Study On Extreme Rolling Force And Shell Ring Ovality Of Large Barrel Shell Rolling Mill

Large barrel-shell rolling mill is a type of horizontal(barrel-shell)rolling equipment that the outside diameter increases and the thickness decreases of barrel-shell under the rolling of the driving roller,the core roller and the holding rollers,and the products widespread used in aerospace,nuclear-electricity and hydrogenation reactor.In large barrel-shell rolling craft,the process of barrel-shell rolling forming has the characteristics of poor stability,non-linearity,closed loop,large size,and large quality,so it is unreality for the physical test of barrel-shell rolling.Therefore,the project established a thermal-structural coupling FEM to simulate the rolling process,deducing the theoretical formula for the extreme roll holding force of the barrel-shell,shortening the development cycle,saving research costs,which has great practical significance for the research and development of large barrel-shell rolling mill and high product quality.The main research content includes:Firstly,the basic technological process of the large barrel-shell rolling mill and the stability problem caused by extreme holding roller force of the barrel-shell were studied.A two-dimensional FEM was established to simulate the rolling process and the force state and metal flow law of the barrel-shell were analyzed,making the rolling force energy parameter curves,which provided the theoretical foundation for the production and practice of the barrel-shell mill.Secondly,based on the conquassation phenomenon of the thin-wall and especially big barrel-shell caused by excessively large holding force,and predigesting the barrel-shell to a linear elastic model,using the unit load method to deduced the extreme holding force formula,and comparing the analytical results with the finite element results,correcting and verifying the formulas,and obtaining the final extreme roll holding force formula,which provides data support for the actual holding roller force.Finally,using the finite element method to analyze the barrel-shell ovality effect by various parameters in rolling process and study the ovality change law under the different holding roller control model.And according the position of driving roller and the two holding roller to measure the barrel-shell ovality that can be a standard for select the rolles control methods during rolling,which provides parameter selection basis for the control of ovality in actual production.This thesis contrapose the study extreme holding roller force and ovality change law large of the large barrel-shell rolling mill,which accelerate the actual production of large tubular sections and the development of rolling processes in China.and has certain theoretical and practical value.