Enhanced granular medium-based tube press hardening

TL;DR

This paper investigates active and passive pressure control strategies in hot tube forming using granular media, highlighting the importance of friction, geometry, and tribology for process optimization and extending forming limits.

Contribution

It introduces new insights into force transmission and deformation mechanisms, and demonstrates how process limits can be extended through geometry and tribological control.

Findings

Friction significantly affects the forming process.

Optimized punch geometry improves process limits.

Passive pressure strategies open new forming opportunities.

Abstract

Active and passive control strategies of internal pressure for hot forming of tubes and profiles with granular media are described. Force transmission and plastic deformation of granular medium is experimentally investigated. Friction between tube, granular medium and die as also the external stress field are shown to be essential for the process understanding. Wrinkling, thinning and insufficient forming of the tube establishes the process window for the active pressure process. By improving the punch geometry and controlling tribological conditions, the process limits are extended. Examples for the passive pressure process reveal new opportunities for hot forming of tubes and profiles.