Analytical Test.—To be made at contractor’s expense.
The copper upon analysis to give the following results:—Arsenic, not less than 0·35 per cent. nor more than 0·55 per cent.; other foreign elements, exclusive of combined oxygen, not to exceed 0·25 per cent.
Clauses are also inserted as to stamping, inspection, and the giving of testing facilities.
Typical analysis of such plates show—
- Copper,99·30 per cent.
- Arsenic, 0·43 to 0·51 per cent.
- Oxygen, 0·1 per cent.
Impurities, chiefly antimony, lead, iron, nickel, tin, and sulphur, not exceeding 0·25 per cent.
The average test on a number of plates gave—
- Tensile strength,14·66 tons per square inch.
- Elongation on 8 inches,43·36 per cent. of original length.
- Contraction of area, 45·9 per cent.
- Close bend test, Double.
The effect of temperature and the influence of impurities on the mechanical properties of the metal intended for engineering purposes are of very great importance, and much attention has been devoted to researches in this subject, particularly by Milton and Le Chatelier, whose published experience gives important information of much practical value. The main conclusions arrived at from practice have had reference to the general effects of impurities in hardening the metal, and the general tendency of heat to soften it and to increase the ductility. The diverse effects of different impurities on strength and ductility will be reviewed in detail at a later stage.
(c) General Industrial Uses.—Copper as metal is also employed to a considerable extent in certain important industries, as in textile manufacture, where it is used for the rollers in calico-printing; and it is in general industrial use in the form of copper heaters, vats, coils, pans, and the like, and occasionally also for roofing and sheathing.