Ok. I know what DOM is and I know that I wish I coud afford to build my cage out of it, but I CAN'T. So everyone who wants to turn this post into another damned debate over DOM vs. pipe and shit can just go do a search and add onto one of the countless BS threads that have already argued over it. I'm not so cheap as to build out of pipe. Plus, most of my cage is already DOM. I'm just adding to it.

My question is: How the hell are HREW and ERW different? I have done several searches and, quite frankly, just got bored with reading through all the bickering DOM vs. Pipe threads and the likes. What I want to know is what the difference is, if any, how they are measured, and how to order it. The only place I can get tubing around here is from the industrial hardware store on special order. I need to place my order tomorrow and the people who work there only know "race car tubing" and pipe. According to them, only one size of tubing exists, and the technical specification and dimensions for it are, "race car tube." I know they can get me whatever I want if I just tell them what it is that I need because I have done it before. But if their life depended on looking up different sizes of pipes in their books and telling me the differences, they would die a quick death.

I have seen tube refered to here on Pirate as HREW and ERW. I suspect they are the same thing with different names, but I am probably wrong. I know that, if I wanted pipe, which I don't, I couldn't order it according to DOM size measurements because it is measured by ID not OD like DOM. Is HREW/ERW the same way? How do I tell the dimensions? Also, is there a web page someone can refer me to so that I can just look at all the different sizes and compare them, and then regurgitate what I want to my dealer? When I order DOM I just go to www.metalmart.com, get the size that I want, and pass the info on to my dealer, who get's is cheaper. But I don't know WTF I am looking for when I say that I want HREW/ERW.

I hope this long-ass message hasn't confused anyone. I believe that this is one of the longest posts I have ever made. :eek: Thanks.

J. J.

PS: Just to save any possible confusion in my own mind, I know what I need to know about DOM. So I don't need that explained to me unless it is in reference to HREW/ERW. So I would appreciate leaving DOM out of this discussion for the most part to save my own inadequately-sized noggin.

Looks the same to me.:D


Electric Resistance Welded Steel Tube

Tube made from strip, sheet or bands by electric resistance heating and pressure, the strip being part of the electrical circuit. The electric current, which may be introduced into the strip through electrodes or by induction, generates the welding heat through the electrical resistance of the strip.


Hot Rolled ERW Tubing

As-welded electric resistance welded tubing made from hot rolled strip, sheet or bands.

Right...I'll try to keep this tight and focused for ya!

DOM, ERW, HREW...all types of "mechanical tubing", as opposed to pipe. All mechanical tubing is dimensioned by OD and a wall thickness.

DOM is actually not a type of tubing, but a process that is applied to tubing after it is initially constructed. It is Drawn Over a Mandrel...which "cold works" it, giving more exact dimensions, smoother finich, and better allignment of the crystal latice structure. It is NOt seamless tubing, and it started life as some sort of EW (electric welded) tubing. Most commonly, when people say "DOM" they mean 1020 mild carbon steel rolled electric welded tubing that is then drawn over a mandrel.

Other mechanical tubing that is not necessarily drawn over a mandrel can be either hot or cold rolled (i.e. rolled from a flat strip into a tube when either hot or cold) and most commonly available will then be electric resistance welded to form the final tube.

Generally...cold forming and cold working add strength and uniformity to a product, and reduce stress.

So VERY BASICALLY, in terms of strength you usually have, in order:

DOM
CREW (cold rolled electric welded)
HREW (Hot....)

Again...these are all just processes, to fully call out the materil, you need to specify the type of steel...but most commonly we are talking about either 1020 mild carbon steel, or 4130 or 4140 Chromium molybdenum alloy steel or 4340 nickel chromium molybdenum alloy steel.

Ya could always search on my name and DOM for more ramblings from me

Just order ROPS tube!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ROPS (ROLL-OVER PROTECTIVE STRUCTURE) TUBE
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Structural tubing that offers high strength-to-weight ratio and a higher impact toughness. The steel is fully killed and melted to fine grain practice. Customers may specify yield, tensile, elongation and charpy impact values according to their needs. This product is to minimize the probability of catastrophic failure of vehicle cab structures in the event of a roll-over accident.
American Specifications: ASTM A500 for dimensional tolerance, squareness, straightness, twist and corner radii. Mechanical properties can vary by end user.

Applications: Cabs for agricultural vehicles, road and off-road construction equipment, and lift trucks.

Size Range: 2" - 12" (50 mm - 305 mm) sq and the standard rectangle sections of the same perimeters. Rounds available as special inquiries.


Typical Chemical Analysis: Alloying elements may be added to achieve mechanical property requirements.
C .22 max
P .04 max
Mn 1.65 max
S .05 max
Typical Mechanical Properties: Can vary to customer specification
Tensile strength (ksi) 70 min
Yield point (ksi) 50 min
Elongation (% in 2") 20 min
Charpy impact Wall Ft/lb (min) Temp (°F)
3/16" 11.0 -20
1/4" 13.0 -20
3/8" 18.0 -20




Machinability: Good

Weldability: Excellent

Testing: Generally one tensile test and one set of three impact tests are taken from each lot of tubing. Tubing is tested in accordance with the latest revision of ASTM A370. Certification of material is available.

Materials Resource Page Number: 41

I find it hard to believe that no one knows what DOM is in all the state of GA.
dont "y'all" live and breathe nascar and dirt track racing?

WOW! What a wealth of information you are! That was exactly what I was looking for! It's so refreshing to not hear, "Just use pipe," and "Would you trust ERW with your life?"

However, if you go to www.metalmart.com, the OD tubing I am looking for is listed as "1-1/2 rd crs 1018 steel c8r1.5 $1.09 " (That's per inch, which is why I will never buy from them!) How do I tell the wall thickness?

And, yes, this is Nascar country. There are a select few race car builders around here, and I know them all. Granted, non of them are racing Nascar, but they do tour dirt tracks around the southeast and, believe it or not, what we refer to as 1.5x.120 DOM, they refer to as "race car tube." One guy knows the difference but doesn't stock anything that I can use and charges me double the ordering price if I order it through him. Most of the racers build their cars out of pipe or whatever they can find at whatever steel stores there are, which there aren't many. I am in steel hell. Sure, there's steel mills eerywhere, but none of them will sell anything less than a $1000000000000000000 order. :mad2: I was looking for someone to notch some tube for me the other day so I called the most professional one that I knew of. he said he could notch only at 90* angles. I asked him how he notched the tens of chassis that he build, and he said he just uses a jig saw. I finally broke down and bought a real notcher, which means my garage is more technically capable of building a chassis than his shop. :rolleyes: It's pathetic.

J. J.

PS: Please continue! I am loving this!

Originally posted by patooyee


PS: Please continue! I am loving this!
HERE ya Go :D
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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

--------------------------------------------------------------------------------
Typical Mechanical Properties: Tensile strength (ksi) 80
Yield point (ksi) 70
Elongation (% in 2") 15
Rockwell hardness RB80



--------------------------------------------------------------------------------


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1018 COLD DRAWN AND HOT FINISHED SEAMLESS TUBE
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1018 is normally used in the manufacturing of cold drawn and hot finished seamless tube. The production of seamless tube is generally made by piercing a hot rolled bar. Hot finished is generally furnished in the unannealed condition, whereas cold drawn seamless is supplied in the unannealed or S/R annealed conditions, depending on the size.
American Specifications: ASTM A519

British Specifications: 070 M 20, 080 A 15

Applications: Axles, shafts, gears, bearings

Size Range: 1/8" - 24" (3 mm - 610 mm) OD; .0218" - 3.00" (.6 mm - 76 mm) wall

Typical Chemical Analysis: C .15-.20
Mn .60-.90
P .040 max
S .050 max
Typical Mechanical Properties: CDS HFS
Tensile strength (ksi) 80 60
Yield point (ksi) 60 35
Elongation (% in 2") 15 30
Rockwell hardness RB88 RB60



--------------------------------------------------------------------------------


1010 ELECTRIC WELD STEEL TUBE


--------------------------------------------------------------------------------

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





--------------------------------------------------------------------------------


1026 STEEL TUBE


--------------------------------------------------------------------------------

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: CDS DOM HFS
Tensile strength (ksi) 87 80 70
Yield point (ksi) 72 70 47
Elongation (% in 2") 10 10 28
Rockwell hardness RB89 RB85 RB78

What about MetalMart's 1018 listing? How do I tell how thick it is?

J. J.

Originally posted by patooyee
What about MetalMart's 1018 listing? How do I tell how thick it is?

J. J.

Pick up the phone!:flipoff2: :flipoff2: :rolleyes:

There listing is clear to me!


1-3/4 od x .120w c1026 dom ew stl tube a513 t5

That's for DOM, which I am not interrested in. Check the listing for round cold rolled. It only says the OD. I would call them but they won't be too happy to supply me with the info if I'm not buying and I knwo the people I'm buying from won't know if their listing is the same.

J. J.

patooyee,

I surfed that metalmart site.

The bit you mentioned, they don't list wall thickness, because there is no wall...that stuff is a solid bar!!!

When a supplier says "rounds"...they mean solid round bars!

They say "tube" for tubes, and it seems this metalmart only sells DOM tubing.

Ahhhhhh . . . that explains it! Thanks! :emb4:

J. J.

Originally posted by BillaVista
patooyee,

I surfed that metalmart site.

The bit you mentioned, they don't list wall thickness, because there is no wall...that stuff is a solid bar!!!

When a supplier says "rounds"...they mean solid round bars!

They say "tube" for tubes, and it seems this metalmart only sells DOM tubing.

lol, that also explains the $1.09 per inch price, rather than normal $3 to $5 tubing price range per foot you can get from spidertrax or something. http://www.spidertrax.com/hardware_dom.htm
I assume the 2" O.D. would be around 6 or $7.
Shaggy

www.metalmart.com

1.5" .25"wall DOM

$1.53/inch :barf:


Someone wanna sell me some? Actually, some 3 foot pieces. There isnt shat here in Louisiana. All the steel places send me back and forth.

I can't believe that they charge by the inch! It's not like they would sell just a few inches and on the same token, no one would ever want 1000 ft and 1", U know? Not only that, I don't see how they can remain competitive with those prices! Nearly 10 times the amount of any normal dealer! It's actually kind of insulting to our intelligence. Who the hell pays those prices????

J. J.

http://www.ryerson.com/stocklist/t-1744-Tubing-Pipe-Round-Mechanical-Tubing-1%2522-to-2%2522.html

Billavista pretty much closed out the thread with his post...one thing to add...

>.134 is 1020 DOM buggy tubing
<.134 is 1026 DOM which is stronger and has a higher rockwell

If you look at yield numbers for tubing you would NEVER build a car out of HREW. The debate over DOM vs 4130 can draw on...both have advantages, but there is NO advantage to running HREW unless you want the tubing to fold. With that said a friend of mine who raced roundy rounds for years would always build bumpers out of .083 HREW because he wanted it to fold and absorb energy in a crash. Not what you want in our sport.

9 year old thread for that? Well thanks anyway...

:shaking: