Aluminum alloys hardness measurement

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Rockwell B and Rockwell E are both used for measuring the hardness of aluminum alloys, but Rockwell B is noted for its wider applicability. Rockwell B employs a 1/16" steel sphere at 100 kg, while Rockwell E uses a larger 1/8" sphere, which may affect the accuracy of measurements. A key consideration is that the specimen thickness should be ten times the indentation depth, making Rockwell E suitable for thinner samples. However, Rockwell testing is limited in its ability to provide convertible hardness values, with Vickers being recommended for more accurate conversions. Ultimately, Rockwell B is favored for its broader range, despite the specific needs for aluminum alloys.
shushu97
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Hello

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

Thank you!
 
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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.
 
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.
 
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.
 
Rockwell B is a better option.
 
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