BEARING STEEL EXHIBITING EXCELLENT MACHINABILITY AFTER SPHEROIDIZING ANNEALING AND EXCELLENT RESISTANCE TO HYDROGEN FATIGUE AFTER QUENCHING/TEMPERING

摘要

Provided is a bearing steel that exhibits excellent machinability after spheroidizing annealing and excellent resistance to hydrogen fatigue after quenching/tempering. By using a steel composition containing by mass 0.85 1.10% carbon 0.30 0.80% silicon 0.90 2.00% manganese up to 0.025% phosphorus up to 0.02% sulfur up to 0.05% aluminum 1.8 2.5% chromium 0.15 0.4% molybdenum up to 0.0080% nitrogen up to 0.0020% oxygen and more than 0.0015% but no more than 0.0050% tin with the remainder comprising iron and unavoidable impurities the formation of WEA is effectively inhibited even in environments in which hydrogen penetrates and rolling fatigue life is thus improved. Machinability properties such as cutting and forging performance are also improved.