ASME VIII

Tal,

While you would most likely need to consult with the board of authors for this Code to find the absolute correct reasons for not providing the provisions for RT for those P numbers, the likely answer is because of design with s/s materials. You may also note that the Code does not provide for RT on 18" thick s/s materials. Why you may ask? It is simply because for Boiler and Pressure Vessel applications, you simply do not find components manufactured in that thickness. The same likely holds true for anything over 1.5" thick. Or, in the rare instance that you would find anything made in that thickness, the quality level of that component need not be very high where it would require RT inspection.

Again, I note that you have posted quite a few Code specific questions. As a suggestion, I would perhaps look in the front of the Code to find a list of the authors and/or contributors. Maybe you could Google them to find contact info. Even if one specific person couldn't answer your questions, he/she might be able to put you in contact with another contributor who could.

Good luck! And when you do find the answers, please come back and share with the rest of us.

thanks

1- (austenitic Stainless Steel can not response to PWHT) this is one reason do uoy have another reason for ferritic Stainless Steel???

2-

(Table UCS-56-1 Applicable Only When Permitted in Table UCS-56)

see also note (3) for Table UCS-56 P no. 5-A

((3) When it is impractical to postweld heat P-Nos. 5A, 5B Gr. No. 1, and 5C Gr. No. 1 materials at the temperature specified in this Table, it

is permissible to perform the postweld heat treatment at 1,200°F (650°C) minimum provided that, for material up to 2 in. (50 mm) nominal

thickness, the holding time is increased to the greater of 4 hr minimum or 4 hr/in. (25 mm) of thickness; for thickness over 2 in. (50 mm),

the specified holding times are multiplied by 4. The requirements of UCS-85 must be accommodated in this reduction in postweld heat treatment.)

( the nominal thickness at the welded joint exceeds 1-1/2 in. (38mm), this for any P. No except the P. Nos in UCS-57 use exceeds the lesser thicknesses prescribed in UCS-57)