HIGH STRENGTH HOT ROLLED STEEL SHEET AND METHOD FOR PRODUCING SAME

WIPO Patent Application WO/2014/171063

A1

This high strength hot rolled steel sheet has a composition that contains, in mass%, from 0.05% to 0.18% (inclusive) of C, 1.0% or less of Si, from 1.0% to 3.5% (inclusive) of Mn, 0.04% or less of P, 0.006% or less of S, 0.10% or less of Al, 0.008% or less of N, from 0.05% to 0.20% (inclusive) of Ti and more than 0.1% but 0.3% or less of V with the balance made up of Fe and unavoidable impurities. This high strength hot rolled steel sheet has a structure that contains a bainite phase as the main phase in an area ratio of more than 85%, while containing one or more phases selected from among a ferrite phase, a martensite phase and a residual austenite phase as the second phase in an area ratio of 0% or more but less than 15%. The average lath interval of the laths of the bainite phase is 400 nm or less, and the average length of long axes of the laths is 5.0 μm or less. This high strength hot rolled steel sheet has a tensile strength (TS) of 980 MPa or more.

YAMAZAKI KAZUHIKO (JP)
NAKAJIMA KATSUMI (JP)
KAMI CHIKARA (JP)

PCT/JP2014/001509

October 23, 2014

March 17, 2014

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JFE STEEL CORP (JP)

C22C38/00; B21B3/00; C21D8/02; C21D9/46; C22C38/14; C22C38/58

JP2012062557A	2012-03-29
JP2007056294A	2007-03-08
JP2010174343A	2010-08-12
JP2012012701A	2012-01-19
JP2002180190A	2002-06-26
JP2005120437A	2005-05-12
JP2012255176A	2012-12-27
JP2012062557A	2012-03-29
JP2007056294A	2007-03-08
JP2010174343A	2010-08-12
JP2012012701A	2012-01-19
JP2002180190A	2002-06-26
JP2005120437A	2005-05-12

See also references of EP 2987887A4

KUMASAKA, Akira et al. (JP)
Akira Kumasaka (JP)

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