连续变截面直接挤压成形技术研究

实现晶粒细化的传统塑性加工工艺所需工序多且要求较高,为了解决这些问题,本文提出了一种能够实现金属材料制备及成形一体化的挤压成形新工艺——连续变截面直接挤压成形技术.对不同工艺条件的连续变截面挤压成形过程的数值模拟研究表明:当模角由90°增大至140°时,塑性区范围明显扩大,金属流动均匀性随之提高;模口处轴向拉应力数值减小了20%,降低了表面产生开裂的可能性;模角为90°时变截面型腔处存在死区缺陷,且流线折叠倾向较严重,模角为140°时成形过程中坯料与型腔间易出现空隙.分析认为,本文条件下模角为120°的情况比较理想.

Research on continuous variable cross-section direct extrusion (CVCDE)

The traditional processing to obtain refined grain by plastic working needs more processes and higher standard.In order to tackle these problems,a new technology,continuous variable cross-section direct extrusion (CVCDE),coupled the producing and forming of the metal material is provided in this article.After simulating the different processes of CVCDE,the results show that:,when die angle increases from 90° to 140°,the plastic zone expands obviously and the flow uniformity of metal improves,meanwhile 20% reduction of the axial tensile stress reduces the chance of cracking in the surface.when the die angle is 90°,there is dead metal zone in the cavity with variable cross-section,the streamlines are tending to fold seriously.When the die angle is 140°,the gap appears easily between billet and die cavity.Based on an overall analysis,the die angle of 120° is an ideal choice.