MATERIALS O F CONSTRUCTION
Aluminum Alloys
DURING
the past IO years, the average growth of American industry was 5 7 c per year. The demand for aluminum increased roughly 10% per year, and kept an edge over supply, in spite of several major expansions. Sufficient capacity to satisfy demand is of vital importance to large scale users such as the automotive, electrical, and home-building industries; there now is assurance that new requirements which arise for aluminum, as the result of design of new parts or redesign of old parts, can be fulfilled. One aluminum company has estimated that U. S. consumption of aluminum will continue to increase a t about 9% per year. General Electric Co. has estimated that its use of aluminum will double in ten years. Major expansions also are anticipated in industrial building, foil packaging, canning, and heavy construction. The chemical process industries have shown a steady. if not spectacular. growth in the use of aluminum, with a strong future in packaging of foods. beverages, and cosmetics, and in architectural prod-
RALPH L. HORST, Jr., author of aluminum alloy review for several years, studied chemical engineering at Columbia University, obtaining his M.S. there in 1948, after World W a r II service in the Navy. He joined the Sales Development Division of the Aluminum Co. of America ( 1 948) where he has been concerned with a variety of corrosion studies. Horst has published articles on cathodic protection, magnesium and aluminum application in the chemical and process industries. He is a member of the NACE, Sigma Xi, and Phi Lambda Upsilon. FRANK B. MURPHY studied chemical engineering a t Grove City College obtaining his B.S. in 1950. He served four years in the Air Force which included the development of Chemical Air Munitions. In 1955, he joined the sales division of the Aluminum Co. of America where he has been active in corrosion work and development of aluminum applications in the chemical and petroleum industries. Murphy is a member of NACE, AIChE, and the ACS.
ucts for new construction. .4pplications for aluminum process equipment increase as more companies take advantage of aluminum’s properties to protect their products from discoloration or to cash in on the low first cost of aluminum products such as heat exchanger tubes, integral steam-traced pipelines, bus bar, and conduit. Chemical companies are learning what aluminum can do: how to install it: and how to handle it properly. Chemical engineers today are expected by management to kno\.\- aluminum as they know steel and copper. The aluminum industry, recognizing this trend, has been holding seminars in industry centers to keep process and design engineers up to date on new alloys, new products, and the latest welding. forming, and finishing techniques. Aluminum is coming of age in the chemical industry. N e w Products
Unistrength pipe is a newly developed seamless variable-wall aluminum pipe with standard Schedule 40 wall thickness at the ends. In spite of almost 407’ reduction in weight (40-foot lengths), the bursting pressure for welded Unistrength pipe is the same as for welded Schedule 40 pipe. .4vailable in alloys 606l-TO and 6063-T6, Unistrength pipe shows significant savings for pressure lines 4 inches and over. A new bonding process for joining aluminum and stainless steel was recently disclosed by Aluminum Co. of America. This process, “pressure bonding,” opens
New Unistrength pipe has Schedule 40 O.D. and wall a t pipe ends, with the balance of the pipe wall reduced to provide uniform tensile properties after welding. The new pipe weighs nearly 4Oy0 less than Schedule aluminum pipe
the door for combination of aluminum with such metals as carbon and alloy steels and copper and for many difficult combinations of aluminum alloys. ,4n interesting application of aluminum in concrete dams has recently been completed on the Williams Fork Dam at Parshall, Colo. Approximately 33,000 feet of 1-inch 3003 tubing was embedded in the concrete structure to serve as cooling tubes. Lt’ater circulating through the aluminum coils removed heat generated as the concrete hardened, helping to prevent cracking of the concrete. The aluminum tube saved an estimated 30 cents per foot over the cost of steel tubing generally utilized. The excellent uncoiling and bending characteristics of aluminum eliminated the need for mechanical tube benders, formerly required. Impact extrusion equipment can produce parts ranging up to 12 inches in diameter and 60 inchesin length. Installation is the result of an increasing demand from the aircraft and missile industries for large impact extrusions. One of the first parts produced on this press is a prototype missile component-a shell 8 4 inches in diameter and 34 inches long with ‘/z inch side walls. .4 new heat-treatable aluminum casting alloy (X250) has been developed for applications requiring good ductility, high tensile strength, and excellent resistance to corrosion. The alloy contains 8% magnesium. 1.5% zinc, 0.2570 manganese, and 0.15% copper. Casting characteristics and mechanical and physical properties are similar in general to those of aluminum-lOyo magnesium alloy 220-T4, but X250-T4 offers better resistance to stress corrosion cracking and greater stability of tensile properties during natural aging. Typical properties are 55,000 p.s.i. tensile strength, 28,000 p.s.i. tensile yield strength. and 18% elongation. The largest aluminum bottom dump trailrrs in the world are in service hauling coal in Southern Indiana. For maximum pay load and high resistance to corrosion, the trailers have plate and structural members fabricated from alloy 5456, the highest strength commercially available aluminum alloy suitable for wdding. Architectural
Corrugated aluminum sheet was used to cover 7500 feet of 24-, 36-, and 54inch conveyor belts a t a new alumina
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MATERIALS OF CONSTRUCTION
This bottom-dump coal hauler i s one o f six of the largest aluminum trucks in the world. Weighing 10,000 pounds less than the same size steel trailer, the aluminum body can carry 60 tons of coal per trip. Plate and structural members are made of alloy 5456
plant a t Gramercy, La. A weathertight seal was obtained by caulking side laps with a '/g-inch bead of aluminumpigmented mastic and using 3/4-inch selftapping screws a t lap fasteners. The ease of handling and fitting the aluminum sections made it possible to double the rate of installation compared to corrugated steel covers and to limit the size and amount of handling equipment, permitting appreciable reductions in installation costs ( 7 4 . American Society of Metals new headquarters building near Cleveland, Ohio, will have an all-aluminum geodesic dome of honeycomb structure, 250 feet in diameter and 103 feet high. The tubing which comprises the dome is 4 and 6 inches in diameter, interlaced with 4inch diameter tension rods for extra rigidity, and secured by heavy bolts. The dome, weighing 166,000 pounds, was erected in hexagonal sections joined on the ground and lifted into place by cranes (2.4).
num. cold-worked 5 to 5052, inclusive. corroded intergranularly, except for the recrystallized aluminum samples. Materials cold-worked 607, and over were immune to this attack. . i t 150' C. and higher temperatures, cold-worked aluminum was susceptible to intergranular corrosion and to selective attack. Atomic Energy Applications
New aluminum alloy X8001 is used extensively in the core of the Argonne Low Power Reactor recently dedicated a t Arco. Idaho ( I C ) . Containing 0 . 5 7 ~ iron and 170 nickel. X8001 is much less costly than other materials used heretofore for certain core components in reactors. When X8001 alloy was exposed to high purity water a t 680' F.. the attack was slight and relativel) uniform. The alloy showed even higher resistance to corrosion a t lower temperatures under
static test conditions. The rate of attack based on 9-week exposure was 8 mils per year at 680' F.. 3 mils a t 600' F., and 2 mils a t 550' F. TRIGA, a training research isotope reactor developed by General Dynamics Co., is designed for installation at the bottom of a n aluminum tank 20 feet deep and 6 feet in diameter. Approximately 16 feet of water in the tank above the core shields the reactor. Fuel rods will be uranium-zirconium hydride clad with aluminum. T R I G A will be installed a t the Lniversity of Arizona ( 2 C ) . General Electric Co. has disclosed details of the plutonium fuel elements used in the new reactor a t Arco, Idaho. .4t the Geneva Atoms for Peace Congress, G E said that the elements are thin strips of aluminum-jacketed plutonium-aluminum alloy brazed to the aluminum side wall to form a box with 18 tiers. Each lamination is 0.060 inch thick. They are unlike the uranium fuel elements for AEC's Hanford plant, which are solid cylinders of uranium about 1-inch in diameter and 8 inches long ( 3 C ) . Chemicals
Fuels. Wells ( 7 0 ) reports that triethylaluminum and trimethvlaluminum pyrophosphoric fuels are being examined for use in jet airplanes. These fuels can be produced in large quantities at a reasonable price and they permit the same amount of thrust from a smaller, less complicated and more reliable engine than other fuels. Jet fuel (JP4) is delivered to .4ir Force planes through aluminum pipelines which deliver the flow to each hydrant on a fueling apron (60). These pipelines are coated, wrapped, and buried directly beneath the apron pavement. Methane. Early in February 1959
Corrosion
LYhiting and Godard (2%) have discussed the corrosion behavior of aluminum alloys in the construction industry: effects of atmospheric conditions on corrosion of aluminum, and behavior of aluminum in contact with building materials such as wood sheathing, building boards, masonry, concrete, steel, copper, insulating materials, joint caulking materials, and mastic compounds. The atmospheric performance of anodized, colored, and porcelain-enameled aluminum is evaluated. The effect of cold working and of cold working followed by annealing to complete recrystallization on the corrosion resistance of high purity aluminum in water a t looo, 150°,and 200' C. has been determined by Lavigne ( 7 2 3 ) . I n distilled water a t 100' high purity alumi-
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The aluminum geodesic dome for the new ASM headquarters near Cleveland is fabricated entirely of 4 and 6 inch 6061-T6tubes and tension rods. The dome is 250 feet in diameter and rises 10 stories into the air
INDUSTRIAL AND ENGINEERING CHEMISTRY
N e w varia ble-wall aluminum pipe reduces weight per standard length b y 4070,yet retains strength of welded Schedule 40 pipe the "Sfethane Pioneer'' sailed to England with the first transoceanic shipment of liquified methane ( 9 0 ) : 32.000 barrels from the Lake Charles. La., gas liquification plant of British Methane? Ltd., for delivery to a British utility near London. The Pioneer's special insulation system which keeps methane liquid at -258' F. without pressurization appears to make such transoceanic shipments practical. Basically, this system is a set of aluminum tanks encased in balsa wood. LYithin a few years, operators of the Pioneer expect to have a full fleet of tankers in operation handling liquid methane. Polyethylene. Polyethylene plastic toda)- is transported to processors' plants in self-unloading trailers made of aluminum, equipped with an integral air stream conveyor (70). They can deliver up to 400 pounds per minute of bulk polyethylene directly into plant storage or internal handling facilities. The pneumatic delivery system provides an unloading process free of contamination. dust, and waste. The light-weight aluminum construction makes possible payloads of 30,000 pounds and assures product purity during over-highway transit. XOWin use by Tennessee Eastman Co. a t Kingsport, Tenn., the trailers caii be designed to handle a variety of dry bulk products. Alloy 6061-T6 is used for the trailer bodies and alloy 6062-T6 for 5-inch winged channel reinforcing members. Polystyrene. Cosden Petroleum Corp. recently put on stream its new 22.000,000-pound-per-yearpolystyrene plant a t Big Spring, Tex. (30). This plant will contain integrated processing from crude oil to polystyrene a t one location. Because of strict product purity requirements, water for suspenzlon polymerization and washing is handled exclusively in aluminum pipelines and tanks Silica. The vapor phase process described by LYhite and Duffy ( 7 70) is used to produce colloidal silica of high p u r i n , low water content, and large external surface area. The basic reaction in the process is between silicon tetrachloride, hydrogen, and oxygen to give silica and hydrochloric acid. This is a highly exothermic reaction. The heart of the process is four cylindrical aluminum furnaces 20 inches in diameter, and j 1 V 2 feet long! in which silicon tetrachloride is burned. The top end ofeach furnace contains a hydrogen burner and an inlet for air and silicon tetrachloride. Hydrogen is introduced a t 4 p.s.i. Internal temperatures run as high as 2000' F. and the colloidal silica and mixture of gases lea\-e the furnace a t 1100' to 1200' F., almost the melting point of aluininum. Air circulated inside the steel jacket keeps the
furnace shell temperature down to 300' F. Each furnace has a separate fan uhich handles about 2000 cu. feet per minute of cooling air. To keep moisture contamination from upsetting the reaction. the air is carefully dried over a bed of activated alumina. Tall Oil. Products storage at Slonsanto Chemical's new plant at Nitro, LV \-a,, consists of aluminum storage tanks blanketed with inert gas to prevent product degradation ( 2 0 ) .
\vhich have led to its use in cooling towers. Alloy selection. fabrication practices, surface finish, and standard water treatments are discussed. Service experience with existing aluminum towers is presented and data from field research and testing are tabulated. The following aluminum alloys are recommended for cooling tower construction: Structurals. 6061-T6, 6062-T6, 6063T6
Stamped sheet. 5052-H32, cast 356-T6 Forged 6051-T6 Decking or fill. Alclad 3004-HI4 sheet, minimum gage 0.032 inch Piping. Alclad (inside) 3003-F Bolts. 2024-T4 with No. 205 Alumilite finish, 6061-T6 Nails. 6061-T91 Rivets. 6053-T61 Screw machine parts. 6061-T6, castings 43, or 356-T6 Fan blades.
Aluminum tanks for polyethylene storage maintain product purity of the plastic
Urea. Urea production has been on a sharp upswing and in its production. corrosion and erosion are major problems. Aluminum can be utilized in certain parts of these processes to provide corrosion resistance a t a moderate cost. In Spencer Chemical's new plant a t Henderson, Ky., urea prills are produced in a 160-foot-tall all-aluminum prilling tower. In -4merican Cyanamid's new plant a t Hamilton, Ontario, aluminum has been used in the decomposerseparator and in all low-pressure lines ( J D ). Waters. Svereta ( I O D ) tested aluminum and its alloys in river waters and in cooling tokvcrs of circulating systems under natural conditions. In river waters, corrosion \vas low and uniform; pitting corrosion occurred in circulating waters. The composition and impurities of the waters were the essential factors influencing the corrosion. The differences between the behavior of several different alloys was slight. No mention was made as to whether .4lclad alloys were evaluated in comparison with bare allo>-s. Haygood and hlinford ( 5 D ) have described the characteristics of aluminum,
An all-aluminum vapor compression still which can convert 120 gallons of sea water per hour into pure drinking water was engineered and fabricated by Badger Mfg. Co., Cambridge, Mass., under contract with the Sanitary Engineering Branch of the U. S. Army Engineer Research and Development Laboratories, Fort Belvoir, Va. (80). The evaporator weighs 3600 pounds, compared with 8300 pounds which would be the equivalent weight of a cupronickel still. The unit was satisfactorily field-tested for 6 months a t Harbor Island. N. C. Industries
Brewing. Early this year, Adolph Coors Co., Golden, Colo., introduced aluminum beer cans to a test market in the Denver area. During the past 4 years: Coors has developed an automatic process for converting aluminum ingot into impact extrusion slugs by continuous strip casting, rolling, and blanking out (3E). After printing and varnishing, the cans are put in a drying oven where they are given an internal vinyl resin coating. The cans are filled with beer in a hermetically sealed room in a n atmosphere of sterile air: which eliminates the need for pasteurizing. Cryogenics. Mikesell and Reed ( 8 E ) have reported the properties of alloy 5086 at extremely low temperatures. The tensile strength of annealed specimens increased about 80% behveen 300' and 20' K . The yield strength inThe tensile strength creased about 1?17~. of welded specimens increased about 40Yc between 300' and 20' K: while the yield strength increased about 357,. Despite a drop in elongation between 76' and 20' K, the annealed tensile specimens exhibited plastic deformation at 20' K. The impact strength of the annealed specimens decreased by abour 257, be-
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SEPTEMBER 1959
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MATERIALS OF CONSTRUCTION tween 300' and 24' K. The impact strength of the weld specimens decreased about 3570 between the same temperatures. However, both the welded and the annealed impact specimens exhibited plastic deformation a t 24' K. Leather. I n the production of tanning agents, 99.5y0 aluminum is reported suitable for diffusion cells, heat exchangers, thickeners, receivers, and their adjacent piping ( 6 E ) . The use of iron vessels lined with aluminum is advisable from the standpoint of strength for receivers and steam-heated autoclaves. Petroleum. A composite porcelainenameled aluminum panel filled with light-weight concrete was not damaged in a fire test (650' F. for 6 minutes) simulating a minor tunnel fire. The panel was a n effective fire barrier even in a severe test (860' F. for 29 minutes) but did deform (70E). A British oil company has experimented in wrapping steam- or water-traced oil lines in a sulfonation plant with aluminum foil. T h e foil originally was intended to prevent the exterior insulation from coming between the tracing pipe and the process pipe; however, there has been a considerable improvement in the heat transfer to the process pipe because of conduction through the aluminum foil. Filling the spaces between the process and trace pipes with a small amount of crumpled foil further increased this heat transfer (7E). A new 60,000-barrel-per day refinery a t Toledo, Ohio, has 29 air cooler bundles made of bimetallic aluminum-steel tubing. These tubes consist of a 1- or 1 1 / ~ inch steel tube inside a n aluminum tube. Fins inch high are extruded from the exterior walls of the aluminum tubes. The fins are integral with the tubing and cannot become detached because of vibration, shock, or pressure variation. The ratio of outside surface area of tube to inside surface area is approximately 17 to 1 ( J E ) . Because aluminum tank decks have proved excellent in stopping vapor space corrosion in lease stop tanks, Brooks (ZE) felt that light-walled aluminum pipe would prove excellent for fabrication of vent lines in these tanks. I n 1955, two aluminum test lines were installed using alloy 5086 and Alclad (7072) 5086 pipe. In July 1957 the lines were inspected and no attack was noted on either the bare or the Alclad vent lines. The author anticipates a service life for the aluminum pipe of a t least 15 years in these test cases. This is comparable to the known performance of the aluminum tank decks in this particular area, which have been in continuous use for 15 years with no repairs. Black (7E) has reviewed the applications of aluminum in the petroleum industry. Major applications are: drilling rigs, oil pipelines, storage tanks, heat
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exchangers, distillation column plates. catalysts, thermal insulation, pressure vessels, road and rail tank cars, sacrificial anodes for tankers, drums, cans, paint buildings, and structures. Power. .4luminum applications in central power plant design include bus bar, conduit sivitch gear, cross arms: control tubing. heat exchangers, roofing, siding, and architectural trim (9E). One 425,000-kw. steam generating station completed in 1951 saved 5670 on bus conductors plus 20% on fittings and installation costs. Based on these savings, a second installation of 450,000 kw. was completed in 1957 using aluminum bus in the outdoor substation and in generator leads. Verink (72E)has presented the case for aluminum heat exchanger tubes for surface condensers and power plants. H e answers questions on water velocity, turbulence, heat transfer, fabrication, welding, and price. The cost of aluminum tubes is one half the cost of admiralty metal tubes. Aluminum sheet covers thermal insulation on two new outdoor boilers and accessory eauipment a t Ohio Power Co's. Muskingum River plant (5E). The installed cost of the aluminum jacketing was less than 27, above the cost of sheet steel jacketing, and savings in painting and maintenance costs easily justify this slight added investment. The aluminum jacketing was cut to shape and formed on the job. Aluminum sheet jacketing also covers stack breeching, air ducts, fan housing. headers, downcomers, and conventional pass hoppers. Refrigeration. Controlled service tests have shown that properly designed aluminum coils are suitable for evaporator and condenser coils (77E). Tests made in three environments under conditions more corrosive than encountered in normal service pointed out the desirability of aluminum construction of other components of air conditioners. In all cases, performance of aluminum was enhanced by designing the air conditioner to eliminate dissimilar metal hazards. Codes
Design rules in the 1959 edition of Sections 8 and 9 of the ASME Boiler Code now include case 1174-2 for alloy .5154, case 1222-1 for alloy 5086, case 1247 for alloy 5083, and case 1248 for alloy 5456. Case XXXX has been approved to permit the use of alloy GM31A (5454) sheet and plate, rod, pipe, and tube for code vessels operating up to 400' F. This alloy has mechanical properties equivalent to those of alloy 5154. but does not have 51 54's slight susceptibility to stress corroiion under certain conditions a t elevated temperatures. The ASME Code also has added design stresses for as-
INDUSTRIAL AND ENGINEERING CHEMISTRY
welded 6061-T4 sheet, plate, bars, rods, shapes, pipe, and tube. Design stresses values also have been included for aswelded Alclad 6061-T3 sheet and plate and as-welded 6063-T6 pipe and tube. Small changes in the specification requirements of 3004 and clad 3004 sheet and plate and clad 3003 pipe and tube will be carried into Sections 2 and 8 of the 1959 edition of the code. The 1958 revisions of the ASTM Specifications covering aluminum products will also be carried into Section 2 of the ASME Code ( 7F). literature Cited
Architectural Applications (1.4) Am. Metal Market 65, 10 (June 25, 1958). (2A) Chem. Eng. L V e u 36, 99 (Dec. 29, 1958). Corrosion (1B) Lavigne, M. J., Corroszon 14, 36 (May 1958). (2B) Whiting, J . F., Godard, H. P., Eng. J . 41,451(June 1958).
Atomic Energy Applications (1'2) Chem. Ens. 65,49 (December 1958). ( 2 C ) Chem. Eng. News36,76 (May 5,1958). 13C) Chem. Week 83, 76 (Sept. 13, 1958). Chemicals (1D) Aluminum Co. of America, News Release, Jan. 19, 1959. (2D) Chem. Enp. 6 5 , 60 (August 1958). (3D) Ibid., p. 99 (December). (4D) Zbid., 66,44 (January 1959). (5D) Haygood, A. J., Minford, J. D., Corrosion 15, 36 (Janu'ary 1959). (6D) Healing, Piping, Air Conditioning 30, 113 (September 1958). (7D) Light ,Metals Bull. 20, 691 (Oct. 8, 19581. (8D) Modern Metals 14, 7 3 (November 1958). 19D) Petrol. W e e k 8 , 38 (Feb. 13, 1959). ilOD) Svereta, O., W'erkstoffe Rorrosion 9, 533 (1958). i l l D ) White, L. J., Duffy, G. J., IND. ENG.CHEM. 51,232 (1959). Industries (1E) Black, S., Petrol. Times 62, 463 (June 6, 1958). (2E) Brooks, R. E., Corrosion 14, 15 (November 1958). i3E) Chem. Eng. News37,49 (Jan. 19,1959). (4E) Chem. Processing 22, 29 (February 1959). (SE) Elec. World 150, 62 (July 14, 1958). (6E) Hollo, M., Light Metals Bull. 20, 712 (Oct. 8, 1958). 17E) Light Metals 21, 303 (October 1958). (8E) Mikesell, R. P., Reed, R. P., PYOC. 1958 Cryogenic Eng. Conf., Sept. 3-5, 1958. (9E) Power 102, 81 (September 1958). (l0E) Ricker, R. W., Manley, C. R., Ceram. Znd. 68, OS (June 1957).
(11E) Vandenburgh, D. G., Haygood, A. J., Refrig. Eng. 66, 42 (September 1958). 112E) Verink, E. D., Jr., Rucker, J. D., Proc. 78th Ann. Water Conf.,Pittsburgh, Pa., Oct. 21, 1957.
Codes (1F) Carlisle, M. E., Aluminum Co. of America, private communication, April 9, 1959.
