Application of an Incremental Constitutive Model for the FE Analysis of Material Dynamic Restoration in the Rotary Tube Piercing Process

Abstract

In the numerical simulation of hot forming processes, the correct description of material flow stress is very important for the accuracy of the results. For complex manufacturing processes, such as the rotary tube piercing (RTP), constitutive laws based on both power and exponential mathematical expressions are commonly used due to its inherent simplicity, despite the limitations that this approach involves, namely, the use of accumulated strain as a state parameter. In this paper, a constitutive model of the P91 steel derived from the evolution of dislocation density with strain, which takes into account the mechanisms of dynamic recovery (DRV) and dynamic recrystallization (DRX), is proposed for the finite element (FE) analysis of the RTP process. The material model is developed in an incremental manner to allow its implementation in the FE code FORGE®. The success of this implementation is confirmed by the good correlation between results of the simulation and experimental measurements of the manufactured tube (elongation, twist angle, mean wall thickness and eccentricity). In addition, this incremental model allows addressing how the restoring mechanisms of DRV and DRV occur during the RTP process. The analysis puts into evidence that DRV and DRX prevail over each other cyclically, following an alternating sequence during the material processing, due mainly to the effect of the strain rate on the material.

Assessment of the possibility of quantitative identification of the Mannesmann effect using ductile fracture criteria

“…Some authors use some simplifications to simulate Mannesmann piercing process. Murillo-Marrodán et al, 10,11 in their work on the modelling of the rotary piercing process, used a billet with a small hole along its length, which was intended to facilitate the separation of material on the plug. The modelling results obtained in this way had a high agreement with experimental studies.…”

Effects of Tool-Workpiece Friction Condition on Energy Consumption during Piercing Phase of Seamless Tube Production

“…During TPP, rollers rotate with axes offset that is called feed angle. The prominent role of the roller is pushing forward the hot billet against the plug direction [3].…”

Microstructure and Hardness of Hollow Tube Shells at Piercing in Two-High Screw Rolling Mill with Different Plugs

“…Regarding the review of two-high screw rolling research publications, it is worth noting articles connected with hollow shell microstructure formation under different deformation regimes [ 20 , 21 , 22 , 23 , 24 ]. Publications [ 25 , 26 ] are about the influence of the shape and dimensions of the plug on the accuracy of the hollow shell dimensions.…”