Cold Rolled Tube Steel - Yielding Concerns

[JohnnyB_]

Hello -

I have a barrel roof to design where the main beam will be arched as shown in the attached image. The arch will be achieved by cold rolling HSS 10x6x3/8 tube steel. My question is, now that the steel has yielded, how will this change my design calculations?

Thanks for the feedback!

 

[dauwerda]

It won't.
Cold working does increase both the yield and ultimate strength of steel while decreasing it's ductility. It is common (in the structural world) to ignore these changes in properties while designing. Decrease in ductility may need to be considered in high seismic regions if it is part of the MLFRS - I'm not sure about that.

https://steeltubeinstitute.org/resources/hss-bending-hollow-structural-sections/

 

[EdStainless]

With that gentle of a arc the strain will be low and the impact on properties will be low.
The tubes may have been strained that much in the factory straightening operation.


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P.E. Metallurgy, consulting work welcomed

 

[dik]

There can be some distortion of the HSS faces that may have to be addressed.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[bugbus]

The HSS has already undergone far more significant yielding to bend it into its hollow shape than any additional rolling will do to it.

 

[dik]

Ya... it likely started out as a round tube and was rolled square/rectangular.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[bugbus]

dik, is that a North American thing?

I think the stuff we get here in Australia (mainly out of China/Korea etc) is normally folded directly from a flat plate and seam welded all in one process.

 

[JohnnyB_]

Thank you all for your input. It is appreciated!