Numberical Simulation Of Bending Process Of The Thick Wall Pipe With The Nozzles

The tube bending technology has a wide application in various field of the industrialproduction. The press bending is one of the most important techniques. The empiricalformula obtained by simplified mechanical model often exhibits great deviation comparedwith actual result, while the experimental analysis tends to result in the waste of humanand material resources. In view of this, the bending tube forming was investigated with thejoint application of the numerical simulations, the theoretical calculations and the physicalexperiments.In this paper, the numerical simulation for AP1000main pipe press-bending processof Shang Hai Heavy Machinery Plant was performed via MSC.Marc finite elementanalysis. This study mainly involves the following:(1)The formula for calculating the stroke was derived by an analysis of the geometricposition of bending tube forming. On the basis of the assumption of the rigid-plastic planestrain and linear hardening model, the formula for the critical roller spacing is obtained.Furthermore, the relationship between the critical roller spacing and the parametersinvolving the yield stress, plasticity modulus and the thick to diameter ratio is alsoelucidated.(2)The critical roller spacing is explored using the change of dispersion effect and theplastic deformation zone(3)The forming quality including the ellipticity, thickening rate, reduction rate, springback angle is investigated by a finite analysis. The deformation process can be predicted,which will provide a theoretical basis for the experiment.(4)The forming force, rotation angle and the spring back angle is analyzed and thenthe corresponding laws are obtained. The factors that influence the bending moment aretaken into consideration and the formulas of the critical roller spacing under differentfriction coefficient are available.(5)The intensity of the die is examined with the assist of the numerical simulation,thus ensuring the security. Taking the45steel as the material, bending test is conducted bythe equal channel pipe. As for the failure stability of pipe, thickness distribution andbending angle in the bending test, the corresponding data are elucidated via theoreticanalyses. This will provide some experience for the batch production of AP1000mainpipe.