Welding Procedure for water tank to be built under AWWA 1

[beercia]

I have a question related to a welding procedure for welding the wall shell plates for a small 4000 BBLs water tank. Material of the wall plates is ASTM A36 1/4" thick 3 by 6 ft and the welding procedure calls for using welding electrodes A6010 for first pass and then A7018 for second and later passes. The thing is the contractor wants to change the A7018 electrode for the A6010 for the remaining passes. What effect could have this on the strength of the joint, finished quality and anything detrimental to the soundness of the joint and the tank itself. Is it OK to make the change? Which is a more appropiate welding electrode to use in this case: A6010 throughout or both A6010 and A7018?

 

[JoeTank]

Good news... Strength-wise, E6010 (60ksi tensile strength) is adequate for ASTM A36 (58ksi tensile strength).

Bad news... E6010 (F3) and E7018 (4) are different F number electrodes, so this is a change in an essential welding variable. A requialification of the welding procedure will be required.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com