Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/06—Resistance welding; Severing by resistance heating using roller electrodes
  • B23K11/061—Resistance welding; Severing by resistance heating using roller electrodes for welding rectilinear seams
  • B23K11/062—Resistance welding; Severing by resistance heating using roller electrodes for welding rectilinear seams for welding longitudinal seams of tubes
  • B23K11/063—Lap welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D51/00—Making hollow objects
  • B21D51/16—Making hollow objects characterised by the use of the objects
  • B21D51/26—Making hollow objects characterised by the use of the objects cans or tins; Closing same in a permanent manner
  • B21D51/2676—Cans or tins having longitudinal or helical seams
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
  • B65D7/12—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by wall construction or by connections between walls
  • B65D7/34—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by wall construction or by connections between walls with permanent connections between walls
  • B65D7/38—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by wall construction or by connections between walls with permanent connections between walls formed by soldering, welding, or otherwise uniting opposed surfaces

Definitions

• This invention relates to a process for forming can bodies from tinfree steel and more particularly to the high-speed sideseam welding of tinfree steel to form can bodies, and to can bodies formed by the process. It is well known to form can bodies from sheet steel container stock by initially cutting the steel sheet into generally rectangular blanks and then shaping the blanks into a cylindrical configuration with the side edges of the blanks in overlapping relation to be joined by resistance welding. Tinplate can be welded by such an operation without edge preparation and billions of welded sideseam cans have been produced from tinplate.
• Another commercially available high-speed sideseam welding bodymaker employs a so-called wire mash electrode wherein a formed copper wire is carried in a track or groove in the periphery of the electrode wheels.
• the copper wire is continuously replaced from a spool or coil so that a clean electrode contact surface is continuously presented at the point of contact with, the container stock.
• This continuously replaced electrode enables high-speed welding of tinplate, but again edge cleaning has been required for the welding of tinfree container stock.
• the overlap of the edges to be welded with currently available wire mash welders can be as small as
• Another object of the invention is to provide an improved welded sideseam container formed from tinfree container stock. Another object of the invention is to provide a method of forming a welded sideseam in a container body which requires less energy and less electrode pressure than normally required to form such a seam utilizing tin-plated container stock.
• an important featu-e resides in providing a coating of nickel on each surface of a steel sheet such as blackplate having a thickness and temper suitable for use as container stock.
• the nickel coating may contain up to about 12% zinc and may be as thin as about 0.013 microns.
• a chemical treatment for example a cathodic dichromate or chromic acid treatment, is preferably applied to the nickel-coated steel to increase its corrosion resistance and enhance lacquer adhesion characteristics.
• a coating of lacquer is preferably applied, leaving a narrow strip unlacquered along the edges which are to be joined by welding.
• the flat sheet steel is cut into can body blanks which are formed into a cylindrical configuration with the side edges overlapping so that the nickel-plated. surfaces are in direct contact.
• the overlapping coated and treated (but unlacquered) surfaces are then welded by a high-speed sideseam welding bodymaker to produce a completed can body having a welded sideseam which has a thickness substantiall less than twice the thickness of the steel sheet.
• the welded seam may be striped for anticorrosiveness in the conventional manner, and can ends may be attached. to the completed cylindrical body utilizing a double seam operation in the conventional manner and utilizing conventional apparatus.
• FIG. 1 is a fragmentary sectional view, on an enlarged scale, illustrating a coated steel sheet suitable for use in the present invention
• FIG. 2 is a schematic illustration of a welded sideseam being formed on an automatic bodymaking machine in accordance with the present invention
• FIG. 3 is an enlarged schematic view showing the electrode positions employed in the apparatus of FIG. 2;
• FIG. 4 is a further enlarged fragmentary sectional view showing the seam being welded.
• FIG. 5 is a fragmentary sectional view of a welded seam formed in accordance with the invention.
• the present invention involves the formation of a can body from tinfree steel container stock in a high-speed sideseam welding bodymaker without requiring edge stripping or cleaning of the container stock. More specifically, the invention involves forming a sideseam welded, container body from steel container stock in the form of thin sheet steel such as blackplate having a very thin coating of nickel plated on its surfaces. The nickel may contain up to about 12% zinc.
• the container stock is cut into blanks which are formed into a cylindrical configuration with the edges to be joined retained in overlapping relation with the nickel-coated surfaces in direct contact.
• the container stock employed in the present invention is illustrated in FIG. 1 and comprises a sheet 10 of mild steel such as blackplate having a thickness suitable for use as container stock.
• the steel substrate 10 has its outer surfaces coated with a layer 12 of nickel, which may contain up to about 12% zinc, by an electroplating process.
• the nickel coating may be very thin and preferably is within the range of about 0.013 to 0.125 microns in thickness. Thicker coatings can also be used, but generally are not considered economical, and excessivel thick coatings may result in only the nickel coatings being welded or fused.
• the nickel coating 12 preferably has a thin layer 14, of an anticorrosive chemical treating solution applied to its outer surface.
• Chemical layer 14 may be applied by subjecting the plated steel to a cathodic dichromate or chromic acid treatment in a manner conventional in treating chrome-plated, container stock.
• the treated, plated steel is then preferably coated with a layer 15 of a suitable can lacquer except for a narrow strip, indicated at 16 in FIG. 1, which will form the side edges of container blanks 17 to be joined by welding.
• the chemically treated nickel-plated steel can not only be welded without the necessity of stripping either the chromate chemical treatment or the nickel plating from the side edges, but it has been determined that substantially less welding current may be employed than is required for welding tinplate of the same thickness. Further, a good weld can be obtained while utilizing substantially less pressure on the electrodes than is normally required for welding tin plate.
• the very thin nickel coating and the oxide coating resulting from the chemical treatment are diffused in the joint and a strong fusion bond is produced.
• FIGS. 2-4 Various commercial sideseam welding bodymakers may be employed in the practice of the present invention; however, the preferred apparatus utilizes the so-called wire mash technique.
• One such apparatus is the Super WIMA automatic bodymaker, manufactured by Soudronic AG, of Bergdietikon, Switzerland, and the operation of which is illustrated schematically in FIGS. 2-4.
• the nickel-coated container stock illustrated in FIG. 1 is initially cut into generally rectangular blanks of the appropriate size and supplied to the bodymaker to be processed automatically by the apparatus.
• the individual blanks 17 are formed into a cylindrical configuration around a hollow mandrel 18 and then moved therealong through a welding station by suitable feed mechanism, not shown.
• the side edges of the blank 17 are brought together in overlapping relation with the nickel-plated, chemically treated surfaces in direct contact as illustrated in FIG. 4.
• Electrode 22 and electrode wheel 26 are supported within the mandrel 18 and contact the inner surface of the formed cylinder while wire electrode 20 and electrode wheel 24 are positioned outside and contact the outer surface of the overlapped portion of the cylinder. Electrical energy is applied to the electrodes from a suitable source indicated at 27, and pressure is simultaneously applied through the electrodes to overlapped portions of the container blank to simultaneously heat and mash, or flatten the overlapped edges and form a flattened fused weld joint as illustrated at 28 in FIG. 5.
• the completed weld joint may be from about 1.2 to about 1.3 times the thickness of the coated container stock and the total length d, measured circumferentially of the formed can body, may be substantially less than twice the thickness t of the original container stock.
• Metallurgical analysis of weld joints thus formed show that a solid fusion joint is formed. Pressure applied by the electrodes during the fusion process substantially eliminates sharp edges and burrs.
• a narrow strip of organic coating material is applied to the welded seam and overlapping the edges of the lacquer coating 15 in a conventional manner.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Rigid Containers With Two Or More Constituent Elements (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=22877773

Family Applications (1)

Country Status (11)

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• 1982
  • 1982-02-09 CA CA000395851A patent/CA1177419A/en not_active Expired
  • 1982-02-10 ES ES509474A patent/ES509474A0/es active Granted
  • 1982-02-11 EP EP19820900895 patent/EP0070900A4/de not_active Withdrawn
  • 1982-02-11 BR BR8206157A patent/BR8206157A/pt unknown
  • 1982-02-11 NL NL8220067A patent/NL8220067A/nl unknown
  • 1982-02-11 AU AU82087/82A patent/AU8208782A/en not_active Abandoned
  • 1982-02-11 JP JP57500919A patent/JPS58500056A/ja active Pending
  • 1982-02-11 WO PCT/US1982/000177 patent/WO1982002697A1/en not_active Application Discontinuation
  • 1982-02-11 IT IT8247771A patent/IT8247771A0/it unknown
  • 1982-02-11 GB GB08228762A patent/GB2108412B/en not_active Expired
  • 1982-02-11 DE DE823231643A patent/DE3231643A1/de active Pending

Non-Patent Citations (2)

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