Abstracts of Technical Articles From Bell System Sources 



Relation of Nitrogen to Blue Heat Phenomena in Iron and Dispersion- 

 Hardening in the System Iron-Nitrogen} R. S. Deax, R. O. Day and 

 J. L. Gregg. It has been generally observed that iron, as an out- 

 standing exception among metals, increases its hardness and strength 

 by low-temperature annealing after cold work, and also by increase of 

 testing temperature to the range of 150° C. to 300° C. This investi- 

 gation was made with the object of ascertaining if similar phenomena 

 were observed in high purity iron and, if not, to the presence of which 

 impurities these phenomena could be traced. After describing the 

 tests made and giving the results, the authors come to the conclusion 

 that commercial irons owe their property of hardening by reheating 

 after cold work, as well as their increase in tensile strength in the range 

 100° C. to 300° C, to the solution of small amounts of iron-nitride 

 present. 



Heat Treatment and Mechanical Properties of Some Copper-Zinc and 

 Copper-Tin Alloys Containing Nickel and Silicon? W. C. Ellis and 

 Earle E. Schumacher. The addition of nickel and silicon to the 

 copper-zinc and copper-tin systems results in alloys which can be 

 hardened by heat treatment. The heat treatment, in general, consists 

 of a quench from 800° C. followed by hardening at 400° C. to 500° C. 

 The dispersion-hardening efifect of nickel and silicon in these alloys 

 opens a considerable field in the manufacture of high strength brasses. 

 The mechanical properties in the rolled condition of the hardened 

 brass containing 30 per cent of zinc and 3 per cent of nickel plus 

 silicon are in general similar to those of high brass sheet in the spring 

 temper. The endurance limit in reversed flexure for this alloy in the 

 hardened condition is, however, approximately 20 per cent higher than 

 that of high brass sheet in the same temper. 



A Metallo graphic Study of Tungsten Carbide Alloys? J. L. Gregg 

 and C. W. Kuttner. This paper gives the results of an investigation 

 of the structure of five of the tungsten-carbon alloys by means of 

 microscopic and X-ray methods, the samples studied being small tools 

 or wire-drawing dies. After a general discussion of the constituents 

 of tungsten-carbon alloys, the preparation of the samples is described, 

 and the structures found are shown in twenty-one figures accompanying 

 the text. 



1 Mining and Metalttirgv, Vol. 10, March, 1929, p. 163 (abstract). 



2 Mining and Metallurgy, Vol. 10, March, 1929, p. 162 (abstract). 



3 Mining atid Metallurgy, Vol. 10, February, 1929, p. 94 (abstract). 



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