Henley's Twentieth Century Formulas, Recipes and Processes. Various

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СКАЧАТЬ Metal.—Tin, 90 parts; antimony, 10 parts. This alloy is suitable as a protector.

      II. Argentine Metal.—Tin, 85.5 per cent; antimony, 14.5 per cent.

      III.—Ashberry metal is composed of 78 to 82 parts of tin, 16 to 20 of antimony, 2 to 3 of copper.

      IV. Quen’s Metal.—Tin, 9 parts; lead, 1 part; antimony, 1 part; bismuth, 1 part.

      Type Metal.

      —An alloy which is to serve for type metal must be readily cast, fill out the molds sharply, and be as hard as possible. It is difficult to satisfy all these requirements, but an alloy of antimony and lead answers the purpose best. At the present day there are a great many formulas for type metal in which other metals besides lead and antimony are used, either to make the alloy more readily fusible, as in the case of additions of bismuth, or to give it greater power of resistance, the latter being of especial importance for types that are subjected to constant use. Copper and iron have been recommended for this purpose, but the fusibility of the alloys is greatly impaired by these, and the manufacture of the types is consequently more difficult than with an alloy of lead and antimony alone. In the following table some alloys suitable for casting type are given:

	Lead	Antimony	Copper	Bismuth	Zinc	Tin	Nickel
I	3	1	—	—	—	—	—
II	5	1	—	—	—	—	—
III	10	1	—	—	—	—	—
IV	10	2	—	1	—	—	—
V	70	18	2	—	—	10	—
VI	60	20	—	—	—	20	—
VII	55	25	—	—	—	20	—
VIII	55	30	—	—	—	15	—
IX	100	30	8	2	—	20	8
X	6	—	4	—	90	—	—

      The French and English types contain a certain amount of tin, as shown by the following analyses:

	English Types	French Types
I	II	III
Lead	69.2	61.3	55.0	55
Antimony	19.5	18.8	22.7	30
Tin	9.1	20.2	22.1	15
Copper	1.7	—	—	—

      Ledebur gives the composition of type metal as follows:

	I	II	III	IV
Lead	75	60	80	82
Antimony	23	25	20	14.8
Tin	22	15	—	3.2

      WATCHMAKERS’ ALLOYS: See Watchmakers’ Formulas.

      White Metals.

      The so-called white metals are employed almost exclusively for bearings. (See Anti-friction Metals under Alloys.) In the technology of mechanics an accurate distinction is made between the different kinds of metals for bearings; and they may be classed in two groups, red brass and white metal. The {79} red-brass bearings are characterized by great hardness and power of resistance, and are principally used for bearings of heavily loaded and rapidly revolving axles. For the axles of large and heavy flywheels, revolving at great speed, bearings of red brass are preferable to white metal, though more expensive.

      In СКАЧАТЬ