HIGH TOUGHNESS SPHEROIDAL GRAPHITE CAST STEEL AND ITS PRODUCTION

• Main Authors: TAKAHASHI TOSHIO, ABE TOSHIHIKO, TADA SHUJI
• Format: Patent
• Language: English
• Published: 27.05.1994
• Edition: 5
• Subjects: ALLOYS; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To jointly secure high toughness and a high longitudinal elastic modulus whose combination has been difficult in the conventional iron series casting material by subjecting spheroidal graphite cast steel having excellent castability and machinability in the molding stage to prescribed austempering treatment and forming its fundamental structure into an ausferritic one. CONSTITUTION:Spheroidal graphite cast iron having a compsn. constituted of, by weight, 0.8 to 2.0% C, 1.0 to 3.0% Si and graphite spheroidizing elements such as Mg and Ca by amounts required for the spherodizing of graphite, and the balance Fe with inevitable impurities is subjected to austempering treatment constituted of austenitizing treatment and isothermal transforming treatment to form its fundamental structure into an ausferritic one in which fine retained austenite is dispersed by >=15% volume%, so that high toughness and a high longitudinal elastic modulus can be secured.