Effect Of Process Parameters On The Formation Of Bismush-containing Stainless Steel Bars

A large amount of stainless steel is needed in the chemical and food machinery industry.The addition of bismuth in stainless steel not only improves its hot workability,cold workability and cutting performance,but also meets the hygiene standards of the food machinery industry.It is being widely used in the chemical and food machinery industries.Three-roller planetary rolling is the main rolling technology for bismuthcontaining stainless steel bars.In actual production,the core of the bar is prone to cracks,voids and other defects,which seriously affect the quality of the product.The purpose of this paper is to optimize the three-roller planetary rolling process parameters of bismuthcontaining stainless steel bars and solve the problem of cracks in the core of the bar during rolling.Through the research on the theory of three-roller planetary rolling and the investigation on the spot,the influence of many process parameters on the rolling process was analyzed,and the optimized process parameters and its range were determined.The finite element software ABAQUS was used to simulate the three-roller planetary rolling process of bismuth-containing stainless steel bars.The flow law,stress state,strain state,temperature field and rolling force of the rolling process were analyzed by simulation results.The different levels under five key process parameters were selected and 16 sets of simulation experiments were performed using orthogonal test.The fracture threshold of bismush-containing stainless steel was used as the standard,and the Brozzo ductile fracture criterion was used to judge the crack of the core of the bismuh-containing stainless steel rod.A set of optimal rolling process parameters were obtained: temperature 1200 °C;friction coefficient 0.7;deflection angle 6°;inclination angle 54°;roll speed 120 r/min,and the sensitivity of five process parameters to cracking were discussed.The hot working diagram of bismuth-containing stainless steel was drawn.The results of the instability zone and stability zone of the hot-worked drawing were compared with the results of finite element simulation.The two were basically the same,and the optimized process parameters could be used to guide the actual production.Finally,the optimal process parameters are rolled on site.The rolling stock under this process parameter has no cracks,and the rolling effect is very good,which can fully meet the practical use of production.