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On our MSA Study, the standard value is shown as 87.2 min & 89.2 max.
The standard is marked 88.2 +/- 1.0
The standard is marked 88.2 +/- 1.0
I have ordered new USA made & certified test block statndards for HRC & HR15n scales. When the new HR15n standard arrives i will mark 10 distinct areas on it & perform a new MSA.
You mention a V interesting point. The parts are small threaded insert nuts & are V difficult to measure. Also, after heat treating, the parts are plated & then thermally trated for hydrogen embrittlement. Any valid testing resluts would only be obtainable from 'test' samples of the actual raw bar stock used to make the part. We use the samples to verify the lot but the customer tests the final parts.
Typically such testing requirements are described in PPAP spec sent by the customer and so if they test it for hardness then you should have common methodology but if PPAP does not show any method then I would suggest to agree with the customer such common procedure so there is no discrepancy between what you measure and what they measure.
If they agree to test samples then it would be the best situation.
The parts are .625" dia x .312" thick. the production run is roughly 2000 parts. they take up V little room in the contractors oven.
Is it case hardening or through? If you do case hardening then you may test for stability of the process through the depth of hard case.
The cusotmer will not modify their specification.
Not likely. As long as material cert is provided our plant manager will always insist purchasing order based on the best price.
What raw material do you use?
Typically you can buy pre-conditioned material so that it's hardness spec is much tighter i.e. you can get EN24 but also you can get EN24T which is hardened and tempered condition.
