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Up Topic Welding Industry / Inspection & Qualification / NR211 Not acceptable for structural??
- - By FinishLine (*) Date 03-06-2016 02:07
I was on a structural welding job the other day and had a CWI bust my chops for running Lincoln NR 211 wire. First time I have had anyone have a problem with 211, so we discussed it, and at the end of the day he said no, I was wrong. I thought I would ask here to see if I was the minority or the majority in my thinking.  Here were the technical details for the job;

Base Metal: A36, 1/4 in. thick, all 1/4 fillet welds
Welding with my Prequalified FCAW-S WPS, any E71-T11 permitted

I know D1.1 limits T-11 to 1/2" base metal or less (Table 3.1 or 3.2 I can't remember), which is what my WPS states.

The CWI stated that 211 wasn't a "structural wire". I asked what he meant by that, and maybe that he meant "seismic qualified". He said "no, it's not structural, read the MFG literature". So I read the Lincoln NR 211 two page publication, sure it didn't say structural, it said general fabrication, but it sure didn't say not-structural, and the fact it is T-11, which is approved in D1.1 Structural Welding Code should be enough. I looked at ESAB Fabshield 21B, another T-11, and it states it's a light structural wire, anything 3/4 in and less.

We are welding 1/4 in. structural members, exactly what I would consider light structural, and T11 is approved for use in AWS D1.1. I really don't want to run 232 for a multitude of reasons, but will if I am in the wrong.

Opinions?
Parent - - By welderbrent (*****) Date 03-06-2016 02:59
Aren't you in AZ?  I'll bet he is a CA inspector.  They don't allow NR 211 on anything structural. 

It isn't a wire I like to see on a job, but for lightweight materials I believe you are good.  I need to do some checking to say that wholeheartedly. 

Brent
Parent - By FinishLine (*) Date 03-06-2016 15:36
Brent, we moved from AZ to CA. I think it is a CA thing, but the drawings reference D1.1 not some special "CA make it harder than it is" Standard :)
Parent - - By 46.00 (****) Date 03-06-2016 22:20
Hi Brent! What is the issue with NR 211? I have used this wire on major projects in the UK in the 80-90'
Parent - - By aevald (*****) Date 03-07-2016 06:52
Hello 46.00, shortly after the Northridge quakes in California there was a lot of inspection and forensic examination of structures and their failures. It was essentially determined that NR211 and other similar welding electrodes were not well suited for use in seismic situations (they were prone to cracking, metallurgically, barring any other discontinuities being found to be at fault) . There was a heavy re-classification of self-shielded wires in particular and this is where the T-8 wires evolved from. They are designed to meet the requirements of seismic applications. I do not believe that all of the jurisdictions in the United States require T-8 wires, most of the west coast does and I believe that other areas that have been judged as being seismically challenged do as well, although I don't know them specifically. That's my take on it and I am sure that others can provide a more thorough and fact based response. Best regards, Allan
Parent - By Superflux (****) Date 03-07-2016 08:55
When "Under the Hood" as it were, I love NR211. Burned it every day for 4 years.
But, back in the early 90s I was (a contract welder) prohibited to use it on a moment frame (they did accept 21B) in a seismic zone and regulated project.
I was told that the charpy tests were too low for the specs on this public works project.
Never researched it, I just bought a couple rolls (21B) of wire and went to work.
Parent - - By welderbrent (*****) Date 03-07-2016 17:35
Allan hit it Glyn,

I also have a hunch they 'feel' because it LOOKS more like a 6010/6011 weld it can't be good. 

CA being CA, everything is different.  LA in particular and anything that falls under DSA or OSHPD (schools and hospitals respectively) has special criteria that goes more along the lines of D1.8 for Seismic applications which definitely restricts NR211 for 'inter-mixing' of welds.

While the manufactures limit it for a particular thickness, and even in some cases limit it to single layer pass welding, CA/LA just says 'NO'. 

That may be a little simplistic but pretty well covers it.

Brent
Parent - By 46.00 (****) Date 03-07-2016 21:11
Thanks for the replies guys! I used it a lot years ago. Never had a problem with welding but I did hear of cracking problems later on.
Parent - By pipewelder_1999 (****) Date 03-07-2016 20:34
The De-oxidizers and denitrifiers (aluminum, Fluorspar is)can lead to subsequent cracking not to mention causing a great deal of pain and suffering when you try to weld over it with another process.

Though "down on the farm" the wire works great because you can vary stickout widely, minor changes in arc lengh in real life can affect the ability of the flux to perform. I think the controls needed to maintain consistent mechanical properties could be hard to achieve based on most methods employed for controlling "special processes" such as welding.
Up Topic Welding Industry / Inspection & Qualification / NR211 Not acceptable for structural??

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