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 Replies: 9 / Views: 873 |
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Pillar of the Community
United States
5239 Posts |
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Bedrock of the Community
United States
74703 Posts |
I don't know Jim. Maybe it's just damage, or a weird type of Struck Through?
Errers and Varietys.
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Pillar of the Community
United States
4404 Posts |
I think it's damage, I'm pretty sure Rockwell tests are supposed to be raised on the coin, not incuse.
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Pillar of the Community
United States
509 Posts |
Rockwell tests do in leave an indentation in the material tested but it should be perfectly round. Below is a paragraph in the AZO Materials information section. Quote:
Technique of Rockwell Hardness Test
A specific load is applied on the indenter of a Wilson tester and the depth of the penetration is measured. The indenter may be a steel ball or a spherical diamond-tipped cone of 120° angle and 0.2 mm tip radius (called a brale). A minor load of 10 kg is applied first, which causes a minor indentation. This is done in order to seat the indenter and also remove any surface irregularities.
Then the dial is reset and the major load is applied. The depth of penetration is measured after removing the major load but retaining the minor load. The hardness number is read directly from the scales. A brale with a load of 100 kg is used for very hard materials and the hardness is read on the 'B' scale. For most materials, a steel ball indenter is used. |
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Moderator
 United States
56855 Posts |
Use the search box,upper left on page. This subject has come up now and again. John1  |
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Pillar of the Community
7234 Posts |
When I worked in a bearing factory we used to Rockwell test all our hardened bearings. Like stated above, the testing aperatice has a ball contact end and when it strikes the metal surface it does indeed leave a perfectly round impression.
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Pillar of the Community
 United States
5239 Posts |
Thanks everyone! A very good lesson learned today.
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Bedrock of the Community
United States
74703 Posts |
Quote:
When I worked in a bearing factory we used to Rockwell test all our hardened bearings. Very interesting Mark! That's pretty cool. Did you like it? Errers and Varietys.
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Pillar of the Community
7234 Posts |
Yeah, it was a fun job. Worked 3-11pm then got to the bar just in time to get in trouble - LOL!
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Bedrock of the Community
United States
74703 Posts |
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Worked 3-11pm then got to the bar just in time to get in trouble - LOL!   Errers and Varietys.
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Replies: 9 / Views: 873 |
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Posted 08/06/2018 11:56 am
