Analysis Crimping Technique Parameter Of Large Straight Welded Pipe

With the rapid development of conveying pipeline construction of global oil andnatural gas in our country, the demand of large-diameter straight-welded welded pipe(LSAW) is increasing. JCO forming is one of the production technique for LSAW. Andpre-bending is the first production technique for LSAW and one of the importantprocess. But on the quality control and parameters adjustment still relyed on theproduction experience, this production method lead to low productivity efficiency,process parameters adjustment error and product quality fluctuation et real problems.Therefore, the comprehensive study of the process of the pre-bending to providinganalytic basis is needed.Firstly, according to forming characteristics of large-diameter longitudinalwelded,based on theory of plastic bending, using the power index elastic-plasticmodel,with the reasonable assumptions and the simplification of the pre-bendingforming, the theory analysis is performed for pre-bending. According to geometricrelation between pre-bending moulds and slab, the angle before pre-bending springback, the angle after pre-bending spring back, the travel distance of the lower die andthe formula of forming force is deduced. According to the tube geometricprogramming model of JCO in ideal forming state, the quality evaluation ofpre-bending is proposed.Secondly, the finite element model of pre-bending forming is established withABAQUS. With the needing of the finite element model, the solving method ofsimulation, element type and the boundary condition is selected. Pre-bending formingstress and strain distribution characteristics is introduced, and pre-bending processparameters influence law on quality of pre-bending and forming force is studied.Finally, the reality pre-bending model is shrinked with3:1. Aiming at the processparameters in the finite element model, the pre-bending experiment is conducted. Inaccordance with the relationship with the angle before spingback,the angel afterspring back and the forming force, the accuracy of the finite element model and the theory analysis is verified.