摘要
为了提高钛合金细棒材的矫直精度,保证钛合金紧固件质量,依据钛合金材料属性和弹塑性理论,提出采用滚压反弯方式来提高矫直效果的辊型设计方法。在辊型设计过程中,根据细棒材的矫直变形规律,提出了εt-10εt矫直硬化系数模型,对细棒材变形的应力-应变关系描述更为准确;结合屈雷斯加屈服准则,分析了滚压反弯矫直的优点;并从接触强度、弹性变形及滚压力限制等角度建立了细棒材二辊矫直辊缝求解模型。在考虑应力中性层偏移、材料硬化规律和残余应力释放等因素对反弯曲率比的影响基础上,结合具体实例,给出了细棒材二辊矫直辊型设计曲线,并对矫直过程进行数值模拟。分析了矫直过程中影响棒材矫后精度的各参量状态,结果表明:采用设计辊型的棒材矫后直线度为0.41 mm·m^-1,二次回弹挠度为0.1737 mm·m^-1,预测弹复后直线度小于0.584 mm·m^-1;最终,利用矫直试验验证了该设计方法的正确性及有效性。
To improve the straightening accuracy of titanium alloy thin bar and ensure the quality of titanium alloy fasteners,according to material properties of titanium alloy and elastic-plastic theory,the roller shape design method to improve straightening effect using rolling and reverse bending was proposed.In the roller shape design process,aεt-10εtstraightening hardening coefficient model was developed based on the straightening deformation feature of thin bar to describe the stress-strain relationship of thin bar deformation more accurately.The advantages of the rolling and reverse bending straightening were analyzed combining with the Tresca yield criterion,and the roller gap solution model of two-roll straightening for thin bar was established from the view of contact strength,elastic deformation and rolling stress limit.The roller shape design curve of two-roll straightening for thin bar was given on the basis of considering the influence of stress neutral layer offset,material hardening law and residual stress release on the reverse bending curvature ratio combined with specific examples,and the straightening process was numerical simulated.The parameter states which affect the accuracy of bar after straightening were analyzed,and the results show that the straightening accuracy of the bar with the designed roller shape is 0.41 mm·m^-1,the hidden deflection is 0.1737 mm·m^-1,and the prediction accuracy after straightening is less than 0.584 mm·m^-1.Finally,the correctness and validity of the design method were verified by straightening test.
作者
范沁红
马自勇
马立东
雷军义
FAN Qin-hong;MA Zi-yong;MA Li-dong;LEI Jun-yi(School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Metallurgical Equipment Design Theory and Technology Key Laboratory of Shanxi Province,Taiyuan University of Science and Technology,Taiyuan 030024,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2020年第10期212-220,共9页
Journal of Plasticity Engineering
基金
山西省重点研发计划(201603D111004)
山西省专利推广项目(20171005)
山西省应用基础研究计划面上青年基金资助项目(201901D211292)
太原科技大学博士科研启动基金资助项目(20192022)。
关键词
钛合金
滚压反弯
硬化系数模型
辊缝
数值模拟
titanium alloy
rolling and reverse bending
hardening coefficient model
roller gap
numerical simulation
