降低7075铝合金厚板淬火残余应力的工艺

Reducing Residual Stresses Process for Quenched 7075 Aluminium Alloy Thick-plates

70 75铝合金可通过淬火时效获得高强度 ,但它在淬火过程中会产生淬火残余应力。本文对 70 75铝合金厚板在不同淬火水温下 ,以及某一水温下淬火后经不同预拉伸量和不同时效工艺制度下淬火残余应力大小及变化规律进行了测试与分析。结果表明 ,随着淬火水温的升高 ,残余应力明显降低 ;水淬后随着预拉伸量的增加 ,残余应力逐渐从压应力转变为拉应力 ,当预拉伸量约 2 %时 ,残余应力基本上趋近于零 ;随着时效温度升高和时效时间延长 ,残余应力呈下降趋势。因此 ,合理的淬火水温、预拉伸量以及时效制度是降低 70 75铝合金厚板淬火残余应力的有效工艺措施。

Precipitation-hardened aluminium alloy 7075 gains its high strength through heat treatment involving a severe quenching operation,which can have the adverse effect of introducing residual stresses.The principles of affecting on residual stresses in quenched aluminium alloy 7075 thick-plates have been studied and concluded in this article under different heat treatments,different water temperature and different pre-stretching techniuqes by the drilling method.The tests show that residual stresses have distinctly been reduced with water temperature increasing.It also has indicated that residual stresses have converted from compress-stresses to tension-stresses with the development of degrees of pre-stretching,and have basically got zero near 2%.As to raising aging temperatures and aging times,residual stresses have been reduced step by step. The studies show that they are effective measures to reduce residual stress in quenched aluminium alloy 7075 by taking appropriate pre-stretching,aging techniques and water temperature,especially well by adaptable pre-stretch and raising water temperature.