International Journal of Computer Aided Engineering, ISSN:2051-3190, Vol.24, Issue.2

1109

Design and Development of Hot Stamping
Simulation System and its Applications
Ninshu Ma
JSOL Corporation, Japan

Bonyong Ghoo
JSOL Corporation, Japan

Nobuhiko Sugitomo
JSOL Corporation, Japan

Hidetaka Ito
JSOL Corporation, Japan
Corresponding Author Email: ma.ninshu@jsol.co.jp

ABSTRACT

Keywords-ンプル

With the increasing application of hot stamped parts toautomobile bodies, simulation has become a basic tool forthe formability evaluation in designing parts and tools.
The hot stamping process is strongly coupled with multiphysical phenomena of thermal transfer, temperaturedependentmaterial
properties,
material
phasetransformation in thermal cycles and large mechanicaldeformation. To answer the strong requests fromindustries, an easy operational and accurate hot stamping
simulation system was designed and developed
considering multi-physical characteristics occurred in the
hot stamping process. Then, formability was evaluated andhardness was predicted. The thermal cycles due to single
shot and multi shots using a test tool with air cooling andwith water cooling were simulated and compared withmeasured ones.

stamping steel and its changes with temperature from
500OC to 800OC. Turetta and Bruschi [5] developed anexperimental apparatus at high temperature andinvestigated formability of a hot stamping steel withdifferent austenite volume fraction. Naderi et al [6]measured the Vicker’s hardness of the hot stamping steel
22MnB5 at different cooling rate and presented thecorrelation between cooling curves and hardness withCCT diagram. This work gave us a hint that the Vicker’s
hardness can be simply estimated for industrial
applications if cooling rate was computed by numericalsimulation.

Hot stamping, Simulation system,
Formability evaluation, Hardness prediction, Thermalcycles.

1. INTRODUCTION

サTo reduce the weight of automotive bodies and to improvethe crashworthiness, convectional stamping parts ofadvanced high strength steels and hot stamping parts withultra-high strength up to about 1500MPa have been
increasingly employed in automotive bodies. Comparedwith the conventional sheet metal forming process of highstrength steels, the hot stamping process utilizes the goodelongation which can improve formability and lower flow
stress of steels at high temperature which can reduce
forming force.
When the forming process ends, the subsequently fastingcooling process in the closed tools induces a very strong
martensite microstructure. As a result, the hot stamping
parts have higher strength and also the less springback
which was measured by Mori et al [1] and Kusumi et al[2] in their hat bending models.
This advanced forming process stimulated the academic
research activities very much which were reviewed by
Karbasian and Tekkaya [3]. As a basic research, Merklein
and Lechler [4] measured stress-strain relation of a hot

This advanced forming process also promoted the researchon the simulation technologies and accelerated thedevelopment of FEM software for hot stamping simulation.
Bergman and Oldenburg [7] investigated thermalmechanical coupled simulation method, developed a thickshell for thermal simulation and proposed a thermalmechanical contact algorithm based on the research byShvets [8]. Akerston et al. [9] developed thermalmechanical material models for numerical simulation.
Shapiro [10] implemented the thick shell thermal element
and thermal contact feature into a commercial software forindustrial application. Olsson [11] implemented solid
phase transformation material model into a commercial
software for the coupling simulation among thermal field,
mechanical field and microstructure field.
In order to verify the capability of FEM software forpractical applications, Oberpriller et al [12] provided an
open hot stamping benchmark and necessary data fornumerical simulation to industrial engineers and academic
researchers. Compared with many participants using
various software codes for the cold metal forming
benchmark provided by Volk et al [13] and benchmark
provided by Roll et al [14], only a few research teams
submitted the hot stamping benchmark results. This isbecause the hot stamping simulation was still difficult forindustrial engineers.
The application of hot stamping parts increased thefreedom of material selection and the design freedom for
automotive bodies. It also accelerated the application ofsimulation technologies to automobile relating industries.
The strong requirements from industries pushed© RECENT SCIENCE PUBLICATIONS ARCHIVES | October 2014|$25.00 | 27703938|*This article is authorized for use only by Recent Science Journal Authors, Subscribers and Partnering Institutions*