Active Standard ASTM A904 | Developed by Subcommittee: A06.02
Book of Standards Volume: 03.04
Historical (view previous versions of standard)
This specification covers the magnetic property requirements of 50 nickel-50 iron soft magnetic parts fabricated by powder metallurgy techniques in the sintered or annealed conditions, intended for parts that require high magnetic permeability, high electrical resistivity, low coercive field strength, and low hysteresis loss. This specification does not cover parts produced by metal injection molding. Parts shall be tested and adhere to the chemical composition, sintered density and coercive field strength requirements listed in this specification. Appendices contain information on typical magnetic properties and heat treatment.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1.1 This specification covers the magnetic properties of 50 nickel-50 iron parts fabricated by powder metallurgy techniques and is intended for parts that require high magnetic permeability, high electrical resistivity, low coercive field strength, and low hysteresis loss. It differs from the wrought alloy specification (see Specification A753) because these parts are porous. A number of magnetic properties such as permeability are proportional to the sintered density.
1.2 This specification deals with powder metallurgy parts in the sintered or annealed condition. Should the sintered parts be subjected to any secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered or annealed.
1.3 The values stated in customary (cgs-emu and inch-pound) units are to be regarded separately as standard. The values given in parentheses are mathematical conversions to SI units, which are provided for information only and are not considered standard.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A34/A34M Practice for Sampling and Procurement Testing of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A596/A596M Test Method for Direct-Current Magnetic Properties of Materials Using the Ballistic Method and Ring Specimens
A753 Specification for Wrought Nickel-Iron Soft Magnetic Alloys (UNS K94490, K94840, N14076, N14080)
A773/A773M Test Method for dc Magnetic Properties of Materials Using Ring and Permeameter Procedures with dc Electronic Hysteresigraphs
B328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings
B962 Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes Principle
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Fusion Techniques
ICS Number Code 77.160 (Powder metallurgy)
UNSPSC Code 31381200(Sintered magnets and magnet assemblies)