Study On Surface Integrity Of High Speed Cold Roll-beating Forming

High-speed cold roll-beating is an advanced,green near-net forming plastic special processing technology.The principle is the use of the plasticity of the material,through the high-speed rotation of the roller on the workpiece for continuous hit,forcing the metal material along the roll wheel contour direction of the flow,gradual plastic forming,forming into the high-performance parts.Cold roll-beating technology is an efficient precision forming technology,can effectively improve the surface quality and mechanical properties of parts.And the surface integrity of the parts directly affect its mechanical properties,is to evaluate the performance of cold rollbeating processing technology is the important indicator,but also to study the hot forming of mechanical processing problems.Therefore,it is of great theoretical significance to study the influence of cold roll forming parameters on the surface integrity evaluation index of cold roll forming,and to realize the optimal control of the forming parameters of cold roll forming surface.In this paper,we study the surface roughness,work hardening,scanning electron microscopy and residual stress of cold roll with the involute spline as the research object.Gauss filter is applied to the profile data of cold roll-beating involute spline surface by MATLAB.The high frequency components of surface roughness are obtained,and the change trend of the parameters.The surface hardness and the microstructure of the surface are affected by the roll speed and the workpiece feed.The formation rule of residual stress under different cold rolling parameters is studied.The microstructure of the spline surface of the cold roll is simulated by MATLAB software.The applicability of the theoretical model is verified by comparing with the experimental data.Based on BP neural network,a prediction model of the effect of cold roll forming parameters on the residual stress of involute spline surface is established.The correlation model is used to analyze the training samples and the test samples,which shows the credibility of the prediction model.The prediction model of the degree of hardening of the involute spline surface of the cold roll-beating is established by using the surface response method.Through the comparative analysis of the predicted value and the experimental value,the validity and accuracy of the prediction model are verified.The method of solving the global optimal value in the particle swarm algorithm is improved,and the improved particle swarm optimization algorithm is used to evaluate the surface roughness,residual stress and hardening degree of the involute spline goal of the integrated optimization.And the surface roughness and the surface integrity performance index are obtained.The results show that the surface roughness,work hardening and residual stress of the cold roll-beating involute spline achieve the optimal synthesis of the rotated speed is 1565.8r/min,the workpiece feed speed is 27.8mm/min.The performance parameters are surface roughness 0.4086?m,surface hardening degree 143.3%,residual compressive stress 72.2MPa.Through the experimental study of the involute spline of the cold rolling with the roll-beating wheel rotated speed of 1581r/min and the workpiece feed speed of 28mm/min,the relative error between the obtained result and the optimized result is only 1.9%,which shows that the optimization result has certain guiding significance.