Dear All
in which standard or guide , establishing of refrence gain or sensitivity for evaluation in PHASED ARRAY is mentioned?
DAC or TCG or another way is applicable?
regards
Hi, You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this. Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime. Again, these simulated no. Of cycles shall be specified in MTC. The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case). One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example. In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...
Comments
The same accept-reject criteria are used for phased arrays as for conventional UT. This makes sense as PA do not change the physics of ultrasound. So, you can find the acceptance criteria in ASME, API, AWS or any internaltional code.
For your second question, TCG is far superior to DAC for encoded PA scans. Here, the operator can set the color palette to detect above threshold defects as a distinctive color. That way, it is quick and easy to see defects. DAC does not allow this easy solution.
MM.