Fem Simulation And Research Of The Radial Forging Process Of P91 Thick-walled Pipe

Thick wall seamless steel tube that made of high-strength alloy steel,stainless steel and other metal are widely used in the fields of electricity, chemical, petroleum, machine manufacturing, ships and national defense, because of its good high temperature enduring strength, thermal stability and high temperature creep resistance, and its working condition and force bearing are heavy and complicated. Thus, improving the quality of thick-walled seamless steel pipes to ensure the safety and reliability during the operation of which is of crucial importance to the improvement of the technology of thick-walled seamless steel pipe and national economy.In order to produce thick-walled seamless steel pipe via radial forging to meet the need of market we combine the advantages of P91(10Cr9Mo1VNb) and the advantages of radial forging. A numerical modeling software called DEFORM-3D was used to make the simulation experiment of radial forging of thick-walled seamless steel pipe made from P91(10Cr9Mo1VNb) and P91 material database was established in the DEFORM.Secondly, the structure of the hammer head seriously affects the quality of forgings was found by studying the influence of different hammer structure to the radial forging process, and when hammer head with preformed section was chosen, the surface of the forging quality was best, at the same time, the stress and strain distribution of forging were the most uniform. Then, the ranges of main technological parameters were determined through single factor method and two passes was chosen to forging the billet to meet the requirement of diameter is 425 mm and wall thickness is 83 mm. Set up that radial reductions of two passes are both 25 mm. Finally, the optimum process parameters of radial direction load and wall thickness were determined by doing the orthogonal test which take five factors, the pressure corner of hammer die, the plastic length of hammer die, the percussive frequency of hammer die, the single rotation angle and the axial direction feed,into account. For radial forming load, the best process parameters are as follows: the pressure corner of hammer die is 20°, the plastic length of hammer die is 400 mm, the percussive frequency of hammer die is 160 times/min,the single rotation angle is38°, the axial direction feed is 50 mm. For wall thickness,the best process parameters are as follows: the pressure corner of hammer die is 10°,the plastic length of hammer die is500 mm, the percussive frequency of hammer die is 200 times/min, the single rotation angle is 25°, the axial direction feed is 50 mm.