Research On The Key Technology Of Roll Extrusion Production Of Curved Rotary Shaped Cylinder

Cylindrical parts with curved revolving shape are more and more widely used in various fields,and they occupy an important position in my country's military and economic development.Roll extrusion is a new type of process for forming cylindrical parts with curved revolving contours.It can achieve continuous thinning of the wall thickness of the workpiece and form cylindrical parts with variable wall thickness.However,in actual production,steps and molds are prone to occur on the surface of the blank.Difficult to warm up and other issues.In this paper,the surface quality of cylindrical parts and mold temperature are studied based on 40 Cr alloy.The roller reset device was designed and compared with the original mold;the Deform-3D finite element software was used to simulate the forming speed and the number of blanks,and the results are as follows:The new roller reset mechanism solves the problem that the gear meshing reset easily causes the axial "step" on the outer surface of the formed workpiece,realizes the reliable and accurate reset of the roller,and reduces the difficulty of mold assembly.The roll extrusion speed is slow and the mold heats up quickly.When the forming speed is 30mm/s,the average temperature rise of the mold after the first blank is formed is 13%.When the third blank is formed,the temperature difference between the blank surface and the flash can be reduced to 35?;when the forming speed is 50mm/s,After the first blank is formed,the mold heats up by an average of 8.5%.When the fifth blank is formed,the temperature difference can be reduced to 33°C;when the forming speed is 70mm/s,after the first blank is formed,the mold heats up by an average of 7%.However,the equivalent stress and strain average of the first blank is relatively large,and it is easy to fold during the flash elimination stage.Therefore,the initial speed of roll extrusion is 30mm/s.The material used for the roller is H13,and its best working temperature is around 600°C.When three blanks are produced,the temperature of the roller can reach about 359?,which achieves the purpose of preheating the roller,and then adopts the forming speed of 170mm/s to maintain the temperature of the roller at about 597?,without the need to perform the roller Cooling treatment can ensure continuous roll extrusion.The roll extrusion test verifies the accuracy of the new roll reset mechanism and simulation,which provides a basis for continuous production of roll extrusion without preheating the mold.