In fact, 3 mm is a low thickness.
In these cases, my personal experience is to use an E-6012 rutilic electrode (since you're talking about SMAW). It has a low penetration (good for thin plates) and a beautiful appearance. Use also 2.5 mm diameter electrodes.
Giovanni S. Crisi
Sao Paulo - Brazil
Boon,
I can see several potential issues in your post. First and most notable, your client doesn't like the idea of using SMAW. Ignoring that has a good chance of ending badly for your company. As Giovanni noted, it can be done, but I'd be for checking my contract docs and whatever code your working with to assure there is no language of restriction. If for instance, your working to D1.3 or D1.1 your going to find that very thing in regards to the EOR having the authority to do so. However that had to be established up front per those codes. Again, I do suggest reading those documents carefully before proceeding.
The second thing I note is, "we have no problem with dye pent test" NDE of any kind does not make a weld good. It was good or bad mechanically long before it ever meet any form of NDE. So you pass dye pen, it only means you have no discontinuities to trap the dye.
NDE is more for assurance that the welder and welding processes create a contigious weld free of harmful discontinuities, and has nothing to do with the mechanical properties of that weld outside that very narrow window.
This leads to the third issue. It's the PQR, WPS, and Welder quals and adherence to the values thereof that assure the mechanical values of the weld. Welding outside the essential variable values of your PQR/WPS leaves you without that assurance. From a technical standpoint, the owner would have the right to ask for whatever has already been done, to be reworked. Therefore if your going to try welding a retro PQR, it would be a good idea to play nice with the clients engineer. You wouldn't be the first contractor that ever had to rework something for reasons as you've stated. Playing hardball with them would probably be a very bad idea if you've already completed a large portion of the work.
My opinion for what it's worth,
Gerald
I have no disagreement that it is good to listen to the customer and to comply with the contract documents. If there are restrictions as to what welding processes are permitted, then by all means it is wise to take heed and comply with the requirements. Charge accordingly. If you feel it is better to use an alternate welding process or manufacturing process it is wise to propose it to your client and present your case. It is even better if you can show a savings in delivery time or cost or both.
If you still consider SMAW to be viable, and if the welds are to be ground flush, I don't see where SMAW isn't appropriate, I would suggest using E6013 with AC to minimize burn-through and to produce smooth weld beads with minimum spatter to minimize the clean-up cost. You can always produce a couple of workmanship samples to show your customer in support of your position that SMAW is appropriate for the work.
In regards to what constitutes "sheet", there are several different systems used by industry. One client I worked with took me on a tour of their facility and I observed a sign that read "Sheet Metal Department". I asked my guide what did they consider to be "sheet metal?"
His reply was, "1/2 inch and under."
Good luck.
Best regards - Al
Here in Brazil "plate" is considered to have a thickness of 1/8 in and over, whereas "sheet" is less than 1/8 in thick.
Giovanni S. Crisi
At the auto & truck frame plant, We got material up to 3/8" - 10mm thick as coil stock. I guess that is not sheet or plate, but a coil of that sure is heavy.
there seems to be no standard for the determination of sheet vs plate then does asme or aws have a determination?
seems to be a little glitch on a unified nomenclature, maybe we could establish something here and propose it to the proper code bodies and get some sorta credit and then supplement it, or revise it with the farm code. just for fun.
darren
It would be appropriate to add it to the farm code.
Al
Not living in the U.S., I know just a few slang expressions, among which "farm code" is not included.
For me, "farm" means an extension of land where the farmer cultivates wheat and corn and breeds cows and sheeps.
Does the "farm code" establish how corn must be fertilized and what kind of grass a cow should eat?
Giovanni S. Crisi
Giovanni: Here in the US there is a saying used to describe work done to a rather crude standard:"It looks like a farmer did it" This saying is based on repair, modification or a home made piece of equipment like farmers do, they get it done but use any unortodox method or material that is at hand, and workmanship is frequently poor. It is not a compliment.
Giovanni,
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