IP Library Granted Patent US 10,144,984
Granted Patent B2
US 10,144,984 · App. 15/029,449 · Granted Dec 4, 2018

Method of producing roughly shaped material for rolling bearing

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Quick Facts
Patent No.
US 10,144,984
App. No.
15/029,449
Granted
Dec 4, 2018
Kind
B2
Abstract

A roughly shaped material for a rolling bearing of the present invention is produced by forging a steel composed of a high-carbon chrome bearing steel containing 0.7 mass % to 1.2 mass % of a carbon, and 0.8 mass % to 1.8 mass % of a chromium to a predetermined shape while heating the steel to a forging temperature in a range of (Ae 1 point+25° C.) to (Ae 1 point+105° C.), cooling a forged article to a temperature of Ae 1 point or lower, and performing an annealing in which the forged article that is obtained is heated to a soaking temperature in a range of (Ae 1 point+25° C.) to (Ae 1 point+85° C.), the forged article is retained for 0.5 hours or longer, and the forged article is cooled down to 700° C. or lower at a cooling rate of 0.30° C./s or slower.

Claims (9)

1. A method of producing a roughly shaped material for a rolling bearing by forging a steel composed of a high-carbon chrome bearing steel of which a Vickers hardness is Hv240 or less containing 0.7 mass % to 1.2 mass % of a carbon, and 0.8 mass % to 1.8 mass % of a chromium, the method comprising:

(A) forging the steel to a predetermined shape while heating the steel to a forging temperature in a range of (Ae 1 point+25° C.) to (Ae 1 point+105° C.), and cooling a forged article to a temperature of Ae 1 point or lower; and

(B) performing an annealing in which the forged article obtained in (A) is heated to a soaking temperature in a range of (Ae 1 point+25° C.) to (Ae 1 point+85° C.), the forged article is retained for 0.5 hours or longer and 1 hour or shorter, and the forged article is cooled down to 700° C. or lower at a cooling rate of 0.020° C./s or faster and 0.30° C./s or slower.

2. The method of producing a roughly shaped material for a rolling bearing according to claim 1 ,

wherein the soaking temperature is set to 760° C. to 820° C.

3. The method of producing a roughly shaped material for a rolling bearing according to claim 1 ,

wherein the cooling rate is set to 0.27° C./s or slower.

4. The method of producing a roughly shaped material for a rolling bearing according to claim 2 ,

wherein the cooling rate is set to 0.27° C./s or slower.

Assignments (2)
CHANGE OF NAME Recorded May 14, 2019
From: NIPPON STEEL & SUMITOMO METAL CORPORATION
To: NIPPON STEEL CORPORATION
Reel/Frame 049257/0828 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 14, 2016
From: YANO, TAKEFUMI; KASHIWAGI, SHINICHIROU; UEKITA, HIROKI; SAITOU, TOSHIKAZU; HIRANO, TETSUROU; NEISHI, YUTAKA
To: NIPPON STEEL & SUMITOMO METAL CORPORATION
Reel/Frame 038286/0431 →