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Results of a survey of the priorities for an increased range of UK traceable hardness scales.

Davis, F (2001) Results of a survey of the priorities for an increased range of UK traceable hardness scales. NPL Report. CMAM 69

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As part of the 1996-1999 NMS mass metrology programme, a project was launched to re-establish hardness standards for the highest priority scales. A consultative document published, in support of this re-establishment, stated that the scales supported were considered a minimum requirement, and that the future mass metrology programmes should reflect the need for an increased range of national traceable hardness scales.
This report has been written as part of deliverable 2.3.3 of the NMS mass metrology programme 1999 -2002, "to establish the priorities for an increased range of hardness scales". These priorities were derived from the analysis of a survey of both manufacturers and users of hardness equipment. The survey was carried out during June -August 200 1 and circulated to the UK hardness community by use of the distribution lists of the BSI hardness committee (ISE/NFE/4/5), BMT A members, UKAS-accredited hardness laboratories, the NPL MATC Materials Measurement flyer, and the NPL Force and Hardness Group. The survey covers traditional indentation hardness methods, rubber hardness, and the instrumented indentation method for hardness and material properties. Provided as appendices to this report are background notes on hardness scales, the questionnaire that was circulated, and a list of the organisations that responded.
The report confirms that the highest priority scales that were established prior to the 1996 -1999 NMS mass metrology programme were correct and provides a prioritised list of the hardness scales that require support from NPL' s hardness standards. The report also recommends the need for further work to be carried out to compare the hardness scales of hardmetal and hardened steel indenters to establish the scale difference. This comparison should include Rockwell and Superficial Rockwell hardness scales and also Brinell. It is considered that for the Brinell scales the comparison is less important as hardened steel indenters have been superseded, and only hardmetal indenters are specified in the BS/ISO standards. However, in niche industries the use of hardmetal indenters for Brinell is problematic and companies have expressed the need to continue measurement using hardened steel balls. As anticipated, Shore and IRHD hardness testing is used primarily by those organisations serving the polymer industry, whilst instrumented indentation techniques are of primary interest to the "thin" surface coatings industry.

Item Type: Report/Guide (NPL Report)
NPL Report No.: CMAM 69
Subjects: Engineering Measurements
Engineering Measurements > Mass, Force, Pressure
Last Modified: 02 Feb 2018 13:17
URI: http://eprintspublications.npl.co.uk/id/eprint/2027

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