Fusible alloys

Iron is hard, brittle, fairly fusible, and is used to produce other alloys, including steel. Wrought iron contains only a few tenths of a percent of carbon, is tough, malleable, less fusible, and has usually a "fibrous" structure. 

Alloys of tin are very important. Soft solder, type metal, fusible metal, pewter, bronze, bell metal. Babbitt metal. White metal, die casting alloy, and phosphor bronze are some of the... 

The solder and ahoy market, including low melting or fusible ahoys, is a principal user of indium (see SoLDERS AND BRAZING ALLOYS). The addition of indium results in unique properties of solders such as improved corrosion and fatigue resistance, increased hardness, and compatibhity with gold substrates. To fachitate use in various appHcations, indium and its ahoys can be easily fabricated into wine, ribbon, foil, spheres, preforms, solder paste, and powder. 

Low Melting Alloys. Lead ahoys having large amounts of bismuth, tin, cadmium, and iadium that melt at relatively low (10—183°C) temperatures are known as fusible or low melting ahoys. The specifications of many of these ahoys are Hsted ia ASTM B774-87 (7). 

Until 1930, approximately 90% of bismuth usage was for pharmaceutical appHcations (9). From that point until the 1970s, research produced new appHcations that greatiy expanded the uses of the metal. At that point the pharmaceutical use accounted for about 50% of the total bismuth consumption. By 1991, the fusible alloy category along with the other subdivisions each accounted for about 10% of the bismuth usage. Pharmaceutical usage was down to 20%. 

The United States consumed 1500 metric tons of bismuth in 1988 and exported 147 t (1). The average domestic dealer price was 12.74/kg. The world mine output, excluding the United States, was estimated to be 2770 t in 1988 the world refinery production was estimated as 3510 t. Of the bismuth consumed in the United States, 679 t was used for industrial and laboratory chemicals, cosmetics (qv), and pharmaceuticals (qv) 333 t for fusible alloys 493 t for metaHurgical additives 12 t for other alloys and 15 t for miscellaneous purposes. 

W orld annual production of bismuth and its compounds has hovered around 4000 tonnes of contained Bi for many years and a similar amount of secondary (refinery) Bi is also produced. Production has been dominated by China, Japan, Peru, Bolivia, Mexico, Canada, USA and Australia which, between them, account for almost of all supplies. Prices tor die free element have fluctuated wildly since the 1970s, from < 4 (Xl/kg to > 44.00/kg at die end of 1990 it was 6.30/kg Consumption of the metal and its compounds has also been unusual, usage in the USA dropping by a factor of 2 from 1973 to 1975, for example. The mam uses are in pharmaceuticals, fusible alloys (including type metal, p. 547), and metallurgical additives. 

Leicht-metall, n. light metal (of sp. gr. less than 5 sometimes, specif., an alkali or alkaline-earth metal) light alloy, -dl, n. light oil. leicht-schmelzbar, a. easily fusible, -schmel-zend, -schmelzlich, a. low-melting, -siedend a. low-boiling. 

Soluble core molding The soluble core technology (SCT) is called by different names such as soluble fusible metal core technology (FMCT), fusible core, lost-core, and lost-wax techniques (3). In this process, a core [usually molded of a low melting alloy (eutectic mixture) but can also use water soluble TPs, wax formulations, etc.] is inserted into a mold such as an injection molding mold. This core can be of thin wall or solid construction. 

Alloys are mixtures of metals combined to obtain specific characteristics and enhanced properties for a particular application. The term fusible metals or fusible alloys denotes a group of alloys that have melting points below that of tin (232°C, 449°F). Most of these substances are mixtures of metals that by themselves have relatively low melting points, such as tin, bismuth (m.p. 275°C), indium (157°C),... 

TABLE 15.1 Melting Points of Fusible Alloys of Variable Composition... 

Note that all combinations of metals yield an alloy with a melting point significantly lower than that of any of the individual metals. Even more extensive listings of fusible alloy compositions and melting points are available. As a point of reference, paper will spontaneously begin to bum when heated to 451°F, just above the melting point of tin. 

Fusible Alloys, Clad Metal Industries, http //www.cladmetalindustries.com/Alloys.html... 

Fusible Alloys with Characteristics, Canfield Technologies, http //www.solders.com/aloyprod.htm... 

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