Comments on: Hardness vs. Hardenability-There Is A Difference http://pmpaspeakingofprecision.com/2009/07/09/hardness-vs-hardenability-there-is-a-difference/ Sensemaking for the precision machining industry Mon, 30 Jan 2012 19:27:14 +0000 hourly 1 http://wordpress.com/ By: Andy steven http://pmpaspeakingofprecision.com/2009/07/09/hardness-vs-hardenability-there-is-a-difference/#comment-3747 Wed, 04 Jan 2012 07:16:32 +0000 http://pmpaspeakingofprecision.com/?p=436#comment-3747 A Brinell test is not as accurate as a Rockwell test because the indentation of the carbide ball is not as consistently finished as a diamond cone” In contrary! It’s much easier to manufacture and calibrate a perfectly round carbide ball, than it is to grind a Rockwell 120º diamond cone with a 0.2um radius round tip. To complete the story of thin metals testing for Rockwell:International standards recognize there is a limit to minimum sheet metal thickness that can be standard conform tested with Rockwell. They there for allow an exception: HR30Tm and HR15Tm – with the M for modified.These modified Rockwell tests are carried out under conditions similar to those of the normal superficial Rockwell test scales HR15T and HR30T, with the addition that a visible imprint on the backside of the sample is allowed. In order to prevent your hardness testing equipment from getting damaged the sheet metal sample must be supported by a special anvil, containing a polished and smooth diamond insert of approximately 4,5mm in diameter. To not damage this special diamond spot anvil, only steel (ASTM E18) and carbide (ISO6508) ball indenters are allowed for this special thin specimen procedure. Most digital Rockwell testers have a separate test program for HR30Tm and HR15Tm, indicating that your results are not subject of the standard HR30T or HR15T, but of these special conditions. This is an important improvement of your data integrity, and beneficial in communication with your customer or supplier.

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]]> By: speakingofprecision http://pmpaspeakingofprecision.com/2009/07/09/hardness-vs-hardenability-there-is-a-difference/#comment-3125 Sun, 18 Sep 2011 22:56:19 +0000 http://pmpaspeakingofprecision.com/?p=436#comment-3125 You’re welcome, Priyanshi. Thanks for connecting!

]]> By: priyanshi http://pmpaspeakingofprecision.com/2009/07/09/hardness-vs-hardenability-there-is-a-difference/#comment-3119 Sat, 17 Sep 2011 06:43:36 +0000 http://pmpaspeakingofprecision.com/?p=436#comment-3119 thanx

]]> By: Irene otieno http://pmpaspeakingofprecision.com/2009/07/09/hardness-vs-hardenability-there-is-a-difference/#comment-2880 Sat, 23 Jul 2011 04:59:00 +0000 http://pmpaspeakingofprecision.com/?p=436#comment-2880 I would like to be associated with you,am taking mechanical engineering

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