| 摘要 |
PURPOSE:To produce a steel pipe excellent in wear resistance not only in the base metal but also in the weld zone and weld heat affected zone by limiting the chemical components and hardness in the base metal and each part of weld metal. CONSTITUTION:The base metal of a steel pipe and the seam-welded metal parts have a compsn. contg., by weight, 0.05 to 0.20% C, 0.50 to 2.00% Si, 0.50 to 2.50% Mn and 0.020 to 2.00% Al and contg. one or more kinds among 0.05 to 1.00% Cu, 0.05 to 2.00% Ni, 0.05 to 2.00% Cr, 0.05 to 1.0% Mo, 0.005 to 0.10% Nb, 0.005 to 0.10% V, 0.005 to 0.10% Ti and 0.0003 to 0.0020% B, and the balance Fe with inevitable impurities and have 200 to 350 Vickers hardness. |
