Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/18—Hardening; Quenching with or without subsequent tempering
  • C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
  • C21D1/20—Isothermal quenching, e.g. bainitic hardening

Definitions

• ABSTRACT A process for treating steel containing up to 0.25% C, up to 0.5% Si, about 0.5 to about 2% Mn, 0 to 0.1% Nb, 0 to 0.2% V, O to 0.2% Ti and 0 to 0.1% A1, balance iron and impurities comprising heating the steel to the austenitizing point, thereafter immediately cooling said steel to the transformation temperature in a 4 Claims, No Drawings 1 METHOD OF PRODUCING A STEEL WITH HIGH STRENGTH, HIGH DUCTILITY AND GOOD WELDABILITY DESCRIPTION OF THE INVENTION
• This invention relates to a method of making steel having the qualities of high strength, good ductility and good weldability.
• steel having the following composition:
• the austenitized strip is fed and where cooling to a temperature of about 300C. occurs at a controlled rate of about 0.6C./sec. to 60C./sec. Subsequently the strip is cold-worked with an areareduction of 0.5- by volume.
• the cold-working operation is carried out suitably as a cold-rolling. Despite the small reduction in surface area occasioned by the cold-working, the yield-point of the steel is considerably increased in the material in question with this procedure without any mentionable decrease of the ductility.
• a cold-rolled strip was used with the following dimensions: 340 X 1.53 mm.
• the composition of the basic material was:
• This material was subject to a special heat treatment in a continuous vertical furnace.
• the heat treatment resulted in a mixed structure consisting mainly of bainite and ferrite with elements of martensite and finelamellar perlite.
• the material was subject to a cold-rolling with a reduction of thickness from 1.53 to 1.50 mm.
• the steel had a hardness in the areas influenced by the heat generated by the welding procedure in the range -90%- of the initial hardness which must be regarded as a good weldability.
• a steel produced according to this invention has excellent formability, that is, a good elongation in proportion to the high strength. Moreover, it has a good weldability which means a broader range of applicability for the steel.
• the steel produced according to the invention combines in a way not known heretofore the three properties aimed at namely high strength, good formability and good weldability.
• a method for treating steel containing a maximum of 0.25% C, a maximum of 0.5% Si, about 0.5 to about 2% Mn, 0 to 0.1% Nb, 0 to 0.2% V, 0 to 0.22 Ti, 0 to 0.1% Al, balance iron and residual impurities comprising 1. heating said steel to a temperature sufficient for said steel to be substantially completely austenitized,
• a steel having the properties of high strength, good formability and good weldability produced by treating a steel containing a maximum of 0.25%C, a maximum of 0.5% Si, about 0.5 to 2% Mn, 0 to 0.1% Nb, 0 to 0.2% V, 0 to 0.2% Ti, 0 to 0.1% Al, balance iron and residual impurities by Y 1. heating said steel to a temperature sufficient for said steel to be substantially completely austenitized,

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Steel (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=20275759

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Cited By (11)

Citations (5)

• 1972
  • 1972-07-10 SE SE7209072A patent/SE373877B/xx unknown
• 1973
  • 1973-07-06 US US377125A patent/US3902927A/en not_active Expired - Lifetime

Patent Citations (5)

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