10 Inch steel pipe for sale.

Hello, Can you tell me what kind of markings/numbers/letters, do I look for when buying pipe from an individual, in order to know if it is weldable, and how strong the pipe is ?
What kind of rod should I use in a stick welder to weld gussett's onto a 1/2 inch steel plate to hold this pipe ?

The pipe is new, and it has maybe 1/2 inch wall thickness ? Also, what kind of strength would it have, when compared to a 12 inch 65 lb. per ft. H beam ?
I can buy this pipe for perhaps a third of what the H beam will cost me. Are there different grades in pipe ? Thanks for your response.

10 inch schedule 60 pipe has an outside diameter of 10.75 inches and an inside diameter of 9.75 inches and weighs about 55 pounds per foot. The moment of inertia (what you need for bending resistance)
is given by the formula
Iyy = pi/64 * (Do**4 - Di**4)

For this size pipe it is thus 212 inches**4

A w12x65 wide flange beam has an Iyy of 533 inches**4

So your proposed 10 inch pipe has 40 percent of the stiffness of the proposed alternative H beam.

Looking at it that way, the pipe isn't that much of a bargain -- 40 percent of the stiffness at 1/3 the cost, and with less known about steel quality, etc.

A W12x30 beam is the rough equal of your 10 inch pipe and would cost 45 percent of the W12x65.

Hey David, Thanks for your information ! You must be an engineer. Anyway, I appreciate your time and help, and again, THANKS !

What are you making? There are many different types and grades of pipe. If you're making a hoist or something that could cause serious injury if it broke, have someone with experience build it. I'm not trying to discourage you but if you don't know what welding rods to use for heavy weldments, I'd bet you don't have a lot of welding experience. It's usually best to use the right materials for a project even if they cost more. Many people have been disappointed after they worked for hours building something and then it failed because they tried to save money and built it cheaper. Do it right the first time. You'll be better off in the end. Dave

Well, yes I am an engineer, though my field is electrical engineering and not structural/mechanical/civil. I just like to tinker with the calculations for various farm projects.

I'll spare you the standard warnings about the hazards of stuff falling on you, needing to know all of the design conditions to make recommendations, hiring a pro instead of relying on internet advice, etc.

But in case you are thinking of building a jib crane, or something similar, I should warn you about one issue that comes down in favor of the steel pipe.

Wide flange beams like your proposed H beams are designed to be used where they are laterally braced (e.g. embedded in a floor). If they are used in an application where there is no weak axis bracing (as in a home made crane) they are subject to a form of structural failure called lateral/torsional buckling. Basically a tall skinny beam will bend or twist perpendicular to the load axis well before it reaches its nominal strong axis design capacity. You can design around this through the use of suitable trussing or bracing, or (obviously) by reducing the amount of load applied. The calculations to optimize in this situation are more complicated than for simple beam bending.

(Similar issues apply to wood 2x12's used for floor joists, in case you've ever wondered why the building code requires blocking or diagonal bracing between joists).

A tube (like your pipe) does not have this issue, since it is equally strong (stiff) in all directions.

Hi David,

As always, it's very informative to read one of your responses. I'd like to know a little more about it---in this case, about as much as I'd know if I understood all the terminology, symbols, and abbreviations you used. Would you mind taking the time to explain those things, including the meaning of asterisks and double asterisks?

Also, is there a point at which a regular H beam becomes a W beam? When you speak of a "w12x65 wide flange beam" and later refer to it as a "W12X65" can that actually be describing a W beam with 12" flanges and a 65" web?

Thanks, Stan

Stan, I think I can help with that one, the 65 = lbs per foot of the given member Now, it would be really interesting to look at the framing plan of a structural steel building, and try to estimate tons of steel required without that in the nomenclature, usually all members are identified unless omitted by mistake. The best reference book I can think of for steel shapes is the A.I.S.C. manual of steel construction handbook, even old editions bring a fair price on our favorite auction site, but are still very useful.

Ixx by convention stands for the second moment of area about long axis in the "strong" direction.

This is commonly called the "moment of inertia", though that is potentially misleading from a physics point of view. It is a measure of the efficiency of the particular shape -- the more material that is distributed the farther away from the center of the beam, the better. That's why a joist is a whole lot stronger when stood on edge vs. laying flat, a wide flange beam is stronger than the same weight of material in a rod or bar, etc.

(I used Iyy in the earlier post; some tables I've used in the past switch the weak and strong axis, but Ixx would be the one to use with the link below)

W12x65 is standard terminology from the American Institute of Steel Construction. It stands for "wide flange shape", 12 inches deep, 65 pounds per foot. (A wide flange shape is what you picture as an "I beam" or "H-Beam"). You can find standard section properties of Wide Flange beams at the link below, among other places. Most steel beams you'd buy at a steel yard are standard AISC Wide Flange Beams. A traditional "I beam" goes back to the early days of hot rolled shapes and has more material in the web, less in the flanges, and a more rounded profile in the transition from the center web to the flanges. It is a less efficient shape for strong axis bending than the "Wide flange" shape.

The formula I gave was written in a notation corresponding to the Fortran computer language. I guess I'm showing my age. A single asterisk represents multiplication, a double asterisk represents exponentiation.

Do means outside diameter.
Di means inside diameter.

Recasting the formula in the c language in case you are more familiar with that.

Ixx = (3.14159 / 64) * (Do ^ 4 - Di ^ 4)

Or to make it really simple

Ixx = (3.14159 / 64) * (Do*Do*Do*Do - Di*Di*Di*Di)
wide flange beam properties

Thanks for taking the time, David. That was informative.

Fortran was a programming language in use before there were micro-computers, wasn't it? The first computer I bought used the CP/M operating system, which sometimes makes me feel that I was present at the dawn of creation. Truthfully, though, I never developed any capability whatsoever with CP/M. I didn't actually know the difference between the operating system and the programs that ran in it.

Thanks again, Stan

Hello, More info on this pipe; The pipe is appr. 30 ft. in length. This is new pipe with cosmetic rust on the outside, and the price of $395.00 is firm. He does not know anything about the kind of steel it is made of etc.. That is why I had asked about the best rod to use in welding on it.

I am either going to buy this pipe, or I will buy the same length of I beam. The beam would be bought at a steel supply/fabrication business.
They also have other sizes of steel I beam as well, perhaps a 10 in. x 77 lb ? Or ?

The application I'll be using this for is to move a steel truss bridge weighing in at 10 to 12 tons. I will be using 2 sets of single axle semi dolly's on each end of the bridge for the move.

I plan on buying 1/2 in. plate steel and using this for a base upon the fifth wheel, welding a new king pin to each plate , and connecting same to the fifth wheel. Then, welding either the pipe or I beam to the 1/2 in. plate.
The 1/2 in. plate will cover the entire fifth wheel.

The pipe will naturally need to be connected by gussets to the flat plate, because it's round, while the I beam itself can be welded by the flange to the plate itself. The length of beam/pipe will be a min. of 14 ft. in length to a max. of 16 ft. in length.

The bridge itself is 12ft. 6 in. wide. This distance of 12 ft. 6 in. will also be the load bearing distance between, and upon each side of the chosen pipe or I beam in question. The weight of the bridge is also equal on both sides, as well as on both ends.

So, what would you do Boss man ?? Thanks for any help and suggestions.

It's going to be pulled on public roads? Get someone with welding and fabrication experience to build it for you. What rods to use is very simple for an experienced welder. Something ever broke and it would be a real mess to get it lifted and moved. You'd also need a special permit to move it on public roads and probably need pilot trucks. It's not a small simple project you're looking at doing. Don't try to cut corners too much or you'll be looking for a disaster. Dave

Now that you have elaborated some of the details, would'nt it be wise to do a little drafting of the proposed design, with details of materials, connections, weldments, and have same reviewed by a structural engineer ? If this were me, I'd hire one on retainer, provide the design criteria and let him/her design something like this, with a safety margin, and some fabrication details included.

The way I see it, point loading a rig that you fabricate, without having any idea of what the span will safely hold, nor having any criteria to fabricate from that has at least been calculated, checked or given even an informal cursory review by an engineer is = to guessing. Not rocket science, nor will it take long to do the checks, analysis and or calculations to at least determine what member is suitable for a span on rollers (your dollies), connection details, bracing, and weld type/sizes etc.

Reason I mention this, is that in my construction career working on all kinds of large commercial building projects, many times we would have to solve problems that required fabricating things, modifying existing designs, use special non typical rigging, placing loads on things, all needed to be checked by an engineer, many times stamped calculations and details provided to back it up, or for approval prior to.

There is risk involved if you don't, if that thing fails, 12 ton is no joke, same weight as what some genius's tried to pick with nylon slings, that poor decision toppled a tower crane recently, and killed 7 people. The lesson here is not to arbitrarily select materials for usage in structual applications without absolutely knowing their safe working capacity. You may hit it right with the member for the span, then again you may undersize it, and you still have other components to coordinate into the design, further complicating matters. How do you really know it's a sound design if no analysis, checks or calc's are performed ? For what a licensed professional engineer costs to hire, for something like this, a good P.E. should be able to figure that out in a day, then you fabricate per the design and details provided, with confidence, and with approved materials. I dunno, maybe I'm missing something, but this sounds like a rigging job that should be checked thoroughly, you'll come out ahead in the long run, cost of an engineer, buying out materials 1x and knowing your'e within safe working loads vs. structural failure and losing that load.... something to be considered here.

The problem I see is that you are going to balance this bridge on a king pin in the center of a dolley that is much narrower than the bridge. One wheel in a pothole and the whole thing upsets maybe ripping out your plate and kingpin.

Why not rent a construction trailer that will handle the size. I suspect you will have to have a crane load it for you anyway unless you have a way to winch it onto a truck or trailer. I used to move big oilfield equipment and drilling rigs all the time. Give me a couple winch trucks and off we go. Not much different than moving a derrick. Just need the right equipment.