US3691972A

US3691972A - Aluminous metal articles and method

Info

Publication number: US3691972A
Application number: US889790*A
Authority: US
Inventors: Linton D Bylund
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1970-07-09
Filing date: 1970-07-09
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19

Abstract

Aluminum foil and other wrought articles including drawn and ironed can bodies are produced from aluminum base alloys containing up to about 2.5 percent iron, having a low work hardening rate above 75 percent reduction and sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving.

Description

United States Patent B lund 1451 Se t. 19 1972 1 ALUMINOUS METAL ARTICLES AND 3,351,442 11/1967 Hooper ..75/ 138 METHOD 3,346,374 10/1967 Jagaciak ..'.....75./l47 [72] Inventor: Linton 1). Bylund, Richmond. Va. 2:32: [73] Assignee: Reynolds Metals Company, 3,105,400 10/1963 Goppelt ..72/199 Richmond, Va. 1 3,572,271 3/1971 Fraze ..1 13/120 H 3,502,448 3/1970 Anderson et al. ..75/147 [22] My 1970 3,571,910 3/1971 Bylund ..113/120 11 [21] Appl. No.: 889,790 3,397,044 8/1968 Bylund ..75/l48 Related pp Data Primary Examiner-Charles W. Lanham 601 Division of Ser. No. 712,314, Jan. 16, 1968, e

Pat. No. 3,571,910, which is a division of Set. Palmer Lyne, G'bbs & Thompson No. 660,132, Aug. 11, 1967, Pat. No. 3,397,044, which is a continuation-in-part of [57] ABSTRACT Ser. No. 573,776, Aug. 8, 1966, abandoned, which is a continuatiomimpan of Ser No Alumlnum fo1l and other wrought articles including 379 782 July 2 1964 abandoned I drawn and ironed can bodies are produced from aluminum base alloys containing up to about 2.5 percent iron, having a low work hardening rate above 75 percent reduction and sufficient ductility at high cold Field 113/116 R H 6 120 R 120 work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or H, 72/365, 199, 379, 206,1g71Z5l/ll3458, 114328, Stress relieving.

[56] References Cited I 15 Claims, 4 Drawing Figures UNITED STATES PATENTS 3,509,754 5/1970 Massingill et a1. 13/120 11 e0 90 ROLLING REDUCTION (Vol ALUMINOUS METAL ARTICLES AND METHOD This application is a division of co-pending patent application Ser. No. 712,314 filed Jan. 16, 1968, now U.S. Pat. No. 3,571,910 which in turn is a division of patent application Ser. No. 660,132 filed Aug. 11, 1967, now U.S. Pat. No. 3,397,044, which in turn is a continuation-in-part of application Ser. No. 573,776, filed Aug. 8, 1966, now abandoned, which in turn is a continuation-in-part of application Ser. No. 379,782, filed July 2, 1964, now abandoned.

The invention concerns an aluminum alloy especially suited for producing high strength, light gage wrought products including foil and cans and it also concerns a method of improving the rollability of aluminum for producing such products.

Metal foil is widely used today in both supported and laminated form for various applications such as packaging materials and the like. Aluminum alloys 1 100 or 1235 or 1 145 have been employed for this purpose, but there is an existing need for higher strength foil products. of the stronger aluminum alloys previously known, most are unsuited to the requirements of packaging materials, particularly the need for a reasonable elongation characteristic and related physical properties in foil gages.

In addition to metal foil products, aluminum alloys have been employed to fabricate drawn and ironed cans. Conventional aluminum alloys include, for in stance, 3004, which contains 1.0-1.5 percent manganese and 0.8-1.3 percent magnesium as the principal alloying elements, and which develops strength in fabricated form as a result of solid solution strengthening and work hardening. The ductility of alloy 3004 progressively deteriorates at high cold work levels, however, and resort is taken to various thermal treatments in making rolled sheet stock therefrom for forming into cans, and preparatory to such forming operations. Thus, for example, it is conventional practice to hot roll an ingot of 3004 alloy to a thickness of about 0.105 inch followed by annealing and then by successive cold rolling reductions, typically with at least one intermediate annealing step, to provide sheet stock having a thickness of about 0.02 inch, after which a final stress relieving treatment is given prior to forming a drawn and ironed can.

The trend toward cans made of a higher strength alloy apparently is due to expanded use of aluminum cans for carbonated beverages which produce considerable internal pressure, thus necessitating a can construction capable of withstanding a test pressure of at least 90 psi. There are disadvantages to employing increased amounts of alloying element, however, not the least of which is greater cost and increased fabrication difficulties.

On the other hand, alloys of aluminum ordinarily are susceptable to work-hardening to some extent, so that strengthening of the alloy in finished form can be effected by cold working, either in the can forming operation or in preparation of light-gage can stock suitable for forming. When producing a drawn and ironed can from about 0.02 inch stock, moreover, with the final wall thickness to be about 0.007 inch for example, it is readily apparent that a reduction of about 65 percent is involved. If the metal is too hard at the outset, the forming operation will render itunworkable and result in tool wear or excessive earring, or may even make it impossible to produce a satisfactory product. That is why stress relieving or other thermal treatment has conventionally preceded can making and other severe forming operations.

Production of Aluminous Metal Products Such as Foil In accordance with the present invention for the production of foil, it has been found that a carefully controlled addition of iron in a commercial purity aluminum base provides an alloy having the desired characteristics; and it has also been found that a limitation of the copper content in such aluminum-iron alloys is also beneficial. This is an unexpected and surprising result for several reasons. To begin with, the addition of iron beyond a small fraction of a percent (for purposes of grain refinement) is ordinarily considered undesirable as promoting brittleness; and particularly in alloys composed almost entirely of aluminum, it would not be expected that the use of iron as the principal alloying addition would result in a material suitable for the heavy rolling reductions incident to producing light gage sheet or foil. Additionally, one type of alloy commonly utilized for foil production typically contains about 0.10-0.20 percent copper for achieving desired properties of the foil in its annealed condition. Thus, the addition of iron and the restriction of copper in foil alloys of aluminum is contrary to prior practices in this regard.

Aluminum-iron alloys suitable for purposes of the invention in the production of foil and other wrought articles include essentially binary systems containing from 0.6 percent to about 2.5 percent iron, by weight, and about 0.05-1.0 percent total of silicon and incidental elements ordinarily present as impurities in commercial grade aluminum of about 99 percent purity. Such alloys are conveniently produced by adding the necessary additional quantity of iron to ordinary reduction cell aluminum containing up to about 1.0 percent of such incidental impurities as silicon, iron, copper, manganese, magnesium, chromium, nickel, zinc and titanium, preferably within the limits of about 0.05-0.3 percent silicon, up to about 0.10 percent zinc, not more than 0.10 percent copper (most preferably a maximum of 0.05 percent copper), the others exclusive of iron not exceeding 0.25 percent each (preferably a maximum of about 0.05 percent each and about 0.15 percent total).

In accordance with the invention, the aforesaid aluminum-iron alloys have been found to exhibit a particularly desirable rolling characteristic, chiefly as a result of their unexpectedly low work-hardening rates in the region of percent reduction. This makes possible the rolling of foil in wider widths and at substantially heavier reductions under comparable mill conditions; and the resulting lower work-hardened properties enable the production of an excellent foil which is tough and ductile even in exceedingly light gages.

The maximum amount of iron in the alloy for purposes of the invention is determined by such factors as formation of massive primary crystals of an iron-aluminum intermetallic compound (e.g., FeAl during casting, resulting in casting defects or excessivelyv reduced ductility for rolling purposes; and increasing iron content eventually leads to deterioration of corrosion resistance in the resulting wrought products. Furthermore, the higher the iron content the more difficult it becomes to utilize recycled scrap (recovered in making or fabricating the alloy) for the production of other alloys in which the iron content has to be controlled, thus rendering the alloys of higher iron content less attractive as a practical matter.

In accordance with a preferred practice of the invention, light gage sheet or foil is produced from an alloy consisting essentially of aluminum, silicon and about 0.75-1.2 percent iron, with no more than 0.05 percent copper and up to about 0.25 percent silicon (typically about 0.05-0.15 percent) and having an iron-to-silicon ratio of at least :1. This may be accomplished conveniently by adding iron to commercial purity 'aluminum of the requisite silicon and copper analysis, preferably containing no more than 0.05 percent each, 0.15 percent total, of theaforesaid incidental impurities such aszinc and manganese.

' The improved characteristics of the alloy are exhibited in the accompanying drawings, in which:

FIGS. 1 and 2 are graphical representations of data showing physical properties (tensile strength and elongation, respectively) of an Al-Fe alloy in accordance with the invention, compared with standard commercial alloys 5005 and l 100 at various rolling reductions;

FIG. 3 is a composite plot of the same properties shown in FIGS. 1 and 2, showing the effect of making a small addition of iron to an alloy of aluminum containing a fractional percentage of magnesium; and

FIG. 4 is a similar composite plot showing the effects of increased copper content in an alloy otherwise similar to the preferred alloy of the present invention.

The reference alloys fall within the following percentage composition limits:

Others, .05 max. each Others, .05, max. each 0.15 max. total Al I 0.15 max. total Bal. Bal. Al (99.00 min.)

The following examples are illustrative of the invention, but are not to be regarded as limiting.

EXAMPLE 1 The aluminum-iron alloy for which the data of FIGS. 1 and 2 were determined had the percentage composition:

0.08 Si, 0.87 Fe, 0.02 Cu, 0.013 Mn, 0.02 Zn,

balance aluminum.

It can be seen from inspection of FIG.. 1 that the work-hardening curve for 5005 alloy typically rises at a progressively increasing rate toward a peak beyond 90 percent reduction, as is the case with l 100 alloy to a lesser extent. On the other hand, a surprising difference is exhibited by the aluminum-iron alloy, which actually has a substantially constant work-hardening rate as the critical heavy reductions are approached. This flattening of the curve is particularly advantageous, of course, where cold rolling to foil gages is to be accomplished.

, FIG. 2, on the other hand, indicates a further beneficial result obtained with the alloy of this application. The elongation characteristic is considerably better than that of conventional 1100 and 5005 alloys. This property renders the alloy itself better adapted to foil manufacturing operations and also makes the resulting use.

TABLE 1 Light Gage Annealed Properties Alloy and Gage Tensile Strength Elon Mullen Test (P (ps Al-Fe alloy 0.00096" 11,900 7.0 26.0 0.00083 I 1,900 6.3 21.4 0.00064 11,300 4.4 l3.0 0.00038 10,400 3.2 6.0 l 100 type alloy Referring now to FIG. 3, a comparison is presented between the same Al-Fe alloy characterized in FIGS. 1 and 2, and a closely similar alloy further containing 0.28 percent mg. The workhardening (tensile) curve (a) of the latter alloy is still inferior and much like that of ordinary l 100 alloy (although approaching the performance of 5005 alloy which has a somewhat greater addition of magnesium as its principal alloying element). The characteristic elongation curve b) likewise is less desirable than that of the Al-Fe alloy.

In like manner, FIG. 4 shows a direct comparison between the novel AL-Fe foil alloy and one which had the analysis 0.07 Si, 0.81 Fe, 0.15 Cu, 0.02 Zn, balance aluminum. The deleterious effect in the latter alloy of additional copper is apparent by consideration of the location of tensile curve (a) and elongation curve (b), again with reference to the corresponding characteristics of the same Al-F e alloy as represented in FIGS. 1 and 2.

The foregoing comparisons shown graphically in FIGS. 3 and 4 emphasize the criticality of iron and copper content in relation to other constituents in alloys made according to the invention.

Further examples of the practice of the invention are the following:

EXAMPLE 2 (a) An ingot measuring approximately 16 inches X the aforesaid composition (i.e., 0.08 Si, 0.87 Fe, 0.02 Cu, 0.013 Mn, 0.02 Zn, balance aluminum), and the ingot was scalped, heated to about 950l ,000 F. and hot rolled to a thickness of about 0.125 inch, and then cold rolled in a 3-stand mill to 0.023 inch gage. Em-

ploying Y conventional foil rollingpractices, the 0.023 inch strip was coil annealed (700 F.) for about six hours, cold rolled into foil in successive passes from 0.023'inch to 0.0099 inch, to 0.0062 inch,,0.0030 inch, 0.0011 inch, 0.00062inch and, finally in a-doubling pass-(two thicknesses)-to about 0.00029 inch.'-The foil was dry annealedin coil form (775 F.) for-about l 1 hours. The foil exhibited theifollowing properties at Nariousstages, as indicated below:

(b) In like manner, an additional sample of the annealed 0.023 inch strip was cold rolled successively to 0.012 inch, 0.0056 inch, 0.0033 inch, 0.0017 inch and, finally, in a doubling pass (two thicknesses) to 0.0007 inch. 'The resulting foil was slick annealed (525.550 F. for about two hours). The foil properties at various stagesare indicated below:

. Tensile 1 Percent Gage I Strength Elongation 0.023" (annealed) 13,900 psi 33.8 0.012" 20,800 1.6 0.0056" 24,800 2.6 0.0033" 26,200 2.9 0.0017" 26,500 3.1 0.007" 25,200 1.3 After final anneal (0.007") 11,700 5.5

It is readily apparent from the foregoing data that in both instances the alloy exhibited a very low work hardening rate at heavy cold working reductions.

EXAMPLE 3 The alloy of Example 2 responded so well to conventional processing that it was decided to try a modified practice, omitting any annealing of the 0.023 inch cold rolled strip prior to the foil rolling operation.

A 20 inches X 66 inches X 93 inches ingot was prepared having a composition 0.07 Si, 0.80 Fe, 0.01 Cu, balance substantially aluminum .(Mn, Mg, Cu, Ni, Zn, Ti less than 0.02 each). This was reduced to a hot line gage of about 0.100 inch, annealed at '750800 F. for about two hours, cold rolled in two passes to 0.023 inch and then directly rolled into foil in successive cold rolling reductions to 0.0109 inch, 0.0077 inch, 0.0033 inch, 0.0014 inch and 0.00065 inch. The work hardening curve was found to be substantially flat and no difficulty was found in the cold rolling operations. The foil was annealed at 525-550 F. The foil was found to have the following properties at the various stages:

Tensile Strength Gage 0.023" (unannealed) 23,800 psi 4.0 0.109" 24,900 3.6 0.0077 25,500 4.0 0.0033" 26,100 5.0 0.0014" 25,700 4.2 0.00065" 24,700 2.9 After final anneal (about 0.00065") 1 1,500 5.0

Mullen bursting strength 16.5 psi EXAMPLE 4 The alloy of Example 3 responded so well that'it was decided to try a further simplified practice, omitting annealingof both the hot line gage and the 0.023 inch cold rolled strip. A 20 inches X 66 inches X 193 inches ingot was prepared having the composition 0.08 Si, 0.84 Fe, 0.03 Cu, balance substantially aluminum (Mn, Mg, Cu, Ni, Zn, Ti less than 0.02 each). This was reduced to a hot line gage of about 0.100 inch, cold rolled in two passes to 0.023 inch, and then directly rolled into foil in successive cold rolling reductions to 0.012 inch, 0.0077 inch, 0.0038 inch, 0.0014 inch and 0.00073 inch. The work hardening curve was found to be substantially flat, and no difficulty was encountered in the cold rolling operations. The 0.00073 inch foil was annealed at 525-550 F. for about two hours. The foil was found to have the following properties at the various stages indicated.

Tensile Percent Gage Strength Elongation 0.012" 31,200 psi 4.4 0.0077" 31,800 4.3 0.0038" 32,300 4.3 0.0014" 28,500 4.4 0.00073" 31,500 2.1 After final anneal' (about 0.0007") 13,000 4.5

Mullen bursting strength 18 psi.

EXAMPLE 5 Following the procedures of Example 4, similar results were obtained using hot line gages of 0.1 10 inch and 0.125 inch, again without any intermediate thermal treatment.

EXAMPLE 6 To explore the effect of even greater amounts of iron, additional runs were made with alloys A and B respectively containing 1.37 and 1.60 percent iron (each having 0.08 Si, with Cu, Mn, Mg and Zn less than 0.02 each, balance essentially Al). Reroll coils of 0.023 inch sheet X 61 as inches width (weighing 22,258 lbs.

Gage Tensile Strength 9 Alloy A 1.37% Fe) 0.023" (annealed) 13,900 psi 36.0

0.0096" 23,500 4.3 0.0072" 24,600 4.1 0.0033" 25,300 3.8 0.0014" g I 1 28,100 3.3 Alloy B (1.60% Fe) J 0.023" (annealed) 14,900 psi 40.2 0.010" 23,800 3.7 0.005" 26,200 3.6 0.0034" 26,200 3.2 0.0015" 25,800. 2.9

The final annealed foil product had the following properties:

I Mullen Burst- Gage T.S. (psi) El, ing Strength Alloy A (1.37% Fe) 0.00067 12,500 7.6 20.6 psi Alloy B (1.60% Fe) 0.00066 15,100 6.5 24.2 psi Production of Can Bodies and the Like particularly as regards the relationship between drawing and ironing operations and the cold rolling steps immediately preceding such operations.

In general, the practice of the invention concerns three principal considerations: 1) selection of aluminous metal on the basis of its ductility at high levels of cold work, so as to provide a starting material which has a low work-hardening rate above 75 percent reduction and sufiicient ductility in work-hardened condition to permit cold working to the extend of at least 90 percent in one or more cold rolling passes without having to anneal or stress relieve the metal;

(2) inclusion in the aluminous metal, in keeping with the above consideration, of sufficient alloying elements to meet the strength requirements of the finished article, including enough iron to keep the work-hardening rate low, and, particularly in making drawn and ironed cans, to minimize die pickup and achieve a desirable die polishing effect; and (3) control of the sheet rolling operation in relation to the work-hardening effect of subsequent forming operations.

In accordance with the invention, and in keeping with the foregoing considerations, it has been found that aluminous metal of various types may be subjected to a fabricating operation which involves the steps of:

a. hot rolling the metal to a hot line gage suitable for single or multi-stand cold rolling, such as between about 0.100 inch and about 0.250inch;

b. rolling the metal from hot line gage in one or more cold rolling passes into coilable sheet stock of a thickness on the order of 10-20 percent of the hot line gage;

c. forming the cold rolled sheet into a finished article, such as by drawing and ironing to efiect a further reduction of about 65 percent (the total cold working reduction from hot line gage being in,

excess of 90 percent);

d. performing the cold rolling and forming operations without the use of a thermal treatment at any thickness of the metal below about 0.100 inch, the metal being workhardened in the course of such operations and still retaining sufi'icient ductility for finishing steps such as necking or flanging of can bodies.

It has also been discovered that the beneficial effects of relatively high iron content in the essentially binary aluminum-iron alloys previously mentioned, particularly in reducing the work hardening rate, are applicable with respect to alloys containing additional alloying elements such as magnesium, manganese, or both. Thus, novel aluminum base alloys provided in accordance with the present invention contain 0.75-2.5 percent iron, by weight, at least one additional alloying element from the group consisting of 0.1-2.5 percent.

amount of iron included is controlled to provide an alloy having a low work-hardening rate above percent reduction and sufficient ductility to permit cold working to the extent of at least percent without the necessity of annealing or stress relieving the alloy in the course of such cold working.

In accordance with this alloy aspect of the present invention, typical alloy systems are the following:

a. essentially ternary Al-Fe-Mg alloys containing 0.l2.5 percent magnesium and 0.75-2.5 percent iron, in approximately inverse proportions;

b. essentially ternary Al-Fe-Mn alloys containing 0.l-l.5 percent manganese and about 0.75l.2 percent iron, preferably with a total iron and manganese content from about 1 percent to about 2 percent; and

c. essentially quaternary Al-Fe-Mg-Mn alloys containing about 01-10 percent magnesium, about 0.25-0.8 percent manganese, and about 0.75-1 .2 percent iron.

In the above ternary and quaternary systems, the balance is commercial grade aluminum of at least 99 percent purity containing about 0.05 to 1 percent total of incidental elements ordinarily present as impurities. Ordinary commercial grade reductioncell aluminum as defined hereinbefore can effectively be used in the present invention.

EXAMPLE 7 A typical and conventionally known technique for making drawn and ironed cans from aluminum alloy 3004 involves rolling to a hot line gage of about 0.105 inch, cold rolling to 0.0275 inch, annealing, cold rolling to 0.0195 inch, stress relieving, then forming a can ditional examples of producing" can stock and the like are the following:

EXAMPLE-8- I, Bottle cap material is commonly produced in aluminum alloy 3003-H12, by hot rolling to about 0.135 inch, annealing, cold rolling to'about 0.024 inch, annealing again, cold rolling to 0.013 inch, annealing for a third time, cold rolling in a third stage to 0.0095 inch, andfinally drawing into a cap. In accordance with the present invention, the procedure involves simply hot rolling an aluminum-iron type alloy to about 0.100 inch, annealing, cold rolling all the waydown to 0.008 inch without any intermediate thermal treatment, and drawing into a finished cap.

EXAMPLE 9 a. Using the same alloy as in Example 4, coil stock suitable for making cans and the like was produced by hot rolling the ingot to 0.100 inch reroll gage and cold rolling to 0.023 inch without prior or intermediate annealing. Then the strip was flat milled by cold rolling to 0.0195 inch and, without annealing-or stress relieving, drawn into cans. v v

b. in like manner, another run was made which in: cluded annealing the 0.100 inch reroll stock at 750 F. for about two hours prior to cold rolling.

Typical properties of the can stock and the resulting cans produced in the foregoing manner are tabulated below:

Bulge Pressure Before T.S. Y.S. El. CoatingAfter (a) 30,100 25,800 4.0 94 90 (b) 23,900 20,500 3.3 78

EXAMPLE l0 Using the same ingot composition as in Example 9 (also Example 4), reroll stock was produced by hot rolling to 0.125 inch (rather than 0.100 inch as in the preceding example), followed by cold rolling in a threestand mill to 0.023 inch (also without annealing). Then the strip was flat milled by cold rolling to 0.0195 inch and, without annealing or stress relieving, drawn into can bodies. Thus, essentially the only difference in the practice was increased hot line gage compared to Example 9 (a). Typical properties obtained werev as follows:

Bulge Pressure Before After T.S. Y.S. *1 El. Coating Coating' 27,000 23,500 3.5 85 85 Finally, as a general indication of the effective performance of Al-Fe alloys and the fabricating practices of theinvention as applied thereto, the coldrolling of

ordinary l

100 or 25 aluminum from a hot line gage of 0.125 inch typically requires a three-step reduction to 0.023 inch gage and also an annealing treatment at 0.023 inch or some other intermediate gage before.

proceeding to lighter foil gages. lncontrast, aluminumiron alloys of the character described correspondingly require only two cold rolling stages from 0.125 inch to 0.023 inch (and no annealing prior to further rolling into foil). Thus, heavier hot line gages can be handled effectively in multi-standcold mills.

' EXAMPLE 11 Coil stock suitable for making cans and the like was produced from an ingot having the composition 0.75

Fe, 0.58 Mn, 0.24 Mg, 0.15 Si, incidental impurities including 0.14 Cu, 0.06 Zn and 0.02 Ti, balance essentially aluminum, by hot rolling to 0.127 inch gage, annealing at 650 F. for two hours to minimize earring of the drawn can, cold rolling to 0.0193 inch and forming into cans without intermediate annealing or stress relieving.

Typical properties produced in the foregoing manner are tabulated below:

. Bulge Pressure (psi) Before After T.S. Y.S. El. Coating Coating 33,400 3l,400 V g 3.0 94-98 92-95 EXAMPLE 12 in like manner an ingot having the following composition: 0.73 Fe, 0.50 Mn, 0.30 Mg, 0.14 Si, incidental impurities including 0.09 Cu, 0.02 Zn, and 0.01 Ti, balance essentially aluminum, was hot rolled, annealed, cold rolled and formed into cans under the conditions set forth in Example 11. The resulting can stock and cans had the following properties:

Bulge Pressure (psi) Before After T.S. Y.S. El. Gage Coating Coating 30,400 29,500 3 0.0l9l -100 EXAMPLE 13 An ingot having the following composition: 0.75 Fe, 0.48 Mn, 0.29 Mg and 0.14 Si, incidental impurities including 0.09 Cu, 0.02 Zn and 0.01 Ti, balance essentially aluminum, was treated in the manner set forth in Example 12 to produce can stock and drawn and ironed cans having the following properties:

Bulge Pressure (psi) Before After T.S. Y.S. El. Gage Coating Coating 32,200 29,500 3 0.0l92 90-100 EXAMPLE 14 An ingot was prepared having a composition 0.85 Fe, 0.5 Mn, the balance being essentially commercial grade aluminum having a purity of at least 99 percent with incidental impurities including Mg, Cu, Ni, Zn, Si and Ti,

the total of which did not exceed 1 percent. Following the procedures set forth in Example ll, drawn and ironed cans of comparable characteristics are produced.

' EXAMPLE 1s The procedures of Example ll are again employed using, however, an ingot having a composition 0.95 Fe, 1 .0 Mg, thebalance beingessentially commercial grade aluminum having a purity of at least 99percent with incharacteristics.

' EXAMPLES 16-17 Again following the method outlined in Example I 1, cans are produced from ingots of compositions tabulated below:

Fe I Mn Mg Si Example l6 0.9 0.5 v 0.8 Example l7 0.9 L 1.0

The balance of each of the'above compositions is commercial grade aluminum of at least 99 'percent purity having conventional incidental impurities, the total of which does not exceed 1 percent.

For purposes of clarity, the following terminology used in this application is explained below:

Hot Rolling Rolling carried out at elevated temperatures, usually to convert thecast structure of an ingot to a wrought structure and toreduce the thickness of the resultant slab preparatory to cold rolling intostrip of lighter -gage. For aluminum and its alloys, the metal temperature during at least the first part of the hot rolling process is well above the recrystalization temperature, e.g. greater than 600 F. and usually 750-l ,000 F. or higher. The temperature usually drops as the hot rolling proceeds, with the final temperature often less than the recrystallization temperature, say 400-500 F so that some cold work is effected. This cold work is called residual or equivalent cold work and is designated as an E factor.

Cold Rolling Rolling carried out attemperatures lower than the recrystallization temperature to decrease the thickness, and causing work hardening of the strip. The input metal temperature for cold rolling is usually room temperature or slightly higher.

Annealing A thermal treatment to effect softening of a cold worked structure by at least partial recrystallization or by relief of residual stresses. v

While present preferred embodiments of the invention have been described, it will be apparent to those skilled in this art that the invention may be otherwise variously embodied and practiced within the scope of the following claims:

What is claimed is:

l. The method of fabricating aluminous metal having a low work-hardening rate and exhibiting sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: cold rolling the aluminous metal into coilable sheet, wherein said cold rolling involves a reduction in thickness to'approximately 0.02 inch; and forming said sheet into a finished article, in-

cluding cold working the sheet to form a hollow portion of said article; said cold. rolling and forming operations being performed without the intervention of a thermal treatment at any thickness of the metal below about 0.100 inch, to effect work hardening of the metal to the extent of at least 90 percent upon completion of said forming step.

2. The method of claim 1 in which said forming step includes drawing. 3. The method of claim 1 in which said cold rolling step involves at least a 75 percent reduction.

, 4. The method of claim 1 in which said cold rolling step produces coilable sheet having a thickness in the range from about 0.010 inch to about 0.025 inch.

5. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized-by a low work-hardening rate in the region above 75 percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress' relieving the metal, comprising the steps of: providing cold rolled can stock of the aluminous metal at a thickness of about 0.010 inch to about 0.025 inch; and forming said can stock into a drawn and ironed can body without the intervention of a thermal treatment, to cause workhardening of the metal to the extent of at least 90 percent upon completion of said forming step.

6. The method of claim 5 comprising the step of providing the metal at a thickness of at least 0.100 inch and rolling said metal into coilable can stock in at least one cold rolling pass.

7. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized by a low work-hardening rate in the region above percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing can stock of the aluminous metal in work hardened condition at a thickness of approximately 0.02 inch corresponding to a cold working reduction of at least 75 percent; and forming said can stock into a drawn and ironed can body, without the intervention of a thermal treatment,.

the peripheral wall of said body having a thickness less than 0.010 inch.

8. The method of claim 7 comprising the step of drawing said can stock into a cup preparatory to the drawing and ironing thereof to form said can body.

9. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized by a low work-hardening rate in the region above 75 percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: hot rolling the aluminous metal to a hot line gage between about 0.100 inch and about 0.250 inch; cold rolling said metal from hot line gage into coilable can stock; and forming said can stock into a drawn and ironed can body; the peripheral wall of said body having a thickness less than 0.010 inch; said cold rolling and fonning operations being performed without theintervention of a thermal treatment at any thickness of the metal below about 0. l inch.

10. The method of claim 9 comprising the step of rolling said metal from hot line gage into coilable can stock in a plurality of cold rolling passes.

11. The method of fabricating aluminous metal having sufficient ductility at high cold work levels to permil cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing cold rolled sheet ofthe aluminous metal at a thickness in the range from about 0.0l0 inch to about 0.025 inch; and cold working said sheet to form a hollow article without the intervention of a thermal treatment, said sheet initially being in work-hardened condition corresponding to a reduction of at least 75 percent, and the metal being work hardened at least 90 percent upon completion of said cold working operation.

12. The method of making an aluminous-metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: cold rolling the aluminous metal into coilable can stock; and forming said can stock into a drawn and ironed can body; said cold rolling and forming operations being performed without I the intervention of a thermal treatment, to achieve a total cold working reduction of at least 90 percent upon completion of said forming step.

, 13. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal having sufficient ductility at high cold work levels to permit cold working to the-extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing can stock of the aluminous metal in work hardened condition corresponding to a cold working reduction of about percent; and cold forming said can stock into a drawn and ironed can body in the absence of any intervening thermal treatment of said can stock, the peripheral wall of said can body having a thickness less than 0.010 inch and being work hardened to an extent corresponding to a total cold working reduction of at least percent upon completion of said forming step.

14. The method of claim 13 comprising the step of drawing said can stock into a cup preparatory to the drawing and ironing thereof to form said can body.

15. In a method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece wherein aluminous metal is cold rolled to provide can stock in work hardened condition and said can stock is formed into a drawn and ironed can body, the improvement comprising cold forming said can stock into a drawn and ironed can body without any intervening thermal treatment of the cold rolled aluminous metal, the peripheral wall of said can body having a thickness less than 0.010 inch, said wall of the can bod bei wor hardened to an extent corresponding to Z1 col i l worliing reduction of at least 90 percent upon completion of said forming operation.

Claims

2. The method of claim 1 in which said forming step includes drawing.
3. The method of claim 1 in which said cold rolling step involves at least a 75 percent reduction.
4. The method of claim 1 in which said cold rolling step produces coilable sheet having a thickness in the range from about 0.010 inch to about 0.025 inch.
5. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized by a low work-hardening rate in the region above 75 percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing cold rolled can stock of the aluminous metal at a thickness of about 0.010 inch to about 0.025 inch; and forming said can stock into a drawn and ironed can body without the intervention of a thermal treatment, to cause workhardening of the metal to the extent of at least 90 percent upon completion of said forming step.
6. The method of claim 5 comprising the step of providing the metal at a thickness of at least 0.100 inch and rolling said metal into coilable can stock in at least one cold rolling pass.
7. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized by a low work-hardening rate in the region above 75 percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing can stock of the aluminous metal in work hardened condition at a thickness of approximately 0.02 inch corresponding to a cold working reduction of at least 75 percent; and forming said can stock into a drawn and ironed can body, without the intervention of a thermal tReatment, the peripheral wall of said body having a thickness less than 0.010 inch.
8. The method of claim 7 comprising the step of drawing said can stock into a cup preparatory to the drawing and ironing thereof to form said can body.
9. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal being characterized by a low work-hardening rate in the region above 75 percent reduction and having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: hot rolling the aluminous metal to a hot line gage between about 0.100 inch and about 0.250 inch; cold rolling said metal from hot line gage into coilable can stock; and forming said can stock into a drawn and ironed can body; the peripheral wall of said body having a thickness less than 0.010 inch; said cold rolling and forming operations being performed without the intervention of a thermal treatment at any thickness of the metal below about 0.100 inch.
10. The method of claim 9 comprising the step of rolling said metal from hot line gage into coilable can stock in a plurality of cold rolling passes.
11. The method of fabricating aluminous metal having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing cold rolled sheet of the aluminous metal at a thickness in the range from about 0.010 inch to about 0.025 inch; and cold working said sheet to form a hollow article without the intervention of a thermal treatment, said sheet initially being in work-hardened condition corresponding to a reduction of at least 75 percent, and the metal being work hardened at least 90 percent upon completion of said cold working operation.
12. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: cold rolling the aluminous metal into coilable can stock; and forming said can stock into a drawn and ironed can body; said cold rolling and forming operations being performed without the intervention of a thermal treatment, to achieve a total cold working reduction of at least 90 percent upon completion of said forming step.
13. The method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece, said aluminous metal having sufficient ductility at high cold work levels to permit cold working to the extent of at least 90 percent without the necessity of annealing or stress relieving the metal, comprising the steps of: providing can stock of the aluminous metal in work hardened condition corresponding to a cold working reduction of about 75 percent; and cold forming said can stock into a drawn and ironed can body in the absence of any intervening thermal treatment of said can stock, the peripheral wall of said can body having a thickness less than 0.010 inch and being work hardened to an extent corresponding to a total cold working reduction of at least 90 percent upon completion of said forming step.
14. The method of claim 13 comprising the step of drawing said can stock into a cup preparatory to the drawing and ironing thereof to form said can body.
15. In a method of making an aluminous metal can body having its peripheral wall and one end formed integrally in one piece wherein aluminous metal is cold rolled to provide can stock in work hardened condition and said can stock is formed into a drawn and ironed can body, the Improvement comprising cold forming said can stock into a drawn and ironed can body without any intervening thermal treatment of the cold rolled aluminous metal, the peripheral wall of said can body having a thickness less than 0.010 inch, said wall of the can body being work hardened to an extent corresponding to a cold working reduction of at least 90 percent upon completion of said forming operation.