January, 1923
INDUSTRIAL A N D ENGINEERING CHEMISTRY
various kinds of type-setting machines alloys are required having in general the following properties: low melting point, with solidification taking place in cooling either at one sharp point or else within a very narrow range of temperature; perfect fluidity above this point; slight amount of shrinkage; and property of taking sharp impressions when cast. Some differences in characteristics are required, however, in the particular alloys most suitable for stereotype and for the separate kinds of type-setting machines. according to whether the latter cast single letters, or a whole line. It has been possible to adapt the alloys to these different requirements from a thorough knowledge of the metallography of the ternary series, lead, tin, and antimony. This has been gained from the complete investigations of the thermal equilibrium of the series by Campbel1,z Loebe,3 and from the work of Heyn and Bauer.4 I n the use of stereotype many separate plates cast in the same matrix may be needed to complete an edition, and for the very large issues of weekly magazines, etc., improvement has been made in the number of impressions possible to be taken from each plate by nickel plating the type face. 2 “Le ad-Tin- Antimony and Tin-Antimony-Copper Alloys,” Proc. A m SOC.Testing Materials, 13 (1915),630. 3 “The Constitution of the Ternary Alloy of Lead, Tin, and Antimony,” Metallurgic. 8, 7, 35. 4 Investigation of Bearing Metals, Antimony-Lead-Tin Alloys, conducted by K Materialprufung Berlin-Lichterfelde.
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OTHERRESEARCH ON ALLOYS Valuable articles have lately appeared on the general subject of alloys by W. Guertler; on white metals by Mundy, Bissett, and Cartland, published as a preprint for the September 1922 meeting of the British Institute of Metals; and on bearing metals by J. Ceochralski and others.6 Interest in the study of white metals has greatly increased through the work which is being done in connection with nonferrous metals by the U. s. Bureau of Standards and Bureau of Mines, committees of the American Society for Testing Materials, the Institute of Metals Division of the American Institute of Mining and Metallurgical Engineers, and other organizations. General problems that are being investigated relate to the subject of corrosion, the effect of impurities on physical properties, standardization of methods of physical testing, and effect of shrinkage on the density and form of solid castingsthis having to do both with the contraction taking place from the instant of complete solidification down to room temperature, and also with the change in volume accompanying the difference in density between the liquid and solid phases of the metal. 6 Czochralski, 2. Metallkunde, 12 (1920),371; Guertler, I b i d . , 13 (1921), 257; Czochralski-Welter, “Bearing Metals and Their Technical Value,” Springer, Berlin, 1920.
T h e Wrought Nonferrous Alloys in 1922 By W.H. Bassett THE AMERICAN BRASSCO., WATERBURY, CONN.
T
HE PAST YEAR has brought to attention nothing novel in the way of alloys or the treatment of alloys in the wrought nonferrous industry. COPPERALLOYS The outstanding feature has been a wider use of copper and copper alloys following the post-war depression. This has been brought about through a better understanding of the properties of the materials and their adaptation to industrial requirements. Much more attention is being given to the study of the properties of the metals and alloys and to methods of treatment than ever before. The advent of the chemist and metallurgist in the industry dates back hardly more than twenty years, and up to the beginning of the World War only the larger and more progressive manufacturers maintained laboratories or attempted metallurgical control. The engineering specifications from the military establishments forced manufacturers who had been delinquent to establish testing laboratories a t least. Within the industry itself notable improvements of the present time are laboratory control of the quality of the raw materials used, of the composition of the alloys, and of the physical and electrical properties of the products, metallographic control of heat treatment and hardness, electric melting, and the better understanding of the properties of metals and alloys. The statement is frequently made that the quality of copper is not as good as it was twenty or thirty years ago. Such statements are indicative of ignorance of the real facts, for a t no time in the history of the industry has the quality of copper in the form of wire bars, cakes, and ingots been equal to that of the present delivery. The purity minimum of 99.900 per cent is now maintained by the important American pro-
ducers. I n wire bars and cakes the conductivity is regularly held a t 100 per cent of the “Annealed Copper Standard.” All this has been gained through systematic control testing on the part of both producers and consumers. IMPROVEMENTS I N QUALITY Standard specifications for copper, zinc, and nickel have been prepared by the American Society for Testing Materials. Considerable progress has been made by the same society on similar standards for lead and aluminium. Such specifications have marked the progress made in improving the quality of raw materials and rendered the production of alloys of the highest grade a much more exact and simple matter. The analytical laboratory is as essential a part in the production of nonferrous alloys as it has become in the steel works. In every modern metal works the composition and quality of the alloys is strictly a matter of laboratory control. While this condition is not a sudden development, it cannot be said to have become general until within the last few years. It certainly marks a notable feature in the progress of the industry. The metallographic study of nonferrous metals and alloys has gradually grown in importance as a means of control and investigation, and 1922 has seen the publication by a national society’ of the first specification in which grain size has been used as a definite measure of the physical properties of the material. The study of the structure of the nonferrous metals at magnifications of 500 and 1000 diameters in the works laboratories, where nothing much beyond 75 to 100 diameters has heretofore been attempted, is another feature marking progress in applied metallography. * American Society for Testing Materials.
