Part 34

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: