Simulation Study Of Extrusion Deformation Of Super Supercritical P92 Steel

North heavy industry group is the main production factory of P92 pipe in China.Because of its high strength,plastic toughness and high temperature oxidation resistance,the P92 pipe is widely used in the heater,reheater and other parts of thermoelectric boiler.In the actual production process of P92 pipe,extrusion forming is often utilized,so the quality of extrusion directly affects the final performance of the product.In this paper,using DEFORM software,combined with the actual production process conditions on site,a certain specification of P92 pipe is taken as the research object.By simulating the flow law of metal in the process of extrusion,the temperature field,stress field,strain field,velocity field and displacement field of the actual pipe product in the process of extrusion are revealed;on the other hand,taking the key factors(die taper angle,friction coefficient,extrusion temperature and extrusion speed)that affect the forming quality of extrusion process as variables,the influence of these factors on the temperature field and strain field in the process of metal flow is analyzed by simulation,which provides information support for the optimization of die structure,size and extrusion process parameters in the actual extrusion process.The results of simulation analysis of metal flow law show that there is a process of temperature reduction before extrusion.The temperature of the outer wall of the billet decreases from 1290?to 970?,and the center temperature is almost the same.During extrusion,the temperature of the inner and outer wall of the pip first decreases and then increases,the maximum temperature is 1000?and 970?,the minimum temperature is630?and 680?,respectively,and the center temperature of the pipe is almost the same.With the process of extrusion,the equivalent strain of pipe from outer wall to inner wall gradually increases,and the maximum strain of inner wall reaches 3.2.The equivalent stress first increases and then decreases,and the maximum stress of inner and outer wall is348 Mpa and 396 Mpa respectively.The extrusion pressure first increases and then decreases,and finally keeps stable,with a stable value of about 1.82×10~7 N.With the extrusion process going on,the flow velocity of the pipe metal increases continuously,the maximum value is about 470 mm/s,relatively speaking,the metal flow velocity in the wall center is larger than that in the inner and outer walls.From the inside to the outside,the radial displacement of the metal first increases and then decreases,lastly increases in the opposite direction,in which the displacement difference of the outer wall is the largest,with a value is about 275 mm.The axial displacement of the metal increases continuously,and the axial displacement of the metal in the central region is slightly larger.In the process of extrusion,die cone angle,friction coefficient,extrusion speed,extrusion temperature are the key factors affecting the quality of pipe extrusion.The simulation was conducted at the die cone angle of 30°,45°,60°,friction coefficient of 0.02,0.04,0.06,extrusion ratio of 4,8,extrusion speed of 40mm/s,60mm/s,80mm/s,extrusion temperature of 1210?,1250?,and 1290?.The results show that when the die cone angle is 60°,friction coefficient is 0.02,extrusion ratio is 4,extrusion speed is 40 mm/s,extrusion temperature is 1290?,respectively,the metal flow displacement,velocity,equivalent strain,equivalent stress,extrusion pressure and temperature difference of P92pipe are minimized,and the extrusion formability of the pipe is the best.