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Re: [MW:26783] Re: Hardness unit

By Materials & Welding
MH310 Leeb Hardness Tester is rebound and  not based on Indentation principle ..which Vickers is.

On Fri, Sep 1, 2017 at 11:25 AM, Bala Guru Nathan <balagurunathan09@gmail.com> wrote:
Dear Sir,

248 HV10(Standard method for specifying vickers hardness value)  - Vickers Hardness value of 248 when 10 Kgf load applied on indenter.

The reason why the machine just gives output value as only HV is that the Vicker's hardness value is independent of the applied load (gives same value for 500 gf and 50 Kgf too). The reason for this is the included angle of 136 degree in the square pyramid which gives same hardness value irrespective of load applied. Also the formula HV = 1.854 F/d^2 takes care of the same.

So, if the load setup in your machine is 10 Kgf (Kilogram Force) then you can easily convince the client. If not, try to validate your values by explaining the principle of vickers hardness testing.


Regards,
Bala Guru Nathan,
QA/QC Engineer.


On Thursday, August 31, 2017 at 5:37:57 PM UTC+5:30, anhtrang nghieng wrote:

Dear Experts,

We are using the MH310 Leeb Hardness Tester to check the hardness of the piping weld joints ( For production- NACE material) . Project specification states that the maximum allowable value is 248 HV10. When using the MH310  Tester to check, the Tester only shows the unit HV (not specified HV10). Client QC worry about unit of value:  the HV unit displayed is HV10 or HV. HV/HV10 are equivalent ? Client required to clarify.

Please help me to clarify this issue and give reference.

Thank you so much.

 

GIGI

Piping Inspector

 

 

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