That, SAW, makes more sense. Sounded a little strange to be doing any volume of that work and be using SMAW.
But, while not at all a big stainless person, it should not be a problem with a little planning, training, and money.
Have a Great Day, Brent
redrua, I must admit that both your initial question and your reply raises some concerns. Firstly, in your opening statement, you admit that your company is not concerned about the appearance of internal welds because as you say, "no one will see them"? That immediately starts MY alarm bells ringing. What is your QA/QC dept doing?
In your second statement, you state that financial investment is not a problem. Believe me, financial investment is never a problem until some one has to sign the cheque. Is the purchase, set up,development and training of welders/operators going to be viable for one tank?
I have worked on several large LNG projects and many petrochem sites all involving SS vessels, many considerably thicker than 6mm. Most of the larger thickness tanks/vessels use SAW for the circumferential and longitudinal welds with no problem. As has been stated, it is quite a pleasant looking weld. Working and fabricating with stainless steel is not rocket science, thousands and thousands of vessels, tanks and other complex designs are successfully fabricated daily around the world every day, using very conventional welding and joining techniques. Just google 'images of Stainless Steel Vessels' and you will see the size and shape of some of them.
Whilst in no way am I adverse to 'NEW' welding techniques or technologies, I think in your case that you maybe you can't see the forest for the trees? I would be more concerned about the inability to control or alleviate your present production problems before throwing cash on a potentially new problematic process.
I would suggest that the apparently unlimited financial investment your company has access too, be directed internally and used to build up your fabrication skill level amongst your workforce and maybe implement a more robust QA/QC system.
To start to consider plasma welding would involve a fairly hefty financial investment and a very long learning curve that would probably take years rather than weeks.
First off, what is the thickness of both the inner and outer members??? Joint configuration??? What code are you welding these to???, What type/design of clamping are you using?? Are you depositing sufficient tack welds prior to starting to complete the welding of each joint and how are they spaced??? and any other pertinent information because there isn't enough for us to assist you Then we can go to welding parameters to limit and control distortion, shrinkage, etc.
