callibrating a micro-hardness vickers tester
callibrating a micro-hardness vickers tester
(OP)
why do we need a specific test block for callibrating a micro-hardness vickers tester?
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
callibrating a micro-hardness vickers tester
|
RE: callibrating a micro-hardness vickers tester
RE: callibrating a micro-hardness vickers tester
You inspect the indenter under a microscope and verify its condition and dimensions.
You verify the load that you are applying.
And you verify the calibration of the microscope that you are using to measure the indentions.
This system does not rely on reference standards.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: callibrating a micro-hardness vickers tester
Case in point- P91 welded to 316H with a inconel 625 filler. The default calibration might be OK for the P91, but not the other 2 solids.
RE: callibrating a micro-hardness vickers tester
RE: callibrating a micro-hardness vickers tester
It is not necessary. The hardness tester is precalibrated for ferritic and other materials having essentially a Young's Modulus of 29,000,000. Accuracy is within specified limits. Any recalibration performed on test blocks of the same material grade as being to attempt produce the same results as stated on the test bar will most likely produce erroneous results (spoken from experience).
If the material to be tested has a different modulus than the precalibrated modulus, recalibration must be performed on calibration blocks having the same modulus.
RE: callibrating a micro-hardness vickers tester
So, for example, MIC-10 testing can be done on the entire family of Cr-Mo alloys (up to 9Cr anyway)?
RE: callibrating a micro-hardness vickers tester
RE: callibrating a micro-hardness vickers tester
Next MIC-10 question: when testing on tubes/pipes, do you have a rule of thumb for when bracing needs to be added? In terms of workpiece diameter and wall thickness (I understand it won't be one single answer).
RE: callibrating a micro-hardness vickers tester
I've never used bracing when using the MIC 10 or MIC 20 testers. Surface finish on the tube material and perpendicularity of the indentor to the tested surface are paramount. Only a 5 Kg or 10Kg load is applied by hand. I note that the smallest diameter and piping schedule subject to such testing under my direction has been 3/4", sch 80.