AR400 plate for structural use

[pbc825]

Hi all,

I recently took on a project for which we're looking at a air cleaning system (cyclones). I knew before I took the project that the cyclone ducting used AR400 plate, but I understood its purpose was for liner only. Looks like some of the ducting walls are made exclusively from AR400 plate. The ducting is relied upon to resist structural loads from connected ducting. The client is replacing the ducting, and our scope is limited, but we will ultimately be responsible for the ducting when it's complete. It's performed well for at least five years as it was. Anybody used abrasion plate for structural purposes before? Can anyone provide advice? I'd recommend using a carbon steel backing plate, but I will likely get negative feedback from the client as they've done it without a backer before.

Thanks in advance.

 

[TehMightyEngineer]

I've seen similar high strength plate doing both structural and abrasion purposes on a cyclone before. Didn't end up doing the leg work on that project other than helping out with some field measuring so I can't offer much beyond that it appears to be common practice and I don't see anything wrong with it on principle, other than trying to connect the plates via welds would be complicated.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[dhengr]

Pbc825:
You will want to use low hydrogen welding processes and consumables. I think these are all quenched and tempered steels, but designed to be weldable. You will want to pay close attention to preheat and inter-pass temps., but otherwise, welding and material processing is pretty much std. fab procedures and equipment. You won’t likely match (won’t want to try to match) the steel props. with the weld filler metal and for that reason you pay some added attention to weld design, but the undermatched weld metal is usually not a problem since the welds are not the controlling design feature, or you can design around the few that might be. These aren’t usually off-the-shelf steels, so mill orders, lead times and material cost can come into play. I suspect that if major abrasion and repeated replacement isn’t a major issue (i.e. wear plates, wear edges, wear liners) the client is just saying... ‘why do I need two layers, when this one works fine and can act as the structure too?’ Good point, when it works. That added layer and its detailing and handling cost more than the added steel cost. For the most part it just involves a little extra attention to detail during design and in fab. Of course, external stiffeners and structural elements can be a more common HSLA steel. Talk with your steel suppliers and welding suppliers, they will have a wealth of info. on this subject for you.