What size tubing do I use?

[Hogback Fabrication]

HREW and DOM are made the same way for the first step. It starts as a flat sheet and gets rolled into a tube and welded by electronic resistance. If you have seen "How It's Made" it is the type of welding the used to weld the individual links of chain together. Kinda like heating both sides and pressing them together until the fuse.

HREW basically stops there while DOM is taken through a second process where the tubing is Drawn Over a Mandrel hence the name. This process smooths the weld out and makes the ID more uniform than its HREW counterpart.

This is the way I understand it if I am wrong I will never admit it

Dick

When the DOM is taken through that second step it is cold worked, the atomic structure changes and the steel becomes stronger.

Since HREW is hot rolled and then shipped off, it is weaker and cheaper.

You should use DOM for a cage. Don't forget that while larger tube diameters are harder to bend, they are easier to dent. Once the tube dents its pretty much worthless and a big pain to replace.

My chassis is mostly 1 5/8" .120" wall DOM

 

[slyguy_22]

Hey 1ton mudder that is a great cage! U gave me some great ideas with mine. i really like how you ran the bars behind the drivers seats. i will definetly be coming back to look at the photos when i get the time and money to do mine

 

[kitasjimmy]

Looks real nice

Your cage is awesome. I always say..."When in doubt...overbuild" yer kids will thank you for it. F**k the buzzkillers bro. You did a nice job. In the end ...it's your rig, build it as you see fit. Do you have any side shots of the whole truck. I'm in the process of building one myself and can always use more visuals.

 

[1-tonmudder]

Unfortunately I'm not doing it.I dont have the equipment or experience to build one so I'm having it done.It is still in the shop,but hope to have it back sometime this week or next and will post some better pics then.

 

[Hogback Fabrication]

As a followup to my previous post, here is some more info on the difference between DOM and HREW:

[FONT=Arial, Helvetica, sans-serif]Electric Resistance Welded (ERW) Tube
ERW is the most economical and readily available type of mechanical tuning. It is produced by taking a flat bar of steel and rolling it into a tube shape (picture rolling up a newspaper - but without any overlap) and then welding the seam - by, you guessed it - electric resistance - hence the name. Electric resistance welding is somewhat like a long, continuous spot weld. It's often computer controlled and extremely consistent. ERW is normally SAE 1010 (for wall thickness < 16 ga) or SAE 1020. ERW tube comes in 2 flavours:[/FONT]

[FONT=Arial, Helvetica, sans-serif]Hot Rolled ERW (HREW)
HREW is rolled into a tube at elevated temperatures, usually way above room temperature. This produces a tubing that is more malleable and therefore easier to form but that is also not as strong, is supplied covered with scale, and not as uniform in dimension as cold rolled. It is also quite a bit cheaper than cold rolled. [/FONT]
[FONT=Arial, Helvetica, sans-serif]Cold Rolled ERW (CREW)
CREW is manufactured by a process in which a steel bar is rolled into a tube and the seam welded, usually at room temperature. Compared to hot rolled, CREW is stronger - (greater yield strength) - because of the improvement in the crystal lattice structure from improved grain size, shape, and orientation imparted by being worked at cold (room) temperatures), straighter, has a much smoother and more uniform surface finish, and is made to much tighter, more consistent dimensions. It is the best economical choice for tube work, and because of the better surface finish and tighter dimensional tolerances it is much nicer to work with than HREW.[/FONT]
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[FONT=Arial, Helvetica, sans-serif]Drawn Over Mandrel (DOM)
Strong and well-finished DOM is an electric resistance welded tube tested for soundness of weld and drawn through a die and over a mandrel. This process imparts significantly improved mechanical properties to the tube, due to the cold working process. It is considered a high quality tube, and is normally constructed from SAE 1020 or 1026 steel. Note that, technically DOM refers to the process by which the tube is finished after having started as an ERW tube. Technically, DOM is not a type of steel tube, but rather a process. As so often happen though - in common use the term has become accepted to mean a specific type of tubing rather than a process. In this case, when people say "DOM" they normally mean an ERW tube drawn over a mandrel at (close to) room temperature and made from SAE 1020 steel. It is normally drawn to O.D. and I.D. dimensions. Here is what the Steel Tube Institute of North America has to say about DOM:[/FONT]

[FONT=Arial, Helvetica, sans-serif]The DOM Manufacturing Process [/FONT]
[FONT=Arial, Helvetica, sans-serif]The manufacturing process for DOM tubing begins with coils of steel, which are slit to the proper width for the desired tube size. The strip is cold formed and passed through an electric resistance welder which joins the edges together, under pressure, to complete the tubular shape. After testing the weld's integrity, the tubing is cut to length for further processing.[/FONT]
[FONT=Arial, Helvetica, sans-serif]The cold-drawing process creates a uniform, precision product with substantially improved tolerances, surface finish and tensile strength, increased hardness and good machinability. In this process, the tube is cleaned and annealed, and one end of each length is squeezed to a point so it can be gripped by the drawing mechanism. The tube is then drawn through one or more dies and over mandrels. This reduces the diameter of the tube and thins its walls to the required dimensions in a controlled fashion to provide the qualities desired in the finished product. Metallurgically, drawing improves the tube's concentricity, tensile strength, hardness and machinability. Close dimensional accuracy is achieved through tight control of both outside and inside diameters.[10]







The difference in UTS (ultimate tensile strength) between hot and colled rolled steel is 16% (UTS of hot rolled is ~70,000 and UTS of cold rolled steel is ~81,000)
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[ntsqd]

Nice find!
One thing it leaves out though is the real world difference btwn 1020 and 1026. You can tell the difference btwn them with a manual bender. The 1026 takes more effort to bend it and is the better alloy choice for a cage.