Title:
PRODUCTION OF HIGH-STRENGTH HIGH-QUALITY BUTT-WELDED STEEL TUBE
Document Type and Number:
Japanese Patent JPH1147826
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To decrease the penetration of scale and outside surface flaws in a butt-welding joint part and to lessen the shear droop of edges of skelp by specifying the tap. and velocity of the high-velocity combustion flame to be blown to the butt welding surfaces just prior to butt welding to specific values, specifying the skelp temp. on the outlet side of a heating furnace to a specific temp. and pressing the edges of the skelp to a seam guide roll. SOLUTION: The skelp which is a material of a butt-welded steel tube is continuously reheated to 1300 to 1350 deg.C in a heating furnace and is formed by perpendicular stand forming rolls and horizontal stand forming rolls 4. The forming of the edges is executed by pressing the skelp edges 10 to the seam guide roll 9 of the calibers of the horizontal stand forming rolls 4. The high- velocity combustion flame is formed by a high-velocity combustion flame generator just prior to butt welding and both edges of the skelp are irradiated with the high-velocity combustion flame. The edges are butt-welded by butt welding rolls. The temp. of the high-velocity combustion flame is specified to 1400 to 1600 deg.C and the velocity thereof to >=800 m/sec. The temp. of the skelp on the outlet side of the heating furnace is kept at 800 to 1200 deg.C.
Inventors:
SAKAMOTO SHINYA
TERADA YOSHIO
SUMIMOTO DAIGO
HAMAYA HIDEKI
TERADA YOSHIO
SUMIMOTO DAIGO
HAMAYA HIDEKI
Application Number:
JP21096397A
Publication Date:
February 23, 1999
Filing Date:
August 05, 1997
Export Citation:
Assignee:
NIPPON STEEL CORP
International Classes:
B21C37/06; B23K20/00; C21D8/10; C21D9/08; (IPC1-7): B21C37/06; B23K20/00; C21D8/10; C21D9/08
Attorney, Agent or Firm:
Yu Shiina (1 person outside)