PRODUCTION OF STEEL FOR IGNITION PLUG BODY FITTING

• Main Authors: KAGAWA JUNICHI, ASHIDA SHINZO
• Format: Patent
• Language: English
• Published: 08.03.1990
• 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

PURPOSE:To produce the steel for ignition plug body fittings having high break ing torque, excellent hot caulking property and cold caulking property, and high tensile strength of a threaded part by hot rolling and cooling a low alloy steel having a specific compsn. under specific conditions. CONSTITUTION:The steel having the compsn. contg., by weight %, 0.02 to 0.10% C, <1% Si, 1.0 to 2.5% Mn, 0.05 to 0.08% Al, and further at least one kind among 0.005 to 0.25% Ti, 0.005 to 0.25% Zr, 0.01 to 0.25% V, and 0.005 to 0.10% Nb, and further contg. at least one kind among <1.5% Cr, <0.3% Mo, <1% Ni is heated to 900 to 1100 deg.C and is then subjected to hot finish rolling at 850 to 1200 deg.C finish temp.; thereafter, the steel is cooled from the temp. range of 800 to 950 deg.C down to <=400 deg.C at 1 to 15 deg.C/sec average cooling rate. The steel for the ignition plug body fittings consisting of >=60vol.% ferrite and the balance martensite or bainite or the mixed structure composed thereof and having >=70 kgf/mm tensile strength of the threaded part is thus produced.