Forming Channels from Thick Plates. Ducitility concerns?

[Jerehmy]

Hello,

We do a lot of work for this manufacturer. They have in house engineers but they aren't PE's in some states, which is where our firm comes in. We will stamp drawings/calcs for states they aren't PE's in.

Problem: They are taking 3/8" and 5/16" plate and bending them into channels. They word it like this "(C10) Designation represents a SS 3/8" formed plate to match C10x15.3 Channel."

The steel is SS type 304L.

Two questions:
1) Does this constitute a cold formed section now? Should I design with AISI?
2) More importantly, does this type of steel even allow cold forming? Are you allowed to form sections this thick? It seems to me you will get significant yielding at the outside corners since the sections are much much thicker than cold formed sections. Aren't there ductility requirements for cold formed sections? Are my concerns valid?

They've maybe done this once before or twice before but for some reason I didn't take issue with it. I'm going to talk to my boss about it in a bit but I was also like to hear what the community has to say about this.

Thanks in advance!

 

[IFRs]

The Steel Construction Institute publishes several documents on SS structures. The ones I use most are "Design Manual for Stainless Steel" which covers bending SS and "Structural Design of Stainless Steel". Well worth the time reading IMHO.

 

[wannabeSE]

I don't have AISI S-100 in front of me. But I believe members over 3/16 thick are not in the scope of this standard. I second Topsisu's recommendation to look at AISC's Design Guide 27 for stainless steel.

 

[alejandrus45]

Jeremy,

I would refer to:
ASCE 8-02 Specification for the Design of Cold-Formed Stainless Steel Structural Members

http://www.asce.org/Product.aspx?ID=2147487569&ProductID=181341642

 

[CELinOttawa]

You need to be careful here. Do not apply modern methods meant for carbon steel when working with Stainless. Stainless does does not have a yield plateau, nor the ductility inherent in C.S. I think dhengr and Sail3 have the right approach - ASD, but I would caution that this has to be intended for stainless.

Small job or large, unfortunately you don't get a choice but to learn how to do something properly. Frustrating when it is a small bit like this... Just imagine the trouble you'll cause (and save!) if you find they've been doing it wrong. *sigh*