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
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0236—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S72/00—Metal deforming
  • Y10S72/70—Deforming specified alloys or uncommon metal or bimetallic work

Definitions

• ABSTRACT A steel sheet and strip for use in the manufacture of easy-to-open cans having excellent can opening and scoring properties, the compostiion of which is characterized by less than 0.02 percent of carbon, less than 0.1 percent of silicon, 0.1 0.5 percent of manganese and less than 0.03 percent of oxygen, with the remainder being iron and'unavoidable impurities.
• This invention is relates to steel sheets and strips having excellent characteristics for use in the manufacture of the so-called easy open can in which a score with suitable depth is engraved on a can body or cover, and the can can be opened without using a tool, such as a can-opener and a manufacturing method therefore.
• the present inventors conducted various experiments and investigations for the purpose of obtaining steel sheets and strips for use in easy open cans having excellent can opening properties and no tendency for crack formation in the score work.
• This invention is based on the findings that steel sheets and strips comprizing less than 0.02 percent of carbon, less than 0.1 percent of silicon, 0.1 0.5 percent of manganese and lessthan 0.03 percent of oxygen, with the remainder being iron and unavoidable impurities, and further, steel sheets and strips containing 0.04 0.10 percent ofphosphorous besides said component elements are excellent for such purposes.
• the steel sheets and strips of this invention differs first of all, as compared with the conventional steel sheets and strips for can use, in the carbon content (0.05 0.08 percent in conventional steel sheets and strips) and the oxygen content (004 0.05 percent in conventional steel sheets and strips).
• the usual manufacturing method of steel sheets and strips for can manufacture means the method whereby molten steel is smelted in a converter, an electric furnace, or by a suitable method, and is made into ingots and cogged to obtain slab, or casted continuously to obtain slab.
• the slab is then hot rolled at a temperature above 850C and cold rolled with a draft of more than 30 percent. Thereafter decarburizing annealing or the usual annealing is carried out at a temperature of 500 1000C and skin pass rolling is effected with a draft of less than 2.0 percent.
• the particular feature of the steel sheet and strip of this invention is that the ease of can opening is improved, depending on the shape of the score (sectional shape and plane shape), when said skin pass is carried out with a draft range of 3 15 percent.
• the range of this skin pass draft corresponds also to the range where the expanding workability necessary for the steel sheet and strip is not substantially lowered.
• the carbon content be as low as possible, because the steel becomes hard when the carbon content is larger than 0.020 percent, thus the opening of the can becomes more difficult and cracks are easily formed at the score portion.
• methods such as subjecting the molten steel to a vacuum degassing treatment or to adecarburization annealing may be used.
• the decarburization annealing is more suitable in improving the can opening properties, because it is possible to reduce the carbon content in the steel to extremely low values.
• Manganese is added in order to prevent the hot shortness of steel material due to the existence of sulphur in steel as anunavoidable component. The existence of 0.1 0.5 percent of manganese is necessary.
• the addition of phosphorous remarkably improves the can opening properties of the present steel sheets.
• the addition of phosphorous is not normally desirable because of.lowered corrosion resistance of the can material.
• the addition of 0.04 0.10 percent of phosphorous has almost no effect on the corrosion resistance.
• Example 1 An example of this invention will be stated in the following: Example 1.
• steels, A, B, C, J and K were annealed at 680C in an atmosphere of H 4 percent and N 96 percent, by using a box annealing furnace.
• Steels, D, E, F, G, H and I were subjected to decarburization annealing at 700C in an atmosphere of H 40 percent and N 60 percent, by using an open coil annealing furnace.
• the carbon contents of these steels after decarburization annealing are also shown in Table l.
• Decarburization annealing of steel I was intentionally suspended halfway through the treatment to give a carbon content of 0.025 percent.
• the force necessary for can opening is particularly low in steels containing phosphorous (C, F, G and H), thus the effect of the addition of phosphorous can be distinctly observed.
• Steel G 2 which is obtained with a skin pass draft of 8 percent, has similar properties both in the force necessary for can opening and in the critical score rest thickness without forming cracks as in the case of G 1.
• the rigidity of the inventive steel which is skin pass rolled with an ordinary draft has some influence on the force necessary for can opening in some instances according to the plane shape of the score.
• the inventive steel sheet and strip skin pass rolled with a draft of 3 15 percent such as steel G 2 is particularly suitable.
• steel sheets and strips within the component range of this invention are quite excellent for use in the manufacture of easy-toopen cans.
• a steel sheet for use in the manufacture of easy-toopen cans which consists essentially of less than 0.02 percent carbon, less than 0.1 percent silicon, 0.1 0.5 percent manganese, less than 0.03 percent oxygen, 0.04 0.10 percent phosphorous, with the remainder being iron and unavoidable impurities.
• a method for manufacturing a steel sheet for use in the manufacture of easy-to-open cans which comprises skin pass rolling, with a draft of 3 to 15 percent, a steel sheet obtained by the usual manufacturing method and which consists essentially, after annealing, of less than 0.02 percent carbon, less than 0.1 percent silicon, 0.1 0.5 percent manganese, less than 0.03 percent oxygen, 0.04 0.10 percent phosphorous, with the remainder being iron and unavoidable impurities.

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

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Citations (6)

• 1970
  • 1970-11-10 JP JP45098335A patent/JPS515333B1/ja active Pending
• 1971
  • 1971-11-05 US US00195923A patent/US3777536A/en not_active Expired - Lifetime

Patent Citations (6)

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