孔型参数对热连轧优特圆钢质量影响的数值分析

Numerical Analysis of Influence of Pass Parameters on Quality of Hot Tandem Rolled Special Round Steel

利用有限元软件对孔型改进前后直径16 mm的40Cr圆钢热连轧工艺进行了数值模拟分析,并通过工业轧制试验进行了验证。结果表明:模拟轧件表面特征点温度及关键道次轧件尺寸与实测值吻合良好;随着轧制的进行,椭圆轧件高宽比及圆轧件直径减小,轧件在圆-椭圆孔型中的宽展系数增大;原有孔型部分道次存在欠充满或过充满缺陷,导致道次间轧件堆拉率较大,圆轧件料形及直径偏差较大;孔型改进后道次间轧件堆拉率减小,圆轧件料形及直径偏差明显改善,有效地提高了产品精度。在此基础上,修正了导卫内腔尺寸及活套调节器控制参数,优特圆钢表面划伤缺陷得到有效控制。

Numerical simulation and analysis were carried out for the hot continuous rolling process of 40 Cr round steel 16 mm in diameter before and after the pass improvement by a finite element software,and verifed by the industrial rolling test.The results showed that(a)the simulated temperatures of surface characteristic points and sizes of the rolled piece in key passes were in good agreement with the measured values;(b)as the rolling went on,the height to width ratio of the elliptic rolled piece and the diameter of the round rolled piece decreased,and the width coefficient of rolled piece in the circular-elliptic pass increased;(c)there were defects such as underfilling or overfilling in some passes of the original pass,leading to larger pile-pull rate of the rolled piece between passes,and larger deviation of the shape and diameter of the round rolled piece;(d)after an improvement in the pass,the push-pull rate of the rolled piece between passes reduced,the deviation of the shape and diameter of the round rolled piece was improved obviously,which effectively improved the product precision.On that basis,the dimensions of guide lumen and parameters of looper regulator control were revised,the surface scratches of the special round steel was controlled effectively.