公开(公告)号：US20180002777A1

公开(公告)日：2018-01-04

申请号：US15542203

申请日：2015-08-28

Applicant: JFE STEEL CORPORATION

Inventor： Nobusuke Kariya ,  Yoshihiko Ono ,  Yoshimasa Funakawa ,  Kazuma Mori ,  Reiko Sugihara ,  Kenji Kawamura

IPC: C21D9/46 ,  C21D6/00 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C22C38/38 ,  C22C38/60

Abstract: Provided are a high-strength steel sheet and a method for manufacturing the steel sheet. The high-strength steel sheet has a specified chemical composition with the balance being Fe and inevitable impurities, a microstructure including, in terms of area ratio, 30% or more of a ferrite phase, 40% to 65% of a bainite phase and/or a martensite phase, and 5% or less of cementite, in which, in a surface layer that is a region within 50 μm from the surface in the thickness direction, the area ratio of a ferrite phase is 40% to 55% and the total area ratio of a bainite phase having a grain diameter of more than 5 μm and/or a martensite phase having a grain diameter of more than 5 μm is 20% or less, and a tensile strength is 980 MPa or more.

公开(公告)号：US20160083819A1

公开(公告)日：2016-03-24

申请号：US14779783

申请日：2014-03-26

Applicant: JFE STEEL CORPORATION

Inventor： Hidetaka Kawabe ,  Takeshi Yokota ,  Reiko Sugihara ,  Kazunori Tahara

IPC: C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D9/46 ,  C25D3/22 ,  C25D7/00 ,  C21D6/00 ,  C21D8/02 ,  C22C38/04 ,  C25D5/36

CPC classification number: C22C38/06 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0247 ,  C21D8/0263 ,  C21D8/0278 ,  C21D9/46 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/22 ,  C23C2/02 ,  C23C2/06 ,  C23C2/40 ,  C25D3/22 ,  C25D5/36 ,  C25D7/00 ,  C25D7/0614

Abstract: There is provided a high-strength steel sheet having a tensile strength (TS) of 900 MPa or more and excellent elongation, stretch flangeability, and bendability in a component system in which an expensive alloy element is not intentionally added. A high-strength steel sheet includes a composition including, on a mass % basis, C: 0.15 to 0.40%, Si: 1.0 to 2.0%, Mn: 1.5 to 2.5%, P: 0.020% or less, S: 0.0040% or less, Al: 0.01 to 0.1%, N: 0.01% or less, and Ca: 0.0020% or less, with the balance including Fe and incidental impurities. The high-strength steel sheet has a microstructure including 40% to 70% of a ferrite phase and a bainite phase in total, 20% to 50% of a martensite phase, and 10% to 30% of a retained austenite phase in terms of an area fraction relative to the entire microstructure.

Abstract translation: 提供了在没有有意添加昂贵的合金元素的部件系统中，拉伸强度（TS）为900MPa以上的高强度钢板和伸长率，拉伸凸缘性和弯曲性优异。 高强度钢板包括以质量％计含有C：0.15〜0.40％，Si：1.0〜2.0％，Mn：1.5〜2.5％，P：0.020％以下，S：0.0040％或 更少，Al：0.01〜0.1％，N：0.01％以下，Ca：0.0020％以下，余量包括Fe和杂质。 高强度钢板具有包括40％至70％的铁素体相和贝氏体相，20％至50％的马氏体相和10％至30％的残余奥氏体相的显微组织 相对于整个微结构的面积分数。

公开(公告)号：US20150027600A1

公开(公告)日：2015-01-29

申请号：US14379968

申请日：2013-02-25

Applicant: JFE STEEL CORPORATION

Inventor： Hiroyuki Masuoka ,  Reiko Sugihara ,  Takashi Kawano

IPC: C23G1/08 ,  C21D6/00 ,  C23F17/00 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D1/26 ,  C21D8/02

CPC classification number: C23G1/086 ,  B62D29/007 ,  C21D1/26 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C21D9/46 ,  C21D2211/002 ,  C21D2211/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/58 ,  C23F17/00 ,  C23G1/085

Abstract: A Si-containing high-strength cold rolled steel sheet has a chemical composition comprising C: 0.0˜20.3 mass %, Si: 0.8˜2.0 mass %, Mn: 1.0˜5.0 mass % and the remainder being Fe and inevitable impurities with a ratio of Si content to Mn content (Si/Mn) exceeding 0.4, and has a tensile strength TS of not less than 780 MPa, wherein a metallic structure of the steel sheet surface contains polygonal ferrite and/or bainitic ferrite having a Si concentration of not more than 3.0 mass % and a grain size of not more than 10 μm and does not have a Si-containing oxide layer on the steel sheet surface.

Abstract translation: 含Si的高强度冷轧钢板具有C：0.0〜0.20质量％，Si：0.8〜2.0质量％，Mn：1.0〜5.0质量％的化学组成，余量为Fe和不可避免的杂质，比例 的Si含量相对于Mn含量（Si / Mn）超过0.4的拉伸强度TS为780MPa以上，钢板表面的金属组织含有多晶铁素体和/或不具有Si浓度的贝氏体铁素体 大于3.0质量％，粒径不大于10μm，在钢板表面上不含有含Si氧化物层。