Stainless Steel Pad Eye

[dik]

I'm trying to source a heavy duty stainless steel pad eye that (316L or something of that ilk) to be welded to a mild steel structure for lifting. The structure will receive a high quality epoxy primer and topcoat and am using stainless steel pad eye for abrasion/abuse reasons.

Can anyone suggest a source for the pad eye and the type of weld material to use?

Dik

 

[dhengr]

Dik:
Why is stainless steel appreciably better than mild steel w.r.t. abrasion and abuse? Why wouldn’t you use mild steel, of a reasonable grade, for the pad eye? Then design conservatively to tolerate reasonable abrasion and abuse, as is usually for these devices, and then apply the same finish to them as the entire structure. What do you gain for the added difficulty in finding or making the pad eye?

 

[dik]

It's in a corrosive environment and subject to abuse. We are looking at using a zinc rich epoxy primer and an abuse resistant epoxy topcoat.

Alternatively, we are looking at HDG and then a two or three part epoxy system. The lifting areas are subject to more abuse than the balance of the cofferdam parts from lifting, etc. and we were looking at using stainless for corrosion protection.

We are designing for a 20 year lifetime and have limited lifting capacity to crane it in place from an existing bridge structure without overloading the bridge structure. We have to keep the weight of the cofferdam panels to a minimum.

Dik

 

[MikeHalloran]

I guess you're looking for a stainless version of something like Crosby padeyes:

http://www.liftingsafety.co.uk/product/crosby-pad-eyes-2432.html

Have you considered an API style padeye:

http://www.excelcalcs.com/repository/machines/pins-and-joints/api-padeye-design/

... design calculator here:

http://www.maximumreach.com/PadEye.asp

... with stainless cheek plates?



Mike Halloran
Pembroke Pines, FL, USA

 

[chicopee]

I guess the pad eye will be resident with the steel frame once the frame is in place. So why not make or purchase a thicker padeye or lifting eye to counter abrasion and use the same grade of steel as the frame; then apply the three coating system to the pad eye.

 

[dhengr]

You hadn’t mentioned corrosion in your OP, although I kinda guessed that might be part of your thinking. But, how is it that the rest of the mild steel cofferdam panels are subjected to a lesser corrosive environment than the pad eyes? All of that kind of equipment is abused and reused, and should be inspected regularly for wear and tear. Furthermore, depending upon where you are working OSHA and/or ASME Below the Hook codes and regs. may come into play in your operations.

Which of the pad eyes MikeH showed where you thinking of? What are the loads, lifting means and angles, etc. I’m sure you could get plate pad eyes fabed from stainless steel, but I still wonder to what real advantage, when the rest of the structure is mild steel. It is also possible that you could just design lifting eyes or holes right into the cofferdam panels. Depending upon the panel designs, you might just weld a reinforcing plates to the panels at the lifting points; welded all around and bored to fit your lifting device.

 

[MikeHalloran]

Basically, you need to pick a shackle, and work from there.

Note also that ordinary stainless, absent work-hardening, is softer and weaker than mild steel, so may not be as abrasion resistant as you expect.
High nickel grades like 254SMO and AL6XN are harder and stronger than mild steel, and harder to work and more expensive than stainless.

Mike Halloran
Pembroke Pines, FL, USA