Metallurgy; an introduction to the study of physical metallurgy . late XVII. La this machinethe hydrauUc cyhnder and ram are in the pit below the floorlevel, while the hydraulic pump and accumulator are in anotherpart of the building, so that the machine as shown in the pictureis only a part of the whole installation. A further disadvantageof the lever and jockey-weight is that they possess a considerableamount of inertia, and may thus momentarily exert forcesfar larger than the scale-reading of the jockey-weight wouldindicate. Particularly when a test-piece is stretching rapidlythis factor ma
Metallurgy; an introduction to the study of physical metallurgy . late XVII. La this machinethe hydrauUc cyhnder and ram are in the pit below the floorlevel, while the hydraulic pump and accumulator are in anotherpart of the building, so that the machine as shown in the pictureis only a part of the whole installation. A further disadvantageof the lever and jockey-weight is that they possess a considerableamount of inertia, and may thus momentarily exert forcesfar larger than the scale-reading of the jockey-weight wouldindicate. Particularly when a test-piece is stretching rapidlythis factor may introduce serious errors, especially if measure-ments of a more delicate type are to be made. The hydraulic measuring type of tensile testing machine isa much simpler and more compact apparatus than the levertype; like the other it possesses, as a rule, an independenthydraulic ram for the purpose of exerting the loading pulland of taking up the stretch of the test-piece, but the loadon the test-piece is transmitted to a second hydraulic apparatus. PLATE [To face p. 200. THE MECHANICAL TESTING OF METALS 201 which serves solely for the purpose of measuring the amountof pull exerted at any moment. This is accomplished by anappliance developed largely by Martens, and known in Germanas the Mess Dose or hydraulic measuring box. Inthis appliance the pull of the specimen is transmitted to oneside of a chamber which is partly composed of a flexible dia-phragm. This chamber is completely filled with water, whichis in communication with a sensitive pressure gauge. Whenthe test-piece exerts the puU on the movable side of this chamberthe pressure within the chamber rises until the pull of thetest-piece is exactly counterpoised, and the pressure thenrecorded by the gauge measures the pull of the test-piece, being,of course, proportional to the area of the movable side of thebox. In this way the actual pull can be very much magnified,and the scale of the pressure gauge, in terms of t
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmetals, bookyear1922
