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Low hydrogen What?

Posted: Sun Mar 22, 2020 7:18 pm
by RockwellSlagger
I have been reading on the interwebs and thumbing through my welding textbook is this just a problem with stick welding. I always assumed that flux core wire was safe from the elements. Now my textbook says you may have to recondition wire you have purchased that has been poorly stored ie, at home depot or what not. I am sure welding supply stores treat their wire with more care, but I am forced to shop at the former. Lincolns website basically said to bake your spools over night at 150 degrees. I am only asking because I am welding some ar400 and it is a relatively expensive slab so I do not want the weld falling apart. I have welded tool steel ie air hammer bits into hammers without any cracking but intial tacks on those always crack prob from lack of post/pre heat. Anyone know anything about this. The textbook just goes into E7018 when it talks about hydrogen imbritlement and HAZ. Or will baking my spool insure a job well done? I did pick up a small toaster oven I will dedicate to my spool conditioning.

Re: Low hydrogen What?

Posted: Mon Mar 23, 2020 9:39 am
by cwby
Heating & drying your wire won't hurt it.

Always pre-heat any high carbon steel to 250 - 350 degrees prior to welding. Tempstick works well for this.

Re: Low hydrogen What?

Posted: Mon Mar 23, 2020 10:34 am
by Oscar
Dare I say, all flux cored wire (whether it be gas-less FCAW-S, or gas-shielded FCAW-G) is susceptible to moisture if stored in an un-air conditioned area for long periods of time. If you are buying E71T-GS or E71T-11 from Home Depot, I doubt that it has picked up moisture just from the place of purchase. Depending on how it is packaged, could it have picked up moisture somewhere else along the line? Sure, but highly unlikely. But as was said, if you have a small oven and the wire spool is not plastic, you can "bake" it to try to re-condition it and it certainly won't hurt it.

Re: Low hydrogen What?

Posted: Mon Mar 23, 2020 10:42 am
by snoeproe
No issues with new wire.
I’ve welded lots of AR400 with s-6 mig with c-25 and with 7018 stick. Never had any problems.

Re: Low hydrogen What?

Posted: Mon Mar 23, 2020 11:12 am
by RockwellSlagger
Thanks for the replies guys I will bake it on the plastic spool as per Lincolns website at 150 degrees and use pre/post heat per the specs of the AR400 plate. This is the NR-211 MP wire that they sell at the Home Depot.

Re: Low hydrogen What?

Posted: Mon Mar 23, 2020 11:15 pm
by sbaker56
Some flux core is rated as low hydrogen, others are not, like 7018s they're only low hydrogen if they've been stored sealed, at an elevated temperature or reconditioned, Fabshield 21B is rated as low hydrogen H8, while NR 211 has the H16 designation, which is right on the limit for a low hydrogen electrode. If you've ever had a roll of flux core sit for several months or years out in a humid shop or damp basement you'll notice you'll get a lot of uncontrollable porosity at first until at minimum you're past the first couple layers of wire, while some of the issue may be due to very light or even unnoticeable rusting of the wire, it also has to do with moisture in the flux.

Hardwire Mig is an inherently low hy process, 70S-6 wire and so forth. If you rely entirely on shielding gas and not flux, there isn't anything to pick up moisture, but anything with flux be it stick welding or FCAW needs to be properly stored to be low hydrogen, and some rods like 6011 aren't ever intended to be and will run like crap if you dry them out.

There is another reason E7018 is frequently the "go to" rod for critical things though. E71t-11 which is the type of wire NR 211 belongs to, has no Charpy V Notch requirements at all. That doesn't automatically mean it's brittle, just that it can be. Something like an Excalibur 7018 has ridiculously high impact resistance compared to your standard 6011 or 6013 and frequently tool steel/high carbon is being used due to it being subject to impacts that would deform soft mild steel.

Re: Low hydrogen What?

Posted: Tue Mar 24, 2020 12:43 am
by RockwellSlagger
Very good info, this is not critical I am just welding a plate of medium steel onto some mild. Just don't want it falling off.

Re: Low hydrogen What?

Posted: Tue Mar 24, 2020 12:44 am
by bap_
I couldn't find any official documentation but be aware that you should be careful with NR211 if doing anything structural. As sbaker mentioned. NR211 is banned in coded work after the Northridge earthquake in CA.

Here is at least some information for you. https://app.aws.org/forum/topic_show.pl?tid=35386

Obviously your millage will vary and to be clear I'm not trying to tell you what to do. Just wanted to share.

Good luck and choose your wire appropriately for your application.

Re: Low hydrogen What?

Posted: Tue Mar 24, 2020 9:31 am
by Louie1961
This is a little bit nit-picky, but the term "Low Hydrogen" only applies to SMAW (stick) welding electrodes, and doesn't appear anywhere in the AWS standards. All other welding processes either need to specify an acceptable level of diffusible hydrogen and/or a charpy v-notch rating. https://www.lincolnelectric.com/en-us/s ... etail.aspx

Re: Low hydrogen What?

Posted: Tue Mar 24, 2020 7:57 pm
by snoeproe
If your worrying about your ar400 plate falling off because of hydrogen, you have other issues to worry about, not hydrogen issues.