Title:
継目無鋼管の製造方法
Document Type and Number:
Japanese Patent JP4359783
Kind Code:
B2
Abstract:
A round billet containing, by mass%, 10.50 to 14.00% of Cr with a value represented by the equation of "Cr + 4Si - (22C + 0.5Mn + 1.5Ni + 30N)" of not more than 9.0%, wherein the symbols of the elements represent the contents, by mass%, of the elements in the steel, is heated at a soaking temperature of 1100 to 1250 °C so that an in-furnace time (min) is not less than "0.5 × Diameter of the round billet (mm)", and then pierced and rolled with a piercing efficiency by a piercing mill of not less than 50%, a value regulated by the equation: "{(Diameter of the round billet - Roll gap at the foremost end of the plug) / Diameter of the round billet} × 100" of not more than 8.0, and a plug shape represented by the equation: "Radius of foremost end of the plug (mm) / Diameter of the round billet (mm)" of 0.06 to 0.17. The thus-manufactured high-Cr seamless steel pipe or tube has excellent internal surface properties with minimized internal surface defects.
Inventors:
Hiroshi Nakaike
Tetsuya Nakanishi
Junji Nakata
Tetsuya Nakanishi
Junji Nakata
Application Number:
JP2006513927A
Publication Date:
November 04, 2009
Filing Date:
May 26, 2005
Export Citation:
Assignee:
SUMITOMO METAL INDUSTRIES,LTD.
International Classes:
B21B19/04; B21B25/00; C22C38/00; C22C38/50; C22C38/54; B21B3/02; B21B17/14; B21B19/06; B21B23/00
Domestic Patent References:
| JP2004043935A | ||||
| JP2002361304A | ||||
| JP10005820A | ||||
| JP2003001305A |
Attorney, Agent or Firm:
Mikiji Sugioka
Terutada Hogami
Chihara
Terutada Hogami
Chihara