considered, the position, the size and the shape of a shrinkage cavity in the low-pressure casting process can be accurately simulated, and thegood reference value is achieved for low-pressure casting actual production.

Description

technical field [0001] The invention relates to the related technical field of porosity defects in the low-pressure casting process, in particular to a calculation method for porosity defects in low-pressure casting. Background technique [0002] Existing commercial casting process simulation software usually uses the isolated liquid phase volume shrinkage method to calculate the size and location of porosity defects in castings. This method is feasible for conventional gravity casting, but not suitable for low pressure casting. [0003] During low-pressure casting, the liquid flows from the bottom of the casting mold to the top of the casting mold to ensure that the liquid rises smoothly and the gas is discharged smoothly, and the feeding direction of low-pressure casting is opposite to that of gravity casting. The pressure is from bottom to top, and the bottom pressure is greater than the top pressure. , the alloy temperature goes up and down, and the casting starts to so...

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Problems solved by technology

[0011] In order to solve the existing problems in the prior art that the accurate calculation of the porosity defect in low-pressure casting cannot be realized, based on the characteristics of the porosity defect in the low-pressure casting, the calculation method for the shrinkage cavity in the low-pressure casting is designed, and the pressure feeding is comprehensively considered. Effect, the inlet pressure leads to the increase of the critical solid phase rate of the molten metal, and the liquid phase connected to the inlet during the pressure relief stage will flow back. These three situations can accurately simulate the position and size of the shrinkage cavity under the low pressure casting process. And shape, it has a good reference value for the actual production of low pressure casting

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