| Due to the lower cost, light weight, higher efficiency of production and narrower width of the steel plate used, the industry of helix welded pipe has undergone a quick development in recent years. However, in the forming process of the helix welded tube, the steel plate will be deformed through a complicated strain bending deformation, involving nonlinear of geometry, material and contact, so it is difficult to carry out the theoretical analysis and there is no common mathematical model yet. Also there are not many studies regarding the forming parameters of helix welded pipe now because the elastic-plasticity of deformation of the helix welded pipe and the long time needed for the steel plate bending operation. Therefore, it is of significance to investigate the relationship between forming parameter and forming quality, so as to improve the design of the welding machine.This paper studied the relationship between the forming parameter of the helix welded pipe and quality of the production. Firstly, both math models of the bending angle's and deformation parameter's are established based on the theoretical analysis of the bending angle and deformation parameter using elastic-plastic bending theory of a beam. Theoretical studies indicate that the tolerance of the diameter could reach±3~4mm when the tolerance of the bending angle is±0.5°. In order to make the helix welded pipe produce zero spring-back or small spring-back, the roller putting down in the three-roll shaper should be a dimension's lower to the theoretical circle position in the process of shaping. Secondly, based on large deformation elastic-plastic finite element method (FEM), the FEM numerical simulation on the thee-roll bending process was carried out using the dynamic explicit FEM code ABAQUS/Explicit, and a 2D and a 3D FE models were established. These will be great benefits to the production of helix welded pipe and lay foundation for further research on automatic control of the helix welded pipe production.
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