PURPOSE: To prepare a chain excellent in toughness in a welded part under a low temp. environment, by using an Fe-Mn-Cr-Mo steel having a specific composition as a steel material for a chain.
CONSTITUTION: As a steel material for a chain used in an extremely cold district at -30°C or less, a steel containing 0.15W0.30% C, 0.10W0.50% Si, 1.30W2.50% Mn, 0.50W1.50% Cr, 0.10W0.60% Mo, 0.010W0.060% sol Al, 0.003W0.020% N, P< 0.040% and S<0.040% and satisfying relation represented by formula (1) between contents of C, Mn, Cr and Mo and containing Ca<0.01% and a rare earth element <0.10% or steel having a composition prepared by further containing one or more of V, Nb and Ti in the former composition in the sum total of 0.20% or less is used. A steel material for a chain having excellent toughness in a welded part even at a low temp. is obtained.
NISHIDA KAZUHIKO
NAKAZATO FUKUKAZU
