Microstructures and mechanical properties of V and/or Nb bearing ultrahigh strength hot stamped steel components

Shota Tateyama, Ryohei Ishio, Kouhei Hayashi, Tatsuhiro Sue, Yoshito Takemoto, Takehide Senuma

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

As a method for producing ultrahigh strength automotive steel components with high gauge accuracy, the hot stamping technology draws attention and the amount of hot stamped automotive components has exponentially increased in the last decade. The concerns about the potential danger of embrittlement and delayed fracture, however, limit the strength of conventional hot stamped components to 1500 MPa. If these concerns are eliminated, automotive steel components with higher strength which is demanded by the automotive industry can be further commercialized. In this study, microstructures and mechanical properties of V and/or Nb bearing ultrahigh strength hot stamped steel components have been investigated. The V addition improves the resistance to delayed fracture by forming VC whose interface with matrix is supposed to act as preferential hydrogen trap site. The Nb addition refines the microstructure, which improves both the toughness and the resistance to delayed fracture. Proper hot stamping conditions for these steels has been discussed to create an ultrafine martensite microstructure and finely dispersed precipitates. The results indicate that 1900 MPa class steel components with good toughness and high resistance to delayed fracture can be produced.

Original languageEnglish
Pages (from-to)1114-1122
Number of pages9
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume100
Issue number9
DOIs
Publication statusPublished - 2014

Fingerprint

Bearings (structural)
Steel
steels
mechanical properties
Mechanical properties
microstructure
Microstructure
Stamping
stamping
Toughness
toughness
Embrittlement
embrittlement
Automotive industry
Martensite
Gages
high resistance
Precipitates
Hydrogen
high strength

Keywords

  • Automotive components
  • Delayed fracture
  • High strength steel
  • Hot stamping
  • Reverse transformation

ASJC Scopus subject areas

  • Materials Chemistry
  • Metals and Alloys
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this

Microstructures and mechanical properties of V and/or Nb bearing ultrahigh strength hot stamped steel components. / Tateyama, Shota; Ishio, Ryohei; Hayashi, Kouhei; Sue, Tatsuhiro; Takemoto, Yoshito; Senuma, Takehide.

In: Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan, Vol. 100, No. 9, 2014, p. 1114-1122.

Research output: Contribution to journalArticle

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