轧辊参数对斜轧穿孔变形过程及内折叠的影响

Effect of roll parameters on deformation process and inner folding in rotary tube piercing process

针对某钢管公司2Cr13钢无缝管穿孔过程中出现的内折叠缺陷问题,在测定2Cr13钢高温力学性能的基础上,借助于有限元软件Simufact,完成对典型规格的2Cr13钢管现有工艺穿孔过程的分析后,对轧辊参数进行了优化设计,在此基础上研究了不同轧辊入口锥角、入口锥分段长度、轧辊辊径和轧辊转速对穿孔内折叠及二次咬入的影响规律。结果表明:将原有轧辊入口锥设计为2段式,第1段变形区长度L_(11)=170 mm,入口工作锥角β_(11)=1.8°,第2段变形区长度L_(12)=110 mm,入口工作锥角β_(12)=3.2°,采用该轧辊设计方案穿孔时,最大轧制力、顶头轴向力和导板力较原有轧辊分别下降了5.56%、3.89%和20.55%,二次咬入顺利,轧件产生内折叠的倾向性较小;轧辊直径从800 mm增大到850 mm,轧制力增大,导板力减小,轧件轴向阻力减小,有利于管坯的二次咬入和穿孔过程的稳定,扩大了顶前压下率的调整范围;当轧辊转速从56.4 r/min增大到62 r/min时,轧件出口速度增大,但轧制力矩增大,能耗增加,轴向滑移增大,轴向速度效率降低,轧件发生内折叠的倾向性增大。

On view of the inner folding defect of 2Cr13 steel seamless tube in actual production of a steel pipe company,based on the determination of mechanical properties of 2Cr13 steel at high temperature,a three-dimensional elastoplastic finite element simulation of the existing process of the typical specification 2Cr13 steel rotary tube piercing process with the help of finite element software Simufact was analyzed,and the roll parameters were optimized.Furthermore,the influence of different roll entrance cone angle,entrance cone segment length,roll diameter and roll rotate speed on inner folding and secondary biting in rotary tube piercing was studied.The results show that the new roll is designed as a two-stage entry cone roll,that is,the first section length L_(11)=170 mm,work cone angleβ_(11)=1.8°,the second section length L_(12)=110 mm,work cone angleβ_(12)=3.2°.The maximum rolling force,plug axial force and guide shoe force decrease by 5.56%,3.89%and 20.55%,respectively,compared with the original roll when using the new design scheme roll in rotary tube piercing process,and the second bite is smooth,and the tendency of the rolled piece to produce inner folding is very small.When the diameter of the roll increases from 800 mm to 850 mm,the rolling force increases,the guide force decreases,which results in the axial resistance of the rolled piece decreases,which is beneficial to the second bite of the round bar and the stability of the piercing process,and the adjustment range of the reduction rate before plug is expanded.When the roll rotary speed increases from 56.4 r/min to 62 r/min,the outlet speed of the pierced shell increases,but the rolling torque increases which results in the energy consumption increases,the axial slip of rolled piece increases,so the axial speed efficiency decreases,and the tendency of inner folding of pierced shell increases.