US2448169A - Zinc-titanium-cadmium alloys - Google Patents

Description

latentecl Aug. 31 1 948 2,448,169 ZINC-TITANIUM-CADMIUM ALBGYS I Edward J. Boyle and Edmund A,.'Anderson, Palms erton, Pa., assignors to 'TheNew Jersey Zinc Company, New York,

New Jersey N. Y., a corporation of No Drawing. Application May 17, 1944', Serial No. 536,017

'7 Claims. C1. 75-178) This invention relates to zinc base alloys and more particularlyto zinc base alloys containing titanium, and aims to provide an improved zinc base alloy containing titanium and cadmium. The zinc base alloys of the invention contain from 0.01 to 1.6%, and preferably from 0.05 to 0.5%, titanium and are characterized by additionally containing from 0.05 to 1.5%, and preferably from 0.1 to 1%, cadmium. The balance of the alloy is zinc. Alloys of-the inventionmay advantageously Contain about 0.1% titanium, 0.3 to 0.6% cadmium, and the balance zinc. The zinc base of the alloys is preferably high grade zinc. Alloys of superior creep resistance, that is resistance to prolonged static loads well below the ultimate limit, and of fine grain size when cast result from the use, as the zinc base, of metal of purity, such. as zinc at least 99.99% pure. On the other hand, satisfactoryalloys are ob 'tained with zinc ofthe grade commonly used in the production of commercial rolled zinc, for example zinc metal containing 0.10% lead, 0.012% iron and 0.005% cadmium. The presence of 0.1% leadis sufiicient, however, .to impart to the alloy-s (as cast) a coarse, columnargrain. structure similar to that of ordinary cast zinc. If thealloy is rolled or otherwise mechanically worked, the coarse grain structure of the cast alloy disappears, and the micro-structure and properties of the rolled or worked alloy are substantially independent of the grade or purity of the zinc metal of the typeshereinbefore mentioned.

The alloys of the invention are particularly adapted for rolling. When transformed to sheet or strip by suitable rolling procedure, the alloys possess high creep resistance. The alloys may be hot rolled at metal temperaturesof from 150 to 300 (3., temperatures of from200'to 2.40 C. giving very satisfactory results. Thehot rollingmay be a finishingg operation consisting'ofisay three 'or more passes through the rolls, and'rnay be appli d to metal either hot or cold rolled'prior to the hot Cold rolling tends to decrease the creep resistance, but the characteristic high creep resistance can be substantially restored by subsequent heat treatment such, for example, as annealing for a short period at a temperature of from 150 to 400 C.-, annealing in oil for about five minutes at a temperature of about 275 C. giving very satisfactory results. Cold rolling, at least in the final stages, imparts to the alloy certain advantages, especially with respect to hardness. Alloys of the invention are to be considered cold rolled when the rolling (or other mechanical Working) is carried out under thermal conditions resulting in a temperature of the rolled strip or sheet after the final rolling pass (final coil temperature) due simply to the mechanical working, and are to be considered hot rolled when the rolling is carried out under thermal condir contemplated 4%.

properties.

tions resulting in afinal coil temperature of'from ISO-to 300 C., and preferably from 200 to 240 C.

In'the production of the alloys of the invention, it is preferable to prepare an intermediate .zinc base: alloycontaininga relatively high-proportion of titanium. Conveniently, the intermediate alloy may contain about 4% of titanium, an'd' is prepared by heating a mixture of 96 parts of zinc and '4 parts of titanium in a clay-carbo-rundum crucible. at. a temperature of 800 C. for about 8 hours. The intermediate alloy' is cast into a thin slab and crushed to a convenient'size foralloying. The final titanium content ofthe cast intermediate alloy usually does not depart -far f-rom -the The contemplated titanium content of the alloy of the invention is then readily obtained by adding the calculated amount of the intermediate alloy to a predetermined weight of molten zinc. Cadmium, in amount calculated: to givethe-"desiredi content inthe final alloy, may be added as such tothe-molt'en mixture of zinc and the intermediate: zinc-titanium alloy, or the cad'm'ium may be included in the zinc, or melted down with the zinc and intermediatezinc-titanium alloy.

The alloys of theinvention are-characterized by hig'h-creep resistance, dynamic ductility','tensile strength-,tensile elongationand good bending These characteristics of 'thealloys (among others) are shown-in I the following; table.

In'-the table; H is scleroscope hardness; DD.

by Standard P ger in an uncut sheet ofthe metal without fracture; Temiis'percent temper,

and is determined by the degree 'to which. a standard test strip returnsto itsoriginal position after'being wrapped around a mandrel; T; 'S. is tensile strength (with'the grain) in pounds per square inch; T. E. is tensile elongation (withthegrain') ,in'percent in a 2 inch test strip;

and GRf is'thecreep'rate-or creep resistance (with the grain) expressed as the inverse creep rate (the more creep resistant alloy having the higher inverse creep rate) which is the number of units of time (days) required to produce an elongation or creep (with the grain) of one percent (i. e. days per percent) in a standard test piece when subjected to dead loads of 8,000 and 12,000 pounds (respectively) per square inch at constant room temperature (25 C.). The cold bend values represent the diameter of uncrackecl 180 bends in multiples of sheet thickness (gauge), and the lower values indicate better bending properties. Cut and draw is the result of an actual drawing operation carried out on a disc cut from the sheet, and the figures given represent the per cent decrease in diameter of the cup, as compared with the blank (per cent take-in). The columns headed by the single 0.05 to 0.5% titanium, from 0.1 to 1% cadmium,

and the balance zinc with not more than 0.1%

lead as an impurity.

7. A zinc base alloy according to claim 6 containing about 0.1 titanium and from 0.3 to 0.6%

the amounts of these alloying metals added to the cadmium. zinc base which was high purity metal. The alloys were compounded in the manner herein- EDWARD J. BOYLE. before described. EDMUND A. ANDERSON.

Table Gold Bends Creep Resistance C t u Ti ca gig H D. D Tem. W h A T. s '1". E am it cross raw Grain Grain 8,000 p. s. 1. 12,000 p. s. 1.

*i k#) ('0) ($2 (3) (fit) (1!) (it) (i) ('3) (i) 0') (t) (it) .1 5 .016 17. 5 .265 300 55 48 3% 3 2 2 24,800 27, 200 45.3 32. 2 2. 22 188. 7 .095 66 43.9

Rolling Treatment:

Slab heated to 230-260 0., rough rolled to 0.00 in ten passes; cold rolled on warm rolls to 0.018" in live passes, flnal C011 temperature 90l30 C. i Y

Rolling Treatment: 7 Q

Slab heated to 230260C., rough rolled to 0.09" in ten passes; cold coil rolled on hot rolls to 0.018" in three passes, final 0011 temperature 160-185 C.

Rolling Treatment: 1

Slab heated to 220-240 0., rough rolled to 0.125 in ten passes; coil cold rolled on Warm rolls to 0.036 in three passes; finally cold rolled to 0.018 in three passes.

" As rolled. As annealed.

We claim: 1. A zinc base alloy characterized by high creep resistance and containing from 0.05 to 0.5% titanium, from'0.1 to 1% cadmium, and the balance zinc with not more than 0.1% lead as an impurity.

2. A zinc base alloy from-0.3 to 0.6% cadmium, and the balance zinc with not more than 0.1% lead as an impurity.

3. A zinc base alloy characterized by high creep resistance and containing about 0.1% titanium, about 0.5% cadmium, and the balance zinc with not more than 0.1% lead as an impurity.

4. A cold rolled and annealed zinc base alloy characterized by high creep resistance and containing from 0.05 to 0.5% titanium, from 0.1 to

1% cadmium, and the balance zine with not more than 0.1% lead as an impurity.

' .5. A zinc base alloy according to claim 4 containing about 0.1% titanium and from 0.3 to 0.6% cadmium. v,

7 6. A hot rolled zinc. base alloy characterized by high creep resistance and containing from characterized by high creep resistance and containing about 0.1% titanium,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Circular of the Bureau of Standards, N0. 395, Zinc and Its Alloys, 1931, page 27, published by U. S. Govt. Printing Oifice, Washington, D. C.

Metals Handbook, 1939 edition, pages 1737, 1765, published by American Society for Metals, Cleveland, Ohio.

Certificate of Correction Patent No. 2,448,169. August 31, 1948.

EDWARD J. BOYLE ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Columns 3 and 4, in the table, description of the rolling treatment immediately below the first horizontal row of figures, for the words cold rolled read cold coil rolled; in the second horizontal row of figures, last column, under the heading Cut and draw, insert the figures 46.9; in the third horizontal row of figures, under the heading T. E., for 43.6 read 43.7; in the last horizontal description of rolling treatment, for coil cold rolled read cold coil rolled;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of December, A. D. 1948.

[smn] THOMAS F. MURPHY,

Assistant Commissioner of Patents.