Mechanical behavior of new press hardening steels at elevated temperatures and technological modeling of their processing

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F19%3A43955234" target="_blank" >RIV/49777513:23210/19:43955234 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Mechanical behavior of new press hardening steels at elevated temperatures and technological modeling of their processing

Original language description

The development of new press hardening steels is given by the requirements of their mechanical properties. Since these materials are used to manufacture complex automotive safety components such as B-pillars, door stiffeners or crossbars, their tensile strength should be around 2000 MPa. These demands are met by the new Press Hardening Steels PHS 1800 and PHS 2000 developed by SSAB. The mechanical behavior of these steels at elevated temperatures was experimentally evaluated and their suitability for press hardening processing was experimentally simulated using a thermomechanical simulator. Thanks to this equipment, it was possible to subject individual steel samples to a thermomechanical treatment, which is equivalent to the real conditions during forming. The simulator requires only small samples, thus saving time and costs. In the first experimental phase, hot flow curves were determined for both materials. They were important for determining the real press-hardening parameters: the austenitization temperature, forming temperature and strain rate. Thanks to the knowledge of their mechanical behavior at higher temperatures, it was possible to design a technological processing window to obtain specific mechanical properties. The PHS steels were also processed on the thermomechanical simulator according to a temperature profile determined with help of data measured in the real process. For both steels, the following process parameters were evaluated: two initial austenitization temperatures of 860 °C and 940 °C, a soaking time of 180 s and forming temperatures ranging between 680 °C and 800 °C. The resulting mechanical properties were determined by tensile tests and hardness measurement. Afterward, the resulting microstructures were characterized by optical and scanning electron microscopy. They showed a martensitic microstructure with a small amount of retained austenite. The resulting ultimate tensile strengths of the PHS 1800 and PHS 2000 steels were 1800 MPa and 2000 MPa, respectively.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20501 - Materials engineering

Project

<a href="/en/project/LO1502" target="_blank" >LO1502: Development of Regional Technological Institute</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů