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Title:
METHOD AND EQUIPMENT FOR MANUFACTURING SEAMLESS STEEL TUBE EXCELLENT IN SURFACE PROPERTY
Document Type and Number:
Japanese Patent JP3307294
Kind Code:
B2
Abstract:

PROBLEM TO BE SOLVED: To provide the method and device for manufacturing a seamless steel tube made of an Fe-base alloy whose Cr content is <15 wt.%, which are immediately applicable to existing manufacturing equipment by which a product steel tube reduced in spock marks due to the partial peeling of oxidized scale and indentation caused remarkably in the case the temp. on the outlet side of a sizing/finishing mill is over 900°C in the steel tube, excellent in the surface properties and good in outward appearance is obtained.
SOLUTION: By arranging high-pressure water type descalers 6a, 6b in the end part of a transporting route provided continuing to the outlet table of the sizing/finishing mill such as a sizer 2 and stretch reducer and, after executing outside descaling process to the steel tube just after sizing/finish rolling, by feeding the steel tube to a cooling bed 3 and on-line heat treating device 4, the thickness of oxidized scale on the outside surface of the steel tube at the point of time when the steel tube reaches the inlet side of a rotary straightener 5 is adjusted to ≤50 μm and rolling for straightening bend is executed under this state.


Inventors:
Nakanishi, Tetsuya
Sekiya, Hozumi
Nagase, Yutaka
Application Number:
JP1997000261240
Publication Date:
May 17, 2002
Filing Date:
September 26, 1997
Export Citation:
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Assignee:
SUMITOMO METAL IND LTD
International Classes:
B21B19/04; B21B23/00; B21B45/08; B21D3/02; C21D1/76; C21D1/82; C21D8/10; C21D9/08; C22C38/00; C22C38/18; (IPC1-7): B21B23/00; B21B45/08; B21D3/02; C21D1/76; C21D1/82; C21D8/10; C21D9/08