| 摘要 |
PURPOSE:To prevent embrittlement occurring in a bond zone at the time of multilayer welding, by specifying the relationship among the quantities of C, Si, and Mn in a steel stock for joint having a specific composition. CONSTITUTION:The steel stock has a composition which consists of, by weight, 0.002-0.07% C, 0.05-0.25% Si, 1.1-1.8% Mn, 0.01-0.1% Al, 0.005-0.010% Ti, <0.0025% N, and the balance Fe with impurities and in which the quantities of C, Si, and Mn are regulated so that 0.64>=(C+Si+1/Mn)>=1.23 is satisfied. Further, proper amounts of one or more element among V, Nb. Cu, Ni, Cr, and Mo and one or more elements among B, Ca, Zr, Hf, Y, Ce, and La are incorporated to the above, if necessary. This steel stock for joint is used in multilayer welding of two or more passes. In the composition of this steel, the quantities of C, Si, and N are reduced, Mn and Al are added by a prescribed quantity or more, and Ti is added to the extent equivalent to N, so that characteristic embrittlement phenomena occurring at the time of multilayer welding can be prevented.
|
