. Transactions. pered H. J. FRENCH 89 steel yoke (shown in Fig. 3) by two annealed, low-carbon steel specimen passes freely through the holes in the base of each ofthe frames. The yokes are clamped to the specimen by three quenched and tem-pered high-speed steel screws. The tendency for the yoke to spread when considerable force is used in settingthe screw is overcome by an additionalbolt. The flanges on the upper frameare so arranged that two Ames dialsmay readily be securely fastened tothem while those of the lower frame arecapped with polished steel plates to givea smooth bearing s
. Transactions. pered H. J. FRENCH 89 steel yoke (shown in Fig. 3) by two annealed, low-carbon steel specimen passes freely through the holes in the base of each ofthe frames. The yokes are clamped to the specimen by three quenched and tem-pered high-speed steel screws. The tendency for the yoke to spread when considerable force is used in settingthe screw is overcome by an additionalbolt. The flanges on the upper frameare so arranged that two Ames dialsmay readily be securely fastened tothem while those of the lower frame arecapped with polished steel plates to givea smooth bearing surface to the pistonsof the dials. The smallest division on the dial isequal to in. ( mm.) butestimated readings to the nearest ( mm.) may readily be stress is applied to the specimen,half the algebraic sum of the deforma-tions recorded by the two dials representsthe deformation of the specimen, whichis centrally located with respect to theentire apparatus. For example, upon. ^WSiR £ .■■iij:iilu. A qss^i VM^.) B Fig. 2.—Apparatus used for de-termining PROPORTIONAL LIMIT. A-SpecimenB-YokeFig. 3.—Carbon-steel yokes. apphcation of load, the apparatus may twist to some extent the dial onthe left showing a negative deformation of in. while that on theright registers a positive deformation of in. Half the algebraicsum m (+ in. - in.) = in.] represents the deforma-tion of the specimen under the load appHed. Heating Furnace The test specimen was heated by means of an electric tube furnace ofthe form shown in Fig. 4. Two spiral resistors in series are used. The 90 TENSILE PROPERTIES OF BOILER PLATE AT ELEVATED TEMPERATURES one covers the entire length of the inner tube (11 in.) and the other isconcentrated at the ends, the two requiring about 80 ft. (24 m.) of22-gage chromel wire. The yokes and major part of the 18 in. (46 cm.)test bar and rods are contained in the heating chamber, which is 11 in. long. A comp
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
