. Railway and Locomotive Engineering. nts andfound to exceed them in elongation andreduction of area, which indicates un-usual ductilitj. The specifications nowin general use are those adopted by Society for Testing Materials,and these require a tensile strength notless than lbs. per sq. in., not lessthan 28 per cent, elongation in 8 ins., anda reduction of area not less than 45per cent. The vibratory tests in the same specifi-cations require that the test bar shallendure a minimum of revolutionswhen a threaded specimen fixed at oneend has the other end moved in a cir
. Railway and Locomotive Engineering. nts andfound to exceed them in elongation andreduction of area, which indicates un-usual ductilitj. The specifications nowin general use are those adopted by Society for Testing Materials,and these require a tensile strength notless than lbs. per sq. in., not lessthan 28 per cent, elongation in 8 ins., anda reduction of area not less than 45per cent. The vibratory tests in the same specifi-cations require that the test bar shallendure a minimum of revolutionswhen a threaded specimen fixed at oneend has the other end moved in a circularpath while under a tensile load of 4,000lbs. The circle described shall have aradius of 3/32 at a point 8 ins. from the fixed end of the specimen. Seven samplesof Falls Hollow Staybolt Iron weretested under the above conditions at Pur-due University, and the average numberof revolutions required for rupture was10,378. The double bending test requiresthat the bar shall be closed in both di-rections without flaw. The illustrations. FIG. I. SHOWING COLD BEXT B.^R. show how well the Falls Hollow speci-men has met this requirement, as well asthe more severe test by bending after thespecimen was threaded. Fig. 1 represents a bar Is in. in di-ameter, bent cold flat on itself and re-taining a smooth surface with no extreme ductilitv of iron is
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