CASE HARDENING STEEL MATERIAL

• Main Authors: HORIMOTO MASAYUKI, KATO GEN, IMATAKA HIDEKI, FUJIMOTO MITSURU
• Format: Patent
• Language: English
• Published: 22.05.2015
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

A case hardening steel material which has a chemical composition that contains in mass% 0.15 to 0.23% of C 0.01 to 0.15% of Si 0.65 to 0.90% of Mn 0.010 to 0.030% of S 1.65 to 1.80% of Cr 0.015 to 0.060% of Al 0.0100 to 0.0250% of N and if necessary a specific amount of Cu and/or Ni with the balance being Fe and impurities and that satisfies 25 = Mn/S = 85 0.90 = Cr/(Si+2Mn) = 1.20 and 1.16Si+0.70Mn+Cr = 2.20 with the contents of P Ti and O as impurities satisfying P=0.020% Ti=0.005% and O=0.0015% and which has a structure that comprises 20 to 70% of ferrite in area fraction with the remainder being pearlite and/or bainite. This case hardening steel material exhibits a low component cost and excellent hot workability and machinability and can ensure excellent bending fatigue strength and wear resistance of a carburized part thus being suitable as a raw material for a carburized part such as a CVT pulley shaft.