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US4279646A Expired / Lapsed US ⏱️ 0.0 years remaining

Free cutting steel containing sulfide inclusion particles with controlled aspect, size and distribution

Assignee: Daido Steel Co Ltd

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Filing: 1979-12-19

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Granted: 1981-07-21

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Expires: 1999-12-19

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Abstract

Abstract A free cutting steel for machine structural use containing C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4%, Te 0.002 to 0.5% and O 0.0010 0.0300%, the balance being substantially Fe exhibits excellent machinability when the MnS-based inclusion is in the form of particles of 5 to 100μ long, 1 to 10μ wide, wherein the aspect ratio length/width is not larger than 10, and at the density of 20 to 200 particles per 1 mm 2 of the matrix cross section. A free cutting steel for machine structural use containing C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4% and Te up to 0.1%, wherein %Te/%S is at least 0.04, O up to 0.003% and N up to 0.0200%, the balance being substantially Fe exhibits improved rolling-contact fatique strength when at least 80% of sulfide-based inclusion particles of 10μ long or more have the aspect ratio length/width of 5 or less, and when areal percentage of alumina cluster in the matrix cross section is not higher than 0.5%.

Inventors

👤 Tetsuo Kato
👤 Shozo Abeyama
👤 Atsuyoshi Kimura
👤 Sadayuki Nakamura

Bibliographic Details

Application Number —

Jurisdiction US

Data Source google_patents

Last Synchronized 2026-11-05 04:13

CPC Classifications

C; C22; C22C; C22C38/00; C22C38/60

Claims Analysis

Total Claims: 12

Claim 1

Independent Claim 89 words

A free cutting steel for machine structural use having excellent machinability comprising: C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4%, Te 0.002 to 0.50%, and O 0.0010 to 0.0300%, the balance being substantially Fe; and containing MnS-based inclusion in the form of particles of 5 to 100μ long, 1 to 10μ wide, wherein the aspect ratio defined by length/width is not larger than 10, and at a density of 20 to 200 particles per 1 mm 2 of matrix cross section.

Claim 2

Dependent Claim 89 words

Claim 3

Dependent Claim 15 words

A free cutting steel according to claim 1, which further contains P up to 0.10%.

Claim 4

Dependent Claim 15 words

A free cutting steel according to claim 1, which further contains Pb 0.03 to 0.30%.

Claim 5

Dependent Claim 28 words

A free cutting steel according to claim 1, which further contains one or more of Ni up to 4.5%, Cr up to 4.5% and Mo up to 1.0%.

Claim 6

Independent Claim 73 words

A method of making a free cutting steel for machine structural use having excellent machinability, which comprises hot rolling an ingot of a steel containing: C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4%, Te 0.002 to 0.50%, and O 0.0010 to 0.0300%, the balance being substantially Fe, under the condition of soaking temperature between 1,200° and 1,400° C., and a finishing temperature above 1,000° C.

Claim 7

Independent Claim 73 words

Claim 8

Dependent Claim 101 words

A free cutting steel for machine structural use having improved rolling-contact fatigue strength comprising: C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4% and Te up to 0.1%, wherein the ratio %Te/%S is at least 0.04, O up to 0.0030%, and N up to 0.0200%, the balance being substantially Fe; characterized in that at least 80% of sulfide-based inclusion particles of 10μ long or more have the aspect ratio defined by length/width of 5 or less, and that the areal percentage of alumina cluster in the matrix cross section is not higher than 0.5%.

Claim 9

Dependent Claim 101 words

Claim 10

Dependent Claim 57 words

A free cutting steel according to claim 6, which further contains one or more of the alloying elements selected from: P up to 0.1%, Pb up to 0.3%, Bi up to 0.3%, provided that Pb+Bi is not larger than 0.4%, Se up to 0.4%, provided that S+Se is not larger than 0.4%, and Ca up to 0.0100%.

Claim 11

Dependent Claim 70 words

Claim 12

Dependent Claim 115 words

A free cutting steel according to claim 6, which further contains one or more of the alloying elements selected from: Ni up to 6.0%, Cr up to 4.0%, Mo up to 2.0%, Al up to 2.0%, B up to 0.010%, V up to 0.5%, Ti up to 0.5%, Nb up to 0.5%, Ta up to 0.5% Zr up to 0.5%, and REM up to 0.1% in total, together with one or more of the alloying elements selected from: P up to 0.1%, Pb up to 0.3%, Bi up to 0.3%, provided that Pb+Bi is not larger than 0.4%, Se up to 0.4%, provided that S+Se is not larger than 0.4%, and Ca up to 0.0100%.

References Cited (Backward Citations)

USRE22021E Cited

US2009714A Cited

US3169857A Cited

US3192039A Cited

US3783043A Cited

US3634074A Cited

US3645722A Cited

US3853544A Cited

US3846186A Cited

US3723103A Cited

US3679400A Cited

US3926687A Cited

US4115111A Cited

US4032333A Cited

US3973950A Cited

US4091147A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-07-20	1985-01-19	1985-07-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-07-20	1989-01-19	1989-07-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-07-20	1993-01-19	1993-07-21	$7700.00	Window Closed / Lapsed

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