CARBONITRIDED COMPONENT MADE OF STEEL

• Main Author: OFUJI YOSHIHIRO
• Format: Patent
• Language: English
• Published: 02.04.2010
• 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 carbonitrided component made of steel which has excellent bending fatigue strength and surface fatigue strength, and can respond to the requirements of reduction in weight, size and higher stress load of a component. SOLUTION: In the carbonitrided component made of steel, its base is composed of steel comprising 0.1 to 0.3% C, 0.4 to 1.5% Si, 0.2 to 1.5% Mn, 0.003 to 0.05% S, 0.5 to 2.5% Cr, 0.01 to 0.05% Al and 0.008 to 0.025% N, and the balance Fe with impurities, and, in the region to a depth of 0.1 mm from the surface, the average C concentration Cs is 0.60 to 0.90%, the average N concentration Ns is 0.15 to 0.35%, Cs+Ns is 0.80 to 1.10%, also, in the case of Cr-(Ns×3.7)≥0, [(1+0.7×Si)×(1+3.3×Mn)×[1+2.2×äCr-(Ns×3.7)+(0.048/Ns)}]×(1+3.0×Mo)≥9], and, in the case of Cr-(Ns×3.7)<0, [(1+0.7×Si)×(1+3.3×Mn)×ä1+2.2×(0.048/Ns)}×(1+3.0×Mo)≥9] are satisfied. COPYRIGHT: (C)2010,JPO&INPIT