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Patent Searching and Data


Title:
METHOD FOR SIZING STEEL PIPE
Document Type and Number:
Japanese Patent JPH07164023
Kind Code:
A
Abstract:

PURPOSE: To attain a forming condition free from the generation of a roll mark by finding the generation limit line of the roll mark according to the ovalities of three roll stands, and limiting the ovalities of two roll stands and a draft in an outside diameter.

CONSTITUTION: In places upper than curves P and Q, where drafts in outside diameter, are large, roll marks occur. Therefore, when the ovalities of three roll stands, are 1.0%, the ovalities of two roll stands and a draft in outside diameter, are selected in the range lower than the curve P. For instance, if the ovalities of the two roll stands, are 1%, its draft in outside diameter, is made ≤0.9%. Like this, if the limit line of the generation of a roll mark, obtained when the ovalities of the three roll stands, are changed within the range of the normal use, is found, and the ovalities of the two roll stands and a draft in outside diameter, are selected within the range not exceeding the found limit line of the generation of the roll mark, not only the roll mark does not generate but also the roundness of a seamless steel pipe, is improved, and the design of a roll calibre and the operation condition, etc., become easy.


Inventors:
Okamoto, Yoshihide
Kobayashi, Nobuo
Yoshida, Hiroshi
Kajiyama, Fuyuhiko
Application Number:
JP1993000316490
Publication Date:
June 27, 1995
Filing Date:
December 16, 1993
Export Citation:
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Assignee:
NKK CORP
International Classes:
B21B17/14; B21B19/10; B21B27/02; (IPC1-7): B21B19/10; B21B27/02
Attorney, Agent or Firm:
佐々木 宗治 (外3名)