Method of producing roughly shaped material for rolling bearing

Patent metadata

Field	Value
Publication number	US-10144984-B2
Application number	US-201415029449-A
Country	US
Kind code	B2
Filing date	Oct 27, 2014
Priority date	Nov 7, 2013
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

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.

First claim

What is claimed is:

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.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Yano Takefumi
• Kashiwagi Shinichirou
• UEKITA Hiroki
• Saitou Toshikazu
• Hirano Tetsurou
• Neishi Yutaka

Classifications

• F16C2204/70

  with chromium as the next major constituent · CPC title

• F16C2204/66

  High carbon steel, i.e. carbon content above 0.8 wt%, e.g. through-hardenable steel · CPC title

• C22C38/04

  containing manganese · CPC title

• C22C38/02

  containing silicon · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title