A numbers

Date 06-09-2009 18:46

I know that a 304 SS pipe welded with ER 308 GTAW will result in a weld that is an A number 8. I know this only because I have been told so. My question is... is a chemical analysis always needed to determine an A number or is there some other way of figuring this out. I could forsee in the future I may need to write WPS's in accordance to ASME IX with other materials/process's and wouldn't know what A number it might be.

By 803056

Date 06-09-2009 21:19

If you are welding dissimilar metals, a chemical analysis is the way to determine the A number. There are other means of determining the A number listed in Article IV.

If you are writing WPSs for ASME you should have a copy of Section IX and the applicable construction code(s). The construction code may revise/alter the requirements listed in Section IX. Anyone attempting to write a WPS for ASME without the applicable sections of the B&PV code is just asking for problems.

Best regards - Al

By GRoberts (***)

Date 06-09-2009 22:50

As Al mentioned, the composition used to determine the A number can, but doesn't have to come from the actual PQR weld metal. The most common way to do it is from the filler metal manufacturer's certification. The permitted ways are all outlined in Section IX QW-404.5