WPS & PQR using combination process. 2

[MECH993]

Dear experts,
If a PQR is qualified with SMAW & SAW weld process, where SMAW is used in root pass only & saw for fill/cap and then SMAW root is completely back gouged before applying SAW from the other side, Can we write the WPS with the same processes, SMAW applied for root pass only which is back gouged before welding with SAW from another side?
Does the UW-31(c)for tack welds is also applicable for root pass?
If Yes, Can we consider the above PQR qualified per ASME SEC IX to apply SMAW in root pass?

 

[DVWE]

If a PQR is qualified with SMAW & SAW weld process, where SMAW is used in root pass only & saw for fill/cap and then SMAW root is completely back gouged before applying SAW from the other side, Can we write the WPS with the same processes, SMAW applied for root pass only which is back gouged before welding with SAW from another side?

Of course you can write a WPS that way. I would suggest using caution if, in the future, you tried to leave in the SMAW root pass for any production welding.

Does the UW-31(c)for tack welds is also applicable for root pass?

No. Only applies to tack welds.

The devil is in the details; she also wears prada.

 

[weldstan]

Fully agree with the above response.

 

[MECH993]

Thank you for your valuable inputs DVWE & Weldstan.

 

[gtaw]

You can only write a WPS for the SMAW if there was some SMAW deposit left in the tensile and bend test specimens when they were mechanically tested.

If all the SMAW deposit was completely removed, there would be no SMAW deposit in the tensile specimen or the bend test specimen, it is as if SMAW was never used.

Consider this, the weld coupon could have utilized a root face of sufficient thickness that the root pass deposited with SAW did not burn through the root face. The second side is back gouged to sound metal, including a small portion of the root bead deposited with SAW. The bottom line is that the entire weld is deposited with SAW. That is the same results as the coupon you welded where the root bead deposited by SMAW was completely removed by the back gouge operation.

Best regards - Al