Magnetic Properties Committee Approves First in Series of Permanent Magnet Materials Standards
ASTM International Committee A06 on Magnetic Properties has approved the first in a series of proposed standards on permanent magnet materials. The new standard, A 1054, Specification for Sintered Ceramic Ferrite Permanent Magnets, and the other proposed standards, are under the jurisdiction of Subcommittee A06.02 on Material Specifications.
While ASTM has long had standards covering soft magnetic materials such as oriented and non-oriented sheet steels, relay steels, nickel-iron alloys and powder metal materials, Reinhold Strnat, chair of Subcommittee A06.01 on Test Methods and technical manager, KJS Associates, says it has not addressed permanent magnet materials until recently.
Users of ceramic ferrite magnets will be able to use A 1054 to identify widely recognized grades of permanent magnet material for use in their device designs. “It is important to design around a magnet that actually exists, so a list of commercially recognized and available magnet grades with defined properties, as is included in A 1054, gives a designer a solid starting point to develop the rest of a machine and predict its performance,” says Strnat.
Strnat further explains that once a design has been proven out, it must be manufacturable and A 1054 can provide guidance in this area as well. “By specifying a grade of material that is listed in A 1054, any manufacturer knows, by reference to the standard, what the properties of the magnet must be in order to satisfy the design requirements,” says Strnat. “Without such a standard, each product would have its own customized list of magnetic requirements that magnet producers may or may not be able to meet. Standardization in this context also offers opportunities for significant cost savings.”
According to Strnat, A 1054 will be used by designers and manufacturers of loudspeakers, electric motors (especially in the automotive area—seat adjust motors, remote mirror adjusters and other devices using electric motors), magnetic sensors and even simple holding magnets like magnetic door latches and refrigerator seal magnets. “Ultimately the producers of the magnets will also be users of the standard, as they strive to meet the requirements of their end-user customers,” says Strnat.
Subcommittee A06.02 is already at work on the next in the series of proposed permanent magnet material standards. According to Strnat, there will be individual standards for each of the commercially important classes of permanent magnets, such as Alnico, samarium cobalt and neodymium-iron-boron. “We are always looking for interested parties to whom such standards have relevance and would welcome their active participation in the development and maintenance of these standards,” says Strnat.
Strnat says that the proposed standards would benefit from as much input as possible about real-world applications and the types of magnetic properties that need to be specified in order to assure reliable product function. Case studies that include a description of the magnetic design process for specific products and a review of how the magnets are currently being specified would be particularly valuable, according to Strnat.
In addition, Strnat notes that A 1054 would benefit from participation from as many magnet producers as possible so that the subcommittee can make sure that all commercially relevant grades of magnets are appropriately referenced. “Since there is a constant influx of magnets with unique, new property sets, it is difficult to keep up with the innovation that is taking place without active input from the magnet producers,” says Strnat.
Technical Information: Reinhold M.W. Strnat, KJS Associates, Indianapolis, Ind.
Phone: 317/841-5519, ext. 19
ASTM Staff: Nancy Morrissey
November Committee Week