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-   -   Wrought-iron vs cold-rolled steel (https://www.shopfloortalk.com/forums/showthread.php?t=51056)

J. Whitton 07-15-2019 12:25 PM

Wrought-iron vs cold-rolled steel
 
Hello all, as a new member I hope I'm posting this inquiry in the correct location. A customer brought in some "handmade" wrought chain that they are wanting to use to hang a rather large antique sign. The chain links are made from .250" square stock and are approximately 2.5" long and 1.125" wide. This sign is a little over 100lbs.

Let me fist state that I know very little about wrought iron but I feel this would not be adequate for safely suspending such a large piece. I suggested that we replicate this look with a cold rolled link version. I've always thought of wrought iron chains being too brittle to be nothing more than decorative.

Anyone have any input on comparing the two?

Thanks

Dr Dean 07-15-2019 12:56 PM

If it is indeed hand made I would say that as long as the links are welded it would probably hold 300-400 pounds. Take a link on the end and proof test it, keep adding weight until it deforms or breaks. Once you get it to deform call that your failure load, then divide that amount of weight by 1.5 and that would be your working load limit. If it deforms at 400 Lb then divided by 1.5 gives you a 266 pound working load.

J. Whitton 07-15-2019 01:06 PM

Quote:

Originally Posted by Dr Dean (Post 738780)
If it is indeed hand made I would say that as long as the links are welded it would probably hold 300-400 pounds. Take a link on the end and proof test it, keep adding weight until it deforms or breaks. Once you get it to deform call that your failure load, then divide that amount of weight by 1.5 and that would be your working load limit. If it deforms at 400 Lb then divided by 1.5 gives you a 266 pound working load.

Thank you for the reply. Unfortunately the links aren't welded. In my opinion these appear to be mass produced by some automated process. The customer said they were handmade but i dont think thats the case. I'll test a link and follow up with the results.

digger doug 07-15-2019 01:44 PM

No need to over think this.

welded, not welded
Worught alloy, cold rolled.

simply set up a test with the actual piece (the whole amount needed, not just a sample)
and apply 3x load, and see if it holds.

astronut 07-15-2019 01:52 PM

Sorry that I dont have any advice to add on your post but, welcome to the forum anyway!

Walker 07-15-2019 02:08 PM

Simple test, hang the chain, make a loop in the bottom, put your foot in the loop and stand on the suspended loop. For me that would be a 200 pound test, and four times stronger than needed, assuming two pieces of chain.

mccutter 07-16-2019 10:58 AM

If chain passes test, be sure to have customer sign some kind of waiver to limit your liability. It is sad that this is something one has to be worried about in this day and age... :(

BTW, Welcome Aboard! :)

USMCPOP 07-16-2019 12:25 PM

True wrought iron can be more ductile than steel. Old chains would stretch a bit when approaching their load limit.

These days, people refer to most any bent piece of steel/iron as "wrought iron".

J. Whitton 07-17-2019 09:23 AM

Thanks for all the input guys. Yes, the liability has me a little hesitant. After consulting with a local blacksmith, this "handmade" chain is most likely imported. My biggest concern was even though it might initially hold for a test that a link might possibly just snap in-two later down the road since I can't be certain exactly what possible impurity's this metal might contain or what process it went through during manufacturing.

I'm going to proceed with the build with the addition of steel cables with the proper load rating. Also a signed document stating that he is aware the chains are for decorative purposes only. If he wants to removes the cables after he takes delivery of it; that's up to him.

mccutter 07-17-2019 12:29 PM

Quote:

Originally Posted by J. Whitton (Post 738883)
I'm going to proceed with the build with the addition of steel cables with the proper load rating.

Feel free to post up pics of your project. We use on-site hosting here--the FAQs will tell you all about it...


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