The deformation characteristics and the roll force are of significant importance in the rolling of seamless steel tubes with a tandem skew rolling (TSR) process. In this paper, finite element methods and dual stream functions are utilized to analyze tube rolling with the TSR process. Finite element simulations reveal the deformation characteristics of the seamless steel tube during the rolling process. In addition, the kinematically admissible velocity field and the strain rate field of the deforming tube are described and derived in terms of the dual stream functions. The roll force in theoretical analysis is obtained through upper bound analysis. Experiments are carried out in a TSR testing mill on a carbon steel, to show the validity of the analysis. The curve of the roll force in the process is obtained and the variation of the roll forces is analyzed in detail. Through the comparison between the theoretical, numerical, and experimental investigations, the constructed analysis model is used to study the TSR process and establish a theoretical basis for further development of the process.

In the tension leveling process, calculation of the strip elongation by the traditional method only considers the extension rate after the tension response, while ignoring elastic bending recovered, so the calculation of elongation is large enough to affect the process control accuracy. This paper considers not only the residual strain after elastic bend recovery, but also the affection of the residual deformation under plain cross-section assumption. The calculation of the elongation is less 4-10% than that of the traditional one. It shows that parameters of the tension leveling process set by the new method will be calculated accurately.

Based on rolling technology of stretch reducing mill group, by using large-scale general-purpose finite element analysis software ANSYS/LS-DYNA, a 3D thermal mechanical coupled numerical calculation of stretch reducing process, stress field, strain field, temperature field and the distribution of wall thickness were obtained, as well as the distribution of asymmetrical metal deformation when pipe passing every mill. The results of numerical simulation provide a reasonable cause for uneven wall thickness distribution, guiding the design of stretch reducing process.

Confronting the problem that echnology parameters are difficult to set in the strip tension levelling process, in this paper takes the tension leveler as research object, using the ANSYS software to make dynamic simulation of strip tension levelling process, mainly analyse relationship between the intermesh and curvature, get result that curvature radius during the straightening process is much larger than bending roller radius, as well as the relationship between curvature and the intermesh under the specific structure condition, the research provides help for the optimization of the tension leveler equipment technology parameters.

During piercing rolling simulation, extreme mesh deformation cannot be solved by the finite element method (FEM). Re-meshing is necessary to prevent the effect of severe mesh distortion. However, the element-free method can solve this problem because the continuous body is discretized with a set of nodes, not meshes. In this paper, three-dimension rigid-plastic element-free Galerkin Method (EFG) is introduced to analyze the piercing rolling process. The approximation functions are calculated considering a moving least squares (MLS) approach. The Newton-Raphson method is used for the solution of the nonlinear system of equations. The equivalent stress, the equivalent plastic strain and the equivalent plastic strain rate obtained by EFG and rigid-plastic FEM are analyzed and compared. The simulation results of the EFG method are in agreement with those obtained by using the rigid-plastic FEM and the effectiveness of the model is verified.