Research On Numerical Simulation And Process Application Of Coreless Spinning Of 439 Stainless Steel Laser Welded Tube

In this paper,the problems of cracking and other defects in the spinning process of the ternary catalyst shell are discussed.Mechanical modeling of coreless hot-spin forming of the double-rotating wheel of a three-element catalytic converter shell was developed and selection of spinning process parameters and forming simulation and study on the Test and Verification of Coreless Hot Rotating Forming of Double Rotary Wheel.The results are of theoretical significance for spinning production in practice.A stress-strain curve of 439 stainless steel was produced by static tensile test,and calculated initial yield strength,work hardening modulus and hardening index in Johnson-Cook constitutive model parameters.The strain rate constant and thermal softening coefficient were obtained by changing the temperature and velocity in the stretching process.The tensile damage simulation and test of 439 stainless steel were corrected to obtain the influence law of Johnson-Cook damage parameters:with the D₁?D₂increase of damage parameters,the maximum equivalent failure plastic strain value increases when the material initial damage and complete failure,the change law of damage parameter D₃ is opposite,the damage parameter D₄ and D₅ have no obvious influence on the tensile failure of the material,and determine parameter D₁?D₂?D₃?D₄?D₅ after correction..This paper further studies the stress of the workpiece during spinning,selects a deformation unit,first analyzes the force relation of the unit,and then,according to the stress equilibrium equation,the formula for calculating the spinning wheel pressure is derived.ABAQUS software is used for spinning simulation.Based on the characteristics of the spinning process,a simplified finite element model of the shell and spinning equipment of the ternary catalyst is established to optimize the spinning process parameters,and the distribution and parameter range of the stress,strain and wall thickness of different parameters in the spinning process are obtained by the single variable factor simulation test.The optimum parameter combination is obtained by orthogonal simulation test is spinning temperature 1000?,rotary wheel fillet 5mm,rotary wheel speed 40r/s,feed ratio 1.2mm/r,The forming diameter is 79.17mm,the port wall thickness welding seam is 1.496mm,the base material is 1.44mm,the forming roundness error is 0.065mm,the primary and secondary order affecting the roundness error of the closing is:feed ratio f>rotating wheel speed n _M>spinning temperature>spinning wheel fillet r.And the test results of coreless hot spinning forming with double-rotating wheels are carried out.The test results are that the wall thickness of the port weld is about 1.66mm,the base material is 1.46mm,the diameter of the formed part is about 78.2mm,and the roundness error e circle is 0.05mm.The test results are better than the numerical simulation results,and the errors of base metal thickness and forming diameter are 1.37%and 1.24%,respectively.Observe the changes in the structure of the formed parts.The microstructure changes of the forming parts were observed,and the microstructure grains were refined at the spinning place after the spinning closing forming,and the deformation amount increased and the hardness increased accordingly,and the deformation amount increased and the hardness increased accordingly,The hardness law of the thickness direction of the forming parts is as follows:the hardness of the outer layer>the hardness of the inner layer>the hardness of the middle layer,the hardness difference between the circumferential weld and the base metal,decreases with the increase of the spinning deformation.