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
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/22—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded
  • B23K20/227—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded with ferrous layer
  • B23K20/2275—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded with ferrous layer the other layer being aluminium
• • 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
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12736—Al-base component
  • Y10T428/1275—Next to Group VIII or IB metal-base component
  • Y10T428/12757—Fe

Definitions

• the invention relates to the plating of sheets of ferrous metal with aluminum having a thickness less than 0.5 mm. by co-rolling, wherein the cold worked sheets are subjected to a residence time of at least 1 hour in a temperature zone of from 275 to 460 C. to avoid the appearance of intermetallic compounds of the AlgFC type.
• This invention relates to composite sheets of ferrous metal and aluminum or with aluminum alloy.
• the plating of sheets of steel with sheets of aluminum by co-rolling is normally completed by a final annealing treatment carried out at temperatures of from 480 to 550 C. in order to soften the assembly for subsequent shaping operations.
• this annealing treatment is accompanied by the formation of intermetallic compounds of the Al Fe type along the interface and in the aluminum component.
• intermetallic compounds make the assembly fragile and, as a result, complicates subsequent shaping operations. If the intermetallic compounds come to the surface, as when the aluminum plating is thin, black-colored streaks appear, accompanied by undesirable porosity.
• an annealing treatment is carried out at the lowest possible temperature and for the shortest possible time. Temperatures as low as 204 C. and annealing times as short as 2 minutes have been proposed. It is possible in this way to minimize or even completely to eliminate the appearance of intermetallic compounds, but, unfortunately, the annealing treatment carried out in this way does not result in adequate softening and subsequent shaping operations are limited as a result.
• the composite sheet is subjected, before annealing, to a pretreatment under time and temperature conditions which will hereinafter be described.
• the heat treatments which the cold worked sheet undergoes, before and after its passage through the critical temperature zone have little influence upon the appearance of intermetallic compounds.
• the product can be kept for a sufiiciently long period in a furnace kept at a suitable constant temperature, being subsequently removed from the furnace for introduction into the annealing furnace after a more or less long time interval, or alternatively the product can be directly introduced into the annealing furnace which is either cold or at a temperature below the critical zone and the rate of temperature increase regulated in such a Way that the product remains in the critical zone for a sufficient period of time.
• these two processes give similar results insofar as the effect on the presence of intermetallic compounds.
• the conditions of the critical zone treatment are governed by the cold working ratio of the composite sheet.
• Thickness (microns) of the composite Cold-working sheet ratio percent When subjected to annealing for 2 hours at 500 C., by introduction without any particular precautions into a furnace kept at a constant temperature, these sheets gave the following result:
• the word average in the same column means that these compounds have locally broken through to the Surface.
• the Word none means that these compounds cannot be detected either visually or under a microscope on a polished section transverse to the surface of the material.
• test specimens either keeping the test specimens under isothermal conditions for different periods at different temperatures, and subsequently transferring the test specimens to another furnace in which they are subjected for 2 hours at 500 C. to a treatment similar to that described above,
• test speci mens are examined for the appearance of intermetallic compounds.
• isothermal dwell treatments using either a two-compartment furnace or two separate furnaces.
• the pro-treatment can be relatively short, it is of greater advantage suitably to select the Appearance of intermetallic compounds Dwell time (hours):
• a process for the production of composite sheets with a thickness of less than 0.50 millimeter comprising a covering of aluminum or alloy of aluminum on a substrate in which at least the portion in contact with the covering is a ferrous metal selected from the group consisting of iron and soft steel formed by cold working to a reduction ratio of the composite sheet of more than 90%, followed by annealing at a temperature of at least 480 0, wherein the composit sheet is subjected before annealing to a pre-treatment comprising a residence time of at least one hour at a temperature within the range of 275 to 460 C.
• a composite sheet of aluminum or alloy of aluminum on a ferrous metal produced by the process of claim 1.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Heat Treatment Of Steel (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Metal Rolling (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9066259

Family Applications (1)

Country Status (7)

Cited By (5)

Families Citing this family (1)

• 1970
  • 1970-12-23 FR FR7046434A patent/FR2119183A5/fr not_active Expired
• 1971
  • 1971-12-03 US US00204734A patent/US3717513A/en not_active Expired - Lifetime
  • 1971-12-20 DE DE19712163308 patent/DE2163308B2/de active Granted
  • 1971-12-21 IT IT54905/71A patent/IT945575B/it active
  • 1971-12-21 GB GB5942671A patent/GB1371200A/en not_active Expired
  • 1971-12-22 BE BE777121A patent/BE777121A/xx unknown
  • 1971-12-22 NL NL7117651A patent/NL7117651A/xx unknown

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