What is the difference .120 wall cold rolled and .120 DOM

[evil69]

What is the strength difference between 2 inch .120 wall CR welded seam and 2 inch .120 DOM??? Any numbers or links???
Thanks.
Evil

 

[Skiddy]

Not a lot of difference, cold rolled will be a little weaker you can try this linkamerican welding society

 

[bsaunder]

Assuming the same material between the two (ie 1020 steel, etc) - the strength gains can be from 5-20% depending on the quality of the non-DOM tubing. I can't find my materials book right now, but I think the industry average is a 15% strength gain. This is due to better uniformity on wall thickness, grain alignment, and stress relief in the DOM tubing.


edit - I found some specs..
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1020 DOM STEEL TUBE
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1020 is normally used in the manufacturing of small-diameter or thin-wall DOM steel tube. 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.
American Specifications: ASTM A513 Type 5
British Specifications: 040 A 20, 070 M 20
Applications: Mechanical, hydraulic cylinders, shaft, tight tolerance requirements

Size Range: 1/4" - 14&1/2" (6 mm - 368 mm) OD; .035" - .625" (.9 mm - 16 mm) wall

Typical Chemical Analysis: C .15-.25
Mn .30-.60
P .040 max
S .050 max
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Typical Mechanical Properties: Tensile strength (ksi) 80
Yield point (ksi) 70
Elongation (% in 2") 15
Rockwell hardness RB80
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1026 STEEL TUBE - DOM
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1026 grade is normally used in the manufacturing of DOM, cold drawn seamless and hot finished seamless. This grade normally furnished over 2" OD, with walls heavier than .156". A variety of thermal treatments can be supplied, depending on the type and size of material.

American Specifications: ASTM A519 (SMLS), ASTM A513 Type 5 (DOM)
British Specifications: 070 M 26

Applications: Mechanical, hydraulic cylinders, shaft, tight tolerance requirements

Size Range: 1/8" - 24" (3 mm - 610 mm) OD; .028" - 3.00" (.7 mm - 76 mm) wall

Typical Chemical Analysis: C .22-.28
Mn .60-.90
P .040 max
S .050 max
Typical Mechanical Properties: DOM
Tensile strength (ksi) 80
Yield point (ksi) 70
Elongation (% in 2") 10
Rockwell hardness RB85
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1010 ELECTRIC WELD STEEL TUBE
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1010 is normally used in the manufacturing of electric-resistance welded tube. The product is available normally in cold rolled strip (16 gauge and lighter), and hot rolled strip (.083" wall and heavier). The product can be obtained in the as-welded condition (flash-in) or in the flash-controlled condition.

American Specifications: ASTM A513 Type 1 and Type 2

British Specifications: 040 A 10, 045 A 10

Applications: Machinery stands, exhaust tubes, handles, hand rails, display stands, conveyor rollers

Size Range: 1/4" - 10" (6 mm - 254 mm) OD; .028" - .375" (.7 mm - 10 mm) wall

Typical Chemical Analysis: C .08-.13
Mn .30-.60
P .035 max
S .035 max
Typical Mechanical Properties: Tensile strength (ksi) 45
Yield point (ksi) 32
Elongation (% in 2") 15 min
Rockwell hardness RB55 min

 

[70_Steve]

Now, aren't you glad you asked?! ?:?

Anybody here speak metallurgy?

 

[House]

Most of the time you would pick DOM for it's dimensional characteristics not yeild strength as far as I know, but yes, it is a couple percent stronger. Normal 1020 DOM is actually welded also, where a lot of people think it is seamless.

 

[evil69]

Wow! I feel stupid now....

I think I can understand some of Saunder's post. Very good, just way above me.

Sounds like my buddy is wasting $ for a cage on DOM. Now I can look smart.

 

[bsaunder]

I'll boil down the main parts -

1020 DOM STEEL TUBE
Tensile strength (ksi) 80
Yield point (ksi) 70
Elongation (% in 2") 15
Rockwell hardness RB80
---------------------------------------------
1010 ELECTRIC WELD STEEL TUBE
Tensile strength (ksi) 45
Yield point (ksi) 32
Elongation (% in 2") 15 min
Rockwell hardness RB55 min

The most common DOM tubing used is 1020 DOM and the most common CREW (cold rolled electrical welded) is 1010.
The 1020 DOM has 43% higher tensile strength, 54% higher yield point, and is quite a bit harder than the 1010 CREW.

What does that mean? You can build the same cage out of DOM that a CREW one was built out of (assuming good design) with a smaller tube diameter and/or thinner wall and save weight, and possibly not need as much cross and corner bracing.

On my cage I went with 1.75"x .120 wall DOM for the main tubes, 1.5"x.120 wall DOM for the support tubes, and 1.25" x.120 wall DOM for seat mounts and other tubing. If I had goen with HREW (more common to find than CREW), I would have gone with 2" x .120 wall for most everything and 1.5" .120 wall for seat mounts - and added corner braces at most junctions.

If the cage is designed well for HREW or CREW use - then that is all that matters. If its just being slapped together and not actually designed - I'd lean towards DOM tubing to get the extra safety factor.

 

[Gummi Bear]

Wow! I feel stupid now....

I think I can understand some of Saunder's post. Very good, just way above me.

Sounds like my buddy is wasting $ for a cage on DOM. Now I can look smart.

I wouldn't say that he's wasting money. I WILL NOT build a cage from anything other than DOM (unless I get a wild hair and find some Cr Mo DOM tubing just for the 'bling')

DOM will take a hit a lot better than a REW tubing. It doesn't dent as easily, is more difficult to bend, and much more difficult to make fail. Yes, it does cost nearly twice as much per foot, but it will provide you with a structure that is quite a bit stronger, and more durable (more rolls before you need to replace it)

Keep in mind that the Bronco is a heavy bugger. You need all the strength you can get, and when it comes to safety, nothing is too strong to protect your life, or the lives of your passengers.

 

[evil69]

Danke. Das ist gut.

Hey bsaunder, wanna come help build cages for vacation?? You seem to know your stuff. What are you talking about designing? Bracing and triangulation, or just planning out? We have done some research on other designs and such. Can I maybe send you some pics and plans of ours for you to check up on us? Granted, this is for a diesel toyota, but I want to screw up on my buddy's stuff first. ;D