The fact that this decrease of strength begins shortly after the carboncontent rises above the eutectoid or pearlite ratio of o 90% is natural, because the brittleness of the cementite which, in hypereutectoid steels, forms a more or less continuous skeleton (Alloys, Pl., fig.
Various nickel-steels all expanded under magnetization, the increase being generally considerable and proportional to the field; in the case of an alloy containing 29% of nickel the change was nearly 40 times greater than in soft iron.
Trans., 1885, 176, 455) employed his yoke method to test the magnetic properties of thirty-five samples of iron and steel, among which were steels containing substantial proportions of manganese, silicon, chromium and tungsten.
For additional information regarding the composition and qualities of permanent magnet steels reference may be made 6 The marked effect of silicon in increasing the permeability of cast iron has also been noticed by F.
In nickel-steels containing about 50 and 70% of nickel the maximum increase of the constants is as much as 7 or 8%.
The peculiarity of these steels is that no quenching or tempering is required.
The badges of the two branches vary slightly in detail, more particularly in the attachment of fire-stones (fusils or furisons) and steels by which the fleece is attached to the ribbon of the collar.
The collar is composed of alternate links of furisons and double steels interlaced to form the letter B for Burgundy.
Alloy steels and cast irons are those which owe their properties chiefly to the presence of one or more elements other than carbon.
Osmond showed that the wonderful changes which thermal treatment andthe presence of certain foreign elements cause were due to allotropy, and from these and like teachings have come a rapid growth of the use of the so-called " alloy steels " in which, thanks to special composition and treatment, the iron exists in one or more of its remarkable allotropic states.
The important manganese steels of commerce and certain nickel steels are manganiferous and niccoliferous austenite, unmagnetic and hard but ductile.
The large massive plates of cementite which form the network or skeleton in hyper-eutectoid steels should, under distortion, naturally tend to cut, in the softer pearlite, chasms too serious to be healed by the inflowing of the plastic ferrite, though this ferrite flows around and Steel White Cast Iron 100 75 K 0 ?
Carbon-Content of Hardened Steels.-Turning from these cases in which the steel is used in the slowly cooled state, so that it is a mixture of pearlite with ferrite or cementite, i.e.
In short, from Ar 3 to Ar t the excess substance ferrite or cementite, in hypoand hyper-eutectoid steels respectively, progressively crystallizes out as a network or skeleton within the austenite mothermetal, which thus progressively approaches the composition of hardenite, reaching it at Ar t, and there splitting up into ferrite and cementite interstratified as pearlite.
The freezing of molten cast iron of 2.50% of carbon goes on selectively like that of these steels which we have been studying, till the enrichment of the molten mother-metal in carbon brings its carbon-contents to B, 4.30%, the eutectic 1 carbon-content, i.e.
These steels then normally consist of y-iron, modified by the large amount of nickel or manganese with which it is alloyed.
Indeed, in the common structural steels which contain only very little carbon, hardly any of that carbon exists as graphite.
Alloy steels have come into extensive use for important special purposes, and a very great increase of their use is to be expected.
Huntsman showed that the mere act of freeing these slag-bearing steels from their slag by melting them in closed crucibles greatly improved them.
For vanadium steels, see Iron And Steel Manufacture.
South Bethlehem is the see of a Protestant Episcopal bishop. The Bethlehem Steel Company manufactures here iron and steel, including Bessemer steels, armour plate, steel rails, government ordnance, drop forgings, iron and steel castings, stationary engines, gas engines, hydraulic pumps, projectiles, steel shaft and pig iron; zinc is smelted and refined; and there are large hosiery and knitting mills, and silk mills and cigar factories.
Nickel is used for the manufacture of domestic utensils, for crucibles, coinage, plating, and for the preparation of various alloys, such as German silver, nickel steels such as invar (nickel, 35.7%; steel, 64.3%), which has a negligible coefficient of thermal expansion, and constantan (nickel, 45%; copper, 55%), which has a negligible thermal coefficient of its electrical resistance.
In steel-making, electric furnaces are used for two distinct purposes, first for making steel sufficiently better than Bessemer and open-hearth steels to replace these for certain important purposes, and second for replacing the very expensive crucible process for making the very best steel.
Steels containing as much as 12% of tungsten are now used as a material for tools intended for turning and planing iron and steel.