铝管强旋的软化现象探讨

EXPLORATION FOR THE SOFTENING PHENOMENON OF STRONG SPINNING OF ALUMINIUM PIPES

研究了纯铝管挤压拉伸后旋压与挤压后旋压的硬度变化现象和规律,以及残余应力对硬度变化的影响．旋压变形率在30％左右时旋压件软化程度最大．要在铝管旋压中有效地提高工件的材料硬度,选用挤压成形的管坯比选用挤压拉伸成形的管坯效果更好．350℃保温2h的热处理工艺可以消除管坯拉伸残余应力,其旋压的硬度效果与挤压后旋压的硬度效果基本相同．

The phenomenon and regularity of hardness changes of pure Al pipes in extrusion plus elongation followed by spinning and in extrusion follcwed by spinning have be studied. Influence of the residual stress on the hardness changes has also been studied.When the spinning deformation rate is around 30%, the spinned workpiece has the largest softening degree. If in Al pipe spinning, the material hardness of the workpiece is to be effectively increased, it is better to select the semi-finished pipe formed by extrusion than to select that formed by extrusion plus elongation. The heat treatment technology (holding the temperature at 350℃ for 2 hours) can eliminate the elongation residual stress and the hardness obtained from spinning is almost the same as that from extrusion followed by spinning.