HIGH-STRENGTH BOLT - NIPPON STEEL & SUMITOMO METAL CORP

Title:

HIGH-STRENGTH BOLT

Document Type and Number:

WIPO Patent Application WO/2017/094487

Kind Code:

A1

Abstract:

Provided is a high-strength bolt having high strength and exceptional hydrogen embrittlement resistance. The bolt according to the present invention has a chemical composition comprising 0.22-0.40% by mass of C, 0.10-1.50% by mass of Si, 0.20% by mass to less than 0.40% by mass of Mn, 0.020% by mass or less of P, 0.020% by mass or less of S, 0.70-1.45% by mass of Cr, 0.005-0.060% by mass of Al, 0.010-0.045% by mass of Ti, 0.0003-0.0040% by mass of B, 0.0015-0.0080% by mass of N, and 0.0020% by mass or less of O, and the remainder comprising Fe and impurities. The chemical composition satisfies formulae (1) and (2), and the bolt has a tensile strength of 1000-1300 MPa. (1) 0.50 ≤ C + Si/10 + Mn/5 + 5Cr/22 ≤ 0.85 (2) Si/Mn > 1.0 Each of the symbols for the elements in formulae (1) and (2) is assigned with the corresponding content content (mass%).

Inventors:

NEISHI YUTAKA (JP)
SANO NAOYUKI (JP)
MATSUI NAOKI (JP)

Application Number:

PCT/JP2016/083738

Publication Date:

June 08, 2017

Filing Date:

November 15, 2016

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/00; C22C38/54; F16B35/00; C21D9/00

Domestic Patent References:

WO2015045951A1	2015-04-02
WO2017002770A1	2017-01-05

Foreign References:

JP2015105428A	2015-06-08
JP2016060933A	2016-04-25
JP2012162798A	2012-08-30
JPH11293401A	1999-10-26
JPH1053834A	1998-02-24
JP2008156678A	2008-07-10

Other References: