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Stick welding stainless nut to A36 angle iron

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Stick welding stainless nut to A36 angle iron

Postby aland » Wed Jan 31, 2018 10:43 pm

Is it possible to weld stainless to mild steel?

Seems I may need some stainless electrodes, of some type of 306 flavor or similar. I'm not sure I've seen that, but vaguely remember seeing some stainless electrodes at my LWS.

I need to weld 4 nuts to some angle iron, so bought 2 sets of 4 nuts in chrome and stainless. I'm currently soaking the chrome nuts in vinegar to remove the chrome, but thought I would post and ask about the stainless nuts and see what the consensus is on using 7018?

I've seen some controversial threads in a quick search, where some old timers insist it must be done with 306 or 306L, but others saying they have welded stainless to mild steel and it's held up fine...

This is a VERY low stress application, it is basically holding a nut to a welding table to screw the caster bolt into...I'm pretty sure solder would work or even jb-weld, but let's say someone was wanting to weld a stainless nut to angle, would you guys even worry about that?

I mean I'm probably more anal than many folks for even soaking the chrome nuts to remove the chrome, I see people welding chrome nuts to steel on the web, just as I do folks welding with no gloves or arm protection...so, with all that said, not looking for a fight, just a discussion about stick welding and what some of you folks that know more than me have to say about it.

Alan
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Re: Stick welding stainless nut to A36 angle iron

Postby cj737 » Wed Jan 31, 2018 11:49 pm

You can use standard TIG rod or 7018. Both mild steel fillers will rust where the stainless won’t. The stainless nut will also melt at a much lower temp than the steel you’re welding to, so be mindful. You could also get a stainless stick rod and have a go.
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Re: Stick welding stainless nut to A36 angle iron

Postby Poland308 » Thu Feb 01, 2018 12:09 am

309 is for dissimilar metals. SS to carbon.

Edit
You can get different kinds of flux on 309. It’s a designation after the numbers 309. It dictates position of the weld. I’d recommend the one for all positions, but the most common one I’ve seen stocked is for flat work.
I have more questions than answers

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Re: Stick welding stainless nut to A36 angle iron

Postby aland » Thu Feb 01, 2018 4:00 am

double post...
Last edited by aland on Thu Feb 01, 2018 1:42 pm, edited 1 time in total.
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Re: Stick welding stainless nut to A36 angle iron

Postby aland » Thu Feb 01, 2018 4:09 am

aland wrote:
Poland308 wrote:309 is for dissimilar metals. SS to carbon.

Edit
You can get different kinds of flux on 309. It’s a designation after the numbers 309. It dictates position of the weld. I’d recommend the one for all positions, but the most common one I’ve seen stocked is for flat work.


Indeed you are correct Josh, they list that 309 and 309L as "Joining stainless steel to mild or low alloy steel". and it looks like the 309/309L are the only ones recommended for that.

I will pick some of those electrodes up, I see that Lincoln makes some of those in Excalibur. It's expensive, so I will see what they have in small packs, don't need 10 lbs. of electrodes for this application. In fact, the guy at my LWS was trying to talk me into using tig for it.

I was at the LWS store today getting some 7018 electrodes, I wanted a tube of Excalibur 3/32". Somehow I let him talk me into buying a 5# plastic tube which he said was the exact same electrode. However, after I got home and looked closely at the container, it's Jet-LH, so even though it's E7018, it has slightly different amps/temps than Excalibur but more importantly it's made in Mexico. Excalibur is made in the U.S.A. (from USA and imported materials). I can't do nothing about the materials, but the price was the same per pound, and I would rather have the sealed metal tube for the same price...so they will get the Jet-LH back tomorrow in trade for some Excalibur and I'll look for that 309/309L electrodes, maybe I can get a pound of that.

Alan
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Re: Stick welding stainless nut to A36 angle iron

Postby Lightning » Thu Feb 01, 2018 10:41 am

I wouldn't make a Mars Mission out of it, if you have to stick weld it, just weld it on there with some 601X.

Regardless of how you weld it, and what you use, it's probably going to:
a) rust, either due to "alloying" between the A36 and SS, or due to carbide precipitation in the SS due to the heat, and possibly
b) shrink and/or move so much that you need to cut it off and try again.

Don't over-complicate it. Put something in the hole (alum foil, mud, whatever) to protect threads from spatter, weld it on (HOT and FAST to limit distortion) and paint it afterwards to protect against rust. No need for $$$$$ Unobtainium electrodes...they won't help much, anyway.
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Re: Stick welding stainless nut to A36 angle iron

Postby aland » Thu Feb 01, 2018 1:45 pm

Lightning wrote:I wouldn't make a Mars Mission out of it, if you have to stick weld it, just weld it on there with some 601X.


Well, that's why I was originally asking. Does seem that 309/309L is the correct electrode for that, touche to Josh for providing the right answer. I know I can just weld it on there with any 'ol rod I have, and can weld the chrome nuts that are soaking in the garage, should be clean of chrome by now.

Thanks for your thoughts.
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Re: Stick welding stainless nut to A36 angle iron

Postby Lightning » Thu Feb 01, 2018 6:04 pm

aland wrote:
Lightning wrote:I wouldn't make a Mars Mission out of it, if you have to stick weld it, just weld it on there with some 601X.


Well, that's why I was originally asking. Does seem that 309/309L is the correct electrode for that, touche to Josh for providing the right answer. I know I can just weld it on there with any 'ol rod I have, and can weld the chrome nuts that are soaking in the garage, should be clean of chrome by now.


309/309L is no more "correct" for your application than 601X (just more expensive), for the reasons I stated. It's still going to rust, unless you paint it because it's going to alloy with the A36 and because the heat will cause carbide precipitation.

BTW, no need to remove the chrome on the nut. You can weld right through it and it will dissolve in your weld deposit (which will have about 25% chrome in it, anyway, if you use 309).
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Re: Stick welding stainless nut to A36 angle iron

Postby aland » Thu Feb 01, 2018 6:40 pm

Lightning wrote:309/309L is no more "correct" for your application than 601X (just more expensive), for the reasons I stated. It's still going to rust, unless you paint it because it's going to alloy with the A36 and because the heat will cause carbide precipitation.

BTW, no need to remove the chrome on the nut. You can weld right through it and it will dissolve in your weld deposit (which will have about 25% chrome in it, anyway, if you use 309).

Lightning,

Just got back from the LWS, boy oh boy, I learned a lesson...I just hadn't realized that stainless fumes are not good for us either, cause I've seen people welding on stainless quite a bit, but usually with tig.

My LWS pointed out that using stainless is merely trading bad plating fumes for bad stainless fumes, and because the metals are different, as you are pointing out, there could be problems between the two.

My LWS gave me these Harris Super MissionWeld electrodes, I think they must sell them to NASA, but he said they will weld anything together. He also mentioned they are very pricey, but he gave me a couple 3/32" and a couple 1/8" electrodes. He said it is some type of 312, but that it will weld any type of different metals together. Anyone heard of these?

BTW Lightning, my LWS also laughed and said it was no big deal to weld up a few nuts for an application like mine, not like all 4 would fail at the same time even if it did fail, but I'm sure any way will work fine. I was mainly wanting to understand that if you did have dissimilar metals, and in this case was stainless/mild what would be the correct choice. The reason I asked is that I did google first and a thread came up on WeldingWeb where someone said they used 7018 to weld up some stainless and mild and even though not recommended he had done it several times and no leaks for over 10 years...

I think this has taught me mostly that it could be good to have some inexpensive exhaust system to pull the fumes away, or in the worst case I will just use a small fan to blow the fumes away from me.

Alan

PS I apologize for my anal retentiveness, it probably matters little, I just like to understand those things... :roll:
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Harris Super MissionWeld, some type of 312 variant
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Re: Stick welding stainless nut to A36 angle iron

Postby Lightning » Thu Feb 01, 2018 6:50 pm

aland wrote:PS I apologize for my anal retentiveness, it probably matters little, I just like to understand those things... :roll:


No trouble...hexavalent chromium should cure it.

P.S. That SuperMissileWeld is some exotic, expensive and effective stuff. I sure as he¡¡ wouldn't waste it for your little "welded nut" project.
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