楔横轧大断面收缩率一次楔成形轧件心部质量规律及原因

The study on the center quality of workpiece during heavy section shrinkage cross wedge rolling by single wedge

为确定楔横轧大断面收缩率一次楔成形工艺心部质量的加工界限,对大断面收缩率下轧件心部质量规律进行了深入探索。采用实轧实验方法得到轧件心部最大孔洞面积数据;对比常规断面收缩率下轧件心部最大缺陷尺寸数据,得到大断面收缩率一次楔成形轧件的心部质量规律;并利用有限元数值模拟方法对大断面收缩率与常规断面收缩率轧件心部应力、应变进行对比分析,找出规律的原因。所得规律为,大断面收缩率轧制轧件心部质量整体好于常规断面收缩率轧制,另揭示出其原因为,大断面收缩率轧制轧件金属瞬时轴向流动量大,杆部中心剩余金属少,可供缺陷发展的空间也较小;不利于轧件心部质量的应力应变作用的时间较短,与工艺时间相同时刻常规断面收缩率的应力应变最大值相差比例也较小,静水压力在整个轧制过程中有利于轧件心部质量。

The law of the center quality of heavy section shrinkage cross wedge rolling by single wedge was explored in depth to set the process limits. The data of the biggest centre flaw size was got through heavy section shrinkage cross wedge rolling experiment and was compared with that of the routine section shrinkage workpiece to find the law of the center quality of workpiece during heavy section shrinkage cross wedge rolling by single wedge. The stress and strain at the center part under both conditions were compared and analyzed by using FEM numerical simulation method. It was found that the centre quality of heavy section shrinkage workpiece is better than the routine one. It is due to the instantaneous axial metal flow during heavy section shrinkage is bigger, the material remaining at the center of rod and the space for the defects development is less, the stress and strain disadvantageous to the centre quality affect in shorter time, the stress and strain variance are smaller, and the hydrostatic pressure throughout the rolling process is beneficial to the center quality of workpiece.