100 ksi yield Tubing sources

[tmschrader]

Hello I'm looking for some 8 by 8 by quarter inch or more, 100 KSI yield tubing.
SSAB.com has some. But I think it's European Steel . I wasn't even sure it existed. It has an ultimate strength of 108 KSI. Very close to the yield.
My older aisc book only covers up to 50 KSI. I don't think the same .66 FY can be used on this stuff. Does anybody know if the newer aisc book covers this.
And I don't think it would like to use .66 times yield even if it is allowed. it doesn't make sense with the ultimate being so close.
I'm designing a long boom the carry quite a bit of moment. About 250,000 foot-pounds.

 

[JStephen]

Try googling the specification to which it's produced along with "700 MPa tube", that got me some other hits. It's not a product I'm familiar with, though.
Sometimes, stuff like this is available, but not in the quantity you need. It may help to design around what is available off-the-shelf.
My AISC book shows two or three different grades of tubing with 70 ksi yield, nothing higher.
Can't help on the allowables.
Connection details may be a problem.

 

[3DDave]

On one project we formed up 17-4PH and welded it into a rectangular tube and then heat treated. It's at 125KSI yield at condition 1075. It costs a bunch. It's interesting to start with the geometry and try to back-solve to a material. Perhaps try the other way around.

 

[tmschrader]

Thanks for the replies.
Waiting on info for the vendors they may have something.
I wonder if the new aisc book lists allowables that is based on Ultimate. My book doesn't.
I could extrapolate from values in the aluminum design manual till I get better info. They list allowables based on Ultimate and yield. The reasoning should be somewhat similar you have to stay a certain distance away from the ultimate

 

[JLNJ]

Could you use round? You might have more options there. We worked with round 4140 material which is close to what you are looking for.

 

[BridgeSmith]

If there's question on the availability of what you're looking for and the suitability of it if you do find it, why not just spec a material that you know you can get and know the properties, with a thicker wall?

 

[tmschrader]

Hello
This is a 100ft tele boom, so weight of the Boom is a significant proportion of the load.
We got to Mount a conveyor system on top of the Boom so it needs to be flat but maybe on the sides we could use the 4140 pipe. Done a lot of Shafts with 4140.
But maybe 4140 pipes with a flat plate welded on top of be cheaper than buying this Ultra stuff. I'm thinking we would probably have to buy mill quantities

It will be used for delivering concrete to job sites
They use ultra-high-strength beams in offshore structures. But the Dnv does not like to use over 500 megapascals which is about 70 KSI. This agrees with the aisc book. I will have to research how valid the concerns are.

Note that the USS steel site has information about ultra high strength materials and beams but it's really difficult to find useful information or contacts on
Thanks. Again

 

[3DDave]

Most such things have a taper to them or external bracing or are open framework/truss/lattice.

I can see where one might wish to do otherwise, so will leave that alone, but I will mention that structures like this are more likely to be unacceptable due to deflection and oscillation than they are from strength limitations.

 

[TimSchrader2]

HELLO

Most of these types are a open framework/Truss/latice with much higher stiffness. I have been asked to check out a boom section somewhat simliar to what they use with the trucks that deliver concrete with the long articulating pipes up to 150FT +. But those systems are much more tolerant to deflection. Yes, a definite issue.

 

[ornerynorsk]

We used to use a lot of SSAB steel sheet. If you find a distributor that carries some of their product, they can likely order in what you need.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.