Casting metals iron castings

Siemens s process A method of steel manufacture by addition of scrap metal, iron oxides and ferromanganese to molten pig (cast) iron. 

Lead and its alloys are generally melted, handled, and refined in cast-iron, cast-steel, welded-steel, or spun-steel melting ketdes without fear of contamination by iron (qv). Normal melting procedures require no dux cover for lead. Special reactive metal alloys require special alloying elements, duxes, or covers to prevent dross formation and loss of the alloying elements. 

Iron is the preferred metal for casting steel and nonferrous metals are used in smaller amounts. Most castings are made in green sand molds, ie, uncured molds of sand, clay, and water. However, the use of sheU mol dings is growing, because such mol dings permit reproducibUity of castings with close dimensional accuracy. In addition, the simplicity of equipment procedures reduces costs. 

A second, more recently developed use for strontium metal is as an inoculant in ductile iron castings. Inoculants provide nuclei upon which graphite forms during the sohdification of cast iron, thus preventing the formation of white cast iron. Elkem Metals Company has commercialized a range of fine-sized foundry inoculants for iron castings. These inoculants, called superseed, are ferrosiUcon alloys containing 50 or 75% Si, 0.8% Sr. Most of the balance is iron. 

The zinc is normally melted in a gas, oU, or coal-fired reverberatory furnace with a capacity up to 100 tons or in a low frequency induction furnace with a capacity of a few tons. The more highly aUoyed compositions are more effectively melted and mixed in low frequency induction furnaces. The furnace must be refractory-lined to eliminate iron pickup by the molten metal. The metal temperature is maintained below 500°C to minimize loss by oxidation. A ladle is used to transfer the metal for casting into molds the pouring temperature is usuaUy ca 440°C. Zinc scrap is not generaUy suitable for remelting because it may contain undesirable impurities. 

Cast Iron and Ductile Iron Cast iron and ductile iron provide more metal for less cost than steel in piping systems and are widely... 

Guss-beton, m. cast (or poured) concrete, -blase, /. flaw in a casting, blowhole, -blei, n. cast lead, -block, m. ingot, -bruch, m. broken castings, cast-metal scrap specif., cast-iron scrap. 

Roheisen, n. crude iron, pig iron, -gans, /. (iron) pig. -guss, m. pig-iron casting, -mischer, m. (Iron) hot-metal mbcer. -ver-fabren, n. (Iron) pig process. 

Cast iron is the standard material used to construct the cylindrical housing, but other materials may be used if corrosive conditions exist. The rotor is usually a continuous piece of steel that includes the shaft and is made from bar stock. Special materials can be selected for corrosive applications. Occasionally, the rotor may be a separate iron casting keyed to a shaft. On most standard air compressors, the rotor-shaft seals are semi-metallic packing in... 

It is also doubtful whether the surface condition of the bare metal at the time of burial has much significance. Some authorities consider that the casting skin on cast iron is protective, but the evidence on this point is conflicting. On the other hand, it is desirable to remove the millscale from steel when, as is usual, a protective coating is applied. If the millscale was left on, it might cause the coating to spall. 

Graphitic Corrosion Graphitic corrosion usually involves gray cast iron in which metallic iron is converted into corrosion products, leaving a residue of intact graphite mixed with iron-corrosion products and other insoluble constituents of cast iron. 

The metal casting industry conventionally divides casting products into ferrous and nonferrous metals, in particular, iron-based, steel-based, aluminum-based, and copper-based castings. The other castings of low fractions include magnesium, lead, zinc, and their alloys. In the U.S., the foundry industry currently produces 11 million tons of metal product per year, with a shipment value of 19 billion. Of them, iron and steel accounted for 84% of metals cast.5 The remaining 15% of foundry operations are concerned with aluminum, copper, zinc, and lead production. Table 4.2 summarizes critical physical and thermal properties of aluminum, iron/steel, and cast iron. 

Gas Cannons. The first cannons were small, crudely made cast metal pots shaped like a vase which fired iron darts. The invention of gun powder about the middle of the 13th century made possible the use of cannon to throw projectiles by use of expanding gas. 

A typical flaker , such as used in manuf of TNT and some other HE s consists of a horizontal, hollow, metallic (usually cast-iron), water-c ooled, drum, with hollow truoions mounted in bearings. It is given in Perry, pll64-L as Fig 68 and reproduced here as Fig 6. The lower part of drum dips into molten material located in a hollow, steam-... 

Producing iron castings requires the metal be melted so it can be poured into the cavity of the mold to produce the desired shape of the casting. Foundries which produce iron castings typically use one of three different processes to melt the iron cupola, electric arc furnace, or an induction furnace. 

Once cooled, the metal from a blast furnace is known as a cast metal. (When the ore is an iron ore, the cast metal is known as pig iron) A cast metal is brittle and soft because it still contains impurities, such as phosphorus, sulfur, and carbon. To remove these impurities, oxygen is blown through the molten cast metal in a basic oxygen furnace, shown in Figure 18.25. The oxygen oxidizes the impurities to form additional slag, which floats to the surface and is skimmed off. 

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