I was wondering if anyone had any experience thru-wall sizing using the delta technique on dissimilar piping welds? Presently no one has passed thru-wall sizing of cracking at EPRI on dissimilar piping welds. You must size the indications looking thru an Inconel weld, the cracking is coming up adjacent to the carbon parent material in the buttering, access is limited to one side. Presently they are looking for a rms of .125 or less over the range of 10 to 12 test pieces you must inspect. The standard has been using ATT or RAT on similar piping welds, but in this case the rms has been .200 average.