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Cross-roll piercing and cross helical rolling

Cross-roll piercing simulation in QForm. Plastic strain distribution field in the cross section Cross-roll piercing (rotary tube piercing, Mannesmann piercing) and cross helical rolling (three-roll skew rolling) belong to the incremental processes class where deformation occurs in a small localized area of the workpiece and the workpiece itself is processed sequentially to obtain a finished product. The deformation zone is moved around the part as it rotates and thus the deformation is performed in the whole volume.

The Mannesmann effect is the principal factor in cross-roll piercing where uniform tension occurs in the workpiece, while the rollers, inclined at a small angle relative to the axis of the workpiece, rotate the workpiece.

Good stress-strain state in the deformation zone can be achieved during cross-roll piercing (three-roll skew rolling) which allows production of pipes with uniform macro and microstructure in the cross-cut section of the forged part. This uniform macro and microstructure provides good mechanical properties of the forged parts. Such rolling processes can be performed on three-high rolling mills and two-high rolling mills.

A characteristic feature of cross-roll piercing (rotary tube piercing) and cross helical rolling (three-roll skew rolling) is that metal continuity failure occurs after some reduction of the diameter and this crack propagation forms the cavity in the central part of the workpiece. It is possible to identify the formation of the cavity and the zone where ductile fracture is occurring by estimating the stress-strain state using the QForm software with the implementation of fracture criteria. It is important to establish whether the formation of cavities happens as the result of brittle metal fracture or severe plastic deformation of the workpiece core under the influence of shear stresses (ductile failure).

Especially cross-roll piercing technology is widely used for the production of seamless pipes and casings up to 1.5 meters in diameter.

Such incremental processes are the most complex for simulation and impose specific requirements for the core of solvers and finite element mesh generator:

  • A special mesh is required in the moving plastic deformation zone.
  • Volume constancy is required throughout the deformation process.
  • An acceptable simulation time must be provided while ensuring an accurate calculation.
  • Consideration for building finite element mesh in a rotating workpiece body.

The modern software package QForm fulfills all the requirements for modeling cross-roll piercing and cross helical rolling.

Cross-roll piercing simulation in QForm. Temperature distribution field Three-roll skew rolling simulation in QForm. Plastic strain distribution

Cross-roll piercing belong to the incremental process class where deformation occurs in a small localized area of the workpiece and the workpiece itself is processed sequentially to obtain a finished product. It is possible to identify the formation of the cavity and the zone where ductile fracture is occurring by estimating the stress-strain state using the QForm software.

Cross Rolling: A Metal Forming Process

  • Matruprasad Rout
  • Surjya K. Pal
  • Shiv B. Singh

Abstract

The chapter deals with cross rolling where the workpiece is rotated by 90° in the rolling plane after each rolling pass. The chapter begins with basics of metal rolling, and later on focuses on cross rolling. A short introduction to texture and its representation is presented followed by an overview of the formation of deformation texture in various materials after cross rolling. Review of some of the research works on cross rolling in last few decades has also been included. A case study has been provided at the end of this chapter.

The chapter deals with cross rolling where the workpiece is rotated by 90° in the rolling plane after each rolling pass. The chapter begins with basics of metal rolling, and later on focuses on…