A revision to the ASTM E 10, Standard Test Method for Brinell Hardness of Metallic Materials, that requires the use of the tungsten-carbide ball indenters for all Brinell hardness testing, has been approved by Committee E28 on Mechanical Testing.

As a result, the tungsten-carbide ball will now be required for all hardness ranges including the softer materials below 450 HBW where the steel ball was previously allowed. This change is expected to improve the performance of the test by eliminating the risk of ball flattening that steel balls experience and increase the useable life of the ball to the user. In addition, ASTM E 10 now aligns with ISO 6506, Metallic Materials-Brinell Hardness Test, with regard to indenter usage.

Brinell hardness test users should only use testblocks calibrated with the carbide ball. The designation HBW should be used exclusively to denote the tungsten-carbide ball in use. Between 300 HBW and 450 HBW, the user may find a small shift in values due to the difference in the elastic properties of the steel and tungsten-carbide balls, however it is considered to be negligible.

A task group of ASTM Subcommittee E28.06 on Indentation Hardness Testing developed the revision. For further technical information contact the task group chair, Robert A. Ellis, Quality Manager, David L. Ellis Co., Inc., Acton, Mass. (phone: 978/897-1795; fax 978/ 897-0844).

Committee E28 meets May 7-9 in Phoenix, Ariz. For membership or meeting details, contact Staff Manager Daniel Shultz, ASTM (610/832-9716). //

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