Title:
METHOD FOR MANUFACTURING WELD STEEL PIPE
Document Type and Number:
Japanese Patent JP2018192521
Kind Code:
A
Abstract:
To provide a method for manufacturing a weld steel pipe by which a weld steel pipe having a high roundness can be obtained.SOLUTION: A method for manufacturing a weld steel pipe comprises: a preparation process in which a weld original pipe is prepared; a first pipe expansion process in which plural dies, which are so located in the weld original pipe as to be arranged in a circumferential direction of the weld original pipe, are brought into contact with an inner peripheral surface of the weld original pipe, thereby expanding the weld original pipe; and a second pipe expansion process in which the plural dies, which are so located in the weld original pipe as to be arranged in the circumferential direction of the weld original pipe after the first pipe expansion process, are brought into contact with the inner peripheral surface of the weld original pipe, thereby expanding the weld original pipe. In the second pipe expansion process, each die is brought into contact with a portion of the inner peripheral surface of the weld original pipe, which is positioned between adjacent dies in the circumferential direction in the first pipe expansion process. A pipe expansion rate in the second pipe expansion process is lower than a pipe expansion rate in the first pipe expansion process.SELECTED DRAWING: Figure 5
Inventors:
SHIMOMOTO TOSHIKI
Application Number:
JP2017100994A
Publication Date:
December 06, 2018
Filing Date:
May 22, 2017
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP
International Classes:
B21D3/14; B21C37/30; B21D37/02; B21D39/20
Domestic Patent References:
| JPH091234A | 1997-01-07 | |||
| JPH0924433A | 1997-01-28 |
Foreign References:
| WO2014188944A1 | 2014-11-27 |
Attorney, Agent or Firm:
Patents corporation Blitas