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Did I do this API calibration sheet correctly?
I've been practicing for the API Qute test. I see that I need some work on the calibration sheet. I have a few questions that the procedure doesn't fully explain.
1- Does the straight beam calibration need a TCG?
2- What range should the straight beam be calibrated to
3-What response do you put in the box "exit point"?
4- Do you set the time base (range) for the calibration block you are using, or for the piece you are examining? (Example, .75" basic block for a 1" plate).
Here are my two calibration sheets. Correct anything that you see wrong please.
Re: Did I do this API calibration sheet correctly? In Reply to David Bunch at 00:53 Jan-25-2010 (Opening).
1- There is no need for a straight beam unit, It is known that there are no defects in the base material, don't waste your precious time with 0deg.
2- See above
3- Exit point measured from the front of the wedge you are using, ex) .2", .3", etc.
Note: As far as I understand this calibration sheet does no affect test results
This test can be passed all while examining in your first leg, a short approach 70deg with a .25" probe is your best bet for this test. Yes, this configuration can see everything from an OD toe crack to the root. This is the config that I used to pass the test. I would practice with this probe a bit first and get the feeling of your sensitivity throughout your range. I set my range at 1.25x the thickness and set my EPOCH to display the end of 1st leg, which is the backwall of the test piece. If you feel comfortable you can use lower angles to verify indications. These are just my opinions and you should take the test however you feel comfortable. I calibrated on a NAVSHIP block running +6db on the .5", .75" and 1" SDHs, a different calibrations for each and corresponding to the different plate thicknesses (2x .5", .70, 1" DV)
Re: Did I do this API calibration sheet correctly? In Reply to Lloyd Nunes at 22:54 Jan-25-2010 .
Excellent information. Did you create a weld profile on graph paper for each test piece?
The method I had planned on employing was to create a weld profile by taking thickness readings every .5" on each side of the weld centerline (and the centerline itself). Then of course plotting the weld defects on the weld profile I made. Did you do this?
I have been using a 5mhz .25" 70 degree probe in my shop to look at different weld flaws. It picks up lack of sidewall fusion beautifully, but it does poorly with lack of penetration at the root (at least on the specimens we have).
USA, Joined Jan 2010, 4
Re: Did I do this API calibration sheet correctly? In Reply to David Bunch at 23:43 Jan-25-2010 .
I used some printer paper. If you are not familiar with these types of samples I would recommend that you take Mark Davis Flaw Detection class, worth every penny. You will get plenty of time scrubbing similar samples, this will allow you to create your own "procedure" of how you are going to take the test and which transducers are good for what. You can also make your weld overlays during this class (since the configs are the same) and take them in during the test. The instructor also can help you with scan plans/ characterization/ sizing and other tips.
I use a custom cut 52 degree to inspect the root area on these plates, less beam spread than the 70 and still maintains good corner trapping ability, great resolution so you can differentiate between LOP and a root crack. The 52 combines the benefits of the 45 and 60 (skipping into LOF) into one wedge, but hey these are just my opinions, you should take the class to figure out what you like to do.