302.5 - Rockwell Hardness (block form)

These Standard Reference Materials (SRMs) are transfer standards intended primarily for use in the calibration and verification of the performance of Rockwell hardness equipment using the applicable Rockwell hardness C scale (HRC), Rockwell hardness 15N scale (HR15N), or Rockwell hardness 30N scale (HR30N).Each SRM unit is a steel test block, nominally 64 mm in diameter and 15 mm thick, having a polished test surface described by a micro-engraved circle 52 mm in diameter. Each SRM unit is individually certified and bears a unique serial number on the edge of the block.

PLEASE NOTE: The tables are presented to facilitate comparisons among a family of materials to help customers select the best SRM for their needs. For specific values and uncertainties, the certificate is the only official source.


- Certified values are normal font
- Reference values are italicized
- Values in parentheses are for information only


Detail - Detail    Certificate - Certificate    Report of Investigation - Report of Investigation    MSDS - MSDS    Data Files - Data Files    Questionaire - Questionnaire


  SRM Description Unit of Issue     Nominal Hardness
Detail Certificate MSDS 2810
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Rockwell C Hardness, Low Range each   25 HRC
Detail Certificate MSDS 2811
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Rockwell C Hardness -  Mid Range each   45 HRC
Detail Certificate MSDS 2812
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Rockwell C Hardness, High Range each   63 HRC
Detail Certificate MSDS 2816
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Rockwell Hardness 15N Scale Low Range (Nominal 72 HR15N) 1 block   72 HR15N
Detail Certificate MSDS 2817
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Rockwell Hardness 15N Scale Mid Range (Nominal 83 HR15N) 1 block   83 HR15N
Detail Certificate MSDS 2818
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Rockwell Hardness 15N Scale,High Range (Nominal 91 HR15N) 1 block   91 HR15N
Detail Certificate MSDS 2819
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Rockwell Hardness 30N Scale Low Range (Nominal 45 HR30N) 1 block   45 HR30N
Detail Certificate MSDS 2820
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Rockwell Hardness 30N Scale Mid Range (Nominal 64 HR30N) 1 block   64 HR30N
Detail Certificate MSDS 2821
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Rockwell Hardness 30N Scale High Range (Nominal 79 HR30N) 1 block   79 HR30N