Hardness standards
Hardness test blocks or hardness reference plates are comparison plates most commonly made of Steel or Aluminum but could also be made of Brass or custom materials.
They are used for the day to to day Indirect Verification and Calibration of hardness testing machines and instruments. There are hardness test blocks for almost all hardness testing methods and scales. Verifying the display reading of a hardness tester against ISO/ASTM certified hardness test block values part of a normal quality assurance process.
Adjusting your hardness tester according to the value engraved in a hardness test block, as long as the adjustments are minor, can be done after assurance that a correct and undamaged indenter/penetrator is installed and the tester operates normally.
ISO & ASTM HARDNESS TEST BLOCKS (UKAS, Etc.)
Hardness test blocks MASTERBLOCK® branded are manufactured according to standards ISO (International) and ASTM (American). Such standards apply to the physical requirements as well to the method & the way the final value is found and confirmed. By adding a grid on the blocks they meet the requirements of NADCAP.
MASTERBLOCK® hardness test blocks are not ‘’just’’ hardness test blocks. Our blocks are of excellent finish and have very low variation, excellent repeatability.
RAW MATERIALS USED
In order to manufacture good hardness test blocks, strict control over the quality of raw materials (Steel, Brass, Aluminum) is required. The entire block material needs to be homogenous, to assure low spread of readings and excellent repeatability.
HEAT TREATMENT
Distribution of the blocks in the hardening furnaces is of utmost importance, time, temperature and quench are all carefully controlled processes, to assure a top class product.
FINISHING
The next step in the process to ensure high quality ‘blanks’’ is the grinding, polishing and lapping of the block surfaces. Any concerns on the surface quality are eliminated due to thorough selection after inspection.
QUALITY CONTROL
Before proceeding with the ultimate verification and engraving of the block hardness, blocks are undergoing a full inspection to ensure that they meet the physical requirements of ISO and ASTM (thickness, flatness, parallelism, surface roughness).
The MASTERBLOCK® appointed Calibration Laboratory D. Ellis, is accredited to ISO / IEC 17025 by NVLAP*.
The National Voluntary Laboratory Accreditation Program (NVLAP) provides third-party accreditation to testing and calibration laboratories in response to legislative actions or requests from government agencies or private-sector organizations. NVLAP-accredited laboratories are assessed against the management and technical requirements published in the International Standard, ISO/IEC 17025:2005 (ISO: Organization for Standardization).
*NVLAP is affiliated to the National Institute of Standards and Technology, NIST.
The blocks are also compliant for the use by organizations or companies that are under the NADCAP Program. (National Aerospace and Defense Contractors Accreditation Program).
Nadcap compliant ‘’grid’’ blocks, are available on request.
ILAC; GLOBAL RECOGNITION OF ACCREDITING BODIES
UKAS, NVLAP, DAkkS, Cofrac and many national accrediting bodies & laboratories are signatories (members) of ILAC.
ILAC- is an international cooperation of laboratory and inspection accreditation bodies. Accreditation bodies are established in many countries with the primary purpose of ensuring that conformity assessment bodies are subject to oversight by an authoritative body. A laboratory calibration performed under the scope of accreditation recognized by the ILAC agreement is considered to be an equivalent calibration to any other laboratory recognized by the ILAC agreement.
For a complete list of ILAC recognized accrediting bodies or ILAC members please refer to www.ilac.org.
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