Part 11

This practical point should be heeded, viz., that pig phosphor bronze should be brought to the specifications that the metal should have shrunk in the ingot mold in cooling, as shown by the concave surface of the upper side, and that it should make a casting in a sand mold without rising in the gate after being poured.

In bearing metal, occluded gas is very objectionable, because the gas, in trying to free itself, shoves the very hard copper-tin compound (which has a low melting point and remains liquid after the copper has begun to set) into spots, and thus causes hard spots in the metal.

Phosphorus is very dangerous to handle, and there is great risk from fire with it, so that many would not care to handle the phosphorus itself. But phosphor copper containing 5 per cent of phosphorus, and phosphor tin containing 2 to 7 per cent of phosphorus, and several other such alloys can be obtained in the market. It may be suggested to those who wish to make phosphor bronze, but do not want to handle phosphorus itself, to make it by using the proper amounts of one of these high phosphorus alloys. In using phosphorus it is only necessary to use enough to thoroughly deoxidize the metal, say 0.3 per cent. More than this will make the metal harder, but not any sounder.

Phosphor bronze is not a special kind of alloy, but any bronze can be made into phosphor bronze; it is, in fact, simply a deoxidized bronze, produced under treatment with phosphorus compounds.

Although the effect of phosphorus in improving the quality of bronze has been known for more than fifty years, it is only of late that the mode for preparing phosphor bronze has been perfected. It is now manufactured in many localities. Besides its action in reducing the oxides dissolved in the alloy, the phosphorus exerts another very material influence upon the properties of the bronze. The ordinary bronzes consist of mixtures in which the copper is really the only crystallized constituent, since the tin crystallizes with great difficulty. As a consequence of this dissimilarity in the nature of the two metals, the alloy is not so solid as it would be if both were crystallized. The phosphorus causes the tin to crystallize, and the result is a more homogeneous mixture of the two metals.

If enough phosphorus is added, so that its presence can be detected in the finished bronze, the latter may be considered an alloy of crystallized phosphor tin with copper. If the content of phosphor is still more increased, a part of the copper combines with the phosphorus, and the bronze then contains, besides copper and tin, compounds of crystallized copper phosphide with phosphide of tin. The strength and tenacity of the bronze are not lessened by a larger amount of phosphorus, and its hardness is considerably increased. Most phosphor bronzes are equal in this respect to the best steel, and some even surpass it in general properties.

The phosphorus is added to the bronze in the form of copper phosphide or phosphide of tin, the two being sometimes used together. They must be specially prepared for this purpose, and the best methods will be here given. Copper phosphide is prepared by heating a mixture of 4 parts of superphosphate of lime, 2 parts of granulated copper, and 1 part of finely pulverized coal in a crucible at a temperature not too high. The melted copper phosphide, containing 14 per cent of phosphorus, separates on the bottom of the crucible.

Tin phosphide is prepared as follows: Place a bar of zinc in an aqueous solution of tin chloride. The tin will be separated in the form of a sponge-like mass. Collect it, and put it into a crucible, upon the bottom of which sticks of phosphorus have been placed. Press the tin tightly into the crucible, and expose to a gentle heat. Continue the heating until flames of burning phosphorus are no longer observed on the crucible. The pure tin phosphide, in the form of a coarsely crystalline mass, tin-white in color, will be found on the bottom of the crucible.

To prepare the phosphor bronze, the {61} alloy to be treated is melted in the usual way, and small pieces of the copper phosphide and tin phosphide are added.

Phosphor bronze, properly prepared, has nearly the same melting point as that of ordinary bronze. In cooling, however, it has the peculiarity of passing directly from the liquid to the solid state, without first becoming thickly fluid. In a melted state it retains a perfectly bright surface, while ordinary bronze in this condition is always covered with a thin film of oxide.

If phosphor bronze is kept for a long time at the melting point, there is not any loss of tin, but the amount of phosphorus is slightly diminished.

The most valuable properties of phosphor bronze are its extraordinary tenacity and strength. It can be rolled, hammered, and stretched cold, and its strength is nearly double that of the best ordinary bronze. It is principally used in cases where great strength and power of resistance to outward influences are required, as, for instance, in objects which are to be exposed to the action of sea water.

Phosphor bronze containing about 4 per cent of tin is excellently well adapted for sheet bronze. With not more than 5 per cent of tin, it can be used, forged, for firearms. Seven to 10 per cent of tin gives the greatest hardness, and such bronze is especially suited to the manufacture of axle bearings, cylinders for steam fire engines, cogwheels, and, in general, for parts of machines where great strength and hardness are required. Phosphor bronze, if exposed to the air, soon becomes covered with a beautiful, closely adhering patina, and is therefore well adapted to purposes of art. The amount of phosphorus added varies from 0.25 to 2.5 per cent, according to the purpose of the bronze. The composition of a number of kinds of phosphor bronze is given below:

─────+──────+─────+─────+─────+────+─────── │Copper│ Tin │ Zinc│ Lead│Iron│Phosp- │ │ │ │ │ │horus ─────+──────+─────+─────+─────+────+─────── I.│ 85.55│ 9.85│ 3.77│ 0.62│trs.│ 0.05 II.│ — │ 4–15│ — │ 4–15│ — │ 0.5–3 III.│ — │ 4–15│ 8–20│ 4–15│ — │ .25–2 IV.│ 77.85│11.00│ 7.65│ — │ — │ — V.│ 72.50│ 8.00│17.00│ — │ — │ — VI.│ 73.50│ 6.00│19.00│ — │ — │ — VII.│ 74.50│11.00│11.00│ — │ — │ — VIII.│ 83.50│ 8.00│ 3.00│ — │ — │ — IX.│ 90.34│ 8.90│ — │ — │ — │ 0.76 X.│ 90.86│ 8.56│ — │ — │ — │ 0.196 XI.│ 94.71│ 4.39│ — │ — │ — │ 0.053 ─────+──────+─────+─────+─────+────+───────

I for axle bearings, II and III for harder and softer axle bearings, IV to VIII for railroad purposes, IV especially for valves of locomotives, V and VI axle bearings for wagons, VII for connecting rods, VIII for piston rods in hydraulic presses.

«Steel Bronze».—Copper, 60; ferromanganese (containing 70 to 80 per cent manganese), 40; zinc, 15.

«Silicon Bronze.»—Silicon, similarly to phosphorus, acts as a deoxidizing agent, and the bronzes produced under its influence are very ductile and elastic, do not rust, and are very strong. On account of these qualities silicon bronze is much used for telegraph and telephone wires. The process of manufacture is similar to that of phosphor bronze; the silicon is used in the form of copper silicide. Some good silicon bronzes are as follows:

I II Copper 97.12 97.37 Tin 1.14 1.32 Zinc 1.10 1.27 Silicon 0.05 0.07

«Sun Bronze.»—The alloy called sun bronze contains 10 parts of aluminum, 30 to 50 parts of copper, and 40 to 60 parts of cobalt. The mixture known by the name of metalline has 25 per cent of aluminum, 30 of copper, 10 of iron, and 35 of cobalt. These alloys melt at a point approaching the melting point of copper, are tenacious, ductile, and very hard.

«Tobin Bronze.»—This alloy is nearly similar in composition and properties to Delta metal.

I II III IV Copper 61.203 59.00 61.20 82.67 Zinc 27.440 38.40 37.14 3.23 Tin 0.906 2.16 0.90 12.40 Iron 0.180 0.11 0.18 0.10 Lead 0.359 0.31 0.35 2.14 Silver — — — 0.07 Phosphorus — — — 0.005

The alloy marked IV is sometimes called deoxidized bronze.

Violet-colored bronze is 50 parts copper and 50 parts antimony.

«CADMIUM ALLOYS:»

See also Fusible Alloys.

«Lipowitz’s Alloy.»—I.—This alloy is composed of cadmium, 3 parts; tin, 4; bismuth, 15; and lead, 8. The simplest method of preparation is to heat the metals, in small pieces, in a crucible, stirring constantly, as soon as fusion {62} begins, with a stick of hard wood. The stirring is important, in order to prevent the metals, whose specific gravity varies considerably, from being deposited in layers. The alloy softens at 140° F. and melts completely at 158° F. The color is silvery white, with a luster like polished silver, and the metal can be bent, hammered, and turned. These properties would make it valuable for many purposes where a beautiful appearance is of special importance, but on account of the considerable amount of cadmium and bismuth which it contains, it is rather expensive, and therefore limited in use. Casts of small animals, insects, lizards, etc., have been prepared from it, which were equal in sharpness to the best galvanoplastic work. Plaster of Paris is poured over the animal to be cast, and after sharp drying, the animal is removed and the mold filled up with Lipowitz’s metal. The mold is placed in a vessel of water, and by heating to the boiling point the metal is melted and deposited in the finest impressions of the mold.

This alloy is most excellent for soldering tin, lead, Britannia metal, and nickel, being especially adapted to the last two metals on account of its silver-white color. But here again its costliness prevents its general use, and cheaper alloys possessing the same properties have been sought. In cases where the silver-white color and the low melting point are not of the first importance, the alloys given below may very well be used in the place of it.

II.—Cadmium alloy (melting point, 170° F.): Cadmium, 2 parts; tin, 3; lead, 11; bismuth, 16.

III.—Cadmium alloy (melting point, 167° F.): Cadmium, 10 parts; tin, 3; lead, 8; bismuth, 8.

Cadmium alloys (melting point, 203° F.):

IV V VI Cadmium 1 1 1 parts Tin 2 3 1 parts Bismuth 3 5 2 parts

VII.—A very fusible alloy, melting at 150° F., is composed of tin, 1 or 2 parts; lead, 2 or 3; bismuth, 4 or 15; cadmium, 1 or 2.

VIII.—Wood’s alloy melts between 140° and 161.5° F. It is composed of lead, 4 parts; tin, 2; bismuth, 5 to 8; cadmium, 1 to 2. In color it resembles platinum, and is malleable to a certain extent.

IX.—Cadmium alloy (melting point, 179.5° F.): Cadmium, 1 part; lead, 6 parts; bismuth, 7. This, like the preceding, can be used for soldering in hot water.

X.—Cadmium alloy (melting point, 300° F.): Cadmium, 2 parts; tin, 4; lead, 2. This is an excellent soft solder, with a melting point about 86 degrees below that of lead and tin alone.

«Cadmium Alloys with Gold, Silver, and Copper.»—I.—Gold, 750 parts; silver, 166 parts; cadmium, 84 parts. A malleable and ductile alloy of green color.

II.—Gold, 750 parts; silver, 125 parts; and cadmium, 125 parts. Malleable and ductile alloy of yellowish-green hue.

III.—Gold, 746 parts; silver, 114 parts; copper, 97 parts; and cadmium, 43 parts. Likewise a malleable and ductile alloy of a peculiar green shade. All these alloys are suitable for plating. As regards their production, each must be carefully melted together from its ingredients in a covered crucible lined with coal dust, or in a graphite crucible. Next, the alloy has to be remelted in a graphite crucible with charcoal (or rosin powder) and borax. If, in spite thereof, a considerable portion of the cadmium should have evaporated, the alloy must be re-fused once more with an addition of cadmium.

«ALLOYS FOR CASTING COINS, MEDALLIONS, ETC.»

Alloys which fulfill the requirements of the medalist, and capable, therefore, of reproducing all details, are the following:

I II Tin 3 6 parts Lead 13 8 parts Bismuth 6 14 parts

III.—A soft alloy suitable to take impressions of woodcuts, coins, metals, engravings, etc., and which must melt at a low degree of heat, is made out of bismuth, 3 parts; tin, 1 1⁠/⁠2 parts; lead, 2 1⁠/⁠2 parts; and worn-out type, 1 part.

«Acid-proof Alloy.»—This alloy is characterized by its power of resisting the action of acids, and is therefore especially adapted to making cocks, pipes, etc., which are to come in contact with acid fluids. It is composed of copper, zinc, lead, tin, iron, nickel, cobalt, and antimony, in the following proportions:

Copper 74.75 parts Zinc 0.61 parts Lead 16.35 parts Tin 0.91 parts Iron 0.43 parts Nickel or Cobalt 0.24 parts Antimony 6.78 parts

{63}

«Albata Metal.»—Copper, 40 parts; zinc, 32 parts; and nickel, 8 parts.

«Alfenide Metal.»—Copper, 60 parts; zinc, 30; nickel, 10; traces of iron.

«Bath Metal.»—This alloy is used especially in England for the manufacture of teapots, and is very popular owing to the fine white color it possesses. It takes a high polish, and articles made from this alloy acquire in the course of time, upon only being rubbed with a white cloth, a permanent silver luster. The composition of Bath metal is copper, 55 parts; zinc, 45 parts.

«Baudoin Metal.»—This is composed of 72 parts of copper, 16.6 of nickel, 1.8 of cobalt, 1 of zinc; 1⁠/⁠2 per cent of aluminum may be added.

«CASTING COPPER:»

«Macht’s Yellow Metal.»—I.—This alloy consists of 33 parts of copper and 25 of zinc. It has a dark golden-yellow color, great tenacity, and can be forged at a red heat, properties which make it especially suitable for fine castings.

II.—Yellow.—Copper, 67 to 70 parts; zinc, 33 to 30 parts.

III.—Red.—Copper, 82 parts; zinc, 18 parts.

«Copper Arsenic.»—Arsenic imparts to copper a very fine white color, and makes it very hard and brittle. Before German silver was known, these alloys were sometimes used for the manufacture of such cast articles as were not to come in contact with iron. When exposed to the air, they soon lose their whiteness and take on a brownish shade. On account of this, as well as the poisonous character of the arsenic, they are very little used at the present time. Alloys of copper and arsenic are best prepared by pressing firmly into a crucible a mixture of 70 parts of copper and 30 of arsenic (the copper to be used in the form of fine shavings) and fusing this mixture in a furnace with a good draught, under a cover of glass.

«Copper Iron.»—The alloys of copper and iron are little used in the industries of the present day, but it would seem that in earlier times they were frequently prepared for the purpose of giving a considerable degree of hardness to copper; for in antique casts, consisting principally of copper, we regularly find large quantities of iron, which leads to the supposition that they were added intentionally.

These alloys, when of a certain composition, have considerable strength and hardness. With an increase in the quantity of the iron the hardness increases, but the solidity is lessened. A copper and iron alloy of considerable strength, and at the same time very hard, is made of copper, 66 parts; iron, 34. These alloys acquire, on exposure to air, an ugly color inclining toward black, and are therefore not adapted for articles of art.

«Copper Nickel.»—A. Morrell, of New York, has obtained a patent on a nickel-copper alloy which he claims is valuable on account of its noncorrosive qualities, therefore making it desirable for ships, boiler tubes, and other uses where the metal comes much in contact with water. The process of making the metal is by smelting ore containing sulphide of nickel and copper, and besemerizing the resultant matter. This is calcined in order to obtain the nickel and copper in the form of oxides. The latter are reduced in reverberating furnace with carbon, or the like, so as to produce an alloy which preferably contains 2 parts of nickel and 1 part of copper.

«Delta Metal.»—An alloy widely used for making parts of machinery, and also for artistic purposes, is the so-called Delta metal. This is a variety of brass hardened with iron; some manufacturers add small quantities of tin and lead; also, in some cases, nickel. The following analysis of Delta metal (from the factory at Düsseldorf) will show its usual composition:

──────────+───────+───────+───────+─────+───── │ I │ II │ III │ IV │ V ──────────+───────+───────+───────+─────+───── Copper │ 55.94 │ 55.80│ 55.82│54.22│58.65 Zinc │ 41.61 │ 40.07│ 41.41│42.25│38.95 Lead │ 0.72 │ 1.82│ 0.76│ 1.10│ 0.67 Iron │ 0.87 │ 1.28│ 0.86│ 0.99│ 1.62 Manganese │ 0.81 │ 0.96│ 1.38│ 1.09│ — Nickel │traces.│traces.│ 0.06│ 0.16│ 0.11 Phosphorus│ 0.013│ 0.011│traces.│ 0.02│ — ──────────+───────+───────+───────+─────+─────

I is cast, II hammered, III rolled, and IV hot-stamped metal. Delta metal is produced by heating zinc very strongly in crucibles (to about 1600° F.), and adding ferromanganese or “spiegeleisen,” producing an alloy of 95 per cent zinc and 5 per cent of iron. Copper and brass and a very small amount of copper phosphate are also added. {64}

«Gong Metal.»—A sonorous metal for cymbals, gongs, and tam-tams consists of 100 parts of copper with 25 parts tin. Ignite the piece after it is cast and plunge it into cold water immediately.

«Production of Minargent.»—This alloy consists of copper, 500 parts; nickel, 350; tungsten, 25, and aluminum, 5. The metal obtained possesses a handsome white color and greatly resembles silver.

«Minofor.»—The so-called Minofor metal is composed of copper, tin, antimony, zinc, and iron in the following proportions:

I II Copper 3.26 4 Tin 67.53 66 Antimony 17.00 20 Zinc 8.94 9 Iron — 1

Minargent and Minofor are sometimes used in England for purposes in which the ordinary Britannia metal, 2 parts tin and 1 part antimony, might equally well be employed; the latter surpasses both of them in beauty of color, but they are, on the other hand, harder.

«Retz Alloy.»—This alloy, which resists the corrosive action of alkalies and acids, is composed of 15 parts of copper, 2.34 of tin, 1.82 of lead, and 1 of antimony. It can be utilized in the manufacture of receivers, for which porcelain and ebonite are usually employed.

«Ruoltz Metal.»—This comprises 20 parts of silver, 50 of copper, 30 of nickel. These proportions may, however, vary.

«Tissier’s Metal.»—This alloy contains arsenic, is of a beautiful tombac red color, and very hard. Its composition varies a great deal, but the peculiar alloy which gives the name is composed of copper, 97 parts; zinc, 2 parts; arsenic, 1 or 2. It may be considered a brass with a very high percentage of copper, and hardened by the addition of arsenic. It is sometimes used for axle bearings, but other alloys are equally suitable for this purpose, and are to be preferred on account of the absence of arsenic, which is always dangerous.

«FILE ALLOYS.»—Many copper-tin alloys are employed for the making of files which, in distinction from the steel files, are designated composition files. Such alloys have the following compositions:

«Geneva Composition Files.»—

I II Copper 64.4 62 Tin 18.0 20 Zinc 10.0 10 Lead 7.6 8

«Vogel’s Composition Files.»—

III IV V Copper 57.0 61.5 73.0 Tin 28.5 31.0 19.0 Zinc 78.0 — 8.0 Lead 7.0 8.5 8.0

VI.—Another alloy for composition files is copper, 8 parts; tin, 2; zinc, 1, and lead, 1—fused under a cover of borax.

«EASILY FUSIBLE OR PLASTIC ALLOYS.»

(These have a fusing point usually below 300° F.)

(See also Solders.)

I. Rose’s Alloy.—Bismuth, 2 parts; lead, 1 part; tin, 1 part. Melting point, 200° F.

II. Darcet Alloy.—This is composed of 8 parts of bismuth, 5 of lead, and 3 of tin. It melts at 176° F. To impart greater fusibility, 1⁠/⁠16 part of mercury is added; the fusing is then lowered to 149° F.

III.—Newton alloy melts at 212° F., and is composed of 5 parts of bismuth, 2 of lead, and 3 of tin.

IV.—Wood’s Metal.—

Tin 2 parts Lead 4 parts Bismuth 5 to 8 parts

This silvery, fine-grained alloy fuses between 151° and 162° F., and is excellently adapted to soldering.

V.—Bismuth, 7 parts; lead, 6 parts; cadmium, 1 part. Melting point, 180° F.

VI.—Bismuth, 7 to 8 parts; lead, 4; tin, 2; cadmium, 1 to 2. Melting point, 149° to 160° F.

«Other easily fusible alloys:»

VII VIII IX Lead 1 2 3 Tin 1 2 3 Bismuth 1 1 1 Melting Point 258° F. 283° 311°

«Fusible Alloys for Electric Installations.»—These alloys are employed in electric installations as current interrupters. Serving as conductors on a short length of circuit, they melt as soon as the current becomes too strong. Following is the composition of some of these alloys.

────+───────────+──────+─────+─────────+──────── │ Fusing │ │ │ │ │temperature│ Lead │ Tin │ Bismuth │Cadmium ────+───────────+──────+─────+─────────+──────── I │ 203° F. │ 250 │ 500 │ 500 │ — II │ 193° F. │ 397 │ — │ 532 │ 71 III │ 168° F. │ 344 │ 94 │ 500 │ 62 IV │ 153° F. │ 260 │ 148 │ 522 │ 70 V │ 150° F. │ 249 │ 142 │ 501 │ 108 VI │ 145° F. │ 267 │ 136 │ 500 │ 100 ────+───────────+──────+─────+─────────+────────

{65}

These alloys are prepared by melting the lead in a stearine bath and adding successively, and during the cooling, first, the cadmium; second, the bismuth; third, the tin. It is absolutely necessary to proceed in this manner, since these metals fuse at temperatures ranging from 850° F. (for lead), to 551° F. (for tin).

«Fusible Safety Alloys for Steam Boilers.»—

───────+───────+────+────+────────+──────── │ │ │ │ Melting│ Atmos. │Bismuth│Lead│Zinc│ point │pressure ───────+───────+────+────+────────+──────── I. │ 8 │ 5 │ 3 │ 212° F.│ 1 II. │ 8 │ 8 │ 4 │ 235° F.│ 1.5 III. │ 8 │ 8 │ 3 │ 253° F.│ 2 IV. │ 8 │ 10 │ 8 │ 266° F.│ 2.5 V. │ 8 │ 12 │ 8 │ 270° F.│ 3 VI. │ 8 │ 16 │ 14 │ 280° F.│ 3.5 VII. │ 8 │ 16 │ 12 │ 285° F.│ 4 VIII. │ 8 │ 22 │ 24 │ 309° F.│ 5 IX. │ 8 │ 32 │ 36 │ 320° F.│ 6 X. │ 8 │ 32 │ 28 │ 330° F.│ 7 XI. │ 8 │ 30 │ 24 │ 340° F.│ 8 ───────+───────+────+────+────────+────────

«Lipowitz Metal.»—This amalgam is prepared as follows: Melt in a dish, cadmium, 3 parts, by weight; tin, 4 parts; bismuth, 15 parts; and lead, 8 parts, adding to the alloy, while still in fusion, 2 parts of quicksilver previously heated to about 212° F. The amalgamation proceeds easily and smoothly. The liquid mass in the dish, which should be taken from the fire immediately upon the introduction of the mercury, is stirred until the contents solidify. While Lipowitz alloy softens already at 140° F. and fuses perfectly at 158°, the amalgam has a still lower fusing point, which lies around 143 3⁠/⁠5° F.