中文摘要：

为研究板料渐进成形时成形极限提高的机理,以数控铣床渐进成形冷轧板方锥台件为研究对象,使用金相显微镜和扫描电镜观察其成形前后显微组织的变化规律,并与一般冲压成形件进行比较。研究结果表明,渐进成形技术可用于制作冷轧板材料零件;油池润滑情况下,渐进成形过程中摩擦产生的热量,不足以引起其组织的改变,变形过程为冷变形;成形后的显微组织表现出与成形工具相接触部位被压碎,并在后续成形中被均匀拉长的现象。因此渐进成形是局部、交替、小增量的变形,变形的均匀分布,提高了成形性能。

英文摘要：

To study the mechanism of forming limit enhancement in sheet incremental forming, a cold-rolled-sheet square frustumwas incrementally formed on a numerical controlled milling machine. The change of the micro-structure in the process was studiedby using metallographic microscope and scanning electron microscope （SEM）, and compared with normal stamping process. Itwas found that cold-rolled sheets can be incrementally formed to produce components; under sump lubrication, the incrementaldeformation was cold since the heat produced by friction was not enough to change part＇s microstructure; the microstructure toldthat the contact part of sheet was smashed and uniformly enlarged later, which demonstrated that the deformation in incrementalprocess is local, alternative, and little increment, and the uniform distribution of deformation enhances the forming ability.