Ermittlung von Berechnungskennwerten an Karosseriewerkstoffen – Bericht über ein Gemeinschaftsprojekt der Stahl‐ und Automobilindustrie

Abstract

Within the scope of a common research project of the steel and automotive industry, 20 sheet steels have been investigated to obtain input data for FE-analysis. In detail, elastic, plastic and fatique characteristical values were determined by several testing institutes for a period of 3 years. The investigated sheet steels differ with regard to the microstructure and the steel concept. Beside several ferritic steels, multiphase steels like dual phase-, complex phase-and TRIP steels as well as 2 austenitic stainless steels were characterised. The starting materials and selected steels with a defined predeformation and heat treatment were investigated. Within this project, the partners developed a testing and documentation precept in which the ways and means were fixed to reach the defined steel condition and to enable a standardised testing and data output for the material database, realised by the automotive industry. Before the actual elastic, plastic and fatique testing, a reception test for all steels was carried out to characterise the materials with regard to the microstructure, surface condition, chemical composition and mechanical properties, obtained in the quasistatic tensile test. The results of the different testing institutes (elastic, plastic and fatique) will be presented in separate publications in detail. As a result of this project it became obvious that the investigated steels can be divided into steel groups which show a similar strain hardening behaviour. Thus, a prediction of mechanical values and flow curves for cognate steels within one steel group seems to be possible. This subject will be the focus of further investigations within the scope of a new project started on January 1 st , 2003.

Influence of Strain Rate, Temperature, Plastic Strain, and Microstructure on the Strain Rate Sensitivity of Automotive Sheet Steels

“…The dynamic properties of those selected steels are compared later on with a larger RWTH dynamic database, which has been generated by the authors on the same testing machines with the same testing method and strain rate range 1, 12, 32–36. This database includes deep drawing interstitial free (IF), mild and structural steels together with high strength steels (HSS), such as isotropic, P‐alloyed (rephos), high strength interstitial free (HSIF) or bake hardening (BH) steels.…”

Werkstoffverhalten unter zügiger elastischer Beanspruchung

“…Mit einem dynamischen Resonanzverfahren wurde eine Ä nderung des E-Moduls in gleicher Größenordnung um ca. 4 bis 5GPa (von RT auf -40 C) sowie 5 bis 7GPa (von RT auf 100 C) ermittelt [14,15].…”

“…Im Rahmen des Projekts "Erarbeitung werkstoff-und verarbeitungsgerechter Kennwerte für Feinbleche aus normal und höherfesten sowie nicht rostenden Stählen", über das in [15] bereits in allgemeiner Form berichtet wurde, stand die Ermittlung von Werkstoffkennwerten an 20 Stählen für Feinblech im Mittelpunkt.…”

Untersuchungen zur Ermittlung der Dehnratenabhängigkeit von modernen Karosseriestählen

“…Ein erster Schritt in Richtung Normung ging in jüngster Vergangenheit von der European Structural Integrity Society (ESIS) aus [7]. Im Rahmen dieses Projektes wurden in der sogenannten Prüf-und Dokumentationsrichtlinie die Prüfparameter und die Auswerteprozedur festgelegt [6]. Figure 12.…”