Pipe vs. D.O.M tubing

oxbronco

Active Member
I have a question, about Pipe and DOM tubing, I work in the welding industry and we fabricate pretty much any thing that comes our way, we do everything from natural gas pipe, steam pipe, water pipe, alot of pipe in chemical plants, to structural fab and every thing in between. My question is it seems like this DOM tubing is mostly almost exclusivley used in the automotive industry for example, roll cages. Over the years we have built a few roll cages for people but out of 2 or 2 1/2'' scd. 80 pipe. All of our notching dies are for pipe, Is it really worth it to get set up to work with DOM?
 

lewis

Fight Till You Die
Location
Hairyman
Pipe doesn't have the strength of DOM. DOM is typically 1018 steel where pipe is most likely 1010. I have seen people use pipe for cages. I have used HREW tube which isn't as strong as DOM and it worked fine but I had to replace pieces everytime I rolled cause it would deform pretty easy.
 

Herzog

somewhat damaged
Admin
Location
Wydaho
DOM also has consistent wall thickness and more strength because it is "Drawn over a mandrel" as opposed to rolled and welded. You could also argue that the strength to weight ratio is much better with DOM vs pipe.
 

Shtmtlman

New Member
Location
Caldwell ID.
Not that i am trying to start a big debate, because i am only speaking from my own experience and i am no expert, but i have seen more dented and kinked DOM cages than i have seen sch.40. The weight difference between 20' sticks is 8.6 pounds. I do know that DOM flexs more than pipe as well. I built my cage out of HREW and i have also built a cage out of SCH.40 and have never had a problem with either. I know nothing about sch.80 what is the wall thickness? I also built my rock sliders out of sch.40 and no dents. My buddys rock sliders are made of DOM and have multiple dents in them. Plus the cost is a big difference to. I may be wrong or right, either way this is only what i have witnessed.
 

Greg

I run a tight ship... wreck
Admin
I understood that pipe was much more brittle vs tube. I wouldn't build a roll cage out of pipe, but have used it for sliders in the past.
 

RockMonkey

Suddenly Enthusiastic
DOM also has consistent wall thickness and more strength because it is "Drawn over a mandrel" as opposed to rolled and welded. You could also argue that the strength to weight ratio is much better with DOM vs pipe.

Actually, DOM is rolled and welded. It's then drawn over a mandrel to normalize the wall thickness. It starts as ERW tube.
 

Crankylove

Crankylove
Location
South Salt Lake
I worked in a sheet metal/steel fab shop for a few years, and we used both pipe and steel tubing. Easiest way to think of it may be that in general, "pipe" is made to carry a substance, be it liquid, gas, etc., and steel tubing is made for use structurally. The pipe was generally less expensive, but not made to stand up to the stresses that may be placed on it when used as a load bearing part of any type of structure (tends to be more brittle than steel tube). With a thick enough wall thickness, the pipe can stand up to quite a bit, but, at that point, you will probably going to have much more weight with pipe versus steel tubing, and may end up spending more for the heavier pipe than the tubing would have been. Of course, this is all just my experience, yours may vary :)
 

Caleb

Well-Known Member
Location
Riverton
oh duh. Any idea if it's cold rolled then drawn?
I think it may be hot rolled and then cold d.o.m. This is in the info you posted in the thread I linked to
DOM is formed from strip and electric-resistance welded, then cold drawn to size. The cold drawing process causes the weld line to virtually disappear.

It kind of emphasizes that it's cold drawn after it's been rolled, but doesn't specify it was cold rolled as well.
 

oxbronco

Active Member
Thanks for the info, some one was wondering what wall thickness schedule 80 pipe was, that depends on the size for example 2'' is just under a 1/4'' thick and 2 1/2'' is just over 1/4'' thick. As for using pipe for structural we are building tank stands for a local chemical plant that were engineered using 5'' schedule 40 pipe. Like one of the previous posts I think that the main difference is the weight to strength ratio. Thanks again for the info about DOM
 
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