The mechanical characteristics which it withstands hot high tension the composite tube null which has the corrosion resistance which

摘要

PURPOSE:To improve strength and corrosion resistance by forming an intermediate layer containing Si, Mn, Cr, Ni, Mo, Fe, and the like between an outer layer composed of Si, Mn, Cr, Ni, Mo, Fe, and the like and an inner layer composed of Bi, Mn, Ni, Cr, Mo, Fe, and the like. CONSTITUTION:The title multiunit tube is composed of 0.05-0.20 (weight percent the rest is omitted) of C, less than 1.0 of Si, less than 2.0 of Mn, less than 1.0 of Cr, 0.2-2.0 of Ni, less than 1.0 of Mo, 0.05-0.15 of V, and Fe, etc., and an intermediate layer containing 0.03-0.07 of C, 0.3-0.7 of Si, 0.5-1.5 of Mn, 6.0-12.0 of Cr, 4.0-11.0 of Ni, 0.9-1.5 of Mo, 75.0-85.0 of Fe, 0.01-0.05 of Al is connected between an outer layer of less than 0.45 equivalent carbon and an inner layer composed of less than 0.30 of C, less than 1.0 of Si, less than 2.0 of Mn, 12.0-16.0 of Ni, 16.0-10.0 of Cr, 2.0-3.0 of Mo, and Fe, etc. The outer and inner layer can be thereby provided with the desired mechanical character and corrosion resistance.