Pre Approved Welds
Pre Approved Welds
(OP)
I am looking to find out if there are any pre approved welds (within AWS D1.1)for welding .375 straight seam pipe? The welding will be for pile casing and has to be performed on site? Any ideas?
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RE: Pre Approved Welds
RE: Pre Approved Welds
RE: Pre Approved Welds
If you are using steel pipe pile material, ASTM 252 grade 2 or 3, you can use any prequalified weld type listed in D1.1. You will have trouble conforming to CJP welds since most require back-gouging or backer bars. You might be able to use PJP welds like BC-P2, or BC-P8. Both assume "Stick-welding" or SMAW
It is my understanding the rejected oil-well casing has a high carbon content which makes it difficult to weld.
Why are you welding the piles. Can you use a splicer, similar to "associated Pile & Fitting Corp", Drive-on Pipe Pile Splicer. Refer to: www.associatedpile.com for additional info.
RE: Pre Approved Welds
RE: Pre Approved Welds
If you are installing a splice ring, you could use a CJP weld. However, B-U4a as do the other welds require a "gap" or root opening between the two materials. The root opening varies with the prep angle, but is usually about 1/4" (+1/16"/-0")for a 45(+10 degree/-0 degree) degrees or 3/8" (+1/16"/-0")for a 60 (+10/-0) degree angle. These root opening dimensions are as detailed. Knowing what field conditions are, you are allowed to deviate from the root opening dimensions, usually by +1/4" or -1/16". The deviation from the detailed dimension is refered to as "Fit-up". Assuming a 45 degree angle, the root opening may vary between 3/16" to 9/16" and the angle can vary from 40 degrees to 65 degrees. Regardless, what the angle is , you still need to provide a root opening.
Now the fun part......how do you "hold" the pile in place and still maintain the opening while the welder is welding the pile?
It is an expensive process to have a welder or multiple welders on site waiting to weld installed piles. Try using shorter pile with the splicer, it might be less expensive in the long run.
RE: Pre Approved Welds
After driving the first pile section, you level off the top of the pile and then set the splice ring over the top of the driven pile. A crane lifts the next pile section into place and the pile is guided into the top of the splice ring. The pile is plumbed (or aligned if a battered pile) while still being held by the crane. Then the weld is made while the crane is still supporting the pile.
If the piles are designed for any tension from uplift or bending, you probably need a welded splice, not a compression splice ring.
Yes, pile splices are expensive, especially in low headroom situations.
RE: Pre Approved Welds
RE: Pre Approved Welds
At least in my experience, the pile is tacked, or welded just enought to hold it securely in position, and the crane moves on to the next pile which is tacked, crane moves on, ect, ect.
The welders at this point have a set of pile splices ready to weld. This keeps the welders welding. By the time they are finished with one set, another set has been driven, and the splices are tacked up and ready to weld.
JTMcC.
RE: Pre Approved Welds