Simulation Of Steel Tube Continuous Rolling Process Of ?140 Mm Full Floating Mandrel Mill And Its Secondary Development Of Rapid Modeling

Seamless steel tube is a very important profile with economic cross section,which plays an important role in national economic construction.The quality of steel tubes determines the competitiveness of enterprises in the market,and the problem of improving the quality of products needs to be solved urgently.Baosteel's ?140 mm unit is a full floating mandrel mill,the steel tube continuous rolling process is one of the core processes in the whole unit production process,which has a direct impact on the quality of products.There are many factors affecting the process of steel tube continuous rolling,such as pass structure parameters,the surface state of roller and rolled piece,the lubrication of the mandrel,steel tube material and its wall thickness uniformity,temperature distribution,speed allocation of each stand,and so on.The mechanism is very complex,and it is difficult to analyze by conventional physical simulation experiments.Finite element method has unique advantages in dealing with metal forming problems,which can completely reproduce the process of metal forming and conduct quantitative analysis.Therefore,in this paper,T91 high-pressure boiler tube,the main product of the unit,is used as typical material.With the help of ABAQUS,a large-scale finite element software,the continuous rolling process of typical specification(?179×21.75 mm)steel tube in the full floating mandrel mill is studied in depth,and the effects of different production conditions on the continuous rolling process and the quality of the steel tube were studied,which provides reference and guidance for improving the quality of the steel tube in actual production.At the same time,in order to shorten the product improvement and development cycle,a rapid-modeling plug-in for full floating mandrel mill is developed by combining actual pass with ABAQUS software.The plug-in can greatly improve the efficiency of pass and process improvement.The main research work and results carried out in this paper are as follows:(1)The high temperature deformation behavior of T91 steel was studied and the deformation resistance model was fitted.It can predict the deformation resistance of T91 steel within a certain temperature and deformation rate range,and provide basic data for finite element simulation.(2)Based on the actual production situation,the the 3D thermal-mechanical coupling model of the full floating mandrel mill was established by ABAQUS software.And according to the simulation results,the metal flow and shape change,rolling force and energy parameters,stress and strain distribution,mandrel movement state and temperature distribution of T91 steel tube during continuous rolling in full floating mandrel mill are studied,which can provide reference for actual production.(3)The influence of the lubrication state of the mandrel on the rolling process was studied.In the actual production,the lubrication state of the mandrel should be improved.The better lubrication measures should be used to reduce the friction coefficient between the rolled piece and the mandrel,which can effectively reduce the rolling force,reduce the speed step trend of the mandrel,reduce the wear of the mandrel,reduce the uneven deformation during the rolling process,and reduce the uneven thickness of the transverse wall thickness of the rolled steel tube,and improve the quality of the steel tube.(4)The influence of the friction coefficient between the rollers and the rolled piece on the rolling process was studied.The friction coefficient increased,the rolling force of each stand increased,and the axial speed of the mandrel also increased.When the friction coefficient increases to 0.5,the uneven thickness of the lateral wall of the rolled tube is more obvious.Therefore,good surface condition between rollers and steel tube should be maintained so that the friction coefficient between roll and workpiece can not be too high.(5)The influence of the inner circle eccentricity of the steel tube on the Wall thickness accuracy of the rolled steel pipe is studied,the results show that:The more serious the inner circle eccentricity of the steel tube is,the higher the uneven thickness of the transverse wall thickness of the steel tube after rolling is,and the free floating of mandrel in non-rolling direction is one of the reasons that the ability of full floating mandrel mill to correct the eccentricity of inner circle in steel tube is not strong.(6)Based on the 152.5 pass series,the Python language combined with ABAQUS software was used to develop the plug-in with the pass parametric modeling as the core.A simple and easy-to-operate interactive interface is established,pass parameters,speed system,steel tube size,mandrel size and so on can be directly input into plug-ins,which can be quickly generated in a few seconds.It realizes unified management of parameters and automation of modeling.