Just a word of caution about QW-403.6, make sure you read the MINIMUM thickness very, very carefully. Most of the ASME B&PV Codes (that I've worked with) do not require notch toughness until the thickness EXCEEDS 5/8 (16mm)... QW-403.6 says the MINIMUM thickness of material qualified, where notch is required is 5/8"... a lot of folks mis-read this paragraph, I'm speaking from personal experience (can ya see me blushing?). If you want a WPS to be qualified for LESS THAN 5/8" then ya gotta qualify progressively thinner members, or go straight to a 6mm thick part and do your tests on it, as well as your thicker members. the good thing is if you already have a heavy PQR all you need to do is the impacts by themselves, not all of the other tests, provided all the parameters etc., are the same.