Is SAW bab for QT steel?

[bmoorthy]

I was shocked when i came saw that "SAW" was not one of the listed processes for Q & T material, this is in ASME Sec VIII Div 2 AF (Additional requirements).

Why is this so?
Where can i find out the rationale of a particular clause that occurs in ASME?

Is ther any document that specifies the basis for inclusion of a particular clause in ASME?

 

[metengr]

bmoorthy;
Submerged arc welding (SAW) is one of the permitted welding processes identified in Article AF-200 of ASME Section VIII, Div 2 Paragraph a (1).

 

[bmoorthy]

Metengr

I missed the correct clause AF 600 and AF 612 C 4.

If i have one of the listed material (Given in the Table) and i choose to use SAW then Production Impact becomes mandatory, where as ther is exemption if SMAW or GMAW or GTAW is used.

Hence the question, what is wrong with SAW (Noting that SAW of High alloy is not listed in Sec II C).

What about PAW?

 

[metengr]

Yes, I reviewed AF-600. The reason for not allowing SAW for Q&T steels that will not be subjected to Q&T after welding is the heat input for the SAW process will degrade base metal properties. SAW is a high deposition process and results in high heat input into the base metals being joined.

Regarding your second question - the reply is no per AF-612 C (4). Plasma-arc welding (PAW) is similar to GTAW, but an orifice gas and shielding gas are used. Since the Code recognizes the PAW process with separate essential welding variables per Section IX, it is not treated the same as GTAW.