Report of the Tests of Metals and Other Materials for Industrial Purposes Made with the United States Testing Machine at Watertown Arsenal, Massachusetts, During the Year Ended ...

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U.S. Government Printing Office, 1913 - Building materials

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Page 111 - and soft states of metals," delivered in 1911 before the Institute of Metals. According to Beilby, a surface skin may be built up by mechanical movement, which gives unmistakable evidence that the surface must have passed through a state in which it must have possessed the perfect mobility of a liquid. This surface possesses distinctive properties which differentiate it from the
Page 111 - properties which differentiate it from the substance beneath it. Hardening thus results from the formation at all the internal surfaces of slip or shear of mobile layers similar to those produced on the surface by mechanical movement. These layers only retain their mobility for a brief period, and then solidify in a vitreous, amorphous state, cementing together all of the surfaces of slip or shear throughout the mass.
Page 73 - в в в с с с D D D E E E F G H I A В I Length of specimen. Ft. in. 5 3 5 3
Page 110 - The microscopic structure of steel hardened by heating through the critical range and quenching is characteristic, but no such structure can be produced in this hard layer by any of the standard reagents commonly used for this purpose. The mechanism of this action has been studied in detail by Beilby. and an interesting résumé of his work will be found in his presidential lecture on "The
Page 101 - not vary in the same way. In section E, where the greatest erosion has taken place, the smallest number of cracks appear. The greatest depth of crack
Page 32 - Remarks. Initial load. 30,000 to 60,000 Ib. per sq. in. Modulus of elasticity» 30,000,000 Ib. per sq. in. Elastic limit. Tensile strength. Marks, 1185-F. Diameter, 0.505 in. Sectional area, 0.20 sq. in. Gauged length, 2 in.
Page 46 - broken from the jackets of A and В indicate that the metal has been heated too far above the critical point, held at this temperature too long, and then cooled too slowly. This is shown by the inclosed microphotographs, 11 and 12, which show clear-cut veins of ferrite, and welldeveloped lamellar structure in the
Page 111 - produced in the combustion of the powder. This would necessitate a very high percentage of carbon. Inasmuch as the hard layer is so thin and so difficult to do anything with, no direct evidence has been obtained. This method would best account for the fact that the hard layer is thickest in the firing
Page 64 - at the points 2, 3, 4, and 6, or where necessary at 1 on collars CD, GH, and IK. The zero reading of the dial was taken at point 1 on collar NO. The various measurements are given in the tables following: Micrometer measurements of each specimen were taken before and after hardening. The
Page 118 - The third structure is that of sorbite similar to the original steel, but not showing the granulation of the original. The carbon has still further transformed into the "carbide" state. Had the carbon been completely transformed into "carbide" carbon, the structure would have been that of pearlite. Sorbite is, therefore, a transition form between troostite and pearlite.

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