IP Library › Granted Patent US 10,119,185
Granted Patent B2
US 10,119,185 · App. 13/138,534 · Granted Nov 6, 2018

Low specific gravity steel for forging use excellent in machineability

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Quick Facts
Patent No.
US 10,119,185
App. No.
13/138,534
Granted
Nov 6, 2018
Kind
B2
Abstract

Steel for forging having high strength and superior machinability due to controlled cooling immediately after shaping by hot forging followed by tempering and having a lower specific gravity than ordinary steel for forging use, the steel containing C: 0.05 to 0.50%, Si: 0.01 to 1.50%, Mn: 3.0 to 7.0%, P: 0.001 to 0.050%, S: 0.020 to 0.200%, Al: 3.0 to 6.0%, Cr: 0.01 to 1.00%, and N: 0.0040 to 0.0200% and having a balance of Fe and unavoidable impurities.

Claims (54)

1. A steel for forging consisting of, by mass%,

C: 0.05 to 0.50%,

Si: 0.01 to 1.50%,

Mn: 5.1 to 5.5%,

P: 0.001 to 0.050%,

S: 0.020 to 0.200%,

Al: 3.6 to 6.0%,

Cr: 0.01 to 0.20%,

N: 0.0040 to 0.0200%, and

having a balance of Fe and unavoidable impurities,

wherein the specific gravity of the steel is 7.44 or less.

2. A steel for forging consisting of, by mass%,

C: 0.05 to 0.50%,

Si: 0.01 to 1.50%,

Mn: 5.1 to 5.5%,

P: 0.001 to 0.050%,

S: 0.020 to 0.200%,

Al: 3.6 to 6.0%,

Cr: 0.01 to 0.20%,

N: 0.0040 to 0.0200%, and

one or more of

V: 0.05 to 0.30%,

Nb: 0.05 to 0.30%,

Ti: 0.005 to 0.050%, and

having a balance of Fe and unavoidable impurities,

wherein the specific gravity of the steel is 7.44 or less.

3. A forged product obtained by hot-forging a steel ingot consisting of, by mass%,

C: 0.05 to 0.50%,

Si: 0.01 to 1.50%,

Mn: 5.1 to 7.0%,

P: 0.001 to 0.050%,

S: 0.020 to 0.200%,

Al: 3.0 to 6.0%,

Cr: 0.01 to 0.20%,

N: 0.0040 to 0.0200%, and

having a balance of Fe and unavoidable impurities,

wherein −3.3×% C+0.2×% Si−0.31×% Mn+0.17×% Al+0.62≤0 (formula 1), and

wherein the specific gravity of the steel is 7.44 or less.

4. A forged product obtained by hot-forging a steel ingot consisting of, by mass%,

C: 0.05 to 0.50%,

Si: 0.01 to 1.50%,

Mn: 5.1 to 7.0%,

P: 0.001 to 0.050%,

S: 0.020 to 0.200%,

Al: 3.0 to 6.0%,

Cr: 0.01 to 0.20%,

N: 0.0040 to 0.0200%, and

one or more of

V: 0.05 to 0.30%,

Nb: 0.05 to 0.30%,

Ti: 0.005 to 0.050%, and

having a balance of Fe and unavoidable impurities,

wherein −3.3×% C+0.2×% Si−0.31×% Mn+0.17×% Al+0.62≤0 (formula 1), and

wherein the specific gravity of the steel is 7.44 or less.

Assignments (3)
CHANGE OF NAME Recorded May 14, 2019
From: NIPPON STEEL & SUMITOMO METAL CORPORATION
To: NIPPON STEEL CORPORATION
Reel/Frame 049257/0828 →
MERGER Recorded Mar 1, 2013
From: NIPPON STEEL CORPORATION
To: NIPPON STEEL & SUMITOMO METAL CORPORATION
Reel/Frame 029905/0735 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 30, 2011
From: TAKADA, HIROMASA; YOSHIDA, SUGURU
To: NIPPON STEEL CORPORATION
Reel/Frame 026900/0712 →