Title:
PRODUCTION OF SEAMLESS STEEL TUBE HAVING FINE GRAIN STRUCTURE
Document Type and Number:
Japanese Patent JP2718865
Kind Code:
B2
Abstract:
PURPOSE: To obtain a steel tube as rolled having a fine grain structure of over an austenitic grain size No 8 by cooling after a hollow steel tube stock containing the prescribed quantity of Nb is worked under the prescribed condition with an inclined rolling mill and forming after successively worked with a final inclined rolling mill.
CONSTITUTION: A hollow steel tube stock, which holds high temp. heat produced by piercing and rough rolling a billet containing 0.01-0.1 Nb heated to high temp., is rolled with two or more inclined rolling mills arranged in row. By the inclined rolling mill of an elongater, the hollow steel stock is subjected to cooling to 1000-1100°C before the inclined rolling mill in front of the final rolling mill and working at 20-70% reduction rate of area with the next inclined rolling mill located immediately after thereof, it is further made to a fine grain over No.6 to lower the recrystallization temp. The steel tube is cooled to 900-1000°C, successively, subjected to working at 20-70% reduction rate of area with the final rolling mill and then to form rolling.
Inventors:
Asahi average
Akira Yagi
Akira Yagi
Application Number:
JP32817092A
Publication Date:
February 25, 1998
Filing Date:
December 08, 1992
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
B21B19/06; C21D8/10; (IPC1-7): C21D8/10; B21B19/06
Domestic Patent References:
| JP250916A | ||||
| JP3240921A | ||||
| JP3180427A |
Attorney, Agent or Firm:
Hiroaki Tamura (1 outside)
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