Rockwell, Vickers hardness and welding procedure

[engr2GW]

Good afternoon all,
I have a NACE hardness survey prepared by a company sometime in 1999. At the foot of the document, they said they used the Vickers' type testing unit applying a 10kgf load (HV 10).
My questions:

1. the procedure was written in 1999, could it have been a Vickers test? I was under the impression that Vickers's test became a required test in NACE after year 2000, or when NACE become ISO (international)

2. the hardness readings range from 2.0 to 17.5, those are not Vickers numbers at'all, the Vickers numbers I know range from 130/140 to 240+. Could that be a different scale like Rockwell, etc. I understand that Rockwell C is usually 21 and above right?

3. The traverse for Vickers on the NACE survey usually have two points of hardness measurement on the rood bead, but this one has only one, whih makes me think it may be some scale of Rockwell hardness.

Any idea???

 

[metengr]

The readings you describe are not HV numbers. I would agree that the reported numbers could be attempted conversions. I would not rely on this hardness data.

 

[TVP]

I think that the values listed are Rockwell C that were converted from the HV 10 measurements. But this is only a guess.

 

[engr2GW]

Thanks TVP,
but are those valid Rockwell numbers? shouldn't it be continued with a Rockwell B scale when Rc gets below 21/
Thank you.

 

[TVP]

mysarah,

No those would not be valid Rockwell C values, but many times people will report invalid Rockwell C values because the maximum limit is 21 Rockwell C and people want to directly compare the results using the same scale. Obviously this is one of the problems inherent with Rockwell testing.