RESULTS OF THE BRINELL HARDNESS PROFICIENCY TEST AND THE IMPORTANCE OF STANDARD INDENTATION

Gunwoong Bahng, Nae Hyung Tak, Jong Soo Chung, Sang Bo Bae

Abstract

Measurement of indentation diameter is a very important factor in Brinell hardness as it can determine the reliability of the result. It is because of the ambiguous boundary line due to the pile up around the indentation. To evaluate the capability of indentation measurement, we prepared Brinell indentation hardness blocks and performed the proficiency test. Participating test laboratories have reported that deviation increases at the nominal diameter of 3 mm or larger. The result of this study indicates that this was because of the generation of up to 0.02 mm deviation or higher uncertainty at the same indentation if the definition of measurement reference is different or unclear when measuring the diameter of indentation with large pile up. We provided Brinell hardness blocks with reference indentations to the participating laboratories which observed the problem in the proficiency test. After retesting, deviation was observed to improve by up to 90 %, thereby proving the importance of applying the reference indentation CRM in Brinell hardness measurement.

Keywords

hardness, reference indentation, Brinell

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IMEKO-TC5-2010-030.pdf

DOI

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IMEKO TC

TC5 - Hardness Measurement

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