Deoxidization

Alloys with other useful properties can be obtained by using yttrium as an additive. The metal can be used as a deoxidizer for vanadium and other nonferrous metals. The metal has a low cross section for nuclear capture. 90Y, one of the isotopes of yttrium, exists in equilibrium with its parent 90Sr, a product of nuclear explosions. Yttrium has been considered for use as a nodulizer for producing nodular cast iron, in which the graphite forms compact nodules instead of the usual flakes. Such iron has increased ductility. 

COPPERALLOYS-WROUGHTCOPPERANDWROUGHTCOPPERALLOYS] (Vol7) -phosphor tin deoxidation PHOSPHORUS COMPOUNDS] (Voll8)... 

Copper and tin phosphides are used as deoxidants in the production of the respective metals, to increase the tensile strength and corrosion resistance in phosphor bronze [12767-50-9] and as components of brazing solders (see Solders and brazing alloys). Phosphor bronze is an alloy of copper and 1.25—11 wt % tin. As tin may be completely oxidized in a copper alloy in the form of stannic oxide, 0.03—0.35 wt % phosphoms is added to deoxidize the alloy. Phosphor copper [12643-19-5] is prepared by the addition of phosphoms to molten copper. Phosphor tin [66579-64-4] 2.5—3 wt % P, is made for the deoxidation of bronzes and German silver. 

Because relatively mild oxidizing agents react with phosphines, the latter are convenient deoxidizers (88) or desulfurizers (89) ... 

More than half of the elements in the Periodic Table react with silicon to form one or more silicides. The refractory metal and noble metal silicides ate used in the electronics industry. Silicon and ferrosilicon alloys have a wide range of applications in the iron and steel industries where they are used as inoculants to give significantly improved mechanical properties. Ferrosilicon alloys are also used as deoxidizers and as an economical source of silicon for steel and iron. 

Calcium—Silicon. Calcium—silicon and calcium—barium—siUcon are made in the submerged-arc electric furnace by carbon reduction of lime, sihca rock, and barites. Commercial calcium—silicon contains 28—32% calcium, 60—65% siUcon, and 3% iron (max). Barium-bearing alloys contains 16—20% calcium, 9—12% barium, and 53—59% sihcon. Calcium can also be added as an ahoy containing 10—13% calcium, 14—18% barium, 19—21% aluminum, and 38—40% shicon These ahoys are used to deoxidize and degasify steel. They produce complex calcium shicate inclusions that are minimally harm fill to physical properties and prevent the formation of alumina-type inclusions, a principal source of fatigue failure in highly stressed ahoy steels. As a sulfide former, they promote random distribution of sulfides, thereby minimizing chain-type inclusions. In cast iron, they are used as an inoculant. 

In metallurgical practice, sodium uses include preparation of powdered metals removal of antimony, tin, and sulfur from lead modification of the stmcture of siHcon—aluminum alloys appHcation of diffusion alloy coatings to substrate metals (162,163) cleaning and desulfurizing alloy steels via NaH (164) nodularization of graphite in cast iron deoxidation of molten metals heat treatment and the coating of steel using aluminum or zinc. 

Residual Elements. In addition to carbon, manganese, phosphoms, sulfur, and silicon which are always present, carbon steels may contain small amounts of hydrogen, oxygen, or nitrogen, introduced during the steelmaking process nickel, copper, molybdenum, chromium, and tin, which may be present in the scrap and aluminum, titanium, vanadium, or zirconium, which may have been introduced during deoxidation. 

Phosphorized deoxidized arsenical copper (alloy 142 (23)) is used for heat exchangers and condenser tubes. Copper-arsenical leaded Muntz metal (alloy 366), Admiralty brass (alloy 443), naval brass (alloy 465), and aluminum brass (alloy 687), all find use in condensers, evaporators, ferrules, and heat exchanger and distillation tubes. The composition of these alloys is Hsted in Table 5. 

Nickel—beryllium casting alloys are readily air melted, in electric or induction furnaces. Melt surface protection is suppHed by a blanket of argon gas or an alumina-base slag cover. Furnace linings or cmcibles of magnesia are preferred, with zirconium siUcate or mullite also adequate. Sand, investment, ceramic, and permanent mold materials are appropriate for these alloys. Beryllium ia the composition is an effective deoxidizer and scavenger of sulfur and nitrogen. 

Dispersed mixtures of boron and another metal are used as deoxidizing and degassing agents to harden steel (qv) (5,6), to increase the conductivity of copper (qv) in turbojet engines, and in the making of brass and bronze (see Copper alloys). Two examples are alloys of ferroboron and manganese boron. 

Calcium metal is produced in the United States by Pfizer Inc., Canaan, Coimecticut, and in Canada by Timminco Metals, Toronto, Ontario. In France it is produced by Pechiney ElectrometaHurgie. It is also produced in the Commonwealth of Independent States (CIS) and the People s RepubHc of China. Both Pfizer and Timminco supply the various grades in a variety of sizes and forms. In addition, Pfizer suppHes an 80% Ca—20% Mg alloy and a steel-clad calcium wire for use in deoxidation of steel and other metals. Timminco and Pfizer both supply ca 75% Ca—25% Al alloy for use in lead alloying. Timminco also suppHes a 70% Mg—30% Ca alloy for use in lead debismuthizing (18), and calcium particulate products, which are purchased by several companies for the manufacture of cored wire for use in the steel industry. 

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