US4659398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reducing internal stresses of roller straightened rails
Assignee: Krupp Stahl AG
•
Filing: 1986-01-14
•
Granted: 1987-04-21
•
Expires: 2006-01-14
Abstract
Abstract The present invention relates to a process for reducing internal stresses of roller straightened rails. After the straightening operation the rail web portion is heated for a short time to temperatures ranging between 200°-700° C., preferably between 350°-500° C., and after reaching the desired temperatures the rail is cooled by air to room temperature. For the purpose of heating the rail is continuously conveyed in front of the heating apparatus. The inventive process permits to reduce internal stresses in the rail head and base portions to a value of less than 50 N/mm 2 thus ensuring increased rupture strength of the rail.
Inventors
- 👤 Wilhelm Heller
- 👤 Lutz Weber
- 👤 Reinhard Schweitzer
- 👤 Jurgen Flugge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:08
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/04; C21D7/00; C21D2221/00; C21D9/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
102 words
A method of heat treating for reducing internal stresses in the head and base portions of roller straightened rails, said rails having a web portion, the method comprising annealing the straightened rail in a temperature range of about 200° C. to 700° C. by continuously conveying the rail in front of a heating apparatus at a speed adapted to the capacity of the heating apparatus, said speed ranging between 0.2 m/minute and 1 m/s, wherein during said conveying, heating only the web portions of the rails to the annealing temperature, and after reaching said annealing temperature, cooling the rails at room temperature.
Claim 2
Independent Claim
102 words
A method of heat treating for reducing internal stresses in the head and base portions of roller straightened rails, said rails having a web portion, the method comprising annealing the straightened rail in a temperature range of about 200° C. to 700° C. by continuously conveying the rail in front of a heating apparatus at a speed adapted to the capacity of the heating apparatus, said speed ranging between 0.2 m/minute and 1 m/s, wherein during said conveying, heating only the web portions of the rails to the annealing temperature, and after reaching said annealing temperature, cooling the rails at room temperature.
Claim 3
Dependent Claim
16 words
A method according to claim 1, wherein the annealing temperature is 250° C. to 500° C.
Claim 4
Independent Claim
76 words
A method for the production of roller straightened steel rails having low internal stresses, the rails having a web portion, the method comprising subjecting the rails to hot rolling, cooling the rails to a temperature of less than 100° C., continuously heating only the web portions of the rails to about 100° C. to 500° C., directing the rails to a roller straightening machine, straightening the rails, and cooling the rails by air to room temperature.
Claim 5
Independent Claim
76 words
A method for the production of roller straightened steel rails having low internal stresses, the rails having a web portion, the method comprising subjecting the rails to hot rolling, cooling the rails to a temperature of less than 100° C., continuously heating only the web portions of the rails to about 100° C. to 500° C., directing the rails to a roller straightening machine, straightening the rails, and cooling the rails by air to room temperature.
Claim 6
Dependent Claim
23 words
Method according to claim 3, wherein the web portion of the rail is heated to a temperature ranging between 150° and 350° C.
Claim 7
Dependent Claim
27 words
Method according to claim 3, wherein the rail web portion, the lower area of the rail head and the upper area of the rail base are heated.
Claim 8
Dependent Claim
17 words
A method according to claim 3, wherein the heating is conducted at 150° C. to 350° C.
References Cited (Backward Citations)
US1285749A
Cited
US1331175A
Cited
US1363601A
Cited
US1914439A
Cited
US4082577A
Cited
US4486248A
Cited
US4575397A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |