Carbon alloys

The Standard covers bar, plates, sheets, strip, structural shapes rolled stock, pipes, sheets with laminar coating and strip of carbon, alloyed and electrical steels and sets up nondestructive magnetic method of mechanical and service properties and microstructure control. 

Iron carbide process Iron-carbon alloys Iron castings... 

Manganese—Aluminum—Carbon Alloys. Anisotropic Mn—Al—C permanent magnet ahoys have been developed usiag warm working (87). Properties as high as B = 0.61 T (6100 G), = 220 kA/m (2.8 kOe) and (BH) = 56 kJ/m (7 x 10 G-Oe) have been obtained. A typical ahoy... 

In ancient India, a steel called wootz was made by placing very pure kon ore and wood or other carbonaceous material in a tightly sealed pot or cmcible heated to high temperature for a considerable time. Some of the carbon in the cmcible reduced the kon ore to metallic kon, which absorbed any excess carbon. The resulting kon—carbon alloy was an excellent grade of steel. In a similar way, pieces of low carbon wrought kon were placed in a pot along with a form of carbon and melted to make a fine steel. A variation of this method, in which bars that had been carburized by the cementation process were melted in a sealed pot to make steel of the best quaUty, became known as the cmcible process. 

Electric-arc furnaces offer the advantages of low constmction costs, flexibiHty in the use of raw materials, and the abiHty to produce steels over a wide range of compositions (carbon, alloy, and stainless) and to operate below full capacity. 

All grades, including carbon, alloy, and stainless steels. 

In order to answer these questions as directly as possible we begin by looking at diffusive and displacive transformations in pure iron (once we understand how pure iron transforms we will have no problem in generalising to iron-carbon alloys). Now, as we saw in Chapter 2, iron has different crystal structures at different temperatures. Below 914°C the stable structure is b.c.c., but above 914°C it is f.c.c. If f.c.c. iron is cooled below 914°C the structure becomes thermodynamically unstable, and it tries to change back to b.c.c. This f.c.c. b.c.c. transformation usually takes place by a diffusive mechanism. But in exceptional conditions it can occur by a displacive mechanism instead. To understand how iron can transform displacively we must first look at the details of how it transforms by diffusion. 

Fig. 13. Flypothetical growth process of SW tubes from a metal/carbon alloy particle (a) segregation of carbon toward the surface, (b) nucleation of SW tubes on the particle surface and, (c) growth of the SW tubes.

KT is grateful to financial support from the project of Institute for Fundamental Chemistry, supported by the Japanese Society for the Promotion of Science -Research for the Future Program (JSPS-RFTF98P00206). ME thanks the support from Grant-in-Aid for Scientific Research on Priority Area (Carbon Alloys, No. 09243105, 1997). W-KH and MT thank The Royal Society for financial assistance. 

Kohlenstoff-hydrat, n. carbohydrate, -kalium, n. potassium carbide, -kem, m. carbon nucleus. -kette,/. carbon chain, -legiening,/, carbon alloy, -metall, n. carbide, kohlenstoffrelch, a. rich in carbon. Kohlenstoff-silicium, n. carbon silicide. -ske-lett, n. carbon skeleton, -stahl, m. carbon steel, -stein, m. carbon brick, -sticlKtoff-titan, n. titanium carbonitride. -sulfid, n. 

Plain tubes (either as solid wall or duplex) are available in carbon steel, carbon alloy steels, stainless steels, copper, brass and alloys, cupro-nickel, nickel, monel, tantalum, carbon, glass, and other special materials. Usually there is no great problem in selecting an available tube material. However, when its assembly into the tubesheet along with the resulting fabrication problems are considered, the selection of the tube alone is only part of a coordinated design. Plain-tube mechanical data and dimensions are given in Tables 10-3 and 10-4. 

Iron Low-carbon steels Low-carbon alloy steels Decarburised malleable Chromium 980-1 050 (Halide) 1. Gaseous 2. Semi- gaseous 3. Pack 25-75 urn Solid-solution (ferritic) 20-25% Cr Ductile (200-300 HV) Weldable Heat treatment acceptable ... 

Iron/ carbon alloy, poured as a hot molten liquid into a mold. Usually produced as either gray iron (where flakes of graphite are embedded in an iron matrix) or nodular iron (spheroids of graphite in the matrix). 

Morancho, R., Constant, G., Gallon, C., Boucham, J., Mazerolles, P., and Bernard, C., OMCVD Elaborating and Optical Properties of Germanium Carbon Alloys, Proc. 5th European Conf. on CVD, (J. Carlsson and J. Lindstrom, eds ), pp. 526-532, Univ. of Uppsala, Sweden (1985)... 

Donnet, C., Recent Progress on the Tribology of Doped Diamond-like and Carbon Alloy Coatings A Review, Surf. Coat. Technol., o. 100/101,1998,pp. 180-186. 

In Figure 3b and c the absolute atomic concentrations of carbon and silicon, respectively, are shown as a function of the carbon fraction. As expected, the carbon concentration increases upon alloying. In contrast, the silicon content decreases rapidly, which implies that the material becomes less dense. As it was reported that the Si—Si bond length does not change upon carbon alloying [116], it thus... 

Ferrous Alloys. Many ancient objects allegedly made of iron actually consist not of the pure metal but of alloys of iron and carbon known by the generic name ferrous alloys. These can be broadly classified into two classes steel and cast iron. Steel is the common name for iron-carbon alloys in which the relative amount of carbon ranges between 0.03% and 2%. If the relative amount of carbon in the alloy exceeds 2%, the alloy is known as cast iron (see Table 33) (Angus 1976 Wertime 1961). Steel is outstanding because of the mechanical properties that it acquires when subjected to heat treatment, which causes changes in its structure and physical properties (see Textbox... 

High-carbon ferrochromium alloys are made by the reduction of chromite ore with carbon in an arc furnace. On the other hand, low-carbon ferrochromium is obtained by silicon reduction of the ore. The carbon content of ferrochromium can be reduced further by heating high-carbon alloys with ground quartzite or by oxidation in vacuum and removal of carbon monoxide formed. Ferrochromium alloys are used in the manufacture of stainless steel. 

Abrupt changes in the concentration of segregating solute were first observed in experimental studies of carbon segregation in interstitial metal-carbon alloys by Hamilton and Blakely . More recently, such transitions have also been observed in substitutional Cu-... 

Armor-Piercing (AP or APC)-. Armorpiercing or armor-piercing-capped projectiles, of such materials as heat-treated, high-carbon alloy steel, are used to penetrate face-hardened armor... 

As you can see, the process by which the iron-carbon alloy is processed and solidified is jnst as important as the overall stoichiometry. Although a discussion regarding phase transformations is more the realm of kinetic processes, it is nonetheless pertinent to snmmarize here the types of important ferrous alloys, particularly those in the cast iron categories. This is done in Fignre 2.13. 

Talballa, M., P.K. Trojan, and L.O. Brockway. 1976. Mechanisms of desulfurization of liquid iron carbon alloy with solid CaC2 and CaO. American Foundrvmen s Society Transactions. 84 775-786. DesPlaines, Illinois American Foundrymen s Society. 

HARDENA8ILITY OF STEEL. The hardenability of steel refers to the ease with which it can be hardened rather than the maximum hardness value attainable. For example, a I - inch diameter bar of a certain 0.20l/fi carbon alloy steel can be hardened to 50 Rockwell "C" in the center by quenching in oil. A similar bar of plain carbon steel requires a drastic quench in brine to attain the same hardness, and therefore, has a lower hardenability. Neither bar can be quenched to a greater hardness because 50 Rockwell C" is ihe maximum attainable for a 0.20 carbon steel. A... 

Pack and go carburizing creaie a diffused caiboii case. Base metals arc low -carbon steels and low -carbon alloy steels. Process temperature range is XIS-9.KO C H500 2000 F>. 

Liquid Lwhttmmg creates a diffused carbon (possibly nitrogen) case. Base metals art low-carbon steels and low-carbon alloy Meets. Process temperature range is 815-980 C 11500-1800 F). 

Gas carbonitriding creates a diffused carbon and nitrogen case. Base niciuls are low carbon steels, low-carbon alloy steels, and stainless steels. Proofs temperature range is 7W)-870JC 11400-1600 K). 

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