優れた靭性を有する溶接性超強力鋼の製造方法

Japanese Patent JP4317321

B2

A method is provided for producing an ultra-high strength steel having a tensile strength of at least about 900 MPa (130 ksi), a toughness as measured by Charpy V-notch impact test at -40° C. (-40° F.) of at least about 120 joules (90 ft-lbs), and a microstructure comprising predominantly fine-grained lower bainite, fine-grained lath martensite, or mixtures thereof, transformed from substantially unrecrystallized austenite grains and comprising iron and specified weight percentages of the additives: carbon, silicon, manganese, copper, nickel, niobium, vanadium, molybdenum, chromium, titanium, aluminum, calcium, Rare Earth Metals, and magnesium. A steel slab is heated to a suitable temperature; the slab is reduced to form plate in one or more hot rolling passes in a first temperature range in which austenite recrystallizes; said plate is further reduced in one or more hot rolling passes in a second temperature range below said first temperature range and above the temperature at which austenite begins to transform to ferrite during cooling; said plate is quenched to a suitable Quench Stop Temperature; and said quenching is stopped and said plate is allowed to air cool to ambient temperature.

Luton Michael Jay
Cooj Eong
Bangal Narasim Harao Vi
Petersen Clifford W
Hiroshi Tamehiro
Asahi Hitoshi
Takuya Hara
Masaaki Sugiyama

JP2000504295A

August 19, 2009

July 28, 1998

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Exxon Mobil Upstream Research Company
Nippon Steel Corporation

C21D8/02; C21D1/19; C21D6/00; C22C38/00; C22C38/12; C22C38/14; C22C38/58

JP8269546A
JP9031536A

WO1996017964A1
WO1996017966A1
WO1996017965A1

Minoru Nakamura
Fumiaki Otsuka
Sadao Kumakura
Shishido Kaichi
Hideto Takeuchi
Toshio Imajo
Nobuo Ogawa
Village shrine Atsuo
Takaki Nishijima
Atsushi Hakoda

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