Numerical Simulation Method On Pulling-straightening Roller Surfacing Process

In China’s steel industry mainly steel molding rely on continuous casting and rolling equipment to produce, and straightening rolls are one of key components of the caster. The function of straightening rolls is casting flow forming, cooling, guiding and driving. The straightening rolls was always working in the severe environment, the surface was touched with high-temperature casting billet and cooled rapidly, Simultaneously the surface was subjected to tangential force.Straightening roll repaired method was generally used by welding, surfacing alloys on base metal. It could repair the worn rolls but also improve the heat resistance and wear resistance of the straightening rolls.0Cr13Ni4MoN is ultra-low carbon martensitic steel by newly developed materials,discovering that 0Cr13Ni4 MoN possessd a good plasticity, abrasion resistance, heat resistance, corrosion resistance and other characteristics by microstructure analysis,suitable for straightening roller surface cladding material, it can improve the quality of billet and the life of roller body. The process of useing 0Cr13Ni4 MoN wire to weld roll body was combined with finite element analysis to study, simulating the whole process and studying the factors affecting actual welding quality, accelerating new material scale in practical engineering applications.Using thermal and structural analysis module of ANSYS software to simulate process of the surfacing. Gaussian model is selected as heat source model, direct methods be used for the calculation of temperature field to obtain welding residual stress and strain fields,using sparse matrix solver can effectively solve the nonlinear computation when computing no convergence problems. Given Gauss load applied and the process of moving steps is cumbersome, lengthy, so using APDL programming methods to improve operability while facilitating adjustment and testing procedures. The analysis results of temperature and cooling at different stages of surfacing study the effect of heat on layer thickness and residual stress and strain state distribution. According to the actual needs of the project to develop the welding process optimization program so it can greatly improve production efficiency and reliability.By studying its impact on the welding process simulation welding program transformation, to draw conclusions from simulation results, changing the welding current and welding speed parameters have the following impact on the size of the surfacing layer:When the arc current increases, bath depth will increase, while the width of the pool will remain basically unchanged; the slower welding speed, weld width size, welding temperature field and temperature peak width will increase, the average depth of the bath is1.2mm, the average width of the bath is 9.5mm; during preheating temperature ranged250~ 350 ℃ a uniform distribution of the temperature field could be obtained.The residual stress during the cooling process continued to spread to the edges of the roll body and the release of large residual stress is concentrated at the roll body and the fixed end of the roll body edge, maximum stress size is about 330 MPa, the roller body average residual stress is about 80 MPa. As the preheat temperature increase, the pipe after welding is relatively uniform temperature field, there is a small roller body strain deformation, temperature field after high temperature welding will make the appropriate microstructure roll more uniform, contributing to reduce the residual stress peak, large deformation of about 4E-3. According to the simulation results obtained for the optimization process: welding current 320 ~ 340 A, welding speed 12 ~ 15 cm / min,preheating temperature 250 ~ 260 ℃.