二辊斜轧延伸大口径P92厚壁管分层缺陷倾向性研究

为研究不同轧辊转速、送进角、轧辊人口锥角等工艺参数对大VI径厚壁P92钢管二辊斜轧延伸过程分层缺陷形成倾向性的影响，借助于商用有限元软件MSC．SuperForm，对不同工艺条件下大口径厚壁P92钢管二辊斜轧延伸过程进行了三维热力耦合模拟；采用Oyane韧性断裂准则分析了轧件损伤场及钢管分层缺陷的倾向性。研究结果表明：钢管内表邻近顶头接触区存在破裂高危带，轧件最大损伤特征值随轧辊转速的降低、送进角和轧辊入口锥角的增大而减小，发生分层缺陷的倾向性降低。此研究为揭示钢管分层缺陷形成机制，确定缺陷发生的敏感工况，制定防止或减轻分层缺陷的有效措施提供科学依据。

Tendency of Lamination Defect of Thick-Walled P92 Pipe With Large Diameter Elongated by 2-Roll Rotary Rolling Process

To investigate the influence of different technological parameters such as roll rotational speed,feed angle and roll entrance cone angle on tendency of lamination defect of seamless P92 steel pipe thick-walled with large diameter elongated by 2-Roll rotary rolling process,with the aid of commercial FE code MSC.SuperForm,3D thermo-mechanical simulations were presented.The damage field of the rolling piece during the elongating process,and the tendency of lamination defect of steel pipes were analyzed using Oyane ductile fracture criterion.It is found from the simulation that a high dangerous crack band exists in the internal surface layer of the rolling piece,adjacent to the contact zone with the plug.Furthermore the influence of roll rotational speed,feed angle and roll entrance cone angle on the damage filed were investigated.The result shows that the maximum characteristic value of ductile fracture of rolling piece decreases with the decrease of roll rotational speed,the increase of feed angle and roll entrance cone angle,and the tendency of lamination defect reduces.The scientific basis can be provided for revealing formation mechanisms of lamination defects of rolled seamless steel tubes with high Cr,determining the sensitive working conditions caused defects,and making the effective measures to prevent or reduce lamination defects.