工程科学学报，第39卷，第2期：267-275,2017年2月 Chinese Journal of Engineering,Vol.39,No.2:267-275,February 2017 DOI:10.13374/j.issn2095-9389.2017.02.015;http://journals.ustb.edu.cn 芯棒直径对楔横轧5Cr21Mn9N4N空心气门壁厚均匀 性的影响规律 闫向哲，刘晋平，纪宏超，王宝雨，郑振华，李姿 北京科技大学机械工程学院，北京100083 ☒通信作者，E-mail:liujp@usth.edu.cn 摘要楔横轧空心轴类件存在壁厚分布不均问题，特别是在小直径大长径比空心件楔横轧成形中更为突出.本文在 Gleeble--l500D热模拟实验机上进行了5Cr2IMn9Ni4N耐热钢的热压缩实验，得到了5Cr21Mn9Ni4N的热变形本构方程.通过 改变芯棒直径，采用有限元仿真和实验相结合的方法，研究了楔横轧轧制空心气门过程中的壁厚变化规律.研究结果表明， 带芯棒轧制时，芯棒直径存在临界值，在该值下进行轧制，空心气门预制坯壁厚均匀性最优：楔横轧空心件时，金属轴向均匀 流动是壁厚均匀的必要条件：轧件轴向拉应变减小，径向压应变变大，周向应变在0附近且为拉应变时，壁厚较为均匀. 关键词楔横轧：耐热钢：本构方程：空心气门；临界直径；金属流动 分类号TG335.19 Effect of mandrel diameter on the wall thickness uniformity of the hollow valve of 5Cr21Mn9Ni4 by cross-wedge rolling YAN Xiang-zhe,LIU Jin-ping,JI Hong-chao,WANG Bao-yu,ZHENG Zhen-hua,LI Zi School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083.China Corresponding author,E-mail:liujp@ustb.edu.cn ABSTRACT Wall thickness asymmetry is a common problem for cross wedge rolling (CWR)hollow shafts,which is especially usu- al in the CWR process of hollow shafts of small diameter and large height-diameter ratio.In this paper,the constitutive equation of hot deformation of 5Cr21Mn9Ni4N heat resistant steel was investigated by the thermocompression experiment on the Gleeble-1500D ther- mo-simulation machine.The law for the variation of wall thickness during forming 5Cr21Mn9Ni4 hollow valve with CWR was presen- ted,which is obtained via changing mandrel diameter and by means of finite element method(FEM)and experiment.The results con- firm that when hollow valve with mandrel is formed with the CWR process,there is a critical diameter of mandrel.It makes wall thick- ness of hollow valve optimal.On the basis of FEM,it is stated that uniform flow of material along the axial direction is necessary for wall thickness uniformity of hollow valve,and circumferential stretching strain near zero,increase of radial compression strain with de- crease of axial tension strain permit to improve wall thickness uniformity of hollow valve. KEY WORDS cross wedge rolling;heat-resistant steel;constitutive equations;hollow valves;critical diameter;metal flow 气门是发动机的重要零件。空心气门具有减重、等缺点.北京科技大学提出楔横轧-模锻成形空心气 降温、节能环保的优点.目前空心气门制坯主要有实 门新工艺]，其具有生产效率高、产品质量稳定、模 心气门钻孔法和反挤压法，但存在生产效率低、成本高 具寿命高等优点.楔横轧是一种成形轴类零件的先进 收稿日期：2016-04-18 基金项目：国家自然科学基金资助项目(51375042)：国家自然科学基金青年基金资助项目(51505026)：广东省“扬帆计划”资助项目 (201312G02)工程科学学报,第 39 卷,第 2 期:267鄄鄄275,2017 年 2 月 Chinese Journal of Engineering, Vol. 39, No. 2: 267鄄鄄275, February 2017 DOI: 10. 13374 / j. issn2095鄄鄄9389. 2017. 02. 015; http: / / journals. ustb. edu. cn 芯棒直径对楔横轧 5Cr21Mn9Ni4N 空心气门壁厚均匀 性的影响规律 闫向哲, 刘晋平苣 , 纪宏超, 王宝雨, 郑振华, 李 姿 北京科技大学机械工程学院, 北京 100083 苣 通信作者, E鄄mail: liujp@ ustb. edu. cn 摘 要 楔横轧空心轴类件存在壁厚分布不均问题,特别是在小直径大长径比空心件楔横轧成形中更为突出. 本文在 Gleeble鄄鄄1500D 热模拟实验机上进行了 5Cr21Mn9Ni4N 耐热钢的热压缩实验,得到了 5Cr21Mn9Ni4N 的热变形本构方程. 通过 改变芯棒直径,采用有限元仿真和实验相结合的方法,研究了楔横轧轧制空心气门过程中的壁厚变化规律. 研究结果表明, 带芯棒轧制时,芯棒直径存在临界值,在该值下进行轧制,空心气门预制坯壁厚均匀性最优;楔横轧空心件时,金属轴向均匀 流动是壁厚均匀的必要条件;轧件轴向拉应变减小,径向压应变变大,周向应变在 0 附近且为拉应变时,壁厚较为均匀. 关键词 楔横轧; 耐热钢; 本构方程; 空心气门; 临界直径; 金属流动 分类号 TG335郾 19 Effect of mandrel diameter on the wall thickness uniformity of the hollow valve of 5Cr21Mn9Ni4 by cross鄄wedge rolling YAN Xiang鄄zhe, LIU Jin鄄ping 苣 , JI Hong鄄chao, WANG Bao鄄yu, ZHENG Zhen鄄hua, LI Zi School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China 苣 Corresponding author, E鄄mail: liujp@ ustb. edu. cn ABSTRACT Wall thickness asymmetry is a common problem for cross wedge rolling (CWR) hollow shafts, which is especially usu鄄 al in the CWR process of hollow shafts of small diameter and large height鄄鄄diameter ratio. In this paper, the constitutive equation of hot deformation of 5Cr21Mn9Ni4N heat resistant steel was investigated by the thermocompression experiment on the Gleeble鄄鄄1500D ther鄄 mo鄄simulation machine. The law for the variation of wall thickness during forming 5Cr21Mn9Ni4 hollow valve with CWR was presen鄄 ted, which is obtained via changing mandrel diameter and by means of finite element method (FEM) and experiment. The results con鄄 firm that when hollow valve with mandrel is formed with the CWR process, there is a critical diameter of mandrel. It makes wall thick鄄 ness of hollow valve optimal. On the basis of FEM, it is stated that uniform flow of material along the axial direction is necessary for wall thickness uniformity of hollow valve, and circumferential stretching strain near zero, increase of radial compression strain with de鄄 crease of axial tension strain permit to improve wall thickness uniformity of hollow valve. KEY WORDS cross wedge rolling; heat鄄resistant steel; constitutive equations; hollow valves; critical diameter; metal flow 收稿日期: 2016鄄鄄04鄄鄄18 基金项目: 国家自然科学基金资助项目(51375042); 国家自然科学基金青年基金资助项目(51505026);广东省“扬帆计划冶 资助项目 (201312G02) 气门是发动机的重要零件. 空心气门具有减重、 降温、节能环保的优点. 目前空心气门制坯主要有实 心气门钻孔法和反挤压法,但存在生产效率低、成本高 等缺点. 北京科技大学提出楔横轧鄄鄄 模锻成形空心气 门新工艺[1鄄鄄2] ,其具有生产效率高、产品质量稳定、模 具寿命高等优点. 楔横轧是一种成形轴类零件的先进