PQR/WPS for ASME B31.1/CSA B51 PRESSURE PIPING

By Dimitriy Zolkin Date 01-23-2019 17:10

Hello all,

Our company is developing a pipe fab shop within our warehouse to fabricate pipe up to 14" dia. Were in the very beginning stages of setting up the shop, buying equipment and developing a QCM.

Our first project is to ASME B31.1 and CSA B51 standards, fabricating pipe from 3" to 14" with some of the spools/lines requiring 10% xray as per spec.

My question is regarding welding procedures. I have asked around and the consensus seems to be that the best method for welding full pen pipe up to 14" is TIG root with SMAW hot pass/cap. I know that SMAW 6010 root with SMAW 7018 hotpass/cap is also an option. And I havent looked into MIG root pass or combinations.

We will be qualifying our own procedures but I need advice/recommendations on which processes and combination methods are most efficient with best results (especially for xray). Should we have a quicker process for non xray welds and one for xray? Can we develop our own procedures or is it best to consult and Engineering firm and have them develop WPS for us.

Appreciate all your help and advice.

By Lawrence (*****)

Date 01-24-2019 18:50

Since you are just setting up. And since you are working in a shop environment.

Some things to consider about process selection.

Travel Speed
GTAW = 3-4 IPM
SMAW = 5-6 IPM

Travel Speed
STT / RMD root 10-15 IPM
GMAW fill = 13-17 IPM

If you can rotate your parts... And maybe even if you can't... Pipe is being welded all over with "waveform" controlled GMAW and MCAW processes that can increase productivity at least 4X without any reduction in quality. Root and fill are often done with the same electrode wire and just a flip of the toggle to change transfer modes.

No chipping slag, no changing machines,,,, So not only is the travel speed 3-5X faster... There is less transition time between root and fill passes.

Both Lincoln and Miller have tons of information out about this kind of work....

By Shane Feder (****)

Date 01-25-2019 00:05

Agree 100% with Lawrence.
There are numerous combinations of processes that can be used - I spent many years in a pipe-shop with pipe being welded GMAW (STT) / SAW on rotators.
Obviously costs a bit to set-up but once done the savings in time are immense,
Cheers,
Shane

By Dimitriy Zolkin Date 01-25-2019 20:39

Hey Guys,

I appreciate your input on this.

Funny enough, in the last 2 days we have come to the conclusion that we will be going with RMD MIG root pass w/ MIG or FCAW fill and cap with MIller Pipeworx 575 Model. The cost is a little bit high for initial purchase but the shear speed, effectiveness, deposition rate, soundness and operator error mitigation, this machine will practically pay for itself in no time.

I have to decide (and very soon) on what process to use for fill and cap. Im leaning towards MIG, to steer away from chipping, cleaning of slag and possibility of slag inclusions but still open to suggestions.