Open-hearth furnace

During the years 1981 to 1986, the average consumption of manganese units (as ferroalloys) for the EEC, the United States, and Japan combined, decreased from 6.5 to 5.5 kg/t of steel. Eor the same period in the United States, the consumption of manganese decreased from 6.2 to 4.7 kg/t of steel (33), and apparendy decreased further in the years of 1990, 1991, and 1992 to 4.15, 4.11, 3.85 kg/t of steef respectively (9). In contrast, in 1984, the steel industry of the former USSR, where 50% of steel production was stiU made in open-hearth furnaces, had an average consumption of manganese units of 13 kg/t steel (35). 

Heavy fuel oil usually contains residuum that is mixed (cut back) to a specified viscosity with gas oils and fractionator bottoms. For some industrial purposes in which flames or flue gases contact the product (eg, ceramics, glass, heat treating, and open hearth furnaces), fuel oils must be blended to low sulfur specifications low sulfur residues are preferable for these fuels. 

The various steelmaking processes were all eventually supplanted (3,4). The first of the newer techniques was the historic pneumatic or Bessemer process, introduced in 1856. Shortiy thereafter, the regenerative-type furnace, known in the 1900s as the open-hearth furnace, was developed in the United... 

FIG, 5-22 Thermal perfo rmance of weU-stirred fiirnace chambers reduced efficiency as a function of reduced firing density D and reduced sink temperature Tj. (a) Radiant section, oil tube stills, cracking cods, (h) Domestic boiler combustion chambers, (c) Open-hearth furnaces, (d) Soaking pits. 

Open-hearth furnaces oxygen blow. Fumes, smoke, SO, particulates Proper hooding, settling chambers. 

Sihca bricks are used extensively in coke ovens, the roofs and walls of open-hearth furnaces, and the roofs and sidewalls of glass tanks and as linings of acid electric steel furnaces. Although sihca brick is readily spalled (cracked by a temperature change) below red heat, it is very stable if the temperature is kept above this range and for this reason... 

Basic oxygen furnaces (BOFs) have largely replaced open hearth furnaces for steelmaking. A water-cooled oxygen lance is used to blow high-purity oxygen into the molten metal bath. This causes violent agitation and rapid oxidation of the carbon, impurities, and some of the iron. The reaction is exothermic, and an entire heat cycle requires only 30-50 min. The atmospheric emissions from the BOF process are listed in Table 30-16. 

Direct-fired combustion equipment is that in which the flamt of combustion are used to achieve the desired result by r and convection. Common examples include rotary kilns and open-hearth furnaces. Indirect-fired combustion equipment is that in wh e... 

Martin-. (Zron) Martin, open-hearth, -fluss-eisen, n. open-hearth iron, -fluss-stahl, m. open-hearth steel, -ofen, m. Martin furnace, open-hearth furnace, -ofenschlacke,/. open-hearth slag, -roheisen, n. open-hearth pig (iron). -Stahl, m. Martin steel (open-hearth steel). -stahlofeQ, m. open-hearth steel furnace. -verfahren, n. (Siemens-)Martin process, open-hearth process. 

The impure iron is made into steel by burning out most of the carbon, sulfur, and phosphorus. Today there are three common furnace types for making steel—the open-hearth furnace (85% of U.S. production), the electric arc furnace (10%), and the Bessemer converter (5%). These furnaces differ in construction but the chemistry is basically similar. 

The process of burning out the impurities is slowest in the open-hearth furnace. This implies there is plenty of time to analyze the melt and add whatever is needed to obtain the desired chemical composition. Manganese, vanadium, and chromium are frequent additives. The properties of the finished steel depend upon the amount of carbon left in and upon the identity and the quantity of other added elements. Soft steel, for example, contains 0.08-0.18 weight percent carbon structural steel, 0.15-0.25% hard steel ox toot steel, 1-1.2%. 

OH molecules, reaction between, 282 Oil-drop experiment, 241 Oil of wintergreen, 346 Oleomargarine, 407 Open hearth furnace, 404 Operational definition, 195 Orbital representation of chemical bonding, 278 Orbitals atomic, 262, 263 dand/, 262... 

Silica bricks are used extensively in coke ovens, the roofs and walls of open-hearth furnaces, and the roofs and sidewalls of glass tanks and... 

Use of regenerators is limited to large steel-melting furnaces for example, an open-hearth furnace, and by-product coke ovens with fuel combustion systems only. 

Ajax An oxygen steelmaking process in which the oxygen is injected into an open hearth furnace through water-cooled lances. Used at the Appleby-Frodingham steelworks, UK. 

Talbot A semi-continuous steelmaking process which combines the Bessemer and Open Hearth processes. Molten pig iron from a Bessemer converter is poured into an Open Hearth furnace containing fresh ore and lime. Impurities in the pig iron oxidize and enter the slag. The process improves the yield of steel and the throughput of the plant. Introduced by B. Talbot at Pencoed, PA, in 1900 and subsequently adopted in Europe. 

Opened fullerenes, 12 232 Open-end spinning, cotton yarn, 8 17 Open-head drums, 18 8 Open-hearth furnace, 12 320 21 408 Open-hearth steelmaking process, 16 150-151... 

Iron and Steel Blast Furnace Open Hearth Furnace... 

In fact they have already been adopted for more than two-thirds of all the open hearth furnaces in this country... 

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