摘要
针对传统浇注工艺制备的空心钢锭内部可能存在空隙性缺陷(球形、径向管状、轴向管状和切向管状孔洞缺陷)的锻合问题,首先,基于孔洞闭合体积能量率变化的特性,建立了体积变形功率与塑性变形功率比值的孔洞闭合新判据T函数,并将其集成至DEFORM软件;在此基础上,采用数值模拟方法,分析获得了空心钢锭内部孔洞缺陷在镦粗、芯轴扩孔和芯轴拔长的自由锻工序变形过程中的闭合行为和临界压下率,验证了T函数预测孔洞闭合的有效性和准确性。结果表明,自由锻工序中,与加载压缩变形方向垂直的孔洞容易闭合、与加载压缩变形方向平行的孔洞最难闭合。空心钢锭开坯压实宜采用局部加载压缩的芯轴扩孔和芯轴拔长工序。对于当量尺寸为Φ10 mm的孔洞,加载压缩变形率达到40%即可实现孔洞完全闭合、从而达到消除孔洞和压实的效果。
In view of the forging problem for void defects of spherical,radial tubular,axial tubular and tangential tubular voids that may exist in hollow ingots prepared by the traditional pouring process,firstly,based on the characteristics of volume energy rate change for void closure,a new void closure criterion of T function was established by the ratio of volume deformation energy rate to plastic deformation energy rate,then it was integrated to the DEFORM software.On this basis,by means of numerical simulation method,the closure behaviors and critical reduction rate were obtained by analyzing void defects of hollow ingots during the deformation process of fress forging which included upsetting,expanding and drawing with mandrel to verify the validity and accuracy of the T function in predicting void closure.The results show that in the free forging process,the voids perpendicular to the loading compression deformation direction can be closed easily,and the voids parallel to the loading compression deformation direction are the most difficult to close.The expanding and drawing with mandrel processes with local loading and compression should be adopted in the cogging and compaction of hollow ingots,and the void of equivalent size forΦ10 mm can be completely closed when the compression deformation rate reaches to 40%to achieve the effect of eliminating voids and compacting.
作者
田继红
张铭心
袁海伦
史宇麟
刘建生
陈慧琴
Tian Jihong;Zhang Mingxin;Yuan Hailun;Shi Yulin;Liu Jiansheng;Chen Huiqin(School of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Beijing Research Institute of Mechanical&Electrical Technology Ltd.,Beijing 100083,China;China Machinery(Jinan)Precision Forming Engineering Technology Co.,Ltd.,Jinan 250200,China)
出处
《锻压技术》
CAS
CSCD
北大核心
2020年第10期176-184,共9页
Forging & Stamping Technology
基金
国家自然科学基金资助项目(51575372)
济南市泉城“5051”引才倍增计划创新团队(2018002)。
关键词
空心钢锭
镦粗
芯轴拔长
芯轴扩孔
孔洞闭合
hollow ingots
upsetting
drawing with mandrel
expanding with mandrel
void closure
