车身一体化铝合金压铸件工艺探究

Integrated Aluminum Alloy Die Casting Process for Automobile Body

采用免热处理铝合金在60 000 kN以上压铸机上制备汽车车身一体化铝合金压铸件,研究工艺参数对其内部品质和力学性能的影响。通过X光检验压铸件内部品质,发现其末端容易形成不良,影响其力学性能。通过对比一体化铝合金压铸件近端与末端力学性能,发现由于尺寸大、铝液流程长,差异较大,伸长率差异达到55%。通过优化铸造压力、提高压射速度、增大高切点,延后低速高速转换点,铝液通过内浇口后快速对模具型腔填充,从而提高压铸件末端致密性,进而改善末端的力学性能。车身一体化铝合金压铸件末端抗拉强度可达220 MPa,屈服强度达到110 MPa,伸长率可达8%,满足整车使用要求。

The integrated aluminum alloy die-casting of automobile body was prepared using a heat-treatment free aluminum alloy with a die-casting mechanism of over 60 000 kN, and influence of process parameters on internal quality and mechanical properties was investigated. Through X-ray inspection of the internal quality of die-casting parts, it is easy to form defects at the end, affecting the mechanical properties. By comparing the mechanical properties of integrated aluminum alloy die castings at the proximal and distal ends, it is found that there exists a significant difference with an elongation difference of 55% due to the large size and long aluminum liquid process. At the same time, by optimizing the casting pressure, enhancing the injection speed, increasing the high tangent point, and delaying the high shifting point, the aluminum liquid quickly fills the mold cavity after passing through the inner gate, improving the compactness of the end of the die casting and thereby improving the mechanical properties of the end. The mechanical properties of end of the integrated aluminum alloy die-casting parts of the automobile body can reach 220 MPa in tensile strength, 110 MPa in yield strength, and 8% in elongation, which can meet the requirements.