Tubing Info (reprinted with permission)

Carolina_Zuk

Carolina_Zuk

Well-known member
Thought this might help, I saw it on another board Im on:

? Electric Resistance Welded (ERW)
? Cold Drawn Welded (CDW)
? Drawn Over Mandrel (DOM)
? Cold Drawn Seamless (CDS)
? Cold Rolled Electric Welded (CREW)
? Hot Rolled Electric Welded (HREW)
? What's the difference between Tube and Pipe?
? Types of Tube and Pipe

Electric Resistance Welded (ERW)
Cold formed, electric resistance welded tubing can be produced in round, square or rectangle shapes. ERW tube is produced by processing a flat rolled steel into strips which are cold-formed, welded and seam annealed or normalized (depending on the manufacturer). You can usually identify ERW tube by the blue strip down one side of the tube (which is the welded area). The ERW process can guarantee the weld to be as strong or stronger than the rest of the tube body. The origin from a flat strip results in a more concentric product than Cold Drawn Seamless (CDS). ERW can also be known as CREW (Cold Rolled Electric Welded).
Typical Applications:
Structural columns, beams, supports, heavy equipment frames with 58,000 PSI tensile.

Cold Drawn Welded (CDW)
Produced from a steel strip by cold forming, electric resistance welding (ERW) and cold drawing to finished dimensions, CDW is the most versatile and widely sold mechanical tubing grade. A variety of thermal treatments can be applied to alter the mechanical properties and machinability. CDW is used for a tremendous variety of machine parts where close tolerances and higher mechanical properties are needed.
Typical Applications:
Automotive components, shock absorbers, hydraulic cylinders, sleeves, bushings, axles and shafting.

Drawn Over Mandrel (DOM)
DOM is formed from strip and Electric Resistance Welded (ERW) then cold drawn through a die and over a mandrel resulting in improved inner surfaces and dimensional quality. This process, called cold drawing, may be repeated more than once to reach the planned OD, ID, or wall dimension. Multiple draws can also be used to increase the strength or improve the surface finish of the tubes. During the drawing operation, the tubes may be process annealed to increase the ductility of the material. Lower cost alternative to CDS with equal or superior physical properties.
Typical Applications:
Machined parts, rollers, shafts, sleeves, steering columns, axle tubes, drive shafts, bushings and is most readily adaptable in cylinder applications with a 80,000 PSI tensile.

Cold Drawn Seamless (CDS)
General purpose seamless tubing, which is a solid bar of carbon steel drawn over a mandrel to form the tube section. CDS allows selection of chemistry and rough tube size. Cold drawing produces higher physical properties without heat treating. Offers widest range of sizes and chemistries in mechanical tubing. Better tolerances and reduced machining allowances over Hot Finished Seamless (HFS).
Typical Applications:
Machined parts, bushings, spacers, bearings, rollers, shafts, sleeves and cylinders with a 75,000 PSI tensile.

Cold Rolled Electric Welded (CREW)
Cold rolled steels are steels that are shaped by high pressure rollers at normal temperature in the steel mill. Cold rolling work hardens the material substantially. The steel is then welded by the electric weld process. A cold rolled steel can be either a mild steel or a high carbon steel. Can also be termed as ERW (Electric Resistance Welded). See ? ERW

Hot Rolled Electric Welded (HREW)
Hot rolled steel is steel that is rolled to size in the mill while red hot. Hot rolling steel does not work harden it as much as cold rolling. For this reason, hot rolled steel is more easily machined than cold rolled.

What's the difference between Tube and Pipe?
The general term for pipe was that it was primarily used for carrying gas or liquid. It was not intended for structural use because the dimensions used in describing pipe was not dimensionally accurate. Measurement was referred to its inside diameter and wall thickness. The inside diameter was a true dimension, but over the years had become "nominal" (in name only) so that when pipe size was referred to, it was an approximate inside diameter measurement with the thickness described by the term "schedule".

? Pipe is generally more rigid than tube, and is usually produced in heavier wall thicknesses.

? Pipe is specified by a nominal dimension which bears little or no resemblance to the actual dimensions of the pipe. 1" Schedule 40 pipe, for instance, has an actual OD of 1.32", a wall of 0.133", and an inner diameter of 1.049". Tube dimensions are actual dimensions.

? Pipe fittings are sized to meet pipe sizes, but not tube sizes. A 1" schedule 40 nipple will fit correctly on a 1" schedule 40 pipe, but not on a 1" OD tube.

Tube refers to round, square, rectangular or any shape of hollow material of uniform thickness which is defined by the outside diameter and wall thickness dimensions. It is the grade of the metals and how tube is produced and processed that is important.

? Structural Tube is generally produced using the ERW (Electric Resistance Welded) process. Identified under the Circular Hollow Section (CHS) or Hollow Structural Sections (HSS) class. Some steel mills specifically develop structural tube for roll over protective structures.

? Mechanical Tubing is usually produced as seamless, as-welded or DOM (Drawn Over Mandrel) tube.

Types of Tube and Pipe

Structural Tube - high strength welded steel tubing
Mechanical Tube - seamless, as-welded and drawn over mandrel
Stainless Tubing and Pipe - several seamless and welding processes requiring resistance to corrosive materials
Standard Pipe - several seamless or electric weld process, carries liquid or gas 
 
If I may add some more info I have found on Pipe from some of the local fabricators:

Pipe is Pipe and Tube is Tube, they are different.

Tube is measured by outside diameter and wall thickness.
Pipe is 'measured' by inside diameter and schedule (wall thickness)

Pipe is still a standard ID, and the OD varies based on the schedule. So for a 1-1/4" pipe, the OD is 1.66". Schedule 80 would have a smaller ID than Schedule 40...etc..

There's a lot of misinfo about pipe, people thinking its brittle, weak, etc. Not really true. There are a lot of different types of pipe, just like there are lots of types of tube. So getting the right material, no matter what you do, is the key to getting strong material. You will find plenty of circle track cars with pipe-built roll cages, which are going to have higher impact forces than on most any 4x4.


There are lots of types of pipe out there. Going to the home depot and buying a $10 chunk of pipe you don't know what you are getting, and its propably crap. Some types of pipe might be butt welded, so there are butt seams in the pipe that may be weak. Some types might be a weaker steel that leads people to think of the pipes being brittle.


A common one used in building cages is ASTM A53 type S grade B.

This is a carbon steel pipe, with a yield strength of 35,000 psi, and tensile strength of 60,000 psi.


I personally use ASTM A500 grade B, which is a carbon steel pipe known as structural tubing. The A500 standard actually covers both rounds and shapes such as square tubing, and is often what you are buying when you buy square & rectangle tube. It is known as tubing although the rounds are available in pipe sizes. It is specifically designed for use in structural applications, and not going to be brittle or weak like people think. Min yield strength is 42,000 psi, tensile strength is 58,000 psi.



For most roll bars, bumpers, sliders, etc, 1-1/4" schedule 40 makes a nice size. That is a 1.66" OD, with a wall thickness of 0.140". Currently, a 21 ft stick of A500b 1-1/4" sch 40 runs about $35 at Pontiac Steel.
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This was a quote from a local board in the fabrication section. There are ALOT of people here in the Detroit area that use Pipe. Most of the Fabricators on the jHeep broads around here that use pipe are Engineers and Welder/Fabricators by trade for the Auto industry and Steel Building industry.  I use both Tube and Pipe.

Its up to you to make your choice, but if you look at the different grades available in both Tube and Pipe, you may be surprised at the structural properties that Pipe really has. Then look at the cost difference and that will suprise you as well.
 
So what's best to use?? I want to build a roll bar for the Tracker, but I'm lost on what size/type to use. I'm also not sure on how to bend it, I have a bender like this at work:
35336.gif

but I'm not sure if it will be good enough, some say it kinks the metal, and some say if the metal is thick enough it won't. I'm lost, and I only need to make 4 bends!!
 
I built my cage with that bender, but it doesn't do pretty bends they kink.  I think most of us use 1 1/2 .120 wall tube.
 
Exactly how bad are the kinks? I need to make 2 90 degree bends, and 2 70-ish degree bends.  Would using thick pipe rather than tubing make a better bend?
 
You can definitly see the kinks.  Mine is a trail only sammi so I ddin't care that much.  Those benders are made to bend pipe so I think it ouwld do better on pipe but I have heard many times that pipe is not good for cages although I dont see why.
 
durnzuki said:
You can definitly see the kinks.  Mine is a trail only sammi so I ddin't care that much.  Those benders are made to bend pipe so I think it ouwld do better on pipe but I have heard many times that pipe is not good for cages although I dont see why.
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I read that too, but I'm wondering if it's just follow the leader without any actual facts. You know how it goes, kids go through it every day at school - "We don't want to play with Arthur 'cause he picks his nose" I'm thinking pipe may have got a bad reputation because of what it's truly meant for ;)
I think I will buy a small piece of sc. 40 and try to bend it to see how it goes.
 
i use one of those benders for onsite handrail jobs at work.    it's ok with 1 1/4" sch 40 pipe.  it'll do a 90,  but you get a little bit of crush at that point.

i've done 1 5/8" od HSS, .100" wall with it,  but much more then 80 degrees, and your crushed

uncivilized,  there must be someone in the city with a good bender that can make a few bends up for ya.  heck,  if your ever in this end of the valley, drop in.  (i'm just below annapolis royal)


one of the reasons people got away from pipe, was weight.  .100, or .80 wall dom, is alot lighter then sch 40 pipe....
i've seen alot of pipe used in the wrong locations, bend, beatin, and broke,  but i've yet to see it splinter up like a samuari sword, and attack the guy who built it  ::)

if i cage my tracker, it'll mostlikely be 1 1/4 pipe,  cause i can bend it,  an i'll be looking for a little extra protection if i flop on my side....  don't plan on gettin too wild with the family on board
 
madbob said:
I'm curious... does anybody know why pipe is "bad" for cages?
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Most pipe off the shelf is not structural. Not to say you cant get it but you will spend just as much for Good quality tubing. Negative is it is HEAVY. and non structural tubing cracks and splinters. Most guys use it because they think it is cheap and a harbor freight Kinkers in inexpensive. Any PIPE off the shelf from Home depot, menards etc  is all china mill material, and I would not trust it Period.. All cages in DOM should be minimum .125 wall and if you use chromoly you can drop material thickness and OD to keep the same strength as heavier wall material.

The simpelest answer is CHEAP.
Harbor freight Kincker $100.
Menards Pipe $60
My time FREE
Adding 300# to my rig Priceless.
 
    For those who don't know, you can buy pre mandrel bent structural tubing. If you are doing structural work you need to have the right material for the job. Non structural tubing is not the material for roll cages and bumpers. I have a background in Aviation Manufacture Engineering Technology (technologist) and well as cheap as tubing can get, a lot of it will split at the seam when loaded. It doesn't shatter per say unless it has been work hardened, but, it will split and bend and collapse catastrophically if pushed past its design rating. 
    When you bend tubing or pipe, those ripples or kinks are a sign of local structural failure. With the weight of the zuk they may not fail when needed. Why take the chance that they may? Now that being said, for my own projects I've put sand in tubing, capped the ends, and used a tubing bender, but not ever for a roll cage. I've also never welded a roll cage myself because I am not going to trust my bubblegum welds to keep my kids from being harmed. My bumpers on the other hand are fair game and my bubble gum and bailing wire work holds up to being bounced occasionally on stumps and rocks.
 
Uncivilized. I had a sand buggy that was built (by previous owner) from pipe. It was built for pleasure rides and now I was using it for Sand Drag Racing. Never failed because it was never put to the test. The fact was that I didn't felt safe on it and ended building one of chrome moly. But, I have to say (and this is in my humble opinion) that it will have a lot to do with the intended use and design. For example, if it is going to used for Racing where the speed and weight of the vehicle will be combined at the time of impact, don't think anyone will want to be inside a questionable cage. On the other hand if you are looking to do a cage so that in case you roll over a stump or rock at 0 miles per hour, (again in my humble opinion) If the design is good, (including mounting points) any material should hold. Long sections without bracing is the part I would stay away from.  It's a matter of who we are talking about because now, that same cage, and the vehicle in the hands of someone with wild intentions, driving through the trails at 20 MPH's and flips the vehicle down a cliff, guess what? As said before macka, why take the chance that they may fail?

Talking about the bender, if it is built for pipe, the dies are larger because pipes are measured on the inside. Be sure that you have the correct dies for the material being bent.
 

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