[Metrology] Hardness Test Blocks

[Moderatemixed]

Hey everyone, quick question.

I’m looking for a test block/calibration block for a recently acquired Wilson Rockwell hardness tester. So over to “ebay” I go. Some are listed as A scale, some B, C ...... the list goes on. Some however are 11, 16, 88. This is where I get lost. I have looked online and there doesn’t seem to be any guidance. If someone wouldn’t mind taking the time I’d appreciate it.

Cheers,

Derek


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[swiftab]

Hardened steel is measured in the C scale.

What you are measuring will define the scale to use. The numbers look like the Brinell scale

Not sure if this answers your question though.

 

[Moderatemixed]

I purchased a B scale “ball” indenter and test block set. I also purchased a C scale “diamond” indenter. I want to get a calibration block for C scale and am wondering how do you know what scale the numbered blocks pertain to. If the listing shows an 88, how do I know if that is an A B C D F N or other scale? Or does the number have anything to do with the hardness at all? How do I identify a block of known hardness as a C scale block from the myriad of available blocks on ebay? OR does someone in the group have a Rockwell C scale calibration block that they would like to part with?

Cheers,

Derek


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[benmychree]

The block would be stamped or etched with both the scale letter and the hardness of the individual block, down to possible fractions, such as Rc 50.7, or any other number that is reliable under that scale; on the C scale, intended for hardened steel, the numbers at the lower end of the scale are not really accurate, like, probably below Rc 30 or thereabouts, There are a bunch of different scales, indenters and combinations of load weights for the different scales, and several testers for special testing, such as for case hardened parts (Superficial hardness tester). There is usually a plate on the side of each tester that tells of scales, indenters and weights used.

 

[Moderatemixed]

This is an example of what I’m talking about. Other than the branding there is an “88”. Any thoughts to what the 88 refers?

 

[Moderatemixed]

After the 88 there appears to be a C or G then 4269 which I presume is a serial number. But of course it just leaves me with more questions and no real answer to the original question. What Rockwell scale would this block measure and does the 88 mean anything?

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[benmychree]

The test blocks that I have, the hardness number is lightly etched with an electric etching pen, not a stamp, such as C42.2+-, or C63.3 (plus or minus). I doubt that the 88 means anything significant; you may have to look closely to find the etched number, it is on the opposite side from the pictures posted.

 

[Moderatemixed]

Awesome. Will do. Thanks.


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[benmychree]

Since the blocks had to be heat treated before testing and final marking, most would be too hard to be able to be stamped, so etching was the only method to mark them, and besides, stamping would likely distort the steel. It would be nearly impossible to heat treat to a very specific hardness, if the blocks were marked prior to hardening.

 

[pdentrem]

Also never grind the dimpled surface smooth. It might not be hardened through. There should be a cert with the block, if it was not thrown away.
Pierre