Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C18/00—Alloys based on zinc
  • C22C18/04—Alloys based on zinc with aluminium as the next major constituent

Definitions

• the new alloys covered by this invention are particularly suited for use in countries having large zinc deposits and where bauxite and other constituents of aluminum are scarce or non-existent. This is for the obvious reason that the alloys covered herein use smaller percentages of aluminum.
• the present invention is realized by preparation of Zn-Al-Cu alloys in ratios by weight of Zn:69-79%, Al:20-30% and Cu:1-8%, or alternatively Zn:69-79, Al:20-30%, Cu:20-30% and Mg:.001%, utilizing 99.99% purity Zn, Al with a minimum purity of 99.5%, Cu with a purity of 99.7%, and Mg with a minimum purity of 99.9%, in order to guarantee the final characteristics of the alloys.
• raw materials with minimal impurities are recommended for smelting, the most suitable being: first melt Al, special high-grade Zn, Cu as cable or cathod scrap, and high-grade Mg. Also, pollution of the Zn-Al-Cu alloy with iron, cadmium and magnesium should be avoided as much as possible, as well as contamination with iron and calcium of the Zn-Al-Cu-Mg alloy.
• the Zn-Al-Cu alloys of the invention have an intermediate density between Al and Cu, and a tensile strength above that of alternative materials. Additionally, it has been demonstrated, through tests performed in accordance with ASTM-B117 standard for saline chamber, that the alloys of this invention have a corrosion resistance above that of all other materials included in the Table, said resistance being thrice that of aluminum and twice that of copper. For these reasons, the alloys of this invention are particularly suitable for applications on which high mechanical strength is required, and for uses in highly agressive environments, such as coastlines and maritime areas.
• the alloys of this invention are especially attractive to substitute bronze and brass pieces, due to the lower cost and the lower specific weight of the former.
• the surface-finishing tests performed on the alloys of this invention showed an excellent adherence to paint, including electrostatic paint, as well as a good acceptance of the copper base to obtain chrome and nickel finishings.
• the electrical connection boxes which normally could be manufactured by pressure-injection of aluminum, silicium or zamak, present various disadvantages in comparison with those made with the invented alloys, since the latter exhibit twice the mechanical strength of aluminum and thrice its corrosion resistance.
• the alloys of this invention have higher corrosion resistance and higher mechanical strength.
• the alloys of this invention in addition to the aforementioned advantages, have much better electrical conductivity.
• the small grain-size of the pressure injected pieces made with the alloys of this invention allow for a much higher detail resolution than those injected with conventional alloys, a better surface quality being obtained in the product, besides having much lower operating costs due to energy savings and other factors.
• Both the plate and the milling rolls were preheated to a temperature of appoximately 260° C.
• the dimensions of the plate were 17 x 60 x 90 cms.
• the plate was subjected to several sheet rolling operations, varying the number of rolling steps between 28 and 42, including water for cooling purposes in one or more steps.
• process temperatures were changed between 180° C and 295° C, in order to determine the optimal quantity of the product according to the number of rolling steps or series of steps, and according to the temperature levels.
• Sheets having different thicknesses were obtained through these tests, said thicknesses varying between 3.5 and 8.55 mm., depending on the number of rolling steps. Said sheets were rolled-up and left to cool at ambient temperature.
• the sheets that were obtained showed good cohesion, rigidity and uniformity characteristics, and when subjected to tests with 100 kg loads for 30 to 40 seconds, the results were: from 35 to 55 RB hardness, and between 150 and 350 MPa in tensile mechanical strength. It was also evidenced, through laboratory tests that the sheet obtained has superplastic characteristics, with the corresponding technological advantages in comparison with conventional copper and aluminum sheets.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Metal Rolling (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19743292

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (8)

• 1991
  • 1991-09-03 MX MX9100915A patent/MX9100915A/es unknown
• 1992
  • 1992-09-03 EP EP92402400A patent/EP0531209A1/fr not_active Withdrawn
  • 1992-09-03 JP JP27764292A patent/JPH06293930A/ja active Pending

Patent Citations (8)

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