BRUCE H . W Y M A
ALUMINUM ALLOYS NEW USES AND FABRICATION TECHNIQUES luminum production last year
A reached a new record total of 2,118,000 short tons-an increase of 214,289 short tons over 1961 and 103,502 short tons over the record set in 1960. At the end of 1962 primary capacity remained a t 2,483,750 short tons, the same as the previous year, with facilities for a n additional 192,000 short tons in the uncompleted stage. Consolidated Aluminum Corp., a new producer, completed installation of a primary smelter a t New Johnsonville, Tenn., with a n initial annual capacity of 20,000 short tons. Mounting emphasis on aluminum in all major market areas has been experienced in 1963, indicating that a new production record will be realized. Major developments described in the literature during the past 15 months are covered here.
by opening doors of adjacent automobiles. Alloy X310. A die casting composition with extraordinary machinability. I t may be machined without cutting fluids, heretofore practically impossible with aluminum, and may be cut at machining speeds far in excess of those used with conventional cast aluminum alloys. T h e new alloy is of particular interest for small, high volume parts or where interchange with ferrous castings is routine. Alloy X335. A permanent mold and sand casting alloy with outstanding machinability. Castings may be machined without lubricants and may be cut at speeds vastly in excess of those used with conventional cast alluminum alloys. I n products where machining is a major cost element, and in operations where
interchange with ferrous castings is routine, X335 will be of special interest. Alloys 354 and 359. Two aluminum casting alloys for sand or permanent mold operations exhibit outstanding strength characteristics of special interest to the aerospace industries. Typical tensile strengths for permanent mold castings in the -T62 temper are 50,000 p.s.i. for 359 and 57,000 p.s.i. for 354. T h e new alloys have weldability, machinability, and other finishing characteristics comparable to earlier alloys, and also high corrosion resistance and less surface shrinkage. Alloys 6070 and 6071. Two heattreatable structural alloys that combine outstanding features of alloy 6061 with substantially greater strength. Alloy 6070 is an extrusion composition; 6071 is for sheet and
Alloy Development
'
A number of new alloys have been introduced which will expand further aluminum applications. Of the following, all were introduced by the Aluminum Co. of America except alloy 7039 which was introduced by Kaiser Aluminum and Chemical Corp. Alloy X5053. A high strength, super bright, dent-resistant, automotive trim alloy. I n identical tempers, the new alloy is 15% stronger than alloy 5252; also, it is more dent-resistant, a n important factor since one of the projected uses for the new alloy will be beltline moldings. The roll-formed tr:m pieces will be placed to protect automotive body panels from impacts
Contour fiouches formed by using air pressure to force the foil into a mold can be filled with conventional equipmmt VOL. 5 5
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plate. They are of particular interest to the chemical process, transportation, highway products, electrical and building products fields because of their high resistance to stress corrosion cracking, good weldability, and resistance to corrosive attack of industrial atmospheres. Alloy X7005. A heat-treatable wrought aluminum alloy with excellent brazing and soldering cliaracteristics. It was developed for large structures that cannot be quenched following brazing, either because of size or danger of distortion. It maintains high mechanical properties with only a moderate corrosion and excellent resistance to stress corrosion cracking. Particular value is expected in complicated structures involving numerous brazed or soldered joints, or in such large structures as heat exchangers for liquid oxygen plants, aircraft heat exchangers and radiators. Alloy X7106. A heat-treatable wrought alloy that displays unique welding characteristics of special interest to the aerospace and process industries. Joint efficiency in both the as welded and artificially aged conditions is unusually high, and resistance to surface corrosion is good. Both parent metal and weldments have excellent resistance to stress corrosion cracking. Potential uses include a wide range of structures whose size makes solution heat treatment following welding impractical. Alloy 7039. A heat-treatable alloy showing excellent properties at ultracold temperatures for applications such as space uses and liquid gas storage and transportation. The alloy is readily weldable over a wide range of thicknesses with no decrease in weld ductility. Crack resistance in restrained plate weldments ( I A )is excellent. A significant advance in aluminum powder metallurgy is the offering of a minimum strength guarantee (Alcoa) for alloy XAPOOI at tem-
peratures up to BOO0 F. In the GOO0 to 1000° F. temperature range, this material is the strongest aluminum alloy commercially available. Resistance to creep and immunity to stress corrosion cracking is excellent. Other important characteristics include: stability at a given temperature regardless of length of exposure time; ability to regain original room temperature properties and dimensions, even after repeated elevated temperature exposures ; high modulus of elasticity at both room and elevated temperatures; strength not dependent upon heat-treatment ; low neutron-capture cross section, and short half lifc. A variety of high strength aluminum alloys are available with varying combinations of strength and physical properties. A detailed rel-iew of these commercially available alloys has been published (2A) along Xvith a discussion of the properties of experimental -T6 type aluminum alloys. Production
Recently much attention has been given to the ((direct reduction” or “by-pass” technique that extracts aluminum from the ore without resorting to the intermediate step of producing alumina. T h e Reynolds Metals Co. has announced that
Fabrication and Equipment
A new, fast, low-cost method of spot welding aluminum to many other metals has been developed. Designated the Alcoa R-305 process, this technique which combines the advantages of aluminum with other metals, is designed to fill the steadily groLving need for such products now existing in the electrical, transportation, architectural, defense, consumer durable goods, and chemical processing industries. Employing standard gas metal arc welding equipment, the new technique requires virtually no pre- or post-M-eld proc-
The largest aluminum plate euer produced in u11oy 5455 encloses the 74f o o t diameter reboiler section of Project Fabrication’s air separation tower. The installation is the largest single-unit oxygen plant in the world
AUTHOR Bruce H . W y m a is a Sales Development Engineer f o r the Aluminum Co. of America. H e authored IBEC’s Aluminum Annual Reviews published i n 7967 and 7962. 54
when ne\v plant facilities are rcquired, it will employ a direct reduction process (7B) which was perfected during World War I1 by a German scientist. Modifications and improvements in the method have been made during the past 10 years. The principal reason for turning to a direct reduction process is that thc cost of building such a plant is substantially lower than the cost of a conventional potline. Since the new type plant would depend less on electric power, location would be more flexible and could be made closer to market areas. Details have not been made available other than that the process is thermal rather than electrolytic.
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
essing. Completed welds resemble riveted joints in appearance, but display better electrical conducti1it)r than mechanical joints. Ductility and corrosion resistance are good, and joint strength is similar to that of &-aluminum gas metal arc spot welds. The process uses a lap joint design; the aluminum member generally is the bottom piece. When a weld is made, aluminum filler metal hardens and forms a "fused rivet" of ductile aluminum-head joined to the top surface and foot welded to the bottom member of the lap joint. If the thickness of the other metal exceeds 0.030 inch, a pilot hole approximately I/, inch in diameter is drilled to provide a path for the filler metal. The R-305 process can be employed with most metals and has been used in joining aluminum to titanium, copper and hare, galvanized and aluminized steel. Aluminum rings in a great range of sizes are demanded by various industries for uses ranging from bearing cages to missile tooling. Kaiser Aluminum and Chemical Corp. has installed a 96-inch vertical mandrel ring mill and auxiliary equipment ( 7 0 . The mill is a 150-ton piece of equipment with a power roll driven by a 750 horse power wound motor. The pressure mandrel is operated by a 3000-p.s.i. oil system that can develop 400,000 pounds. Seamless rolled rings, 96-inches 0. D., 14 inches thick, and weighing as much as 2500 pounds can he produced. The first continuous heat-treating line now is in operation at Aluminum Company of America's Alcoa, Tenn., works. For heat-treated coils of aluminum sheet, coil width has been increased to 56 inches and maximum coil weight is approximately seven times greater than was formerly available. Built around a vertical furnace installation more than eight stories high, the line employs electronic controls and processes primarily 2024, 6061, and 7075 alloys, both bare and AIcIad. I n addition to savings in material cmts for users, the broader mnge of thicknesses and widths makes this sheet amactive for a wide area of applications formerly limited to non( C o & ' d on p o p 56)
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P i g m e n t s - F O R PAME IMKS, PLASTICS, ETC. c r ~ s f a / s - P O L l S H E D OPTICS, R4DIATIOi DETECTORS, SOLID STATE MATERIALS
Fluorides
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heat-treated sheet, with a resulting weight saving. Thin-wall aluminum impact extrusions measuring 96 inches in over-all length and believed to be the world’s largest have been produced by Harvey Aluminum Co. (3C). The large impacts offer exceptional dimensional accuracy, one-piece construction, elimination of machining, superior finish, and excellent physical properties. The giant parts are suitable for pressure vessels, gas containers, and uses where properties of aluminum are advantageous. A unique process, designated Magneform, uses magnetic force to expand, compress, shape, form or punch aluminum without actually touching the metal (42). Operation of the equipment is based on the interaction of pulsed magnetic fields with eddy currents which they produce. An aluminum work piece can be compressed or expanded in a fraction of a second to perform swaging, forming, blanking, shearing, perforating, flanging, or coining operations. Aluminum is especially adaptable to the new metal-forming process because of its good electrical conductivity. Pressures up to 50,000 p.s.i. are exerted on the work piece, which is more than adequate for a wide range of operations involving light to medium gage tubes, sheets, and shapes. A proposal by Alcoa involves fabricating at the launch area mammoth aluminum rocket motor cases 10 stories high and 22 feet in diameter. The object is to avoid transportation problems, reduce cost, and obtain high strength-to-weight ratio. Separate methods of fabricating the cylinders for motor case sidewalls are proposed, each involving a different metalworking process. I n one, rollformed plate is joined longitudinally into cylindrical sections, which in turn are joined circumferentially to obtain the desired length. I n the other, a continuous sidewall in the total required length is poured, using a method currently employed to produce smaller cylinders. Then cylindrical sections are roll-extruded up to 20 feet long in the desired diameter, and these are joined to arrive at the final length. Circle NO. 510 on Readers’ Service Card
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INDUSTRIAL AND ENGINEERING CHEMISTRY
No difficulties would be expected in using either welding or mechanical techniques to accomplish joining. All proposed techniques are in current use. The first successful method of aluminum pipe line “hot tapping”welding branch connections to oilor gas-carrying lines ivithout intcrrupting service-was announced by Alcoa. This development promises a substantial increase in the use of aluminum pipe for such applications as gathering lines where new production customarily is tied into existing lines operating under full pressure. Aluminium Ltd. has developed a new high current welding technique -400 amperes and above-to join aluminum plates up to one inch thick with only two welding passes. The method offers the additional advantages of reduced porosity and the complete elimination of plateedge preparation. The method employs the standard argon-shielded consumable electrode process and is being used to fabricate the internal aluminum tanks of two ships that will transport liquefied gas at cryogenic temperatures. The vessels will carry the liquid gas at a temperature of -258’ F. from North Africa to Canvey Island, England. Reynolds Metals Co. has announced a process for rolling sheet from pellets that could effect large savings in both plant investment and production costs (2C). The new process operates continuously, produces a coil of sheet which can be of any length, and needs less equipment than a conventional rolling mill. In contrast to heating and reheating large ingots, heat transfer to the small pellets is excellent and results in further savings in fuel costs. Pellets average inch in length and l / l e inch in diameter and must be free flowing. They are dropped through a vertical preheating furnace which brings their temperature to between 750’ and 1000’ F. Furnace time for each pellet is approximately four seconds, compared to several hours for an ingot. Hot pellets are fed bctween a pair of rolls where they are formed into a fully consolidated sheet. Thickness of sheet produced
ranges from inch down to foil gage. The company believes that the new process will have a significant impact on the aluminum sheet industry and foresees its use in new U. S. or foreign facilities (IND.ENG. CHEM.5 5 , 30 (1963). Packaging and Containerization
With an estimated $24 billion spent in 1963 on packaging of all types in the United States, aluminum has moved into a variety of packaging roles including improved versions of traditional applications. Aluminum foil is combined with materials such as paper board and plastics-e.g., a foil-fiber can has been predicted to consume at least 8 million pounds of foil in 1963. These cans are well established in the motor oil and frozen juice fields, and are making inroads in the packaging of other products such as candies and nuts. Another fast growing segment of aluminum’s packaging market is that served by the rigid all-aluminum can. According to the U. S. Department of Commerce, use of aluminum in cans will have risen 80% to 180 million pounds by the end of 1963. Greatest potential is for beer, citrus concentrates, soups, cheese, and fish, with top priority being given the aluminum beer can. Reynolds Metals Co. has entered a long term contract to supply impact-extruded 12-ounce cans to a St. Paul, Minn., brewing company. Four production lines will turn out cans at a rate of 48,000 per hour. Alcoa has introduced a 12-ounce impact-extruded can in test pack quantities. The cans weigh 73 pounds less per 1000 than tinplate cans; thus, for a 60,000-pound minimum carload shipment from St. Louis to Pittsburgh, savings in freight costs would be 45 cents per 1000 cans. New air-formed foil packaging components in a variety of shapes and sizes have been announced by Alcoa. The components are formed by applying air pressure to foil and forcing the metal into a shaped cavity. Packages can be filled on conventional equipment and then sealed with a flat sheet of foil. Or
two contoured sheets can be sealed on three sides, filled, and then sealed on the remaining side. Shapes presently include squares, rounds, large circles with raised dividers, and special configurations such as playing card symbols. Alcoa also introduced a tamper-proof aluminum and plastic bottle closure developed especially for packaging pharmaceuticals, liquors, and cosmetics. The closure features a band that breaks but remains on the bottle to expose tampering. At its Torrance, Calif., plant the Reynolds Metals Co. has installed equipment for the production of aluminum tuna cans and beer can lids. Two tuna can lines with a total annual capacity of more than 80,000,000 units turn out seamless cans that weigh less than half as much as thin tin-plate. The containers are produced at a rate of 300 per minute by a shallow drawing process, and emerge from the lines ready for filling. Aluminum beer can lids will be produced on two presses having a total annual capacity of more than 200,000,OOO units ( 7 0 ) . Containerization is seen by the aluminum industry as increasing in potential in each of the next five years. In addition to its nontoxic characteristics, aluminum increases the paylsad of containers carried by truck, rail, sea and air transport. Estimates are that well over 10,000 large aluminum container units will be built next year, with the actual figure probably being closer to 20,000. Petroleum
Aluminum has been used in five main classes of drilling-completion equipment ( 2 0 ): -Drilling structures, including masts and substructures. -Drill-string equipment, including drill pipe, nonmagnetic collars, lifting subs, pipe protectors, stabilizers, tongs and well-survey equipment. -Well-completion and servicing equipment including bridging plugs, cementing shoes, jet perforating guns, desanding equipment, and propping agents. -Supply and maintenance equip-
ment, including water and gas piping and hand tools. -Machinery and equipment components, including cementing, pump castings and connecting rods. Aluminum drill pipe, although still under evaluation, is probably the one completely new tubular product offered the drilling industry in the past 50 years. It permits rigs to be upgraded to drill deeper-e.g., 6500 feet of 41/2-inch diameter steel drill pipe with tool joints and 50,000 pounds of drill collars weigh approximately 167,700 pounds. With the same drill collar weight, 10,000 feet of the same diameter internally upset aluminum pipe weigh only 140,000 pounds. I n addition to ease of handling and lower transportation and fuel costs, aluminum drill pipe increases wire-line life. The latest published tally lists 30 strings (227,540 feet) of aluminum drill pipe being used throughout the world in desert drilling, Arctic operation, drilling in hard and soft formations, and in limited drilling of deviated holes. Architectural and Construction
At the Westinghouse Electric Corp. Telecomputer Center, a onestory, 30,000 square-foot structure, 14-foot long extruded aluminum members carry the weight of the building roof and also serve as the mullions which frame the windows. The one-piece system, serving both as a load-bear column and window mullion, is comprised of two 14-foot long vertical members and three 5foot horizontal extrusions. Weighing 220 pounds and light enough to be handled by a four man crew, the aluminum system replaced a steeltube curtain wall system originally considered. Saving in construction costs are estimated at $13,000. Featherweight panels of aluminum sheet encasing a foamed plastic core possessing excellent heat and sounddeadening qualities are being used to build “Atomedic,” the hospital of tomorrow. The new concept in medical care is expected to supply the answer to an international need for low-cost, local hospitals affording the best in diagnosis and care at
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minimum cost. The building is round with a center activity core encircled by 22 wedge-shaped rooms. An exterior corridor ringing the rooms keeps visitors moving without hindering the staff or risking contamination of the sterile dispensing, diagnostic, and surgical facilities in the central core area. Transportation
SALINE WATER CONVERSION-II Three years of important work in this active research area are represented in this new volume on saline water conversion. The 14 papers it offers are based on symposia sponsored by the Division of Water and Waste Chemistry at the 139th and 141st National Meetings of the ACS in March 1961 and March 1962, res pectively. Different methods reported here include: spray evaporation . . , phosphate preci itation , . , vibration . , . wiped tRin-film distillation . . . the use of the diffusion still . . . the use of the osmotic membrane. . . flash evaporation utilizing solar energy. Cost problems are fully covered. There are abundant charts and i Ilust rat ions. Authors are drawn from universities and industry, research institutes, government. They provide experimental data and discussion from work in the U. S., Canada, Australia, South Africa and Israel. Both basic and applied research is covered. All those concerned with technical aspects of saline water conversion will want this up-to-date compilation of significant papers on the subject. 199 PAGES.
PAPER BOUND.
PRICE: $6.00
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Hydrofoils mark one of the newer ventures in marine transportation. The HS Denison, a 90-ton hydrofoil designed to fly through water, built for the Maritime Administration, employs approximately 30 tons of aluminum in her construction. The framework is formed of aluminum plate joined by welding to extruded aluminum structural members. Aluminum sheet riveted to the framing completes the hydrofoil’s sleek seaplane type hull. The unusual craft’s foils are supported by large high-strength forgings. The craft has been accepted by the Government and currently is on a demonstration tour. The world’s largest railroad container car unit in operation built for the Pullman-Standard Division of Pullman, Inc., contains 10,000 pounds of aluminum. Mounted on a n 88-foot flatcar, the super container measures 78 feet long, 8 feet wide, and 13l/2 feet high. I t has a total volume of approximately 9500 cubic feet, and has been described as a new concept in the design of lightweight superstructures. The Hydroskimmer or SKMR, a unique high-speed naval vessel, designed and constructed for the Navy’s Bureau of Ships, is the largest air cushion vehicle built in the United States. I t will flash along at speeds up to 70 knots (approximately 80 miles per hour) while supported 11/2 feet above the ocean surface by a cushion of air. Special aluminum extrusions with integral lengthwise stiffeners, joined by the inert gas metal welding process, form the outer skin of the Hydroskimmer’s hull. Built-in strength of the aluminum panels simplified construction by eliminating the need to join stiffeners to sheet, as in conventional shipbuilding practices.
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
Process industries
The world’s largest single unit oxygen plant now is in operation at Bayou Oxygen Co. The unit has a record-setting daily production capacity of 800 tons of vapor oxygen and 500 tons of vapor nitrogen. An aluminum tower, 126 feet high and 11 feet in diameter, has a 200,000-pound shell made of alloy 5456 sections, 96 inches wide, 532 inches long, 1.625 inches thick, and weighing about 8000 pounds. Aluminum was chosen because of its ability to maintain both strength and ductility at the low temperatures at which the plant will operate. A new galvanic anode material, alloy CB75, protects steel structures against sea water corrosion. O n an equal weight basis, the new material will last twice as long as magnesium, three times as long as zinc, and one and one-half times as long as the best previous aluminum anode material. Bundled aluminum pipe lines for offshore installations are increasing in popularity. A recent successful line installed off Santa Barbara consists of a bundle of three 2-inch schedule 80 lines and an additional 3-inch line of a special alloy that serves two purposes : it provides cathodic protection for the three line bundles and also serves as an anchor line. Pipe for the installation was furnished in 40-foot lengths with ends beveled for welding. After welding and bundling, the entire line was launched through the surf and towed into position. The anchor pipe then was flooded with sea water to sink the bundles (30).
REFERENCES Alloy Development
Production (2B) J . Metals 15,538 (August 1963) Fabrication and Equipment
Applications (1D) LiqhtMetol Agc 28, (August 1963). (2D) Shiring, C. G., Wanderer, E. T., Oil Gus J.87 91 (October21 1963). (3D) danderec, E. T’., Materials Protection 5 5 , GO (June 1963).
