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
• • 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
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
  • C22F1/165—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon of zinc or cadmium or alloys based thereon

Definitions

• My present invention relates to a method of making zinc-alloy bodies and, more particularly, to a method of treating zinc-alloy bodies consisting at least in major part of high-purity zinc and containing, as alloying ingredients, aluminum, copper, magnesium and, possibly, nickel.
• the principal object of the present in- 5 vention to provide an improved zinc-alloy body with high creep resistance and good mechanical properties, especially for use as strips, bands and sheets in construction.
• a further object of the invention is to provide a zincalloy body having good mechanical properties and high creep resistance.
• high-purity zinc is used herein to describe high-grade or special high-grade zinc in accordance with ASTM specification B649.
• special high-grade zinc may contain up to 0.006% by weight lead, up to- 0.005% by weight iron and up to 0.004% by weight cadmium, the total of lead, iron and zinc not exceeding 0.01% by weight.
• High-grade zinc, in accordance with the specification may contain up to 0.07% by weight lead, up to 0.02% iron, up to 0.07% by weight cadmium and the total of lead, iron and cadmium ranging up to 0.1% by weight.
• the zinc-alloy body of a composition within the ranges given above, is subjected to a three-stage treatment including a hot deformation, a cold deformation and a subsequent heat treatment.
• the zinc-alloy body Prior to the first stage of this treatment, however, the zinc-alloy body is subjected to a. homogenizing heat treatment for a period ranging from 10 minutes toseveral hours, e.g. ,five hours, at a temperature of 250 to 350 C. to ensure complete uniformity of the grain and crystal structure throughout the cross section of the body which may be extruded or cast.
• the body is subjected to hot deformation at a temperature between 200 and 300 C. and designed to reduce the cross section of the body by at least 50%, preferably 85 to 95%.
• the second stage, or cold deformation is carried out at a temperature between ambient or room tempertaure (e.g. 20 C.) and C. and reduces the cross section of the body by a minimum of 70% (preferably to 98%).
• the subsequent heat treatment is efiected at a temperature be- 3 tween 120 and 220 C., preferably 160 C. and represents a tempering of the body.
• the tempered step may be carried out for a period ranging from about minutes to several hours (e.g. 5 hours) and is preferably performed for a period of about 2 hours.
• the resulting zinc-alloy body is found to have a high ductility in spite of its magnesium content and yet excellent creep resistance which appears to result from an ideal distribution of the magnesium in the crystal structure of the zinc alloy in the form 'of a fine-grain segregation or precipitation uniformly distributed by virtue of the cold deformation, throughout the cross section. While the use of nickel is optional, as noted above, it has been found that the nickel accelerates the segregation of the magnesium from the alloy-solid solution.
• the bar is maintained for a period of 2 hours at a temperature of about 300 C. to ensure homogenization and then is rolled to a thickness of 2 mm., corresponding to a cross-sectional reduction of about 90% at a temperature of about 250 C. Subsequently, the bar is cold-rolled at a temperautre of about 40 C. to reduce its cross-section by 60% and yield a strip having a thickness of 0.8 mm.
• the zinc-alloy strip is tempered for 2 hours at 160 C.
• the tensile strength of the strip was found to be 30 kg. per mm. and the creep resistance 7.5 kg. per mm. for a deformation of 1% per year. Upon folding, through 180, breakage occurred.
• Example II The alloy of Example I is hot-rolled to a thickness of 8 mm. with a cross-sectional reduction as in Example I and thereafter is subjected to a cold rolling at a temperature of 40 C. to the thickness of 0.8 mm. but with a cross-sectional reduction of 90%. After 2 hours of tempering at 160 C., the body was tested and found to have a tensile strength of 28 kg. per mm. a creep resistance of 6.5 kg. per mm. for a 1% deformation per year, and to be break-free upon folding through 180.
• Example I A comparison of Example I with Example 11 demonstrates that, while both zinc-alloy bodies have a high creep resistance, the indicated extent of the cold deformation is essential to provide the ductility necessary for practical application of the alloy in construction. However, both alloys represent an improvement over conventional systems.
• step (c) tempering the cold deformed body of step (b) at a temperature of 120 to 220 C.
• step (a) is maintained at said temperature between 250 and 350 C. in step (a) for a period ranging between 10 minutes and 5 hours and is tempered in step (c) for a period ranging between 10 minutes and 5 hours.
• step (c) 8. The method defined in claim 7 wherein said body is cold rolled in step (c) with a cross-sectional reduction of about 90%.

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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 Steel (AREA)
• Contacts (AREA)
• Heat Treatment Of Nonferrous Metals Or Alloys (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=5741188

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (1)

• 1969
  • 1969-07-29 DE DE19691938385 patent/DE1938385A1/de active Pending
• 1970
  • 1970-06-24 GB GB1265928D patent/GB1265928A/en not_active Expired
  • 1970-06-24 BE BE752447D patent/BE752447A/fr unknown
  • 1970-06-24 FR FR7023354A patent/FR2056327A5/fr not_active Expired
  • 1970-07-07 US US00053037A patent/US3720550A/en not_active Expired - Lifetime
  • 1970-07-22 NL NL7010863A patent/NL7010863A/xx unknown
  • 1970-07-29 JP JP45066991A patent/JPS4940051B1/ja active Pending

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