Design And Experimental Research On Extrusion Process Parameters Of Hollow Helical Aluminum Profiles

As the core components of mechanical superchargers,screw air compressors,rotameters and other equipment,helical rotor mechanisms are widely used in machinery,metallurgy,mining,power,chemical and other fields.At present,most of the helical profiles are made of steel,cast iron,etc.,and are manufactured by machining methods such as milling and planing.Compared with the traditional machining method,the aluminum alloy extrusion forming process is less time-consuming,high in work efficiency and high in material utilization.This paper takes the Roots supercharger rotor as the research object,mainly explores the extrusion forming process of aluminum alloy hollow helical profiles,and improves the torsion angle accuracy after extrusion by designing the hollow structure.The main research contents of this paper are as follows:(1)Analyze the cross-sectional shape and working requirements of the Roots rotor,design in combination with the die design theory,and use Solidworks software to model the extrusion shunting die in 3D.The flexural and shear strength of the shunt bridge is checked,and the results show that the designed shunt die meets the strength requirements.(2)The finite element model of aluminum alloy hollow helical profile extrusion was established by Hyper Xtrude software,and the velocity field,temperature field,stress-strain distribution and deformation during extrusion were analyzed.By adding a choke block,changing the shape of the welding chamber,and shortening the length of the torsion working belt,the mean square deviation of the flow velocity of the die outlet section decreased from the initial 3.9518 to 1.3708,and the deformation displacement of the outlet profile was reduced from 55.04 mm to 41.74 mm,and the deformation trend was more gentle.(3)Using the control variable method,the effects of extrusion speed,aluminum billet temperature,die temperature,and extrusion cylinder on the extrusion process of aluminum alloy hollow helical profiles were analyzed.Combination of extrusion parameters with better uniformity of flow rate and smaller required extrusion force;use range analysis and contribution ratio calculation to determine the mean square deviation of extrusion speed,aluminum billet temperature,die temperature,and extrusion barrel temperature on the die outlet flow rate and the degree of influence of the extrusion force.(4)The extrusion test was carried out,the size of the profile was measured by an optical 3D scanning system,and it was found that the width of the tooth surface was slightly reduced.The rotor design twist angle was120°/100 mm.The obtained twist angle is 78°/100 mm,and the twist angle of the solid helical profile after forming under the same conditions is33°/100 mm.The test proves that the hollow structure can significantly improve the twist angle of the helical profile;Through OM and SEM techniques,it is determined that the optimal solution scheme of the profile studied in this paper is 540℃×1h.Tensile test and hardness test were carried out on different parts of the profile,and it was found that the middle part of the profile had better mechanical properties and higher hardness,the tensile strength reached 242 MPa,the hardness reached 89.4HV,and the elongation of the profile near the tooth top was the best,reaching 20%.57 Figures,18 Tables,74 References.