Taking into account the curvature of non-contact zone of steel pipe billet at its bending on the pre-forming press with non-asymmetrical rocking arm of TESA 1020 line

Abstract

In the production of the large-diameter steel pipes according to JUOE technology on TESA 1020 line, the steel sheet is bent sequentially on the flanging press (J-press), the pre-forming press (U-press) and the final forming press (O-press). On the flanging press, the longitudinal edge of the steel sheet is bent along the entire length of the sheet. On the pre-forming press, the steel sheet is given a U-shape by bending its central part. The final forming press gives the cross-section of the steel pipe’s billet the shape of a circumference (O-shape). There are two main constructions of the pre-forming press for various types of the large-diameter pipe’s production: the press with a vertical cylindrical punch and the movable horizontal reduction beams with the cylindrical rollers and the press with a vertical cylindrical punch and a movable swinging rocking arm with the cylindrical reduction rollers. In given paper, we consider the forming of a steel pipe billet on the pre-forming press with an non-symmetrical swinging rocking arm having the cylindrical reduction rollers of different diameters. The hardening zone of steel is described by the nonlinear dependence that takes into account the Young’s modulus, the hardening modulus, the yield strength and the ultimate strength of steel. The calculations take into account the non-linearity of the transversal neutral line of steel sheet (pipe billet) in the non-contact zone between the punch and the reduction rollers of the swinging rocking arm. When forming a pipe billet on the final forming press, the effects of Bauschinger, Masing and Hencky for the pipe billet’s zones with sign-alternating bending during forming process on TEWA 1020 presses are taken into account.