A kind of low-pressure casting method of aluminum alloy automobile wheel hub

Abstract

The invention discloses a low-pressure casting method for an aluminum alloy automobile hub. The method of the present invention optimizes the alloy composition design, adds appropriate content of Al-Ti-B-C refiner and rare earth modifier, and optimizes the low-pressure casting process parameters and heat treatment parameters, so that the prepared automobile wheel hub has fine and uniform a branch Crystal and fine uniform worm-like or spherical silicon structure, improve the performance of aluminum alloy automobile wheels.

Description

technical field [0001] The invention relates to the field of casting, in particular to the field of low-pressure casting. Background technique [0002] Car wheels rotate at high speed during driving and carry various complex stresses caused by car weight, driving torque and uneven road surface. The wheel materials are required to have high strength, high elastic modulus and high fatigue strength to meet the requirements of automotive products. safety and reliability requirements. The car wheel material is initially made of steel plate, which is formed by extrusion after welding. Due to the complicated manufacturing process, heavy weight and the surface quality of the wheel can not meet the requirements of modern automobile development, the car wheel material has been replaced by aluminum alloy steel plate; due to light weight , corrosion resistance, simple processing method, good room temperature and low temperature impact toughness and excellent appearance quality and othe...

AI Technical Summary

Problems solved by technology

A356.2 is a hypoeutectic aluminum-silicon alloy with a silicon content of about 7%. Its conventional structure is inhomogeneous a-dendrites with thick massive and needle-like silicon distributed between them. The form of silicon causes stress concentration. It reduces the mechanical properties such as tensile strength and flash plasticity such as elongation of aluminum alloy, and at the same time increases the tendency of thermal cracking and shrinkage porosity during solidification, reducing the mechanical properties of aluminum alloy wheels; in order to reduce the harmfulness of irregular silicon forms In actual work, the aluminum alloy solution is treated by adding a sodium-containing salt or a strontium-containing master alloy to change the distribution and form of silicon in the aluminum alloy; but under the production conditions of low-pressure casting, the processing A good aluminum alloy solution must maintain a stable metamorphic effect within a certain period of time in order to meet the uniformity of the performance of aluminum alloy wheels. There is a phenomenon of metamorphism and recession in the metamorphism of sodium salt and strontium alloys.

At the same time, the thick and uneven dendrites will cause the thermal cracking tendency of the aluminum alloy wheel, increase the shrinkage porosity, cause the compactness of the aluminum alloy wheel to decrease, and often cause the aluminum alloy wheel to be scrapped due to air leakage. Uniform a dendrites also cause a reduction in the mechanical properties of aluminum alloys; therefore, aluminum alloy wheels also have requirements for the morphology distribution of a dendrites