New here, looking to hear some opinions on my current workplace dilemma 

Q1 - Is it a poor practice to use mild steel "tacking rings" to squeeze and round out components for tacking purposes?

Q2 - How many inclusions are acceptable in ASME U & UM longitudinal and latitudinal weld seams, on the inside of the vessel?

I have question that is going to require some experience in the construction of stainless steel tanks. The contractor I work for has recently constructed 5 tanks that measure 75' by 30' by 50'. 316 stainless is the base metal and 317L is the filler used using the GMAW process. Shielding gas was 75/25. This far we already have problems. After construction the welds were vac/boxed as the standard testing procedure. Welders were all tested under the D1.1 code. Another problem as this is a large, unpressurized vessel so I believe that the code should have been API 650. Upon completion we are finding tons of discontinuities and to make matters worse the tanks are leaking at a rate of 2 1/2 gallons a minute!. Pinpointing the flaws are the biggest problem at this point because the client is ready for them to go back online. I know that they should have used a different shielding gas but, at this point they are trying to repair the leaks to run the units. Mind you, I'm a welder, I cried foul from day one of the testing procedure, filler metal, and code however I didn't write the PQR. Any advice or recommendations would be greatly appreciated at this point as this job is over a million in the hole!!

Hello,

The welder is qualified for P8 group material (ASTM A312 TP 316L). Are they can do the welding on P1 group materials?? Or else required to make new WPS. Please advise back