. Railway mechanical engineer . noted that three tensile and Izod tests weretaken at different distances from the outside. Each groupof fatigue tests was formed into the following series: 1, 6,7, 12; 2, 5, 8, 11; 3, 4, 9, 10 and 13, 14, 15, 16. The resultsof a few of these tests are given in Table IV: Table IV- -Tests of .^^•NE^LED .^XLE Steel Ultimate Yield Elastic limit lb. per lb. per lb. per Elong. Red. Izod. Brin. sq. in. sq. in. per cent per cent ft. lb. No. 77,625 37,000 35,500 7 79,625 37,75J 35,500 7 156 80,625 37,625 34,000 35 8 149 pieces 1, 6, 7 and 12, gav
. Railway mechanical engineer . noted that three tensile and Izod tests weretaken at different distances from the outside. Each groupof fatigue tests was formed into the following series: 1, 6,7, 12; 2, 5, 8, 11; 3, 4, 9, 10 and 13, 14, 15, 16. The resultsof a few of these tests are given in Table IV: Table IV- -Tests of .^^•NE^LED .^XLE Steel Ultimate Yield Elastic limit lb. per lb. per lb. per Elong. Red. Izod. Brin. sq. in. sq. in. per cent per cent ft. lb. No. 77,625 37,000 35,500 7 79,625 37,75J 35,500 7 156 80,625 37,625 34,000 35 8 149 pieces 1, 6, 7 and 12, gave an endurance, or true elasticlimit of 32,000 lb. per sq. in. The inner layer, comprising the series of fatigue testpieces 3, 4, 9 and 10, gave an endurance, or true elasticlimit of 31,500 lb. per sq. in. These points have been mentioned because in all good de-signs, these various characteristics have to be predetermined. Material Not in Accordance with Specification In view of the requirements of modern specifications, the. Fig. 4—Location of Test Specimens case of a material not being in accord with these should beof rare occurrence, but is, of course, possible and, therefore,must be considered. Material Not Suitable This phase of the subject is important because many fail-ures in service have been due to ignorance as regards the Max. stress in Ten and Shear-Yield Point-Elastic Limit in Tons/o osgss&ssssiss Reduc 4^ tion a ^Eli., oa+i^ F^rce ■Y leOD Impact i 1 Ft. Lb / \\ N y 1 1 \ \ \j \ /i A \ ^r ^ \ V r A ^^ \ A \ \ // [/■ \i ? V V / \ \ v VV f 1 1 5^^ \ / 1 ^^ \ \ / 1 1 ,\ \ 1 / 1 l \ \ The outer, layer, comprising the series of fatigue test Fig. 5—Diagram Showing Results of Physical Tests materials used. Two cases will be given, (a) Applicationof non-ductile alloys, such as those of aluminum for high-speed pistons without considering the effects of temperaturechange, (b) Application of ferrous material in a coarsecrystalline condition for a part subjected to s
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