Abstract
IN the study of the constitution of alloys, as well as in the practical and commercial use of both pure metals and alloys, that form of heat treatment known as annealing plays an important part, and a complete knowledge of the effects of various temperatures and conditions of annealing is of vital importance. This statement is not invalidated by the fact that many of our large metal works conduct their annealing operations in the most crude and haphazard way, a state of affairs which is, happily, becoming a thing of the past. In this connection it is interesting to note that one-third of the papers read at the recent meeting of the Institute of Metals deal, to a greater or less extent, with this important subject. J. Phelps shows that the presence of hydrogen in the atmosphere surrounding silver which is being annealed, increases the temperature required to obtain complete softness in thirty minutes, from below 150° C. to about 300° C. F. Johnson emphasises the necessity of annealing Admiralty brass castings to a temperature of about 700° C. Bengough and Hanson show that copper tested to destruction in an oxidising atmosphere has an elongation four times as great, and a maximum stress one-third as great, as that obtained when the test is carried out in a neutral atmosphere such as carbon dioxide.
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H., J. The Institute of Metals . Nature 94, 153 (1914). https://doi.org/10.1038/094153a0
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DOI: https://doi.org/10.1038/094153a0