| abstract |
PROBLEM TO BE SOLVED: To provide a technique for reducing energy consumption when manufacturing a pipe material having high strength and improving the recyclability of the pipe material. SOLUTION: A long and solid raw material is prepared, which is made of a steel material containing 0.05 to 0.25% by weight of C. Next, the prepared raw material is cut to form a solid billet 910, and then the billet 910 is processed into a hollow blank 920. Then, the blank 920 processed into a hollow is formed into a tubular 950 by warm extrusion molding. [Selection diagram] Fig. 1 |