Process design of press hardening with gradient material property influence

Journal Article · Wed May 04 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3589739· OSTI ID:21516733

Neugebauer, R ^[1]; Schieck, F ^[1]; Rautenstrauch, A ^[2]

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1. Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz (Germany)
2. Professorship for Machine Tools and Forming Technology, TU Chemnitz (Germany)

Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

• OSTI ID: 21516733
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1353; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
BORON ALLOYS
CARBON ADDITIONS
CHEMICAL REACTIONS
CRACKING
DECOMPOSITION
DESIGN
DIMENSIONS
DUCTILITY
ELASTICITY
FABRICATION
HARDENING
HARDNESS
HEAT TREATMENTS
HEATING
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MATERIALS WORKING
MECHANICAL PROPERTIES
MICROSTRUCTURE
PRESSES
PYROLYSIS
QUENCHING
SHEETS
SPECTRA
STEELS
STRAINS
TENSILE PROPERTIES
THERMOCHEMICAL PROCESSES
THERMOMECHANICAL TREATMENTS
THICKNESS
TRANSFORMATIONS
TRANSITION ELEMENT ALLOYS