ASTM A773/A773M-14

5.1 Hysteresigraphs permit more rapid and efficient collection of normal induction and dc hysteresis (5.2 Hysteresigraphs are particularly desirable for testing of semihard and hard magnetic materials, where either the entire second quadrant (demagnetization curve) or entire hysteresis loop is of primary concern. Test Method A977/A977M describes the special requirements for accurate measurement of hard (permanent magnet) materials.

5.3 Hysteresigraphs are not recommended for measurement of initial permeability of materials with high magnetic permeability such as nickel-iron, amorphous, and nanocrystalline materials due to errors associated with integrator drift; in these cases, Test Method A596/A596M is a more appropriate method.

5.4 Provided the test specimen is representative of the bulk sample or lot, this test method is well suited for design, specification acceptance, service evaluation, and research and development.

1.1 This test method provides dc hysteresigraph procedures (B-H loop methods) for the determination of basic magnetic properties of materials in the form of ring, spirally wound toroidal, link, double-lapped Epstein cores, or other standard shapes that may be cut, stamped, machined, or ground from cast, compacted, sintered, forged, or rolled materials. It includes tests for normal induction and hysteresis loop determination taken under conditions of continuous sweep magnetization. Rate of sweep may be varied, either manually or automatically at different portions of the curves during measurement.

1.2 The equipment and procedures described in this test method are most suited for soft and semi-hard materials with intrinsic coercivity less than about 100 Oersteds [8 kA/M]. Materials with higher intrinsic coercivities should be tested according to Test Method A977/A977M.

1.3 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.