CASE HARDENING STEEL MATERIAL

• Main Authors: HORIMOTO MASAYUKI, IMATAKA HIDEKI, KATO HAJIME, FUJIMOTO MITSURU
• Format: Patent
• Language: English
• Published: 07.11.2013
• 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

PROBLEM TO BE SOLVED: To provide a case hardening steel material which exhibits low component cost, has excellent hot workability and machinability, and can ensure excellent bending fatigue strength and wear resistance of a carburized part.SOLUTION: A case hardening steel material contains, by 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 the balance Fe with impurities, and satisfies [25≤Mn/S≤85], [0.90≤Cr/(Si+2Mn)≤1.20], and [1.16Si+0.70Mn+Cr≥2.20], wherein the contents of P, Ti and O as impurities satisfy P≤0.020%, Ti≤0.005% and O≤0.0015%, respectively. The steel material has a structure that comprises 20 to 70% of ferrite in area fraction with the remainder being pearlite and/or bainite. Further, the steel material may contain a prescribed amount of Cu and Ni.