Homogenizing annealing thermal treatment technology for A390 aluminum alloy cast ingot

Abstract

The invention belongs to the technical field of metal material thermal treatment, and particularly relates to a homogenizing annealing thermal treatment technology for an A390 aluminum alloy cast ingot. The homogenizing annealing thermal treatment technology comprises the steps that the A390 cast ingot obtained through the electromagnetic stirring-semicontinuous casting technology is placed in a heating furnace to be heated to 350-500 DEG C, the temperature is maintained for 2-6 h, and then, the cast ingot is cooled to 250 DEG C in the furnace and finally discharged to be subjected to air cooling. According to the homogenizing annealing thermal treatment technology, the Brinell hardness of the A390 aluminum alloy cast ingot is reduced to be below 70 HB from 130 HB, and ductility is increased to be more than 8% from 2.5%. The homogenizing annealing thermal treatment technology is conducted on the A390 aluminum alloy cast ingot. Due to dissolution of an alloy phase and elimination of microsegregation, the composite structure homogeneity of the A390 aluminum alloy cast ingot is improved, the microstructure of alloy is improved, the residual stress is eliminated, and the machinability of the alloy is improved. The technology is simple, cost is low, the high production efficiency is achieved, and the homogenizing annealing thermal treatment technology is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of metal materials, and in particular relates to an A390 aluminum alloy ingot homogenization annealing heat treatment process. Background technique [0002] A390 aluminum alloy is widely used in brake drums, automobile hubs, and engine rotors due to its small thermal expansion coefficient, high volume stability, good casting and welding properties, excellent wear resistance and corrosion resistance, and certain high temperature strength. It is one of the preferred materials for engine systems such as automobiles, motorcycles, and construction machinery, and is the most widely used hypereutectic aluminum alloy in commercial applications. However, the conventional solidification structure of this alloy is composed of primary silicon and eutectic structure. The primary silicon is generally in the shape of thick plate, polygonal block and five-petal star, and the eutectic silicon is in the shap...

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Problems solved by technology

[0003] The A390 aluminum alloy ingot with fine primary silicon, uniform distribution and nearly spherical shape was prepared by electromagnetic stirring-semi-continuous casting technology. However, through the analysis of the microstructure and properties of the alloy, it was found that the eutectic silicon had poor morphology The existence of segregation phenomenon, coupled with the existence of residual stress in the as-cast alloy, makes the alloy have high hardness and poor processability

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