BASE METAL FOR HIGH-TOUGHNESS CLAD STEEL PLATE GIVING WELD WITH EXCELLENT TOUGHNESS, AND PROCESS FOR PRODUCING SAID CLAD STEEL PLATE

摘要

The present invention provides a base metal for a high-toughness clad plate having excellent toughness at a welded joint by composite addition of alloy elements. A base metal for high-toughness clad plate having excellent toughness at a welded joint contains, in terms of mass%, C: 0.030 to 0.10%, Si: 0.10 to 0.30%, Mn: 1.00 to 1.60%, P: 0.015% or less, S: 0.003% or less, V: less than 0.010%, and at least one selected from Mo: 0.05 to 0.50%, Nb: 0.010 to 0.060%, Ti: 0.005 to 0.020%, Al: 0.040% or less, Ca: 0.0010 to 0.0040%, and N: 0.0030 to 0.0060%, the balance being Fe and unavoidable impurities, in which a percent ductile fracture is 85% or more in a -20°C DWTT test and vE-20°C is 100 J or more at a HAZ 3 mm position.