Brinell to Rockwell hardness conversion 1

[jjengel]

Hi all. I've exhausted all the Google searches I can think of and didn't find any threads related to this, so here I am, with a question; Is there a way to convert a HBW (Brinell) of 50 on the 2.5/62.5 scale to a measurement on the 10/3000 scale? Ultimately I'm trying to cross this to a Rockwell hardness but cannot find any tables that use the 2.5/62.5 scale. Tables? Formulae? Mystical ball of answers?

Thanks for any help or direction.

Jason

 

[Clyde38]

Try

http://www.gordonengland.co.uk/hardness/

[link

http://www.linkedin.com/in/clydehancock

]

[/url]

 

[ione]

Since one scale exploits a 2.5 mm diameter indenter with 612.9 N applied force whilst the other exploits a 10 mm diameter indenter with 29420 N, I thought they were used for different materials and so not comparable.

 

[jjengel]

Clyde38, Thank you for the link...I'm still looking around that site.

ione, I agree. My goal isn't to necessarily find an equivalent on the 10/3000 (29420 N) scale, but rather to find a Rockwell hardness cross. So far, all my searching has yielded no tables or conversions that include a Brinell hardness as low as 50.

 

[katmar]

Any two hardness scales can only be compared for their behavior with a particular material. So if value X on Scale A is equivalent to value Y on Scale B for steel it does not automatically follow that a sample of aluminum that has a value X on Scale A will also have a value Y on Scale B.

Most of the published data is for steel, and you will probably not find Brinell hardnesses as low as 50 for steel. Certainly when I was collecting data for inclusion in my unit conversion program Uconeer I did not find any values as low as 50. If you Googled hardness conversions I am sure you will have seen Uconeer, but it has a lower limit of 52.9 on the Brinell scale.

Perhaps you will have better success if you approach suppliers of the material that you are measuring the hardness of. Or approach the hardness tester manufacturers.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[TVP]

jjengel,

If this Brinell measurement was achieved on an aluminum alloy, then you can use ASTM E 140 or ISO 18265 to convert it to an approximate Rockwell number. 50 HB is equivalent to 56 HV, 59 HRE (1/8" ball, 100 kgf), or 64 HR15T (1/16" ball, 15kgf). This is extremely soft, and therefore does not register a valid reading on the HRB scale (1/16" ball, 100 kgf). The sample would need to be substantially harder in order to achieve a valid HRB reading, e.g. 70 HB is ~ 80 HV, 28 HRB, 80 HRE, or 74 HR15T.

You can obtain ASTM E 140 and ISO 18265 directly from their respective publishers, or from a licensed reseller such as Global Engineering Documents:

http://www.astm.org

http://www.iso.ch

http://global.ihs.com

 

[ione]

I still consider such different Brinell scales not comparable, anyhow I would like to make a consideration to be handled with care.
The application of a different load and a different diameter indenter (keeping the same indenter material) on a sample should be to get a different indentation diameter.

HBN = 0.102*2F/(PI*D*SQRT(D^2-d^2))

Now as it is known a correlation exists between Brinell hardness number and ultimate tensile strength (UTS), taking the UTS as a constant value the HBN should be unambiguous and not dependent on the scale used to perform the test. So, allowed from a theoretical point of view, one could perform the test with different Brinell scales on the same sample, the Brinell number should be the same.

 

[ABritTurner]

There are printed tables available of Rockwell-Brinell conversions and have existed for many years. Most steel suppiers will furnish you with a hard copy of their literature. Macready steels comes to mind.