METHOD FOR PRODUCING SEAMLESS PIPE

Title:

METHOD FOR PRODUCING SEAMLESS PIPE

Document Type and Number:

WIPO Patent Application WO/2005/068098

Kind Code:

A1

Abstract:

A method for producing a seamless pipe in which carburization occurring in the production process of a pipe is prevented and the stretch-rolling process is rationalized. In the process of producing a seamless pipe, a pipe bored in a boring-rolling step is rolled without using an inner surface restricting tool in the stretch-rolling step or without performing stretch-rolling, swaging-rolling is performed in a swaging-rolling step, and wall-thickness machining is performed by means of a cold-rolling machine or a cold-drawing machine in a cold-rolling step. According to the method, trapping of graphite fine particles to the inner/outer surfaces of the pipe caused in conventional stretch-rolling is reduced and carburization of pipe can be prevented. The method is especially effective as a carburization preventive measure of extremely low carbon stainless steel and high alloy steel.

Inventors:

HAYASHI CHIHIRO (JP)

Application Number:

PCT/JP2005/000379

Publication Date:

July 28, 2005

Filing Date:

January 14, 2005

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
HAYASHI CHIHIRO (JP)

International Classes:

B21B17/14; B21B23/00; B21B19/04; B21B19/08; (IPC1-7): B21B17/14; B21B23/00

Foreign References:

JPH0327805A	1991-02-06
JPH105818A	1998-01-13
JPH1058013A	1998-03-03

Other References: