Standard Rockwell Test Blocks
- Set of 3 in ranges: 25-30, 35-40, 60-65 .
- Specially made for us to calibrating our Ultrasonic Hardness Testers. Not for Leeb/Rebound type tester calibration. These blocks are NOT the same as standard bench tester calibration blocks that are not suitable as only 3/8" thick. These are per ASTM standard 5/8" thick, especially for a UCI tester.
- Calibrated to ASTM E18, ANSI (NCSL) Z540-1, (ISO) 10012-1, ISO/IEC 17025, ISO 6508
- Highest quality steel
- Rockwell test block surface hand lapped and diamond polished to a mirror finish
- Superior accuracy and ease of testing for the operator
- Special heat treat process ensures maximum consistency and repeatability
The following is from ASTM A1038-26 . This is the latest 2026 year revision for that standard .
Standard Test Method for Portable Hardness Testing by the Ultrasonic Contact Impedance Method
15. Hardness Reference Block
15.1 In order to avoid perturbing vibrations in the reference blocks caused by the ultrasonic sensor, they should be sufficiently large. Recommended is to use steel blocks with dimensions not less than 80 mm in diameter and 16 mm in thickness.
15.2 Each block shall be specifically prepared and heat-treated to give a specific hardness and the necessary homogeneity, such as in Test Methods E18, and stability of the surface hardness distribution.
15.3 The test surface shall be polished or fine ground and free of scratches and other discontinuities, which would influence the UCI measurement. The surface finish of the test
surface shall not exceed 0.4 μm maximum.
15.4 To ensure that no material is subsequently removed from the test surface of the reference block, an official mark or the thickness to an accuracy of 60.025 mm at the time of calibration shall be marked on the test surface.
15.5 The hardness reference block shall be calibrated using a standard and certified hardness testing device in accordance with Test Method E10, Test Methods E18, or Test Methods E92. Make at least five randomly distributed hardness measurements on the test surface of the reference block and take the arithmetic mean of all of the readings as the mean hardness of the block.
15.6 Each block shall be marked with (1) the arithmetic mean of the hardness values found in the standardization test suffixed by the scale designation letter (for example HV, HRC,
HRB, HBW, HBS, etc.), and (2) with the name or mark of the supplier. If edge of block is marked, the lettering shall be upright when the test surface is upward.
