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Title:
DRAWING METHOD FOR SEAMLESS STEEL PIPE OF AUSTENITIC HIGH ALLOY SUPERIOR IN SOUR RESISTANCE
Document Type and Number:
Japanese Patent JPH03297505
Kind Code:
A
Abstract:

PURPOSE: To roll the pipe with a good surface quality and without cracking by specifying the temp. condition before drawing and strain condition in drawing to a pipe stock after piercing when manufacturing the seamless steel pipe of a high alloy of which components are confined.

CONSTITUTION: When rolling the seamless steel pipe of the high alloy contg., by weight, ≤0.03% C, ≤0.50% Si, ≤0.50% Mn, 20-25% Cr, 20-40% Ni, 2.5-4.5% Mo, ≤2.0% Cu, ≤1.5% Ti, ≤0.07% Al, ≤0.02% P, ≤0.0020% S, ≤0.03% N, ≤0.0060 % Ca and ≤ 0.0050% O and consisting of the balance Fe with impurities, the inside and outside temps. of the shell after piercing are taken as ≤1050°C on the inside surface and as ≥950°C on the outside surface before drawing and this pipe is rolled by controlling the rolling strain that is expressed by the formula to ≤1.0. In the formula, t1 is the thickness (mm) of shell before drawing, t2 is the thickness (mm) of shell after drawing, I1 is the length (mm) of shell before drawing and I2 is the length (mm) of shell after drawing.


Inventors:
TAKAHASHI AKIHIKO
OGAWA HIROYUKI
Application Number:
JP9826690A
Publication Date:
December 27, 1991
Filing Date:
April 13, 1990
Export Citation:
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Assignee:
NIPPON STEEL CORP
International Classes:
B21B3/02; B21B19/06; C21D8/10; C22C38/00; (IPC1-7): B21B3/02; B21B19/06; C22C38/00
Attorney, Agent or Firm:
Kazuo Ozeki