Key Technology And Experimental Research On Precision Hot Extrusion Of Special Material Tubular Parts

The current international situation is intricate and the military strength of various countries has been greatly enhanced.With the development of science and technology,new types of weapons and equipment have emerged in an endless stream.In order to prevent invasion and maintain national security,we must vigorously develop new weapons and equipment.Based on the existing steel material technology and damage mechanism,the power is close to the limit and cannot meet the needs of new military struggles.We must achieve breakthroughs in weapons and equipment technology from new materials,new mechanisms and new design methods.Special materials(called materials A)because of their special properties,can improve the ability of weapon equipment to damage several times,is a breakthrough in the weapon equipment system to increase the power.Material A cylindrical parts are both warheads and important structural components in new weaponry.They have high requirements for organizational performance.In the past,they were usually formed by traditional manufacturing methods such as casting and machining,but the material utilization rate was low and the mechanical properties It is also difficult to meet the requirements.This article starts with the basic performance of material A.According to the characteristics of material A,such as severe oxidation at high temperature and narrow forging temperature range,comprehensive consideration of factors such as the high price of material A,the difficulty of obtaining materials,and the limitations of manufacturers'equipment,etc.The feasibility of the method finally obtained the two-process hot extrusion forming process as the best plan.This process plan adopts the method of one-step composite extrusion forming the upper end of the forging,and the two-step reverse extrusion forming the forging.The simulation results show that the one-step composite The upper end of the extruded forging can effectively reduce the forming force required for extrusion,and the punch required for forming the upper end is thicker and shorter,and the rigidity is enhanced.While bearing the maximum forming force,it can resist the deviation caused by temperature difference,lubrication and other factors The load-bearing force can effectively reduce the eccentricity of the forging.The second process uses a thinner punch to form a smaller inner hole.The upper part extruded from the first process can guide the second process punch to ensure the centering of the punch and the extrusion process.The lateral support of the counter punch.On the basis of the forming process,a special die for the extrusion of sleeve-shaped parts is designed according to the existing equipment.In order to achieve the two-process forming required in the process,the upper die adopts two movable punches,which solves the problem that the equipment cannot meet the double process At the same time,it can leave enough space for removing the forgings.Due to the high temperature oxidation characteristics of material A,the blank must be protected during the heating of the blank.In this paper,the protective glass UM-4 of material A was successfully developed through multiple protection experiments.The experimental results show that this coating can effectively prevent the heating process The billet is in contact with air and can play a role of heat preservation after the billet is released from the furnace.Developed an extrusion lubrication scheme for a cylindrical part of material A that uses glass powder to lubricate the outer surface and glass pads to lubricate the inner hole,which solves the problem of extrusion cracking in the shrinkage experiment.Based on the above research,a complete process experiment was carried out at a cooperative manufacturer,and a qualified extrusion product was produced,which proved the rationality of the two-process hot extrusion scheme,and opened a new route for the production of material A cylindrical parts.