WPS QW-408 Gas
ASME Section IX WPS : QW-408 Shielding Gas Example
ASME Section IX Welding Variables for a WPS : QW-408 Gas
QW-408.1 - Trailing Gas or Gas Composition
the addition or deletion of trailing gas and/or a change in composition of the trailing gas
QW-408.2 - Change in Shielding Gas
The addition or deletion of shielding gas
A change in the composition of the shielding gas
Some exceptions are provided in this paragraph regarding changes within certain ranges of the shielding gas “oxygen equivalent” or “OE”.
QW-408.3 - Change in Shielding Gas Flow Rate
A change in the specified flow rate range of the shielding gas or mixture of gases
QW-408.5 - Addition or Deletion or Change in Backing Gas Flow
The addition or deletion of backing gas, a change in backing gas composition, or a change in the specified flow rate range of the backing gas
QW-408.9 - Deletion or Change in Backing Gas Composition
For groove welds in a variety of P-Numbers (see the paragraph details) the deletion of backing gas or a change in the nominal composition of the backing gas from an inert gas to a mixture including non-inert gas(es)
QW-408.10 - Change in Shielding or Trailing Gas
For a variety of P-Numbers (see the paragraph details) the deletion of trailing gas, or a change in the nominal composition of the trailing gas from an inert gas to a mixture including non-inert gas(es)
Essential Variable: Variables for which a change is considered to affect the mechanical properties (other than notch toughness) of the joint. Essential variable changes that fall outside their qualified range requires re-qualification.
Supplementary Essential Variable: Variables for which a change is considered to affect the toughness properties of the joint, heat-affected zone (HAZ), or base material.
Supplementary essential variables become additional essential variables in situations where toughness testing is required. When toughness testing is not required supplementary essential variables are not applicable.
Non-Essential Variable: Variables for which a change is considered to not affect the mechanical properties of the joint. This allows for editorial revisions to procedures within that permitted by Section IX without the need to requalify the procedure. Nonessential variables shall be documented on the procedure.