Influence of holding time in the die on structure development of the low-alloyed TRIP steels

Kód výsledku v IS VaVaI

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Výsledek na webu

<a href="https://www.metalconference.eu/files/uploads/02//METAL2019_Conference_Proceedings_Content.pdf" target="_blank" >https://www.metalconference.eu/files/uploads/02//METAL2019_Conference_Proceedings_Content.pdf</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Influence of holding time in the die on structure development of the low-alloyed TRIP steels

Popis výsledku v původním jazyce

Press-hardening is a modern forming technology for the production of shaped sheet parts. Its use has been growing in recent years because of high production accuracy, lower spring back effect and lower forming forces. This technology is also suitable for high strength TRIP steels (transformation induced plasticity). The problem with this technology is, in the case of forming into a die at room temperature, a high cooling rate which leads to the formation of martensitic structures with a low ferrite content. These structures, while achieving high strength limits, but low ductility. Therefore, after forming, it is important to terminate the quenching in the tool at the right time, or to carry out further heat treatment in the furnace. Two low-alloy TRIP steels with a carbon content of 0.2% with the difference in niobium content were selected for the experiment. In the first part, there was performed quenching of the sheets between the die of the hydraulic press. The holding time was varied from 0 to 10s and the sheet temperature after removal from the die was measured with a thermal camera. In the second part, an experiment was carried out directly in the flat press-hardening tool, which was supplemented by an isothermal holding time in the furnace. Mixed structures formed by martensite, bainite, proeutectoid ferrite and retained austenite were obtained with proper parameter selection.

Název v anglickém jazyce

Influence of holding time in the die on structure development of the low-alloyed TRIP steels

Popis výsledku anglicky

Press-hardening is a modern forming technology for the production of shaped sheet parts. Its use has been growing in recent years because of high production accuracy, lower spring back effect and lower forming forces. This technology is also suitable for high strength TRIP steels (transformation induced plasticity). The problem with this technology is, in the case of forming into a die at room temperature, a high cooling rate which leads to the formation of martensitic structures with a low ferrite content. These structures, while achieving high strength limits, but low ductility. Therefore, after forming, it is important to terminate the quenching in the tool at the right time, or to carry out further heat treatment in the furnace. Two low-alloy TRIP steels with a carbon content of 0.2% with the difference in niobium content were selected for the experiment. In the first part, there was performed quenching of the sheets between the die of the hydraulic press. The holding time was varied from 0 to 10s and the sheet temperature after removal from the die was measured with a thermal camera. In the second part, an experiment was carried out directly in the flat press-hardening tool, which was supplemented by an isothermal holding time in the furnace. Mixed structures formed by martensite, bainite, proeutectoid ferrite and retained austenite were obtained with proper parameter selection.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20501 - Materials engineering

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název statě ve sborníku

METAL 2019-28th International Conference on Metallurgy and Materials, Conference Proceedings

ISBN

978-80-87294-92-5

ISSN

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e-ISSN

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Počet stran výsledku

6

Strana od-do

691-696

Název nakladatele

Tanger

Místo vydání

Ostrava

Místo konání akce

Brno, Česko

Datum konání akce

22. 5. 2019

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000539487400111