50ksi W21x44 over 60' long Welding 2 together?
50ksi W21x44 over 60' long Welding 2 together?
(OP)
I need a W21x44 about 70'long. They come in 60' lengths. What is important to consider when specifying how to weld them together? Also is there a special inspection I must do (xray the full penetration weld)?





RE: 50ksi W21x44 over 60' long Welding 2 together?
Regarding nondestructive testing of the full penetration I- beam weld joint, you have several choices for a volumetric examination - radiographic (x-ray) or ultrasonic examination. I would also make sure you have blend ground the weld cap across the entire web and flange surfaces to assure complete removal of all weld toe undercut and high/low spots. In addition to the volumetric examination, I would perform a final surface NDT – wet fluorescent MT.
From a Code view, you need to review AWS D1.1 carefully to make sure all welding requirements are met. Also, I would review this idea with a licensed Structural Engineer regarding placement of the full penetration weld relative to the load carrying capacity of the I-beam.
RE: 50ksi W21x44 over 60' long Welding 2 together?
One other important point, I just noticed that in the title of your post you stated 50 Ksi for the I-beam. If this is what I think it is you are dealing with a high strength low alloy (HSLA) structural steel in lieu of A-36, and are going to have to watch your heat input during welding, and use lower preheat temperature requirements to avoid increased heat input which could adversely affect the mechanical properties of the I-beam adjacent to the weld joint.
This material is readily weldable but you need to use caution, and use low hydrogen electrodes (H4). Post weld heat treatment is probably not advisable because of deleterious effects on toughness – you will need to confirm. In addition to qualifying a weld procedure I would obtain some material for welding coupons to optimize the process.
RE: 50ksi W21x44 over 60' long Welding 2 together?
RE: 50ksi W21x44 over 60' long Welding 2 together?
The flanges are thick enough to consider UT for volumetric examination. The web is too thin to UT per AWS D1.1. X-ray is expensive when compared to UT. Verify the individual performing the NDT is certified per SNT-TC-1A, CP-189, or ACCP. Like the welder, the techician should have a written procedure to follow. I like ACCP certification because the certification process is handled by a third party, i.e., the American Society for Nondestructive Testing.
I also like "meteng's" suggestion to use the wet fluorescent magnetic particle test method to check for surface discontinuities. It is sensitive to small discontinuities open to the surface or slightly subsurface. Fluorescent penetratrant could be a second choice in place of MT if this is a field application and electrical power is not readily available.
If this is a critical application, and a 70 foot span should fit the bill, you might want to consider having a certified welding inspector witness and monitor the welding to make sure the welding procedure is actually followed.
Insist on a written welding procedure specification and make sure the welder is certified for groove welds.
Good luck - Al
Best regards - Al
RE: 50ksi W21x44 over 60' long Welding 2 together?
Dik
RE: 50ksi W21x44 over 60' long Welding 2 together?
I have a few questions, I'm a little green:
1) Is UT the same as Ultrasonic?
2) What is a castellated beam? Sound's like it hurts:)
RE: 50ksi W21x44 over 60' long Welding 2 together?
UT can mean ultrasonic test or in Code language is it referred to as ultrasonic examination.
RE: 50ksi W21x44 over 60' long Welding 2 together?
A castellated beam is a beam which has been cut in a "zig-zag" pattern down the center of the web, picked up, slid over, and welded back together to form a deaper section with wholes in the web. They are useful for passing ductwork through etc. They are generally produced as proprietary products by different manufacturers. An example would be the "smart beam" http://www.cmcsteelproducts.com/thumb10.html
RE: 50ksi W21x44 over 60' long Welding 2 together?
RE: 50ksi W21x44 over 60' long Welding 2 together?
The castellated beam is neat.
You have all been very helpful.
RE: 50ksi W21x44 over 60' long Welding 2 together?
Dik
RE: 50ksi W21x44 over 60' long Welding 2 together?
The castellated beam may work for my application. I'll keep it in mind. Thank you.
RE: 50ksi W21x44 over 60' long Welding 2 together?
Check the AISC Steel Manual for appropriate weld access hole shapes and finish.
Metengr--ASTM A 992 is now the standard for rolled structural shapes, rather than A 36. It's basically A 572 Gr. 50 plus a limit on yield point and yield-to-tensile ratio. It's not anywhere as rare a specialty material as you imply (most structural material has been met both A 36 and A 572 Gr. 50 for years even when the spec says "A 36"), and doesn't need such extremes as H4 electrodes or qualified procedures--most typical weld details will be prequalified per D1.1, where A 992 is listed in Group II in Table 3.1 for prequalified base and filler metal combinations.
Hg
Eng-Tips policies: FAQ731-376
RE: 50ksi W21x44 over 60' long Welding 2 together?
My statement regarding A 572 Grade 70 was to imply more of a cautionary approach related to welding, not rarity of material. This material is a HSLA steel, and I would still recommend H4 electrodes, especially for material thickness above 3/4".
RE: 50ksi W21x44 over 60' long Welding 2 together?
Dik
RE: 50ksi W21x44 over 60' long Welding 2 together?
The use of H4 electrodes is NOT standard practice for A 992, A 572 Gr. 50, A 709 Gr. 50 or 50S, etc., or else pretty much all structural welding would be done with H4 electrodes.
Low-hydrogen electrodes, procedures, and practices are recommended, but "low-hydrogen" doesn't mean H4, or even H16. "Low-hydrogen" SMAW electrode classifications are listed in AWS A5.1 and A5.5; the H designations are optional further restrcitions. (For 50-ksi material, the low-hydrogen classifications would be E7015, E7016, and E7018. I'd be stepping outside my comfort zone if I tried to tell you which one of those to use and why, but the bridge welders mostly seem to use E7018.)
AWS D1.1 has lots of info about low-hydrogen practice.
Not that the H4 will hurt, but if the shop has a hermetically sealed canister of regular E7018 on hand, there really shouldn't be any problem with that.
If you want to be as cautious as you reasonably could be, follow the fracture-critical provisions of the AWS D1.5 welding code, though the codewriters' intent is really more for the cyclic loading provisions of AWS D1.1 to be used for your application.
Hg
Eng-Tips policies: FAQ731-376
RE: 50ksi W21x44 over 60' long Welding 2 together?
RE: 50ksi W21x44 over 60' long Welding 2 together?
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