ALLOYS. Prof. Thurston's researches on copper-tin and copper-zinc alloys are referred to in Vol. 1 of this work. llis later researches, on the triple alloys of copper, tin. and zinc, have since been published (see Report of the U. S. Board appointed to test Iron, Steel. and other Metals, and Tr«ns. Am. Sur. Cir. Bayrs., 1881). The following table is an abstract of the tests in tension made by Prof. Thurston : The values of the elastic limit in the lower part of the table were not well defined.
Bronzes with high Tensile following table gives the analysis of a number of alloys which have recently come into extensive use. They are described at length by F. Lyn wood Garrison in Journal of the Franklin Institute, June and July, 1801: Nos. 1 and 2. Tobin bronze, claimed to have a tensile strength of 79,600 lbs. per sq. in., elastic limit 54.250 lbs., and elongation 19 to 17 per cent with best rolled bars. 3. Da mascus bronze, said to wear slower as a bearing metal, than the phosphor bronze. No. 4. No. 4. Phosphor bronze, bearing metal used by the Pa. E. R. Co. No . 5. Deoxidized bronze. Is largely used for wood-pulp digesters, as it is found to resist the action of sodium hyposnlphite and sulphurous acid. No. 6. Aluminum bronze, used for firing pins, by the Colts Fire-Arms Co. No. 7. Manganese bronze, used for propellers, east metal, averages 35, 000 to 43,000 lbs. elastic limit. 63.000 to 75.000 lbs. per sq. in., 13 to 22 per cent elongation in 5 in. When rolled the elastic limit is about 80,000 lbs. per sq. in.. tensile strength 05,000 to 100.000 lbs., and elongation 12 to 15 per cent. These rPsults have been obtained from manganese bronze made by B. E. Cramp & Co., of Philadelphia. No manganese is present in the alloy, but it may have been used as a flux in casting it. No. 8, Delta metal, formerly known as Sterro metal, and practically the same as Aich's metal. When cast in sand it has a tensile strength of about 45,000 lbs. per sq. in. and about 10 per cent elongation. When rolled a tensile strength of 60.000 to 75.000 lbs., and 9 to 17 per cent elongation. Prof. Thurston's strongest bronze was found to have the composition : copper 55. tin 0.5, zinc 44-5. Tobin's alloy, one of the strongest of the triple alloys contained: copper 58.2, tin 2.3, zinc 39-5. This alloy, like the strongest bronze, is capable of being forged or rolled at a low red heat or worked cold. Rolled hot, its tenacity rose to 79,000 lbs., and when moderately and carefully rolled, to 104,000 lbs.
alloy appears to have been invented about the year 1881, by N. Weiner, of Angon16'ine. In experimenting with phosphor-bronze wire for telegraphic and telephonic use he found its conductivity was insufficient for telegraphic purposes, so he de vised the alloy now fettled silicon bronze. The silicon copper compound, from which the silicon bronze is produced, is made by melting, in a graphite crucible. a certain amount of cop per with a mixture of fluor-silicate of potassium, produced glass, chloride of soda, carbonate of soda, and chloride of calcium. It is claimed that the silicon and sodium in this mixture absorb all the oxides present in the mass. The action of the silicon on the copper is similar to that of phosphorus. It acts as deoxidizer, and the silica formed being an acid, is a valuable flux for any metallic oxides rem:titling unreduced. Wire made Erten this alloy is said to have the same resistance to rapture as phosphor-bronze wire, but with a much higher degree of electric conductivity. According to Preece, phosphorus has a most injurious influence on the electric conductivity of bronze, and silicon bronze is far superior. It also seems that, although wires made from this alloy are very much lighter than onlinary wires, they are of equal strength. According to E. Van der Ven, phosphor-bronze has about 30 per cent, silicon bronze 70 per cent, and steel 10d per cent of tile electrical conductivity of copper.
Remarkable Aluminum Alloys.—Some recent experiments at Chalais, in France, were made on alloys of the composition given in the following table. The alloys Were rolled into sheets 1 mut, thick, and strips 5 min. in width were cut and tested: An interesting peculiarity of these alloys is the large divergence between the specific gravities calculated from those of their constituents and the spe cific gravities directly determined. Each 2 per cent of copper might be ex pected to raise the specific gravity by 0.12, whereas the actual observed in crease is only abort 0-05. It will also be observed that the addition of only 2 per cent of copper increases the tensile strength from 26.535 to 43,563 lbs. per sq. in., while 6 per cent more than doubles it. Thus it appears that an alloy of aluminum having double the tensile strength of aluminum itself can he made which is less than one twentieth heavier. The tensile strength and other properties of the Cowles aluminum bronze and brass are shown in the following table, taken from the official report of tests made under the direction of the Engineer-in-Chief of the Navy at the Watertown Arsenal : Manganese Garrison, in the paper above mentioned. says : " For several years past, manganese bronze appears to have /teen IlladC in large quantities by Mr. P. M. Parsons, of the Manganese Bronze Company, Deptford, England. Dr. Percy was probably the first to observe the action of the manganese in combining, with the traces of enimeats oxide of cropper present in the copper, deoxidizing the same, and thns making the metal denser and stronger. Mr. Parsons, I believe, adds the manganese in the form of ferro-manganese. A portion of the manganese in the alloy thus added is utilized in the deoxidation above mentioned, while the remainder, together with the iron, becomes permanently combined with the copper. The manganese onee alloyed with the copper isnot driven off by remelting, but. usually the quality of the bronze is improved by a snbsequent remelting. The Manganese Bronze mil :not forge the alloy lint. ..1eeerding to Mr. Parsons, its mean tensile strength as delivered
from the rolls is about 137,200 lbs. per sq, in.. with an elastic limit of -19,000 to 51.01)0 lbs, per sq. in., and an elongation of from 23 to 25 per cent. In cold rolling its ultimme tensile strength rises to about 90,000 lbs. per sq. in., with an elastic Ihnit of 07,200 to 70,000 lbs, per sq. in..:uul nn elongation of 10 per cent. If annealed, the ultimate tensile strength is very little altered. lint the elastic limit is reduced about Intl, and the elougat ion increased to 30 or 35 per eent." Clipper Schneider S.; Co., of Crensot, Prance. have patented a process which consists in making in a blast-fin-mice, it cupola or at reverlwratory furnace, castings eontaining a varinble amount of copper with a less variable proportion of the ordinary elements. These castings are used for the manufacture of copper steel for armor-plate, ordnance, projectiles, steam cylinders, etc., these articles being hardened or tempered in oil. The copper ore is mixed with the charge in the cupola, or else copper filings can be mixed with the coal to form a copper coke, which is then used in melting the iron in a blast-furnace or cupola. Copper compounds may also be incited in a reverberatory furnace, with a mixture of iron or steel under a layer of anthracite to prevent oxidation. In a paper published in the Journal of the Iron and Steel Institute, in 1889, Messrs. E. J. Ball and Arthur Wingham describe some experiments on copper steel made by adding, to a very pure basic Bessemer steel varying percentages of an alloy of iron and copper. This alloy was produced by melting pig-iron, and then adding to the molten metal oxide of copper. The carbon and silicon acted as the reduc ing agents for the cupric oxide, and the copper was thus introduced into the iron by a "reaction," and not by simple solution. A part of the other impurities in the pig-iron was also burned out in this manner, and a metal was obtained which had the following composition: This metal was bright, white in color, crystalline, and very hard, but it did not offer any great resistance to impact. Varying quantities of it were then incited down with the basic Bessemer steel previously mentioned. The products of these fusions were allowed to cool very slowly, the crucibles in which the fusions had taken place being permitted to remain in the furnace until quite cold. Test-pieces, 1 X + Xve in., were then cut, and submitted to tensile tests in a multiple lever testing machine. the test-pieces being first carefully annealed. In the alloys produced in this manner, the percentages of carbon and of copper necessarily increased simultaneously. The following table shows the percentages of copper and of carbon in the metals tested, and the results of the tensile tests of the various specimens : The total elongation of the test-pieces was also noted. but owing to their small size the results are not trustworthy. The elongations observed, however, were as follows: 'rest-piece, (1) 10 per cent ; (2) 5 per cent : (3) 5 per cent ; (4) no visible extension, or the extension was but very slight. The tensile strength of the copper steel is greater than that of steels of like percentage of carbon which contain no copper. Copper also increases the strength of iron and of low carbon steel, as appears from the following results: Mr. F. Lynwood Garrison, in his paper read before the Franklin Institute in 1891, says : " Copper-steel alloys are almost. too new to determine for what particular purposes they would 1)e most useful. It is stated in the Schneider patents that they are useful for making ord nance, armor-plate. title-barrels. and projectiles, and also for girders for building purposes. and ship-plates. In view of the remarkable elastic limit of copper steel, while maintaining at the same time a very considerable elongation, it would not be surprising if its use became very extensive in the arts. It has the advantage of aluminum, nickel, and tungsten steels, in being cheaper to manufacture. In many of the steel alloys, the alloying metals have to be added to the steel when they are combined with iron, which iron must necessarily contain some carbon—such an increase of carbon in the alloy is nearly always undesirable. Thus, for instance, if the manganese in manganese steel could be added as metallic manganese and not as ferro-manganese (which must contain carbon), we would probably obtain better results with manganese steel. The undesirable increase of carbon in this way is avoided in making copper steel, for as we have seen, the copper can be added in the metallic state, or as an ore." Alloys for Electrical Conductors.—Mr. Edward Weston has made the remarkable dis covery that the metal manganese, besides imparting a very high electrical resistance to alloys into which it enters. as a constituent, has the property of rendering the electrical resist ance of such alloys nearly or quite constant under varying; conditions of temperature, lie therefore uses such alloys for the coils or conductors of electrical measuring instruments. lie prefers to use ferro-inanganese in the proportion of copper 70 parts and ferromanganese 30 parts or thereabouts. This, however, is capable of being rolled and drawn, and is made up into wire in the usual way. Ile has also dis covered another alloy, of which is lowered by an increase of tetnixzmture. and he utilizes the seine in making coils, etc., for such electrical instruments as should have a constant resistance under variable temperature, by making one part of the coil of said alloy and the other portion of German silver, or some other of the ordinary metals. In such ease, the resultant resistance is constant, provided the change in the two parts of I he coil be equal as well as opposite. This alloy preferably consists of 03 to 70 parts of copper, 21 to :Jo parts of ferromanganese, and 2 to 10 parts of nickel.