STEEL FOR MECHANICAL STRUCTURES - NIPPON STEEL & SUMITOMO METAL CORP

Title:

STEEL FOR MECHANICAL STRUCTURES

Document Type and Number:

WIPO Patent Application WO/2018/008621

Kind Code:

A1

Abstract:

Provided is a steel for mechanical structures, which has excellent machinability, rusting characteristics, and hot ductility. This steel for mechanical structures contains, in mass%, 0.30-0.80% of C, 0.01-0.80% of Si, 0.20-2.00% of Mn, 0.030% or less of P, 0.010-0.100% of S, 0.010-0.100% of Pb, 0.010-0.050% of Al, 0.015% or less of N, and 0.0005-0.0030% of O, the balance being Fe and impurities, and has a chemical composition satisfying formula (1). The total number of specific inclusions contained in the steel and having an equivalent circular diameter of not less than 5 μm is 40/mm2 or more, the specific inclusions being one of a MnS inclusion, a Pb inclusion, and a complex inclusion containing MnS and Pb. Mn/S≥8.0 (1), wherein each element in formula (1) is to be replaced by the contained amount (mass%) of that element.

Inventors:

HASHIMURA MASAYUKI (JP)
EGASHIRA MAKOTO (JP)
IWAHASHI TAKANORI (JP)
TOUDOU SHOUJI (JP)

Application Number:

PCT/JP2017/024442

Publication Date:

January 11, 2018

Filing Date:

July 04, 2017

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/00; C22C38/60; B22D11/00; B22D11/124

Domestic Patent References:

WO2013183648A1

2013-12-12

Foreign References:

JPH11222646A	1999-08-17
JP2003183770A	2003-07-03
JPH06114500A	1994-04-26
JPH11293391A	1999-10-26

Other References: