Control-Oriented Characterization of Product Properties during Hot Hole-Flanging of X46Cr13 Sheet Material in a Progressive-Die

Juri Martschin,Daniel Klöser,A. Erman Tekkaya,Rickmer Meya,Thomas Meurer

doi:10.3390/met11020349

Abstract

Robust and versatile production is enabled by a closed-loop control of product properties. This essentially relies on the characterization of the interaction between properties and available degrees of freedom to control the process. In particular, this work examines the setting of collar height, thinning, curvature, and hardness during hot hole-flanging of X46Cr13 sheet material with simultaneous heat treatment to identify approaches for a closed-loop property control in hot hole-flanging during multi-stage hot sheet metal forming. To scrutinize the adjustability of the hardness of X46Cr13 sheet material by heat treatment with rapid heating and short dwell times, quenching tests with austenitizing temperatures from 900 to 1100 °C and dwell times from 1 to 300 s were carried out. A hardness between 317 and 680 HV10 was measured. By analyzing the force-displacement curve and the contact situation between tools and blank during hot hole-flanging, an understanding for the process was established. To determine the adjustability of geometrical collar properties and the hardness of the collar, collars were formed at punch speeds between 5 and 100 mm/s and at different temperatures. Here, a dependency of the geometry of the collar on temperature and punch speed as well as setting of the hardness was demonstrated.

Highlights

Published: 19 February 2021Hot sheet metal forming by multiple consecutive forming operations combined with press hardening in multi-stage tools enables the production of hardened components while facilitating advanced shaping capabilities [1]
First approaches for a sole closed-loop control of springback [8], microstructure [9] or strength [10] in hot sheet metal bending in a progressive-die were developed
Treatment hardness set by heat treatment of sheet the X46Cr13 withofa variation of

Summary

Introduction

Hot sheet metal forming by multiple consecutive forming operations combined with press hardening in multi-stage tools enables the production of hardened components while facilitating advanced shaping capabilities [1]. The realization of a zero-defect production represents one of the major challenges in press hardening [5]. The targeted setting or, the batch-dependent variation of product properties represents an additional challenge. To allow for a robust and versatile production in forming processes, a closed loop control can be employed [7]. Process variables and product properties are measured, fed back to the system by means of a controller, and set by variation of process parameters using real-time capable models. First approaches for a sole closed-loop control of springback [8], microstructure [9] or strength [10] in hot sheet metal bending in a progressive-die were developed

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Conclusion