Change welding process from FCAW SS semi auto to automatic

By Denny Agus Date 08-14-2018 07:44

We have a plan to running one PQR as per pre-WPS parameters as below:
1. Code: AWS D1.1/D1.1M : 2015
2. Material & Grade: 8”S80 pipe (machined from 8”S120), API 5L X52 grade.
3. Position: 6G.
4. Backing: Not applicable
5. Welding process: SMAW (Root & Hot pass) and FCAW SS (Filler & Capping).
6. Welding consumable:
- Root + Hot pass : Kobelco, LB52U, E7016, 2.6mm diameter.
- Filler + Capping : Hobart, FabShield offshore 71Ni (E71T8-K6J H8), 2.0mm diameter.

On PQR, we plan to use a weld technique as usually done:
- SMAW: manual
- FCAW SS: semi auto
But in production (on board / offshore), we will use a different weld technique for FCAW SS process:
- use auto cutting rail and setting FCAW SS over there (likely same as auto method: all travel speed and wire speed will be controlled by machine).

AWS D1.1, Table 4.5 & Table 4.6 did not state the essential variable / requirement in same welding process if we use a weld technique by Semi Auto method / Manual in the PQR then convert to Automatic method on production or vice versa.

Please advise on this issue whether still acceptable to change FCAW SS semi auto to FCAW SS auto process even we use same FCAW SS process?

By 803056

Date 08-15-2018 14:19

It sounds like you are transitioning from semi-automatic to mechanized welding. As long as the welding parameters are within the ranges qualified by the PQR, you should be fine.

Essentially you are clamping the FCAW gun to the tractor that runs on the track. The operator is still setting and monitoring the parameters of voltage, wire feed speed, travel speed, and electrode extension. The track and tractor simply guide the gun along the joint.

I would not expect the change you have proposed to have an affect on the mechanical properties provided the ranges of the welding parameters are within the ranges permitted by Table 4.5. If the ranges used in production are not within the qualified ranges, all bets are off and a new PQR will be required.

One question: if you know you will be using the mechanized method in production, why not qualify the process as mechanized to begin with and work out any bugs before backing yourself into a corner. Discovering an issue on aboard a barge can be mighty expensive and could cause a serious delay. The last thing you need is for delays and the associated costs to be attributed to you or your team. The question will be asked why all the bugs were not worked out before assembling a crew, the barge, support boat, NDE team, etc. There will be a learning curve!

Al

By Denny Agus Date 08-21-2018 02:54

Great, Al..Thanks for your input. I believe semi auto can cover auto as long welding parameter within the range of qualified PQR/WPS but auto can't cover semi auto due to auto welding parameter is more higher than semi auto. Now, we are managing 2nos of PQR, one use FCAW semi auto to cover semi auto and another one use FCAW auto to cover auto. Our erection joint have an inaccessible area if use by auto only, the machine clash with internal bulkhead. Hopefully this 2 PQR can cover both area for accessible area by auto and inaccessible area by semi auto.

Denny