Simulation And Experimental Study Of Brass Alloy Continuous Extrusion Control Die Outlet Velocity Uniformity

Continuous extrusion technology is an efficient,economical and energy-saving plastic forming method.In this paper,H62 brass is selected as the raw material for simulation and experiment.Because H62 brass has very good mechanical properties in brass alloys.It has good plasticity in both hot and cold states,wear resistance,electrical conductivity,thermal conductivity and corrosion resistance.In the continuous extrusion process of H62 brass,the uneven distribution of flow velocity at the exit of the die easily results in the uneven internal structure of the product,the defects of external bending and cracking of the product,which leads to the decline of the quality and performance of the product.Based on TLJ250 continuous extrusion press,the process of continuous extrusion of copper rod was simulated and analyzed by Deform-3D software,and the effects of different process parameters on the quality and performance of copper products were analyzed,which provided effective theoretical guidance for the optimization of process parameters in the process of continuous extrusion of copper rod.The results of simulation and experiment are as follows.Product diameter 0=6mm,9mm,15mm,the area expansion ratio is defined.With the increase of area expansion ratio,the temperature of metal decreases,and the velocity presents symmetrical laminar flow distribution.When ζ=3.52,the velocity at the die sizing zone changes slightly and the velocity at the die exit is more uniform.Speed of extrusion wheel n=5r·min-1,7r·min-1,9r·min-1,the metal flow velocity and deformation temperature decrease with the decrease of extrusion wheel speed.When the extrusion wheel speed n=5r·min-1,the longitudinal flow velocity curve is the smoothest and the die exit velocity is the most uniform.Extended channel length L=0mm,3mm,6mm,with the increase of the expanding cavity length L,the overall temperature gradually increases,and the metal flow rate slows down and tends to be stable.When L=6mm,the mean square deviation and variance of the flow rate are the smallest,that is,the flow rate at the outlet of the die is the most stable.Products of different shapes(06 Round bar、Equal section area L6 square bar、Circumscribed circle 06 six square bar),with the increase of product shape complexity,the effect of temperature is not significant,and the equivalent stress and maximum stress at the corner of billet increase and are not uniform.The mean square deviation of transverse velocity increases and the extreme value increases at the fixed diameter zone.The experimental results show that there is little influence on the inner structure center of products with different shapes,the metal fluidity of the inner structure center is stable,and the flow velocity of the die outlet is uniform.The internal organization edge and corner parts of products with different shapes,circumscribed circle 06 six square bar,inclusion stratification,metal flow rate is not uniform.Hardness test analysis,06 Round bar is better than circumscribed circle 06 six square bar.Elongation after breaking,06 Round bar is longer than circumscribed circle 06 six square bar.Tensile strength,06 Round bar is better than circumscribed circle 06 six square bar.