不同孔型参数对薄壁无缝管顶管过程管壁拉凹的影响

Effect of different groove parameters on pulled concave of tube wall in push bench process of thin-walled seamless steel tubes

针对某钢管公司Φ114 mm CPE顶管机组薄壁无缝管顶管过程中出现的管壁拉凹缺陷,借助于有限元分析软件Simufact,对典型规格Φ111 mm×4. 35 mm的42CrMo4钢管顶管过程进行三维弹塑性有限元模拟,分析了不同孔型参数对顶管过程的模辊力、各机架出口轧件壁厚及应力应变的影响。结果表明:顶管过程中,减壁量较大的机架之间存在张力作用;不同孔型系列,机架减壁量(减壁率)越大,机架间张力、轧件在辊缝处产生的附加变形、壁厚拉薄量和所受的轴向拉应力越大,管壁发生拉凹的倾向性增大。因此,在设计孔型时,要合理分配各机架的减壁量(减壁率),使单个机架的减壁量(减壁率)不宜太大。通过现场生产探伤数据对模拟结果的正确性进行了验证。

In view of tube wall pulled concave in the push bench process of thin-walled seamless steel tube for Φ114 mm CPE push bench mill of a steel tube company,with the aid of finite element analysis software Simufact,3D elastic-plastic finite element simulations of the push bench process of 42 CrMo4 steel tubes with typical specification of Φ111 mm × 4. 35 mm were constructed. The effect of different groove parameters on the rolling force,the wall thickness of rolled tube at the outlet of each stand and stress/strain in the push bench process was analyzed. The results show that there exists tension effect between stands with larger wall thickness reduction during the push bench process. For different groove schedules,the greater the wall thickness reduction( rate) of the stand is,the greater the tension between stands,the additional deformation,the thinning amount of the wall thickness and the suffered axial tensile stress of rolled tube at the roll gap are,which results in the increase of the pulled concave tendency of tube wall. Therefore,in groove schedule design,the wall thickness reduction( rate) in each stand should be reasonably allocated,namely the wall thickness reduction( rate) of single stand should not be too large. The correctness of simulation results were verified by the inspection data from practical production.