Aluminum alloys hardness measurement

[shushu97]

Hello

Rockwell B or Rockwell E - which one is better to measure the hardness of aluminum alloys?

Thank you!

 

[cloa513]

Rockwell B has a wider wide range of applicability judging by the test comparison data. Consider http://www.newageinstruments.com/problems-in-rockwell-testing.pdf
Test your given alloy and check the typical indentation- is it small compared to your thickness. Are the results repeatable? Of course Rockwell is not much good as descriptor of other properties so the scale is usually decreed by other considerations.

 

[shushu97]

Thanks!
I know B is a wider scale but I am only interested in measuring aluminum alloys.
There is also a rule of thumb that the higher the load the better (B is 100 kg with 1/16" steel sphere compared to 100 kg with 1/8" steel sphere in E).
Another rule of thumb says the specimen thickness should be ten times the indentation penetration which is (130-Hardness number)/500 in mm. So E will enable me to measure thiner specimens than B.
I don't know how accurate the conversion between hardness scales really is.

 

[shushu97]

Thanks!
I know B is a wider scale but I am only interested in measuring aluminum alloys.
There is also a rule of thumb that the higher the load the better (B is 100 kg with 1/16" steel sphere compared to 100 kg with 1/8" steel sphere in E).
Another rule of thumb says the specimen thickness should be ten times the indentation penetration which is (130-Hardness number)/500 in mm. So E will enable me to measure thiner specimens than B.
I don't know how accurate the conversion between hardness scales really is.

 

[cloa513]

http://www.engineersedge.com/manufacturing_spec/hardness_testing.htm
recommends only limited use of hardness testing for aluminium. Don't use a Rockwell test if you want something convertable. Vickers or one of the others is better for that.

 

[deepat]

Rockwell B is a better option.