ASTM E140 vs. ISO 18265 - preference?

[dbooker630]

The metallurgists in our company are discussing the two standards as to which one is more suitable. One of our engineers checked a Brinell test block with HRC and the ISO conversion is closer than the ASTM document. I'm interested in the Eng-Tips community's thoughts on these standards.

 

[EdStainless]

"Soap Box"
Hardness ref blocks marked 43.7HRC (or whatever) are a statistical representation of the testing on the material that it is made from.
It does not mean that any single test should yield the exact value reported.
Likewise hardness testers that read in fractional hardness points are ridiculous.
Have you ever done a Gage R&R on hardness testing?
Across different operators and different days you will be lucky to get an RSD less than 4%.
Hardness within a few points is identical.
Did you test on the same alloy that you are looking at? At the same strength level? With the same surface finish?
"off of Soap Box"

I was in the SS business and internally we had our own conversion tables.
And we always reported the actual measured value, even when we then converted it.
In our business you cannot reject on hardness, only on tensile data.

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P.E. Metallurgy, consulting work welcomed

 

[Steven_D_P]

As a designer I only convert from hardness to tensile strength so the ASTM standard is useless to me.
I've to choose between ISO 18265 and SAE J417.
I've noticed with other standards that the ISO and DIN standards are usually far more detailed than American standards and this is also the case with ISO 18265 vs. SAE J417.
ISO 18265 has uncertainty curves based on your measured hardness which none of the other standards have. And ISO 18265 differentiates based on the type of steel whereas as far as SAE J417 is concerned steel is just steel. But you could easily argue the other way around that J417 is easier to use and that ISO 18265 is just nitpicking.