摘要
为解决棒材连续挤压过程中坯料流动不均匀的问题,利用物理模拟与数值模拟相结合,将模拟结果与实际产品金相组织进行对比,获得连续挤压过程中坯料的流动特征。在物理模拟阶段,为了更直观地展现连续挤压过程中坯料的具体流动特征,采用黏土模拟高温条件下的黄铜合金,并基于自行设计的物理模拟装置挤出黏土棒材,将挤出的黏土棒材取横纵切片进行观察并与数值模拟和产品金相进行对比。经对比分析发现腔体的上侧死区范围小于下侧死区范围,上下两侧的死区范围大于左右两侧的死区范围,且在下侧出现上翻现象,该流动特征会影响产品截面组织分布,腔体横截面死区呈圆环形,纵截面死区呈三角状。对于直径为Φ5 mm的产品,腔体横截面死区面积约占整体的30%,纵截面死区面积约占整体的11%。以上结果表明,腔体内部金属流动不均匀,这是由于连续挤压侧面摩擦驱动力与温度分布不均引起的,通过优化腔体流道,对死区部分进行温度补偿可以使金属流动更加均匀。
To solve the problem of uneven flow of billet during continuous extrusion of rod billet,physical simulation and numerical simulation were combined,and the simulation results were compared with the microstructure of the actual product,so as to obtain the flow characteristics of billet during continuous extrusion.In the physical simulation stage,to show the concrete flow characteristics of billet in the continuous extrusion process more intuitively,clay was used to simulate the brass alloy at high temperature.The clay rod was extruded based on the self-designed physical simulation device,and horizontal and vertical sections of the extruded clay bar were taken for observation and compared with the metallography of numerical simulation and product.Through comparative analysis,it is found that the upper dead zone of the cavity is smaller than the lower dead zone,while the upper and lower dead zones are larger than the left and right dead zones,and the lower dead zone is upturned.This flow characteristic affects the structure distribution of the product section,the dead zone of the cavity cross section is circular and the dead zone of the longitudinal section is triangular.For product with diameter ofΦ5 mm,cavity cross section dead area accounts for about 30%of the whole,vertical section dead area accounts for about 11%of the whole.The above results show that the metal flow in the cavity is not uniform,which is caused by the uneven distribution of friction driving force and temperature on the side of continuous extrusion.By optimizing the flow channel of the cavity,the temperature compensation to the dead zone can make the metal flow more uniform.
作者
王凌博
李冰
赵颖
运新兵
WANG Ling-bo;LI Bing;ZHAO Ying;YUN Xin-bing(Engineering Research Center of Continuous Extrusion,Ministry of Education,School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2021年第1期52-59,共8页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(51675074,51705062)
辽宁省教育厅基本科研项目(JDL2017020)。
关键词
棒材
连续挤压
物理模拟
数值模拟
流动特征
rod billet
continuous extrusion
physical simulation
numerical simulation
flow characteristics
作者简介
通信作者:李冰,男,1977年生,博士,副教授,主要从事合金材料连续挤压成形技术和理论研究,E-mail:libing@djtu.edu.cn;第一作者:王凌博,男,1989年生,硕士研究生,主要从事连续挤压成形技术研究,E-mail:137074739@qq.com。
