Title:
HIGH STRENGTH THIN STEEL SHEET HAVING EXCELLENT HOLE EXPANSIBILITY AND LOCAL DUCTILITY AND METHOD FOR PRODUCING THE SAME
Document Type and Number:
Japanese Patent JP2011225938
Kind Code:
A
Abstract:
To provide a high strength thin steel sheet which has excellent hole expansibility and local ductility using a mixed structure of precipitation hardened ferrite and bainite, and a method for producing the same.
Nb of 0.01 to 0.10% and Ti of 0.01 to 0.20% are incorporated into a steel, the structure of the steel is made of the one made of a ferrite phase and a bainite phase, cooling after hot rolling is controlled to regulate the spacing of the precipitated faces of interphase boundary precipitation in the region of ≥40% of the ferrite phase to 20 to 60 nm, and the carbon nitrides of Ti and Nb are precipitated into the ferrite phase by the interphase boundary precipitation, thus the ferrite is subject to precipitation hardening.
Inventors:
OKAMOTO TSUTOMU
YOSHINAGA NAOKI
MAEDA DAISUKE
YOSHINAGA NAOKI
MAEDA DAISUKE
Application Number:
JP2010097211A
Publication Date:
November 10, 2011
Filing Date:
April 20, 2010
Export Citation:
Assignee:
NIPPON STEEL CORP
International Classes:
C22C38/00; C21D9/46; C22C38/14; C22C38/58
Other References:
JPN6013062328; Ｒｉｋｉ Ｏｋａｍｏｔｏ ｅｔ ａｌ．: 'Ｎｂ添加低炭素鋼における相間界面析出' 材料とプロセス（ＣＤ-ＲＯＭ） Ｖｏｌ．２３， Ｎｏ．１, 20100301, Ｐａｇｅ．ＲＯＭＢＵＮＮＯ．２５４, 社団法人日本鉄鋼協会
JPN6013062328; Ｒｉｋｉ Ｏｋａｍｏｔｏ ｅｔ ａｌ．: 'Ｎｂ添加低炭素鋼における相間界面析出' 材料とプロセス（ＣＤ-ＲＯＭ） Ｖｏｌ．２３， Ｎｏ．１, 20100301, Ｐａｇｅ．ＲＯＭＢＵＮＮＯ．２５４, 社団法人日本鉄鋼協会
JPN6013062328; Ｒｉｋｉ Ｏｋａｍｏｔｏ ｅｔ ａｌ．: 'Ｎｂ添加低炭素鋼における相間界面析出' 材料とプロセス（ＣＤ-ＲＯＭ） Ｖｏｌ．２３， Ｎｏ．１, 20100301, Ｐａｇｅ．ＲＯＭＢＵＮＮＯ．２５４, 社団法人日本鉄鋼協会
Attorney, Agent or Firm:
Atsushi Aoki
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Nakamura Asayuki
Nagasaka Tomoyasu
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Nakamura Asayuki
Nagasaka Tomoyasu