As compared to AISI Grade M-15 electrical steel, the use of cube textured 3% Si–Fe steel, 0.012-in. thick, as limination material in cores of 400-Hz generators covering ratings between 15 and 90 kVA, brought about improvements in generator weight, stack length, efficiency, and voltage transients. Conventional core fastening and stress-relief annealing practices were applicable, but stress concentrations during lamination punching had to be minimized in order to prevent cleavage cracks in the highly cube-textured material.
The effects of composition, magnetic annealing and texture on the magnetic properties, magnetostriction, and core noise of pilot-produced 6.5% Si–Fe sheet and transformer cores have been studied and the results compared with the core-loss and core-noise characteristics of domain-oriented 2V-CoFe and cube-textured 3% Si–Fe transformer cores. The application of magnetic annealing reduced magnetostriction of 6.5% Si–Fe sheet to 1×10−6 at 18 kG. The use of a low-magnetostriction core material, such as 6.5% Si–Fe, was shown to result in a considerable reduction in transformer core noise, reducing in turn the maximum noise level of a 3-phase, 400-Hz, 1250-VA static inverter to 50 dB in an acoustic frequency range of 0.4–20 kHz.
A study was made of the magnetic properties of 3% aluminum iron sheets which had been cold rolled and annealed to obtain a (100) [001]-type texture. Torque curve measurements as well as microscopic domain pattern observations indicated that approximately 70% (100) [001] texture was obtained in 0.025-in.-thick sheets. These sheets had induction values for a field of 10 Oe, of 16 000 and 15 300 G at 0° and 90° to the rolling direction, respectively, while a value of 13 900 G was obtained at 45° to the rolling direction, indicating the double orientation in the material. Oriented sheets were also obtained at thicknesses of 0.008, 0.012, 0.014, and 0.018 in. The degree of orientation decreased to some degree with decreasing sheet thickness, while 60-cps watt losses decreased considerably with decreasing sheet thickness.
The need for soft magnetic materials to operate at high temperatures in space electric-power systems requires a more fundamental understanding of the effects of nonmagnetic phases on basic magnetic behavior of synthetically strengthened metals. Coercive force (Hc) was measured at room temperature and 1200°F (649°C)–1600°F (871°C) on nineteen Co-base and ten Fe +27% Co-base extrusions dispersion-strengthened with 0.02–0.3 volume fraction (V) of oxide and boride particles ranging from 0.1 to 1.6 micron average diameter (d). The measured effect of this range of dispersoid parameters on Hc was correlated and interpreted by reference to equations of the form developed by Kersten, Néel, and Mager for particular inclusion sizes. The increase in Hc with V/d ratio was linear in most instances. Small changes in Hc resulted from the development of a fibrous subgrain structure by secondary working treatments (cycles of swaging and partial stress-relief annealing). These treatments provided both a substantial strengthening effect and thermal stabilization of the matrix for those materials containing finer dispersions, V/d≧0.75. Conclusions were reached concerning the limits of application and refinement of theoretical equations for predicting the influence of dispersoids and temperature on Hc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.