We at Applied Thermal Technologies follow ASTM E-18 for Rockwell hardness testing; this specification limits the size and geometry of parts for accurate testing.
- Test results of cylindrical parts require a correction factor prior to reporting the results. Correction factors for diameters less than .125″ are not provided in the standard, therefore we interpret this as untestable and look for other test methods.
- For other geometries, two parallel surfaces are required.
- Spherical surfaces cannot be tested.
- Minimum thickness is listed in tables attached.
Note: Although not covered in ASTM E-18-11, Applied Thermal Technologies Inc. has submitted concerns and recommendations to ASTM about the testing of tubular products. ASTM has informed us that our concerns will be addressed in the next revision. Possible deflection when testing the OD of tubular will result in erroneous readings since hardness is measured by the deflection of the diamond, when testing on the end is not possible to due insufficient wall thickness or geometry. The feasibility of testing tubular products will be assessed at final inspection.
Tables A5.1, A5.2, A5.3, A6.1, A6.2, and A6.3 are available for review at our location. We have reviewed the requirements with all employees to perform as follows; “If for some reason the part cannot be tested, list the hardness as “N/A”, quantity tested as “None” and reference in the “Other” section “Unable to test due to configuration”. Write a discrepancy report describing listing “Final inspection hardness test could not be performed”, write the name of the purchasing agent in the customer contact field and return to customer for disposition.”
We are requesting that you please review this information and consider the following options;
- Include a test piece of the same material lot with your order prior to heat treatment with an outer diameter greater than 0.125”. Tests pieces must conform to the guidelines of ASTM E-18 outlined above.
- Accept the heat treat process certification “As-Is”.
- Perform a microhardness test per ASTM E384, which is a destructive test and will incurr an additional charge.
If you would like to discuss this please contact Mark Adley, Quality Manager, email@example.com or (574) 269-7116.