Foundries

CARBON - CARBONANDARTIFICIALGRAPHITE - APPLICATIONS OF BAKED AND GRAPHITIZED CARBON] (Vol 4) -use in foundries pIOLYBDENUM AND MOLYBDENUM ALLOYS] (V ol 16)... 

Fossil copal Fossil flour Fossil-fuel furnaces Fossil fuel prices Fossil fuels Fotoform/Fotoceram Fougere Royal Foundry alloys Foundry core binders Foundry furnaces Foundry resins Fountains Fourcault process... 

Worldwide furfuryl alcohol capacity in 1993 was estimated to be 110,000 metric tons (38). As with furfural, new capacity in developing countries is replacing older capacity in developed countries. China and South Africa have become significant producers of furfuryl alcohol. New plants have been built in Asia and Indonesia as well. Consumption of furfuryl alcohol is spread over the globe the largest use is in the foundry industry which is increasingly moving away from heavily industrialized countries. 

Furan hot-box resins are used in both ferrous and nonferrous foundries (66,67). In this process, resin and catalyst are intimately mixed with dry sand and then blown into heated metal boxes containing a cavity the shape of the desired core. In seconds, the surface of the sand mass hardens and, as soon as the core has cured sufficiently to be rigid and handleable the box is opened and the core removed. Automotive cores with exceUent dimensional accuracy and high strengths are made via this forty-year-old process. 

Both FNB and Hot Box appHcations are mature and declining as new technology is being used more and more in the foundry industry. 

Resins. As mentioned above, both furfural and furfuryl alcohol are widely used in resin apphcations. Another resin former, 2,5-furandimethanol [1883-75-6] (BHME), is prepared from furfuryl alcohol by reaction with formaldehyde. It is usually not isolated because oligomerization occurs simultaneously with formation (competing reaction). Both the monomer and oligomers are very reactive owing to difuntionahty, and are used primarily as binders for foundry sand (72) and fiberglass insulation (147,148). 

The steel (qv) iadustry is also an extremely large user of fluorspar which is added to slag to make it more reactive. Smaller amounts are also used ia the aluminum, ceramic, brick, cement, glass fiber, and foundry iadustries. 

Phenol—formaldehyde resins are used as mol ding compounds (see Phenolic resins). Their thermal and electrical properties allow use in electrical, automotive, and kitchen parts. Other uses for phenol—formaldehyde resins include phenoHc foam insulation, foundry mold binders, decorative and industrial laminates, and binders for insulating materials. 

Foundy Yearbook, 1977, Part III, Eoundry Trade Journal, RedhiU, Surrey, U.K., p. 254 Table 21 is a detailed appHcation chart for fuel-fired and electric foundry melting furnaces. 

E. Doetsch and H. DoHwa, "Economical and Process Technology Aspects of Cast Iron Melting," Electrowarmeint. 37(B3), B157 (1979), contains an economic comparison fuel-fired and electric iron foundry melting furnaces. 

Refractory Linings. The refractory linings (2,3) for the hearth and lower wads of furnaces designed for melting ferrous materials may be acidic, basic, or neutral (see Refractories). Sdica has been widely used in the past, and is stid being used in a number of iron and steel foundries. Alumina, a neutral refractory, is normally used for furnace roofs and in the wads for iron foundries, but basic brick can also be used in roofs (4). 

Electrode consumption for ferrous melting a-c furnaces usually averages 2.5—6 kg/1 of molten metal dependent on the particular furnace practices. D-c furnaces have electrode consumptions that are about 30% lower for similar operations. A typical energy consumption for a typical high productivity ministeel mill practice is 400 kW h/t. In comparison, power consumptions exceeding 600 kW h/t ia foundries is not unusual because of longer furnace cycle times. 

A typical m el ter iastalled in a medium sized brass foundry contains 4500 kg of brass and its inductor is rated 500 kilowatts. Brass is an alloy containing copper and zinc. Zinc vaporizes at temperatures weU below the melting temperature of the alloy. The channel iaductor furnace s low bath temperature and relatively cool melt surface result in low metal loss and reduced environmental concerns. Large dmm furnaces have found use in brass and copper continuous casting installations. 

Most ferrous scrap is recycled in steelmaking processes by melting the scrap in either a basic oxygen or an electric arc furnace. However, a significant market exists for cast-iron products, which are also made by melting ferrous scrap. In 1991, world production of cast irons was estimated at nearly 3.9 X 10 t at over 14,000 iron foundries (15). 

Over 95% of the world s DRI production is consumed in electric arc furnace steelmaking. The remaining 5% is spHt among blast furnaces, oxygen steelmaking, foundries, and ladle metallurgy (qv) faciUties. 

These ahoys are used as fuses, sprinkler system ahoys, foundry pattern ahoys, molds, dies, punches, cores, and mandrels where the low melting ahoy is often melted out of a mold. The ahoys are also used as solders, for the repHcation of human body parts (see Prosthetic devices), and as filler for tube bending. Lead—iadium ahoys are often used to joia metals to glass. 

Equipment. The standard equipment in magnesium foundries consists of large stationary brick-lined reverbatory furnaces which can hold up to 10—15 t of molten magnesium. Reverbatory furnaces are furnaces in which heat is suppHed by burning a fuel in a space between the reactants and the... 

Because the production of magnesium is a large-scale iadustrial process, fast and rehable methods for magnesium analysis have been developed for the quick turnaround times necessary ia a production foundry (76,77). Referee methods which are more time consuming but have larger ranges and greater accuracy compared to the production methods have also been developed (78). 

Molding and Core Practicefor Magnesium Foundries, bull. no. 141-29, The Dow Chemical Co., Midland, Mich., June 1957. 

Dryings of Castings and Other Products. The use of microwaves in the curing and drying of foundry cores is weU estabhshed (185). The best example is the use of microwaves for drying water-based core washes at 2450 MHz with up to 150 kW. These apphcations have not, however, found apphcation in manufacturing. Many similar drying apphcations have been examined (186,187). 

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