. Transactions. in, for some time, its elas-ticity, the elastic limit becoming practically zero. The iron in thistemporary state will show hysteresis in its stress-strain curve; the load-ing curve and the unloading curve do not coincide. Measurements weremade to determine whether the magnetic induction was, under thesecircumstances, subject to the same hysteresis. For this purpose aspecimen was loaded and unloaded cyclically, and at each step the HANEMANN AND MERICA 211 inductions B were measured for several values of the field strength. Itwas found that as long as the material under test poss
. Transactions. in, for some time, its elas-ticity, the elastic limit becoming practically zero. The iron in thistemporary state will show hysteresis in its stress-strain curve; the load-ing curve and the unloading curve do not coincide. Measurements weremade to determine whether the magnetic induction was, under thesecircumstances, subject to the same hysteresis. For this purpose aspecimen was loaded and unloaded cyclically, and at each step the HANEMANN AND MERICA 211 inductions B were measured for several values of the field strength. Itwas found that as long as the material under test possesses an elasticHmit, and the upper value of the stress applied was not greater than thislimit, no difference or hysteresis in any part of the induction cycle for aconstant field strength could be detected; any such difference was notin any case greater than from 5 to 7 gausses, a matter of per cent.,which was of the same order of magnitude as the error of measurement in 9,5()0 8,500 7,500 6,500 5,500 4,500. VtAOf ^ S< Fig. 8.—Material 1—Iron. Ab-scissas—Stresses in Kilograms perSquare Millimeter. Ordinates—Inductions in Gausses; ElongationsIN Per Cent. 17,50C -Jl^hl^ -___ ^-~ II 2 15,000 H ^^ 12,50010,000 H7T~^ ^ ^ 7,500 ..MJ:0 ^ 5000 2,500 2 0 ? - — —1 ot 1 1 20 30 Fig. 9.—Material 1—Iron asDelivered, Hot-Rolled. Ab-scissas—Stresses in Kilogramsper Square Millimeter. Ordi-nates—Inductions in Gausses. this case. The induction cycle, as well as the cycle of elongations, wasperfectly reversible. When, however, the iron was stressed over theyield point, and then immediately tested, both the elongation andthe induction curves showed hysteresis. The results of one such testare shown in Fig. 8, in which the abscissas represent the stresses and theordinates, in one case, the elongations, and in the other, the magnetic 212 MAGNETIC STUDIES OF MECHANICAL DEFORMATION inductions B for loading (the up curve) and u
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
