stainless weld

[Manufacturer02]

In general, which welding machine should be used for API650 stainless steel tank welding, if purchased has not specified? MIG or TIG? I think for CS to SS welding on tank it should be MIG

 

[JStephen]

Generally, a question like that would depend on the equipment, people, skills, conditions, thicknesses, alloys, economics, etc., and may vary depending on those factors.
It might help if we knew the motivation for the question.

 

[Manufacturer02]

Hey Stephen, Thank you for responding on my post regarding API650 Stainless steel weld MIG or TIG. Our company has been building non code compliance tanks for agricultural sector since couple decades and now wants to step into industrial market with API650 shop built SS tanks. The company has CWB 47.1 certified welders. I am looking to see if any additional certification require for a company including welder certification, Inspector qualification or any other that needed to get our shop certified to make code compliance tanks. We are using MIG welding as of now. Do we have to use TIG for SS API & ASME tanks?

 

[Geoff13]

You should review API 650 Section 9 which discusses weld requirements. API 650 requires welding and welders qualified per ASME Section IX. Thus I believe you would need all new weld procedures and welder certifications.

In the end I do not expect that for small shop built tanks there would be any real quality difference between the finished products, but I also believe you could not certify the tank as API 650 if you used CWB welding.

You also mention ASME tanks in your final sentence, but that would be a much greater challenge. Anyone can build an API tank as long as they follow all the rules. For ASME work in Canada you would need to get your company registered with your provincial ASME authority (ie ABSA in Alberta, TSSA in Ontario, etc). That is a major undertaking.

 

[Manufacturer02]

Thanks Geoff13 for response. Just for API 650 stainless steel shop built tank, do I have to use TIG or MIG? any idea? API sec.9 doesn't specify that. But in general, TIG is mostly use for Stainless steel so thinking about which one to choose TIG or MIG.

 

[Geoff13]

My expertise is in design, not welding. Hopefully someone who knows Section IX welding requirements can answer you.

 

[JStephen]

Generally, you're allowed to use any process that will produce adequate quality. Assuming that's done, it's usually an economic issue as to which process is used.