Heat treatment method for Al-Si-Cu-Mg casting alloy

Abstract

The invention relates to Al-Si-Cu-Mg casting alloy. The Al-Si-Cu-Mg casting alloy is formed by smelting electrolytic aluminum, silicon metal, pure magnesium and Al-Cu intermediate alloy and comprises, by weight, 5.5%-6.5% of Si, 1.8%-2.2% of Cu, 0.45%-0.55% of Mg and the balance Al, and the ratio of the Cu to the Mg is 4:1. The Al-Si-Cu-Mg casting alloy is subjected to two-stage solid solution treatment and two-stage aging treatment, it can be ensured that precipitated phases of the Al-Si-Cu-Mg casting alloy are all dissolved in a matrix through suitable solid solution temperature and time, and overburning of crystal boundaries cannot be caused; and then the characteristics and mechanical properties precipitated by the alloy phases are controlled through two-stage aging treatment, so that the tensile property of the Al-Si-Cu-Mg casting alloy obtained through the method is obviously improved in index compared with the tensile property of Al-Si-Cu-Mg casting alloy subjected to T6 treatment.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a heat treatment method for an Al-Si-Cu-Mg casting alloy. Background technique [0002] The typical heat treatment method for Al-Si alloy used in sand mold and gravity casting is T6 heat treatment, which mainly includes: [0003] 1. Solid solution treatment is carried out at a higher temperature to dissolve the formed Cu-rich and Mg-rich phase particles to obtain a highly uniform alloy composition. [0004] 2. Quenching treatment. Generally, quenching at room temperature is used to obtain a supersaturated solid solution of solid solution atoms and vacancies. [0005] 3. Age hardening treatment, at room temperature (natural aging) or elevated temperature (artificial aging), the strengthening phase is precipitated from the supersaturated solid solution. [0006] The temperature of solution treatment is generally selected close to the eutectic point temperature of the alloy, wh...

AI Technical Summary

Problems solved by technology

However, if the solid solution temperature is too high, it will lead to local over-burning of the alloy, and the mechanical properties of the alloy will drop sharply. Gradually, this contradiction has escalated into a barrier in the industry, so for Al

Images