HV Hardness Testing Conversions - CRA 1070, tempered 440-520 HV10

[Ron Rompen]

We are currently receiving a product from our supplier which is specified as CRA 1070, tempered 440-520 HV10

Due to a recent problem on the line, we are performing some investigation, and I have requested material and hardness certificates from this supplier.

The certifications I received are for CRA 1075 steel, tested to 440-520 HV500.

The comparative analysis between 1075 and 1070 is ok, but I am unable to find a comparison or equivalency table for HV10 to HV500. I understand the difference in the test methodology, but am still unsure as to whether the end results are the same.

Anyone out there able to assist?

 

[Piero]

Re: HV hardness testing conversions

Hi Ron

As you know the number following the letter HV indicate the load insisting on the diamond indenter. The more hard the material is the higher the load should be to have a clearer reading of the print. To say in different way the higher is the load the bigger is the print left by the diamond on the material.
Different loads give near identical hardness numbers on uniform material. This means that the ratio between the different loads is equal to the ratio between the area of the prints.

I hope I was able to help you.

See also http://www.gordonengland.co.uk/hardness/vickers.htm

Regards

Piero

 

[Ron Rompen]

Re: HV hardness testing conversions

Thanks Piero. I was ALMOST certain that this was the case, but couldn't find anything to back me up.