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Posts Tagged ‘Stainless Steel Vessel’

An interesting project has come to our shop that is leading to a new welding procedure. The project is a simple stainless steel pressure vessel, 6” diameter pipe, 0.432” wall approximately 18” long. While this seems overly simple it has led me to investigate the welding options we have qualified for stainless in our shop. We have stainless hardwire, flux core, stick, and TIG procedures but which one to use? Flux core fills very fast, hardwire is clean and neat, TIG has an artistic look when done right but is slower then hardwire and flux core. Stick welding is smoky and unless the welder is REALLY good it just doesn’t look as nice as the others. I’m beginning to think multiple processes. If we hardwire the root then no backing gas is required (meaning we don’t have to purge the inside of the vessel to remove any oxygen exposure on the back side of the weld) then we can fill the majority of the weld joint with either spray arc hardwire or flux core and finish with TIG. We get a solid, quick welded joint that looks like art! But I don’t have a weld procedure that includes three different welding processes. Do I need to break out some stainless steel scrap and weld up a coupon using the three selected processes and have it tested? Conveniently, I do not. Because I have Procedure Qualification Reports (PQR’s) for all three processes I can write a new procedure using the existing PQR’s. I can take the information from each PQR and implement a new procedure that includes all three processes. Each process must be noted on the new weld procedure and the essential variables must also be noted. One other item to be sure to review, the thickness of the additive PQR’s must yield the thickness range required for the intended joint. Maintaining documentation of all our welding processes and procedures makes this an easy accomplishment, an accomplishment that allows us to utilize our knowledge and history to go forward. If you like the way a certain welding process looks but have been told it costs too much or takes too much time, give us a call. We’ll help you find a happy medium that yields beautiful welding and cost effectiveness.

Denver Stainless Steel Welding

TIG Cover Pass

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At Precision Pipe we have built a variety of vessels configured in every way one could possibly imagine.  Yet, we are always surprised by new ideas that come through our doors.  As a company that strives to exceed our customers expectations we are always looking for new ways to save money and bring value to our clients projects.  Recently, we were asked to bid on stainless steel vessels that are ASME rated above 1000 PSIG.  We returned a bid as requested but we also supplied an alternative bid using carbon steel that still meet the needs of the project but had the potential to save several thousand dollars off each pressure vessel.

How do you make a stainless steel vessel out of carbon steel?  There is the age old technique of cladding a vessel with stainless steel welding wire.  However, it is ugly, time consuming, and even distribution is unlikely.  In this particular case the esthetics of the vessels (inside and out) were equally important as the function.  Thus, we needed to supply quality, function, and appealing form to the project. What we have accomplished is Precision Clad.  We have effectively used seal welded stainless steel liners with stainless head and nozzles.  Using this methodology we have made the entire inside surface a stainless steel ASME pressure vessels while replacing the expensive, thick, and  high pressure shells with less expensive carbon steel.  In times like these Precision Pipe knows our clients need ways to get their projects finished in economically feasible ways.  However, this is not a new trend for Precision Pipe but an ethos of our company with 30 years of practice.

The results of these vessels have been well received and the savings have been remarkable.  In addition the vessels look great inside and out, they are 100% functional as corrosion resistant, this is Precision Clad.

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