The use of advanced high-strength steels in the press-hardening technology

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F19%3A43955236" target="_blank" >RIV/49777513:23210/19:43955236 - 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

The use of advanced high-strength steels in the press-hardening technology

Original language description

Press-hardening is used in the manufacture of automotive safety components from high-strength martensitic steels. With these components, great emphasis is put on high mechanical properties as well as their behaviour in a collision situation. Therefore, new materials that can absorb great-er collision energies are sought – in addition to martensitic steels of 22MnB5-type. Besides ma-terials with tailored microstructures, which are demanding in terms of process control, advanced high-strength steels, which contain retained austenite, are available. In the latter, cold defor-mation converts retained austenite to strain-induced martensite, while the TRIP effect (transfor-mation-induced plasticity) occurs. These are the TRIP steels, which contain a mixture of ferrite, bainite and 10–14% of retained austenite, and martensitic steels for Quenching and Partitioning (Q&amp;P) processing, whose toughness is improved by the presence of foil-like retained austenite. Suitability for press-hardening processing of two high strength steels alloys was evaluated by thermomechanical simulation. They are the CMnSi steel from the group of TRIP steels, and the 42SiCr steel, which is suitable for Q&amp;P processing. Several thermomechanical profiles were designed, which involved heating temperatures of 860°C and 940°C and forming temperatures of 680, 750 and 800°C. In order to keep the material under stress during cooling (as if cooling took place in a die), some specimens were held by force to prevent free expansion/contraction. For comparison, free expansion/contraction was allowed in other specimens and profiles. In the 0.2%-carbon CMnSi steel, this treatment led to ultimate strengths in excess of 950 MPa and elongations over 10%. 42SiCr steel reached an ultimate strength of more than 2100 MPa, owing to its higher carbon content and a chromium addition. Its mechanical properties showed a strong response to variation of heating and deformation temperatures.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20301 - Mechanical 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