DOM Vs Welded Tube

[ajjelly]

I am purchasing a tube bender for to start my roll cage project. I will be using 1 3/4 tube for my roll cage. I wanted to know what tube you guys are building your cages out of. I am trying to make the best decision between strength and price. (BTW, the cage will be for a CJ7)

1 3/4 .120 DOM

1 3/4 .095 DOM

1 3/4 .250 DOM

1 3/4 .120 Welded Structural

Or do you use some combination of tubes for your cages.

[zachv]

I know you are new, but this has been covered MANY times, but to save you from having to search the best material listed would be 1.75x.120" DOM. You can use HREW to save some cash if the design is strong or you can make the main parts from DOM and the rest from HREW. Currently, DOM is about twice the price of HREW, in my area.

[ajjelly]

Thanks for the response, I did search, but I guess not long enough.

[DRM]

Wait... are you saying DOM is *not* welded?

[cj7jeep81]

Try looking in some of these threads.
http://www.pirate4x4.com/forum/search.php?searchid=855661

[utahjeepr]

1 3/4 .120 DOM- Great material, best choice of the materials listed. Only problem is cost. Much stronger than HREW

1 3/4 .095 DOM- Too thin of wall for your main structural members. You could use it in less critical areas, but why bother?

1 3/4 .250 DOM- Too thick of wall for anything in a cage. It would work, but it would weigh a freakin ton. And of course a lot of that weight would be nice and high so you would be able to "test" your cage quite often.

1 3/4 .120 Welded Structural- Good material, it is strong enough for the application while not being overly heavy. Not as strong as DOM but it works. I rolled a Jeep off a 70' cliff with a 1-3/4" x .120" HREW cage. I'm still here, that says a lot.

FWIW here are the numbers for HREW vs DOM

HREW is made from 1010 A513 type 1
Tensile strength 45KSI
Yield strength 32KSI
Hardness RB55

DOM is made from 1020 A513 type 5
Tensile strength 80KSI
Yeild strength 70KSI
Hardness RB80

[wheelsup]

You sure of those numbers? I would swear I have some HREW in my material rack that is stamped 1020 or 1028, can;t recall right now. I could go did for it.


1 3/4 .120 DOM- Great material, best choice of the materials listed. Only problem is cost. Much stronger than HREW

1 3/4 .095 DOM- Too thin of wall for your main structural members. You could use it in less critical areas, but why bother?

1 3/4 .250 DOM- Too thick of wall for anything in a cage. It would work, but it would weigh a freakin ton. And of course a lot of that weight would be nice and high so you would be able to "test" your cage quite often.

1 3/4 .120 Welded Structural- Good material, it is strong enough for the application while not being overly heavy. Not as strong as DOM but it works. I rolled a Jeep off a 70' cliff with a 1-3/4" x .120" HREW cage. I'm still here, that says a lot.

FWIW here are the numbers for HREW vs DOM

HREW is made from 1010 A513 type 1
Tensile strength 45KSI
Yield strength 32KSI
Hardness RB55

DOM is made from 1020 A513 type 5
Tensile strength 80KSI
Yeild strength 70KSI
Hardness RB80

[camo]

there are so many factors that you the builder must consider it is almost impossible if not irrasponsible for somebody to just throw out a size and type that will work. your best bet is to reserch the subject to the point that you have zero question in your own mind as what is gonna keep you alive using your cage under the worst conditions.

[fj40guy]

your best bet is to reserch the subject to the point that you have zero question in your own mind as what is gonna keep you alive using your cage under the worst conditions.

Uh, like rolling in your own back yard! :flipoff2:

Only problem... after watching the Jeep roll off Lion's Back... Damn, I don't think any cage would surive that. :(

Tom :usa:

[camo]

i guess that is my point. you go tell a guy he can use 1.5 .095 without knowing what he is gonna do in his rig or how he is gonna abuse it and then he dies...how does that make you feel ? I think guys building their own chassis and cages need to have a deep enuff understanding of the subject that what tubing to use is not even a question.

of course a bit of reading is gonna reveal what most fabricators and builders choose and you are free to copy cat them but even then you should have a deeper understanding of physisc and engineering before "recomending" what tubing a cage needs to use.

i tend to study rigs that have been wrecked crashed and what they used and how they used it rather than the current crop of pretty newly build chassis we all envy when deciding on materials. in other words, learn from what didn't and what did work in the past before jumping on the latest lightweight trend

[Toyota FJ40]

Wait... are you saying DOM is *not* welded?

DOM stands for drawn over mandrel, so no it is not welded it is drawn over a mandrel, it is basically extruded steel. Because of this the tolerances, strength and looks are better than welded tubing.

[ajjelly]

i

i tend to study rigs that have been wrecked crashed and what they used and how they used it rather than the current crop of pretty newly build chassis we all envy when deciding on materials. in other words, learn from what didn't and what did work in the past before jumping on the latest lightweight trend


That's partly why I asked the question. I wanted to hear other people's experiences. I am researching and will not make a decision until I feel I completly understand all the variables.

[desertCJ]

Wait... are you saying DOM is *not* welded?

DOM stands for drawn over mandrel, so no it is not welded it is drawn over a mandrel, it is basically extruded steel. Because of this the tolerances, strength and looks are better than welded tubing.


You're wrong....DOM is welded. Then it is drawn over a mandrel to smooth the seam and tighten the tolerences/cold work it. Seamless tubing is not welded.

[DRM]

lol - I knew someone would fall for that one ;)

[born loser]

all bets are off when you start rubbing them all over the rocks. One good scrape is all it takes to 'ruin' .120 wall DOM. I deliberately put my D-side 'doorbar' against a rock as a pivot a few days ago, and it ate over 1/2 way thru the tube. I knew it would...thats the nature of da 'wheelin beast'.
I wouldnt expect any .120 wall tube to last more than a season or 2 w/o a rebuild if you are really gettin in the rocks.

[Geesh]

Like it's stated above, DOM is welded, just the seam is smoothed. Don't know what 'welded structural' tubing is. The other two types of tubing I am familiar with are CREW and HREW. One is hot rolled, electrically welded, while the other is cold rolled, electrically welded. Both can be had for nearly the same price here from my metal source. Cold rolled will have slightly higher values for some mechanical properties. I use CREW.

but the cage design has far greater impact on cage stiffness and strength that the choice between DOM and CREW/HREW. Consider all factors before making the tube-type trade

[CrustyJeep]

DOM is CREW that has been FINISHED by being Drawn Over Mandrel (to squish (like that?) the weld, tighten the dimensional tolerances, and work harden the steel). Just to clear that up (even more)...

Oddly enough, true seemless tube is (a lot) more spendy than DOM, but made to looser dimensional tolerances, making it obsolete for most stuff.

[21TToy]

Why not weld a second layer of tube(cut in half) over areas of tube that are in known, high wear areas. Sure you can't predict them all but. You could replace the wear pieces as needed. If it' a stupid idea, it's because I'm a "newbie".

[Bigger Valves]

Wow, tons of misinformation yet again.

Most DOM is of the A513 type 5 variety. DOM is electric resistance welded after rolling the tube that is then drawn over a mandrel giving it it's final dimensions and "smoothing" over the weld seam. It may be hot rolled or cold rolled. It can be all kinds of grades. 1010 to 4140 and more. You can find it all. 1020 is common and always a good choice.

A512 tubing is butt welded after rolled. Not quite the strength of electric resistance welded tube. This can be different grades as well. Not all is 1010.

A519 is your seamless tubing that is basically a pierced rod. It can be found in all grades as well and is common for alloy tubing.

I would never use A512 for a cage, but that's my choice. I also don't plan to ever use any mild steel tubing other than A513 type 5 (DOM). I just prefer it.

You have to get a grasp of all the ways tube can be made and explained. There are all kinds of classifications, types, processes, etc. that have their own pros, cons, and specifications. It gets very deep.

[broncofreak2000]

Ok, I want to stir the pot a little. How does Sch 40 aka"poop pipe" rate compared to DOM or welded seam. I read the strengths of those two so how does sch 40 compare.

[ElPasoEric2005]

Your main concer should be bracing triangles and the sctructure, then you can choose the material that would do best. Putting 150ft of bracing and main tubing will cut the size requirement.