Liquid phase diffusion bonding for steel with excellent low-temperature transformation cracking resistance

摘要

PROBLEM TO BE SOLVED: To provide steel for liquid-phase diffusion bonding by which the hardening crack or reheat crack sensitivity of a joint to which refining heat treatment is applied after liquid-phase diffusion bonding can be reduced.;SOLUTION: The steel for liquid-phase diffusion bonding has a composition containing, by mass, 0.05 to 1.0% C, 0.01 to 1.0% Si, 0.05 to 3.0% Mn, 0.005 to 0.1% Ti and 0.01 to 0.2% Al, also containing P, S and O in the amounts limited to ≤0.01%, ≤0.003% and ≤0.01%, respectively, further containing As, Sn, Sb, Pb and Zn in the amounts each limited to ≤0.005% and satisfying the relation of inequality (As%+Sn%+Sb%+Pb%+Zn%)≤0.015%, and having the balance Fe with inevitable impurities. When liquid-phase diffusion bonded joints using the steel are reheated to a temperature not lower than the Ac₃ point and subjected to accelerated cooling at a rate of ≥0.1 °C/s or are tempered, after the accelerated cooling, to a temperature not higher than the Ac₁ transformation point, Charpy absorption energy at 0°C is ≥47J.;COPYRIGHT: (C)2004,JPO