HIGH STRENGTH STEEL HAVING EXCELLENT STRESS CORROSION CRACKING RESISTANCE AND PRODUCTION METHOD THEREFOR

• Main Authors: TAMURA MASARU, MINE TAKAYUKI, YASHIRO TOSHIYUKI, KOBAYASHI KOJI
• Format: Patent
• Language: English
• Published: 23.08.2002
• Edition: 7
• 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 produce an inexpensive high strength stainless steel which has a strength level of the Vickers hardness >500 Hv, excellent toughness and stress corrosion cracking resistance, and to provide a production method therefor. SOLUTION: A steel having a chemical composition containing, by mass, 12 to 16% Cr, 0.1 to 0.3% Ni, 0.07 to 0.13% C, 0.04 to 0.085% N and <=0.1% Cu is subjected to primary quenching treatment. The steel is next cold-rolled, and is thereafter subjected to secondary quenching treatment to form a metallic structure containing a martensitic phase of, by volume, 50 to 75% and a ferritic phase of 50 to 25% and having an average grain size of <=10 μm.