best metal for eyebolt in corrosive enviroment 1

[alliedeng]

I have an eyebolt that sheared off because of corrosion in one of the treads. The eyebolt was a Turned Eye Bolt (TEB) ½ x 2.
I want the strongest metal that can resist corrosion because of this failure.

What metal would be best for this application?

 

[kingnero]

what kind of corrosion? what kind of environment?
What is the mating material?
What material is your current eyebolt? How long was it in service, and what is your desired service life?
...

 

[alliedeng]

what kind of corrosion? water causing rust
what kind of environment? steel bolt on steel bracket
What is the mating material? Motorcycle trailer tiedown
What material is your current eyebolt? I presume grade 2, manufacturer doesn't know
How long was it in service 2 years
desired service life? forever, when it fails I get damage on motorcycle and have to take trailer apart

 

[CoryPad]

The strongest metals that will also resist chloride ion corrosion would include MP35N, Inconel 718, and Ferrium S53.

Based on your current parts and application, I would suggest that you don't need the strongest material nor one that lasts forever.

Consider a forged part rather than a turned one.

Consider a heat treated steel (e.g. grade 8 or property class 10.9) and use a high performance zinc coating (hot dip, mechanical deposited, zinc-rich dip-spin).

 

[TVP]

Like CoryPad said, you want a forged Eye Bolt instead of Turned. Quenched and tempered steel with galvanized zinc coating should meet your requirements.

http://catalog.lexcocable.com/viewi...p-forged-br-eye-bolts/shoulder-nut-eye-bolts?

http://www.deltarigging.com/doc/Wire Rope/Rigging Hardware/Forged Eye Bolts.pdf

 

[tbuelna]

alliedeng-

Have you considered that your eye bolt may have failed due to factors in addition to corrosion? Even a mild steel eye bolt with a 1/2" thread would seem to have adequate strength for a motorcycle trailer tie-down attachment if loaded correctly. It appears that you might have installed the eye bolt such that the tie-down strap loaded the eye out-of-plane rather than in-plane.

A swivel tie-down ring would prevent this condition from occurring.

 

[ameyerrenke]

I tend to agree with tbuelna. How was the load applied to the eyebolt? Even a good quality tie down strap should fail before a rusted eye bolt loaded correctly. I prefer bolted D-rings personally, but any of the above mentioned replacements would likely be better than what was likely Grade 2 hardware.

If you want to stick with the eye bolt get a forged and galvanized one. Also consider if you can go up to a larger diameter, it'll be less prone to fail, and more steel there to sacrifice if you're worried about corrosion.

 

[alliedeng]

Thanks for all the replies. Just as an update the eye bolt is set on a swivel so that the load is always perpendicular to the load. The shear face of the bolt had a typical flaw at one of the treads due to corrosion. Luckily the other eyebolt did not have any corrosion and saved the bike from totally falling. for more information see Moki ez lock

http://www.moki-ezlock.com/.

I think I will add some grease periodically to make sure there is less of a chance for corrosion at the metal/metal interface of the eyebolt threads.

 

[redpicker]

OK, even though I am having trouble with
"...the load is always perpendicular to the load"
I have a few comments to add that, hopefully do make sense.

First, I doubt the eye-bolt failed in shear, or even "sheared off". I suspect fatigue. Throw corrosion in the mix, and it becomes much more likely. In looking at the photos, I would suspect that side-to-side rocking of the bike would place high bending loads on the eye-bolt, in-line with the turnbuckle. The easiest way to lower the fatigue loading I can come up with after a beer and 10 minutes is to replace the eye-bolt with a clevis and bolt the clevis to the frame with a bolt through the hole the eye-bolt uses.

http://secure.chassisshop.com/partdetail/C73-175/

Use galvanized or cad-plated Grade 5 bolts. Make sure you can check the torque on the nut holding the clevis to the frame to make sure it is tight and stays tight.

rp

 

[EdStainless]

And plenty of silicone sealant when it is assembled.
Reduce amount of road salt that gets into the threads and under the head.
And of course, you need to make sure that it kept tight.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[Tmoose]

I'd install flanged eyebolts, with a large, thick washer on the other side.

http://www.nuttybolts.com/fasteners/images/BEMS-Eye Bolt-Mach-Shldr.jpg

If the bolt passed thru a hollow member there needs to be a spacer inside to prevent crushing the tube when the nut is tightened. Because the link is offset I think loosening of the eyebolt will be a common occurrence too.
IF i'm looking at the correct picture I think the rigid links will be doing their best twisting (loosening) and bending that poor eyebolt every bump they get.

http://www.moki-ezlock.com/images/Design Page/Moki EZ Lock on XL1200c Sportster.jpg

The links, not the MC suspension will be resisting the inertia going over bumps, and the eyebolts will take the hit.
I'd expect the clamps are going to make a mess of the frame as well, even if a sheet of rubber is inserted, in which case I think the clamps will migrate along the tube as well.

I'd use ratcheting tie downs in addition this setup. Ratcheting tiedowns are needed because the MC suspension can't be compressed to preload them. A rubber bungee between each tie down hook is good insurance that the tiedowns can't bounce loose and unhook.

Depending how the frame on the floor is configured and secured there is potential to crack it over time.

 

[RedVette]

If moisture-induced rusting without the presence of strong chlorides or other chemicals, Nitronic 60 (alloy 218) may the economic solution to your problem. Its galling (though not abrasion) resistance surpasses many superalloys, and its antiseizing properties ensures that a tightened thread will not become fused (cold-welded) over a long period of time, which is seen in most other steels. In addition, its chloride pitting resistance is greater than that of 316L stainless. But, again, its abrasion properties are not up to par with cobalt alloys, and corrosion in Nitronic 60 tends to occur after seizure.

I am not a metallurgist, so please regard my recommendation accordingly. I just did a lot of research on this alloy a while back.