Ferro-chrome and Chrome Wed.—M. Brust lei IL of Holtzer Co.'s steel works in the Loire, France, read a paper before the International Congress of Mines and 3letallurgy, in Paris, in 1889, on fcrro-o1n•ome and chrome steel, from which we extract the following: There may be introduced into steel vary ing pmportions of chromium of which the effect is to increase the resistance of steel without diminishing the tenacity corresponding to its carbon contents, and even, it appears, to slight ly increase that tenacity. In consequence, it is possible to obtain, with a resistance given to the rupture, :t bending corresponding to that which is obtained with a steel that is ordinarily less resisting or softer: that is to say, in de scribing it, as a metal which, well handled, off ers a very great security. At the forge, an in got of chrome steel may be worked with no more difficulty than with ordinary steel of the same hardness: nevertheless, when hot, it offers a greater resistance to deformation. When an ingot is cut hot by a cutter, the metal is more ductile; the point of contact between the two pieces is flattened out into a thin web be fore breaking. It is influenced by the fire even less than all ordinary steel of the same hard ness. In the cold, when worked on a• lathe or with a plane, a steel containing, for instance, 2 per cent of chromium is idways it little harder to cut than ordinary steel; nevertheless, if it is properly reheated the difference is not great. Steel that contains less chromium, even when it has I per cent carbon, may be worked with• out difficulty on a. lathe. Tempered with oil or with water, the temper penetrates more deep ly than in a carbonized steel of the same degree of carbonization without chromium, Chrome steel offers a resistance to shock and to fracture which, for the time being, makes it preferable for a certain number of uses, On the other hand, when once mule into ingots, it can be manipulated like ordinary steel, which is an ad ditional advantage. But it offers in its manu facture dhlicultie• of a special nature. In a state of fusion. which takes place at high temperatures, the chromium which it contains has a tendency to lake up oxygen from the air. In such case there is not formed, as is the case with oxide of manganese, a liquid and fusible silicate light er than steel. which comes rapidly to t he surface, but instead there is caused the dccarbonizal ion of the steel nod the oxidation of the iron, giving rise to a creamy layer, of which the litt he fragments rest readily, not only on the edges of the casting-pot, bin even in the MS'S of the metal. The portions thus oxidized will not unite tinder any working, no matter to what temperature they may be heated. For the same reason, the layer of oxide which is formed on heating the ingots or bars is strong er and adheres closer than in ordinary steel, and does not easily dissolve in borax. Also, chrome steel only unites with difficulty or not at all, according to the amount of chromium it contains. For these reasons chrome steel will require most delicate treatment, and it will be exceedingly difficult to use it in the manufacture of sheeting." The accompanying table (page 26), showing analyses and physical properties of several samples of chrome steel, is abridged from a table in Howe's Metallurgy of Steel : Steel.—Steel containing a small per tentage of nickel has recently been found to possess the valuable property of increased ten sile strength and hardness, as compared with ordinary steel of the same carbon percentage, without the decrease of ductility which in car bon steel accompanies increase of tensile strength. It has been found to be especially valuable for armor-plate, as shown by experi ments Made at the Annapolis proving-ground, and also in Europe in 1890 and 1891 (see. Irons. U. S. .A'acal Institute, 1891). The mantifae tore and properties of nickel steel are thus Ile scribed in a paper by Mr. James Riley, of Glas gow, published in the Journal of the Iron and Steel Institute, May, 1889 : " The alloy can be made in any good open-hearth furnace work ing at a fairly good heat. The charge can be made in as short a time as an ordinary • scrap' charge of steel—say, about 7 hours. Its work ing demands no extraordinary care: in fact, not so much as is required in working many other kinds of charges. the composition of the resulting steel being easily and definitely con trolled. If the charge is properly worked nearly all the nickel will be found in the steel —almost none is lost in the slag, in this respect being widely different from elmrges of cln•ome steel. The steel is steady in the mold, it is more fluid and thinner than ordinary steel, it sets more rapidly, and appears to be thorough ly homogeneous. ingots are clean and smooth in appearance on the mit side, but those richest in nickel are a little more ' piped' than are ingots of ordinary mild steel. There is less Equation of the metalloids in these ingots, therefore liability to serious troubles from this cause is much reduced. Any scrap produced in the subsequent operations of hammering, rolling, shearing, etc., can be remelted in mak ing, another chargo without loss of nickel. No extraordinary care is required when reheating the ingots for hammering o• rolling. They
will stand quite as ranch heat as ingots having equal contents of carbon but no nickel, except, perhaps, in the ease of steel containing over 25 per cent of nickel, when the heat should be kept a little lower and more care taken in fo•,ging. If the steel has been properly made, and is of correct composition, it will hammer and roll well, whether it contains little o• much nickel : but it is possible to make it of such poor quality in other respects that it will crack badly in working, as is the ease with or dinary steel. In endeayo•ing to obtain a cor rect idea of the value o• usefulness of alloys of nickel and iron or steel, we shall find it of use to consider their behavior under tensile and other mechanical tests, and if these'were sufficiently numerous, our task would not be a very difficult one. If it be remembered, how ever, that in the composition of nickel steel we have present nickel and manganese and iron, with carbon, silicon, sulphur, and phosphorus. and that even a very small difference in the contents of some of these has a considerable influence on the character of the alloy, it will be evident that several series of tests (involving a very large number of separate experiments) are necessary to a full investigation. For instance, we all know the effect of very small in crements of carbon in steel ; hence to estimate correctly, the influence of the addition of nickel, the carbon (as well as manganese and other contents) should remain constant ; then that contents of nickel should be constant and the carbon, etc., varied ; further, that the sub sequent treatment of all the products should be identical in every partic•ular." In the table given on page 27 there are several points of interest which it is desirable to notice.
1. In No. 6 test the carbon present is low enough to enable us to make comparison with ordinary mild steel, which would give (when annealed) results about as follows: E. L. 16 :3 tons, extension 23 per cent on S in., and contraction of area 48 per cent. There fore in this case the addition of 4.7 per cent of nickel has raised E. L. from 16 to 28 tons, and the B. S. from 30 up to 40•6 tons, without impairing the elongation or contraction of area to any noticeable extent. In No. 3 test somewhat similar results are found, with an addition of only 3 per cent of nickel, onnbined with an increase of the carbon to per cent.
2. In Nos. 2. and 5 tests there is extreme hardness, due in part to the large quantity of carbon present, but also to the presence of nickel in addition. In No. 11 test, with the carbon very much reduced, this characteristic of hardness is intensified by the increase of nickel to 10 per cent. This quality of hardness obtains as the nickel is increased, until about 20 per cent is reached, when a change takes place, and successive additions of nickel tend to make the steel softer and more ductile, and even to neutralize the influence of carbon, as is shown in No. 11 test. in which there is 25 per cent of nickel and per cent of carbon.
3. In the 25-per-cent nickel steel there are some peculiar and remarkable properties. In the unannealed specimen the B. S. is high and the E. L. moderately so; but in the annealed piece, in which the B. S. remains good. the E. L. is very greatly reduced. down to one third of the B. S. Again, in both cases, the ductility as shown by the extension before fracture is marvelous, reaching 40 per cent in S in.
There are a few other properties of these alloys which may be noticed. The specific gravity of nickel is given as to that, of ferro-nickel, if 25 per cent nickel, that of 10-per-cent nickel, 7•S00; that of 5-per-cent nickel, 7.846: while the mean of results of harmne•ed steel is The whole of the series of nickel steels up to 50 per cent nickel take a good polish and finish, with a good surface, the color being lighter with the increased additions of nickel. The steels rich in nickel are practically non-corrodible. and those poor in nickel are lunch better than other steels in this respect. Thus, experiments we have made show that, as compared with mild steel of carbon, 5-per-cent nickel steel corrodes in the ratio of 10 to 12, and, as compared with steel having carbon, with 1.6 chromium, in that of 10 to 15. In the case of 25-per-cent nickel steel, these ratios are as 10 is to 870, and 10 to 1,160, respectively. These results were obtained by immersion of samples of the differ ent steels in Abel's corrosive liquid, and the results confirmed by subsequent immersion in water acidified by hydrochloric acid. Sonic samples of the richer nickel steels which have been lying exposed to the atmosphere for several weeks still show an untarnished fracture. The alloys up to 5 per cent of nickel can be machined with moderate case; beyond that strength they are More difficult to machine. The poorer ones stand punching exceedingly well. both as rolled and after annealing. The punch-holes can be put as elose together as A in. without the metal showing any signs of cracking. The 1-per-cent nickel steel welds fairly well. Isit this quality deteriorates with each addition of nickel. The poorer alloys do not show any luster, but the richer ones have a lustrous appearance when the scale is removed. See ARMOR.