How Welding Process are Selected

It's best to hire experienced welders, but here's what some experts say:
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The Metallurgy of welding :Welding Design and Process selection ...
Welding Processes - Praxair

Thanks for the links, especially the second link is very good for reference.It is a good idea to hire experienced welders to execute this work. But, whole Welders I interviewed do not know much about whole welding processess currently available in the world. Moreover, none of them do not have a Graduation or Post graduation or Phd (Doctorate) or Post Doctoral.That is why I asked this question in CR4.

You will probably have far better luck finding a decent TIG welders (for example) searching in a random selection of Post Grad and Doctoral candidates; than you will finding Post Grads and Doctoral Candidates among a random selection of welders.

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Welding is fairly diverse and people are the best at certain aspects often know vvery little about some other aspects.

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I enjoy TIG welding and perhaps that will allow you to properly weight what I'm about to say:

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If from the outset you plan for welding to be part of the production process, then it has very good chance of ending up as part of the process. Welding is great for joining readily available stock (tubes, pipes, plate), or alterations thereof. Serious consideration should be given to eliminating or at least minimizing welding when possible though.

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Welding is often great for prototypes and one offs, but when possible keep optionss open to minimize or eliminate welding from production processes.

Well, if you admit that you know nothing about welding, and also want to produce commodities, you must realize that the processes used must be selected by someone who understands metallurgy, and the welding process and how to implement them into the fabrication of pressure vessels. There are safety and regulatory rules and regulations that must be understood and complied with, and by your own admission you are not the person to do this.

Hire a welding engineer, metallurgist or other well qualified individual to set up your fabrication operation. Certification and insurance requirements demand that you do that.

Also, since you insist on anonymity you may not get the same help/cooperation as a registered, known member might.

You have not stated if any specific codes are to be adhered to. One does not need post graduate or PHD qualifications to be ceritified as a designated "welding engineer" for design or for practise/procedure. If you do not have to adhere to any specific codes, most "ceritified" welders with experience will probably be able to make your welds from their past experience and even tell you what process(es) they prefer. If you have codes to adhere to, that is another ball game as you will at least have to retain (or hire) a certified "welding" engineer to do your weld design and oversee the procedures. Any one of these worth their fees, will also be able to recommend what process(es) are the most economical to use.

As others have commented below, there are a myriad of welding processes to choose from, so, unless you want to do a lot of studying and reading(I know it took me a few months to get my designation), best off to find someone who is already qualified. Yes you will pay for the services, but unless you want to get into this very seriously, it will likely be cheaper in the long run.

There are numerous methods of welding pressure and no-pressure containers. Much of the selection depends upon what materials you are welding, the configuration of the piece(s) being welded, the working and test pressures of the pressurized containers, what type of thicknesses you are contemplating welding, the equipment available, the skills of the welders and the types of welding they know and numerous other factors. Most important is the quality of the finished piece that you are welding. Stick, tig, and mig are the most popular but all of them require skills to do either good. Personally I like either depending what I am doing.

With your lack of knowledge you would be best to hire a welding consultant and have him guide you through the decision process and have him recommend a good welding instructor. If an instructor is not available ask the consultant to recommend an experienced welder to teach you in the particular type of welding you want to learn.

If you are welding pressure containers this is a very complicated task requiring very definite skills. There are several things that must be done correctly including: preparation grinding; selection of rods or fillers for the root pass and fillers; selection of proper heat (current); preheating if necessary; flux cleaning; grinding between passes; and others. Without knowledge of these factors and doing them right the least you will have to do is grind out bad spots and reweld them. This can be a very costly extra step depending upon how much and where you have to do it. Actual welding is not cheap on a per hour basis.

Welding good is not something that comes without much learning and practice. The striking the arc and filling are the easiest part, the learning what to do and when to do it are the hardest part.

Good Luck, Old Salt

The AWS (American Welding Society) is your best resource for selecting your process. You will need to list your final criteria, such as fabrication cost, pressure maximums, thickness of intended material (which will actually dictate the allowed pressures, if there will be joining of ferrous to non ferrous metals...

The AWS had set down industry standards as to what processes are suitable. Don't consult a welder, ask for a fabrication engineer. They will have a better understanding, hopefully, of what processes are applicable based on your final criteria.

Welding processes vary for the types of welding you would like to perform, level of automation you would like to achieve is important as well.

Skilled ASME and API qualified welders (others as well) are able to produce most ferrous or non ferrous pressure containment welds using SMAW, GTAW, GMAW and FCAW. A combination of these process may be used also. The key is to find welders who have specific experience in these processes. I do not think automated welding with robotics or automatic welders will work at the level you are at currently due to overall cost.

A welding consultant or engineer versed in piping or vessel welding who has years of experience can direct you thru these processes and help you establish a welding program as weld as pick of equipment required.

I'm not sure why you marked your comment 'off topic'. It is about as 'on topic' as can be.

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I really appreciate this last response. It isn't that often that someone summarizes the suggestions of the post to verify they have the crucial points right.

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That is a big list you have there, and several of the suggestions in the list are sophisticated requirements. This suggests the task as a whole will not be easy and should not to be taken lightly, but given your excellent communication and attention to detail in just this informal blog format, I think your chances for success are probably quite good.

sorry truth is not a compromise, if my comment hurt your feelings. when i found some discrepency, i just tried to correct it.i am always looking for perfection..

Enjoy

'hurt my feelings'?

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Oh, Anonymous Poster, what you noticed isn't any one of my feelings. What you noticed is a reading comprehension failure. If you work hard and focus on reading comprehension, your pursuit of perfection may develop beyond always looking for perfection, to a point where you actually find some (or a reasonably convincing facsimile thereof) occasionally, and so only spend most of your time on fruitless searches.

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'....Enjoy....'

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Oh, I do. Thanks for the reminder. I hope you also remembered to tell the sun to shine, the plants to photosynthesize, and Zebras to stay stripey.

Thanks

This is an excerpt from the document which i am trying to prepare.if you find any discrepancy, pls let me know, so that i can improve it.

guys i have strong interest in design of equipments, welding engineering, codes and standards, quality, metallurgy, corrosion, fracture mechanics, sports,politics etc. i feel some outside people closely monitoring my ip address and secretly infiltrated in my computer system. i am not a problematic person or a terrorist. i can give complete details of all fabrication requirements of equipments including reactor, reactor cyclones and regenerator used in refinery (not nuclear reactor and pls don't confuse). i have blue print of reactor and regenerator used in refinery, it's material of construction and weld map. again, i am not a problematic person or a terroristt. i just want to know as much as i can. is it a wrong thing? if any one need it. let me know, i can display a portion of that as it is a copyrighted material.

i have plenty of wps, pqr and wqt (cs (Process as well as pipeline) ,ltcs ,p11, p22,p91,ASS,DSS,SDSS,CRO, purge less TIG). if anyone need it pls contact me secretly.again, i am not a problematic person.

Above displayed images are the specifications in my posession. again i am not a terrorist. if anyone need it pls contact me secretly.

sorry i forgot to add complete material spec.

Carbon Steel Pipes&Plates

· SA 106 Gr.B, SA 336 Gr.6 (LTCS)

· SA 36, SA283, S275JR (Structural Steel)

· SA 285, SA 515,SA 516,SA 537 (Pressure Vessel Plates)

Low Alloy Steel Pipes&Plates

· SA 335 (Pipes)

· SA 387, P235GH (Plate)

Stainless Steel Pipes&Plates

· SA 312 (Stainless Steel pipes)

· SA 240 (Stainless Steel plates)

Titanium Plate

· SB 265 Titanium Alloy (Plate)

CRO Clad Plates

Stainless Steel

· SA 263 Chromium stainless steel (400 series - Martensitic and Ferritic)

· SA 264 is Austenitic stainless (300 series) clad steel plates for corrosion resistant application

Nonferrous

· SA 265 is Nickel Alloy clad plate

· ASTM B432, Copper Alloy Clad Plate (No ASME listing)

· ASTM B898, Titanium Clad Plate (No ASME listing)

took plenty of data from casti guide book and internet

if anyone need it pls contact me secretly