SA516 Gr.70

GTAW is characterized by its deep penetration, so we prefer it for stainless steel, but it is considered as an expensive weld which requires a shielding gas like Argon and high skill welder.

In piping A106-B, we used to carry out the 1st pass by GTAW and filling with SMAW by using E7010G or E7018.

In pressure vessel plates A516-70, we can use SAW for 1st passes and filling with SMAW by using E7018 uphill.

Very Important Note. Before carrying out any welding procedure, you are kindly requested to proceed a WPS & PQR to insure with the soundness of procedure and filler metals.

Very good answer by Abdul Halim. Same advice here :)

SA 516 Gr. 70 being a plate material, you can avoid using GTAW process and this process is generally recommended for root welding of CS, AS, SS pipes and full welding of SS, AL, CU, Ni etc.

SMAW/GMAW/FCAW follows GTAW to economise the welding,where ever applicable. or

You can use SMAW all the way up to cap pass or SMAW followed by SAW/ GMAW/ FCAW if the material thickness is 20-25 mm and above or for higher volume production.

Towards, consumable recommendation:

ER 70S-2 (with triple de-oxidizers) for GTAW root application and E 7018 for filler & cap passes (or)

E 7018 / E7016 for root , filler and cap passes.

ER 70S-6 for GMAW, E 71T-1 (or) E 70T-5 for FCAW and EL8/EM12K for SAW processes.

Pre heating to 100-150⁰C and inter pass temp. are recommended for thickness above 20 mm or so.

Sridhar.