Aluminized steel

Fig. 4. Process flow diagram for aluminum enameling showing (a) enamel preparation and application, and (b) metal preparation, where the cleaning processes A, B, and C represent primarily sheet D, primarily castings and E, aluminized steel (11).

Aluminum is the liighest melting point metal (660°C) applied by hot dipping. Aluminized steel can be used at temperatures up to SSO C without appreciable oxidation. Tliis steel has very good resistance to gases and vapors containing small quantities of sulfur dioxide and hydrogen sulfide [41,42,43]. 

Barry, A., Exhausts Boost Demand for Aluminized Steel , Metal Bulletin Monthly, July 32-26 (1987)... 

Jones, R. D. and Jones, D. P., Hot-dip Aluminized Steel Strip for Corrosion Resistant Applications , in Surface Treatment for Corrosion and Wear Resistance, Strafford, Datta and Googen (eds), Ellis Horwood, Chichester (1984)... 

Reininger, H., Further Developments in Metal Spraying Technique , Metalloberfldche, 15, 52, 88, 118, 148 (1961). (Translation available as TM460, Aluminium Federation, Brimingham) Scott, D. J., Aluminium Sprayed Coatings Their Use for the Protection of Aluminium Alloys and Steel , Trans. Inst. Met. Fin., 49 No. 3, 111-122 and 49 No. 4, 173-175 (1971) Sprowl, J. D., Aluminized Steel-A Description, Report of the Department of Metallurgical Research, Kaiser Aluminium and Chemical Corporation, April (1958)... 

Coburn, K. G., Aluminized Steel.Its Properties and Uses , Metallurgia, Manchr., 60, 17 (1959)... 

Hughes, M. L., Hot Dipped Aluminized Steel Its Preparation, Properties and Uses , Sheet Metal Industry, 33, 87 (1956)... 

Whitfield, M. G., Rolling of Hot Dipped Aluminized Steels to Make Them More Durable , Anti-Corrosive Materials and Processes, 2, 31, Oct. (1963) and US Pat. 2 170 361 Anon., Largest Aluminium Line in UK , Product Finishing, 21 No. 7, 61-65, July (1968) Anon., Welded Aluminized Steel Sheet , Anti-Corrosive Materials and Processes, No. 2, 4-7, Oct. (1963)... 

A spray coating of aluminum on a steel is not likely to spall or flake, but the coating is usually not continuous and may leave some areas of the steel unprotected. Hot-dipped aluminized steel gives a continuous coating and has proved satisfactory in a number of applications. 

In addition to the above subcategories, porcelain enameling on continuous strip is a subdivision within this industry. However, because there are only two plants in the U.S. producing this product, a separate subcategory is not necessary. These plants start with coils of steel, aluminum, or aluminized steel, porcelain enamel them and either recoil them for sale to metal fabricators or shear them into pieces for use as architectural panels or chalkboards. The estimated production was 2.0 x 106 m2 (22 x 106 ft2). This figure represents the area of enamel applied. For multiple coats, the area for each coat is considered. 

FIGURE 8.1 AlFe phase diagram showing intermetallic phases, such as FeAlj, FcjAlj, FeAlj, and FeAl, which can form as separate layers in aluminized steel. 

Permeation reduction factors of up to 10,000, or 10 , have been realized with the best coatings based on aluminized steels. Ferritic-martensitic steels that were aluminized had the Fe2Al5 phase predominant in the layer sequence, while a 316L steel had FeAlj and FeAl2 as the main aluminide phases. The best permeation barrier resulted from an external alumina film of about 1 micron in thickness grown on the aluminide layers. ... 

The advantages of aluminizing steels go beyond hydrogen barrier formation, however, as such surface treatments also provide additional corrosion protection. The fusion materials community continues to study these processing methods and may continue to be the main driving force for research in this area until hydrogen infrastructure issues become more important. ... 

FIGURE 8.3 A typical aluminized steel surface following the polymer slurry method at 800°C in air. Any of the methods mentioned in this section about aluminized films will produce similar reaction layers. Ease of processing and cost may dictate which method is preferred for a given application. 

Conveying-screen dryers are fabricated with conveyor widths from 0.3- to 4.4-m sections 1.6 to 2.5 m long. Each section consists of a sheet-metal enclosure, insulated sidewalls and roof, heating coils, a circulating fan, inlet air distributor baffles, a fines catch pan under the conveyor, and a conveyor screen (Fig. 12-51). Table 12-23 gives approximate purchase costs for equipment with type 304 staimess-steel hinged conveyor screens and includes steam-coil heaters, fans, motors, and a variable-speed conveyor drive. Cabinet and auxiliary equipment fabrication is of aluminized steel or stainless-steel materials. Prices do not include temperature controllers, motor starters, preform equipment, or auxiliary feed and discharge conveyors. These may add 75,000 to 160,000 to the dryer purchase cost (2005 costs). 

Following the Albert and Mahe procedure, LiH is prepared in quantities of 1 kg. in a low-carbon steel pot, externally protected from scaling with an aluminized steel jacket. The upper part of the pot and its flat, rubber-gasketed lid are water cooled. The lid has nozzles for Hg input, a vacuum connection, and a thermocouple. Two concentric cylindrical Armco iron crucibles are placed Inside the pot. These fit snugly inside each other and in the pot. 

Specimen Type (3)—Lap shear samples were made by bonding the glass side of 1 in. x 1 in. pieces of silvered glass mirrors to a 1 in. x 6 in. piece of aluminized steel with a common adhesive and then bonding a second 1 in. x 6 in. piece of aluminized steel to the mirrored side with Urethanes A, B, and C. 

The physical properties of aluminized steels are determined not only by the high temperature of the coating process but also by the physical character of the coating itself. 

Above 900°C, the life of aluminized steel is limited, although extended over that of the bare metal (e.g., at 900°C-980°C, the life is increased 20 times, at 980°C-1000 C, five times). Below 750°C, the life of aluminized steel components can be considered to be indefinite. Results obtained between 750°C and 900°C are conflicting, although the presence of silicon has been shown to be detrimental (Figure 10.15) at all temperatures [135]. Aluminum-coated steels have also been shown to be particularly resistant to sulfurous atmospheres [131]. In this respect, such coatings are particularly useful for the protection of heat-resisting grades of steel. 

Uses Corrosion inhibitor for coatings, inks, oil refineries, engine coolants, and other prods, where metal protection is a concern surf, passivation agent which forms a monomolecular bond with metal surfs, to prevent oxidation esp. effective on aluminized steel Properties Tan vise. Iiq., mild odor sp.gr. 0.92 (15/4 C) flash pt. 82 F 4.8-5.3% P, 3.4-3.7% N... 

Table 3.13 Corrosion Rates for Galvanized and Aluminized Steel in Four Waters of the Soviet Union...

Lowe, T. A. (1961). Aluminum, aluminized steel and galvanized steel in severe coastal environments. Corrosion, 17, 177t-180t. 

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