welding procudure.

[p7a7u7l]

Hie Team.

Am in dilemma on which WPS to use for API 5L grade B pipe schedule 20. Am proposing to use
1.GTAW/SMAW
GTAW with ER70S 2.4MM for root run and SMAW E7018 3.2MM for hot pass and capping.
2. SMAW.
To use E-6010 all through.
Between the two which one will qualify and have good penetration since all the joints will be subjected to 100% RT and bearing in mind the TS is 414Nmm.
kindly advice.

 

[Shmulik]

I would clearly prefer your first option of ER70S GTAW + E7018 SMAW.
You can expect much less problems in root, since GTAW root provides smooth concave face vs. SMAW root having convex shape that you shall carefully grind in order to avoid slag inclusions and lake of fusion in hot pass.

Additionally, Low hydrogen consumable is preferable to avoid hydrogen cracking (you have to bake the electrodes), especially in case your system is for LNG LPG or other hydrocarbons.

 

[p7a7u7l]

Yes Mr shmulik I agree with you the low hydrogen rods has to be baked for 18-24hrs using electric oven and temperature mainted by use of welding quivers.

 

[weldstan]

Welding out with E6010 or E7010 will prove the least expensive method as long as you have competent welders. You don't give the diameter, so thickness is somewhat unknown and the potential of the need for preheating (added cost) is also unknown. Acceptable quality can be met with either welding method stated.

 

[Shmulik]

p7a7u7l : For AWS A5.1 electrodes its normally at least 2 hours between 260°C to 430°C.
Please refer to manufacturer's instructions.