Do 1/2" nuts get brittle from welding?

[chowland28]

Had a project going where I needed a 1/2" nut mig welded onto some steel. Found a 1/2" nut that was not zinc coated or anything, ideal finish for welding. Cleaned 'er off with some brake clean and then layed a few good, hot tacks on a couple of the flats of the nut. (I did not weld the p*ss out of it.)

Didn't really think much of it until now, but this nut is going to have a substantial amount of weight being pulled vertically down on the threads. I have no idea what grade nut I used and I am semi concerned about the nut becoming brittle from the welding?

Unfortunately, the re-do process would be a major PITA. 1/2" hardware will definitely handle the load, I'm just not sure how confident I should be about the grade of the nut and possibly weakening it from welding?

 

[f150skidoo]

Re: Do 1/2" nuts get brittle from welding?

I welded the ten 1/2" nuts to the C channel on my press. Those Gr.8 nuts/bolts that hold the cylinders base plate to the frame withstand 42 tons with no issue.

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[dogdog]

Not sure about the break clean..................

I did weld some 5/8 coupling nuts found in home depot on some plate for shelf support....then used a those long threaded rods to hang the 3' wide about 12' length shelf to the ceiling joist. It's been holding ok. this way I can adjust , level and support the long shelf

 

[jimgood]

Queue the brake clean warnings!

As for the nut, it'll be fine.

 

[sberry]

It will be fine, it's done 1000's of times every day. As as for the brakeclean as long as it's dry and not sitting in a puddle it's fine, doesn't hurt to vent the place either but you don't need to have it sterile for this either. It shouldn't be covered in grease.

 

[f150skidoo]

I should clarify incase OP doesn't know. Chlorinated brake cleaner is dangerous to weld if it hasn't fully dried because it creates phosgene gas which was a very effective WW1 chemical weapon. Non chlorinted is fine to use.

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[chowland28]

I just used the brake clean to clean off any grease and what not that may have been on the nut before I did the welding. I didn't mean for that to be the highlight of this post lol. I should not have added that detail.

 

[dogdog]

I just used the brake clean to clean off any grease and what not that may have been on the nut before I did the welding. I didn't mean for that to be the highlight of this post lol. I should not have added that detail.

It's for your safety.... not exactly a bashing. these things most likely your welds will fail before your nuts does... all dependents.

 

[taumac]

It's for your safety.... not exactly a bashing. these things most likely your welds will fail before your nuts does... all dependents.

I'll agree

 

[chowland28]

Thank you for the additional info on the brake clean!

 

[kwb]

Typically a nut is softer than the bolt so the material is less likely to get brittle (have brittle areas in HAZ)

The design should be that the nut is trying to be pulled through the part it was welded to not pushed out. The welds should be there just to react the forces of twisting a bolt into it.

 

[chowland28]

Typically a nut is softer than the bolt so the material is less likely to get brittle (have brittle areas in HAZ)

The design should be that the nut is trying to be pulled through the part it was welded to not pushed out. The welds should be there just to react the forces of twisting a bolt into it.

That is exactly how it is assembled...Besides the brittleness, my only concern would be that I am unsure of the grade of the nut. Even if it turned out to be the crappiest nut sold, could the threads really get ripped out THAT easily? I would assume not?

 

[Advan]

That is exactly how it is assembled...Besides the brittleness, my only concern would be that I am unsure of the grade of the nut. Even if it turned out to be the crappiest nut sold, could the threads really get ripped out THAT easily? I would assume not?

A standard 5-6 pitch nut will always have at least the "holding strength" equal to the tensile of the male-threaded element. So if it turns out you've used a grade 2 nut, you'll still have 10,000 lbs tensile and 8000lbs proof load. At this point you're most likely relying on the material that you've welded the nut too.

 

[RAYJAY]

Thank you for the additional info on the brake clean!

here is a link to info about brake clean and welding, we here at garage journal just like you to live another day ...........


http://www.brewracingframes.com/safety-alert-brake-cleaner--phosgene-gas.html

 

[chowland28]

Wow. I was totally unaware how dangerous brake cleaner can really be. Thankfully, I was using non chlorinated. I will be sure to be extremely careful as well as pass the information along. Thanks for the lesson everyone!

 

[Fueler]

You boys notice the "chlorinated" part of the warnings?
Use NON-chlorinated brake cleaner and the issue is moot.
It is still a pressurized can that should not be around heat or red hot slag.

Talked to a sales rep a while back. When the supply of chlorinated runs out there will be no more. Said they haven't made any new for a while now. Must have been one hell of a stock pile. True or just rep talk I don't know.

 

[BD1]

You can buy extra heavy nuts too. Where you located and how many nuts do you need ? You can get 1/2'' rod couplings if that would work .

 

[slip knot]

And don't leave the brake clean can on the welding table where you may accidentally hit it with the stinger when striking an arc. It makes on hell of a bang... Don't ask how I know this.

 

[CNGsaves]

+1 for GJ doing great job on safety warning on brake clean !!

. . . AND . . . OP did just fine welding his nuts !!!

 

[pamike]

The one issue with welding nuts is many of plated. The plating makes issues when welding and is toxic to a degree. Unplated, "black" or stainless nuts will weld better. Also, they make "weld nuts" which are bigger outside diameter and tend to shrink less when welded. you may have to run a tap through a standard nut once its welded on to cleanup the threads.

 

[BD1]

The one issue with welding nuts is many of plated. The plating makes issues when welding and is toxic to a degree. Unplated, "black" or stainless nuts will weld better. Also, they make "weld nuts" which are bigger outside diameter and tend to shrink less when welded. you may have to run a tap through a standard nut once its welded on to cleanup the threads.

As for the plating, let them soak in white vinegar for a few days. the plating will come off .

 

[chowland28]

As for the plating, let them soak in white vinegar for a few days. the plating will come off .

The whole reason I chose that nut was because it wasn't zinc coated or anything like that. Didn't need any work to become weldable.
It wasn't until after the complete install that I thought to myself, "****! I hope that wasn't a low-grade nut and I now just weakened it even more by welding on it!" So I came here to ask other opinions

 

[matt_i]

Imo, if its non plated its probably a grade 2. However, unlikely to weaken it much. the threads are rolled (formed) and not cut.

The design rule of 1x bolt diameter in steel or cast iron still applies here. If its any more critical than that then there are several areas which should be looked at.

 

[chowland28]

Imo, if its non plated its probably a grade 2. However, unlikely to weaken it much. the threads are rolled (formed) and not cut.

The design rule of 1x bolt diameter in steel or cast iron still applies here. If its any more critical than that then there are several areas which should be looked at.

What do you mean 1x bolt diameter?

 

[LumpyMusic]

Imo, if its non plated its probably a grade 2...

That seems backwards to me. Every grade 8 bolt and nut I own is non-plated.

I think nearly all my lower grade nuts and bolts are galvanized (zinc plated).

I think every plated fastener I own is lower grade, not hardened.


Lump

 

[sberry]

Welding it isn't going to hurt a thing and millions of plated nuts are tacked on. Keep head out of fumes. A tack is different than continious welding on them for days.

 

[red92s]

That seems backwards to me. Every grade 8 bolt and nut I own is non-plated.

I think nearly all my lower grade nuts and bolts are galvanized (zinc plated).

I think every plated fastener I own is lower grade, not hardened.


Lump

The yellow/gold color on most grade 8 hardware is zinc plating followed by a hexavalent chromate for additional corrosion resistance. The "clear" zinc you typically see on grade 5 hardware, which is a shiny silver color, uses a different chromate conversion process that is more environmentally friendly but less corrosion resistant.

Hot Dip Galvanized fasteners are coated with zinc as well, but have much thicker coatings than plated hardware.

 

[sberry]

I am not familiar with all brands and colors but usually been getting it from the farm type stores. Most bare is 2 and isn't marked, most shiney silver plated is 2, the gold used to be 5 and now they use green and where they do stock a small selection of 8 it may also be gold or blue. 5 welds very well as does 2 and there is almost absolutely no reason for mos5t on this forum to think they need 8 for anything they are building.
It is so rare I don't even stock it, the only use for it is in highly engineered machine connections, usually mfg designed and even then fairly rare. About the only place I see it on auto is head bolts, a few internal engine bolts. Possibly on bearing caps in rear ends.
I will have to add a disclaimer I spose, generally only used when super clamping power is needed and provided with high tensile bolts.

 

[kmacht]

As soon as you welded on the nut you changed its temper. A big difference in grade 8 vs other grades is the heat treatment process that the nut goes through. If your project will work with a low grade nut of the same size you will be fine. If you were counting on the strength of a grade 8 nut I would be looking at changing the design. Ideally the welds should be used only to keep the nut from turning, not for suspending a critical load. What is the worst that will happen if the nut fails? Will someone get hurt, significant damage incurred or will the part just stop working and you have to weld on another nut.

 

[chowland28]

I found a couple more nuts around the shop that I believe to be the same as the one I installed.
It has stamped on it, "2H" as well as a basic Triangle. I was intending on posting a pic in here, but apparently I never took the picture.

 

[matt_i]

What do you mean 1x bolt diameter?

Meaning 1x the major diameter of the bolt, as engaged threads. In contrast good practice imo is 2x diameter in aluminum.

 

[matt_i]

That seems backwards to me. Every grade 8 bolt and nut I own is non-plated.

I think nearly all my lower grade nuts and bolts are galvanized (zinc plated).

I think every plated fastener I own is lower grade, not hardened.


Lump

I guess my theory is shot. I own no non-plated Grade 5s or 8s.

Its tricky to know about the quality of a nut unless you bought it. There are no grade markings like a hex bolt head.

 

[Advan]

I guess my theory is shot. I own no non-plated Grade 5s or 8s.

Its tricky to know about the quality of a nut unless you bought it. There are no grade markings like a hex bolt head.

An unmarked nut is typically a grade 2.

 

[waynem]

A 2H nut conforms to ASTM A194 for nuts for high temp/ high pressure piping. Typibpcally used with B7 stud bolts in flanges and are heavy hex. It calls for a minimum carbon content of 0.40 which is not a low carbon nut. They are heat treated to 24 to 38 Rc. I am no expert on welding but would think as a minimum should be preheated. The triangle is the manufacturers marking.