Why following ASME Section IX is not (always) enough

There is a common misunderstanding that if you follow ASME Code Section IX requirements to qualify and describe your welding process, you will be fine for the upcoming projects and audits, but this is definitely not true.

The basic roadmap through Section IX is to weld a test coupon, record the variables used for the parameters required by the particular process on the PQR, have a successful test and determine the qualification ranges for your WPS.

However, we should be aware that Section IX is not a stand-alone Code so you have to take into consideration the requirements of the specific design as well as the higher ranked Construction Code which is referencing Section IX, for instance Section VIII for Pressure Vessels or B31.3 for process piping.

Some examples are:

EXAMPLE 1: Impact Testing – ASME Section VIII, Division 1 para. UG-84(h)(2)(-b) requires that CS materials used for test plates of weld procedures with impact testing must be in the same heat treatment condition as the material welded in production.

This often “forgotten” requirement implies that if you weld normalized material with impact testing as a design criteria and your PQR does not indicate the heat treatment condition of the material used for the test coupon, the welding procedure might be invalid, unless you can prove that you fulfil the paragraph by backup documentation like Material Test Reports of the base metals used for testing.

Learned lesson here is that if impact testing is required, indicate on the PQR the heat treatment condition of base metal used for testing e.g. as-rolled, normalized, etc. Even if you are not sure which Construction Code you will follow when welding the test coupon in the future.

In addition, as Impact Testing makes the welding process more complex (see supplementary essential variables), take special care about the specific material-related acceptance criteria, test temperature, number of test coupons, sizes etc. And last but not least, make sure the impact test machine is calibrated properly.

EXAMPLE 2: Tube-to-Tubesheet weld qualification may be conducted in 2 different ways. The easier way is to have a proper butt joint welded which would cover the set-up of your tube-to-tubesheet joint design and the applicable variables. Sometimes dissimilar base metal thickness qualification QW-202.4 may be applicable.

Alternatively, Section IX QW-193 and QW-288 would require you to weld 10 mock-up welds of a similar tube-to-tubesheet joint configuration applied for production. Subsequently the mock-up will be sectioned and examined (e.g. 20x Macro-Examinations!). There is a big difference in time and money, but we should be aware that QW-193 clearly states that this paragraph shall be applied only if “required by the applicable Code Section” (this might also be a Client requirement though).

By Piotr Paluszkiewicz