Angle iron

I needed some 3/4"x3/4"x1/8" angle iron for a project. Previously I bought a 3-foot length in Home Depot so I headed back there. They had an item with that description but it did not look like what I had bought before.

I believe that "regular" angle iron is made by extrusion. These pieces looked like someone put a 1.5" flat in a brake and bent it at right angles (I believe the term for this is "formed"). I was reluctant to buy this as it just did not *look* as strong as the regular extruded type. I tried to work out the relative strengths from the Machinery's Handbook but without success.

So the questions are:

1) Am I right in assuming that the extruded angle iron is stronger compared to the formed type? If so by how much?

2) Is there a good reason why a 72" length of stock should cost 1.5x as much per inch as a 36" length?

Michael Koblic, Campbell River, BC

Reply to
mkoblic
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I think your 'extruded' angle is hot-rolled steel, the 'formed' angle is cold-rolled. Is it smooth and zinc-plated? Typically cold-rolled has a higher yield point since it has already been deformed and moved up the stress-strain curve by the rolling process, while hot rolled steel is in the softer annealed condition.

If that's unclear, it's because Gwyneth is singing Do You Want to Touch Me There on TV right now.

jsw

Reply to
Jim Wilkins

The "formed" angle has internal and external radius - Rolled angle has internal radius and square outer edge. GENERALLY the rolled material is stiffer ( at least torsionally) than the formed angle but it does depend on the alloy and heat treating, if any.

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Reply to
clare

Moreover, hot rolled angle has a fillet on the inside of the angle that gives extra strength there.

Angle made by forming sheet doesn't have that. I have no idea how commercial quantities are made. I'd surmise: by rolling or drawing a strip. But no fillet in any case.

Reply to
Mike Spencer

Check with steel suppliers. Many have "rems" or "drops" that they sell for $.30 (that's 30 cents a pound). If you're lucky, you can get what you need for a couple of bucks.

Worth a shot.

Steve

Reply to
Steve B

I may be misinterpreting what you're saying, but if it's stiffer, it's not because of alloy or heat treating. It could be stronger or weaker depending on alloy and heat treatment, but the stiffness is almost the same regardless of alloy (except for stainless, which is a little less stiff), and regardless of heat treatment.

Reply to
Ed Huntress

One could make a larger bend radius, which would be like having a fillet.

Reply to
CaveLamb

[snip]

Because you're buying it from home despot. Look up Steel in the yellow pages and go to your local steel or scrapyard. They will sell you the stuff, and LOTS of other stuff, by the pound, or by the foot, at prices that will probably be 1/3 or less what you are paying at the despot. It's a lot more fun, too.

Jon

Reply to
Jon Danniken

No real hardware stores around? Virtually every one around here has a rack of rolled steel shapes in 3-6' lengths. Not as cheap as at a steel yard by the pound but very convenient on a Sun. afternoon. Ace is da place.

Stan

Reply to
stans4

I wish. I went to three steel yards that day. The best I could do was a 20 ft length for $18 provided I bought 6 of them (minimum $100 sale). If I bought it from the dealer they sell to, the price doubles after cutting. Not that they had any...

In the end I got it in Home Hardware. I just did not trust that formed stuff in HD.

Interestingly, about a month ago I went to Nanaimo "Metal supermarket". When I compared the prices from there (factoring in cutting but not the travel) Home Depot was actually cheaper if one bought the 48" lengths of comparable stock.

I took the opportunity to ask about other things in the said steel yards. Tha availability of stuff was very limited (12L14, 303, 416 etc.) The same story in Nanaimo. OTOH I got a line on small quantities of aluminium so it was not altogether a waste of time.

Michael Koblic, Campbell River, BC

Reply to
mkoblic

For steel (angle & square tubing type stuff), my local structural steel place that sells beams & lintels for construction is cheaper than the steel store. They consider pretty much anything under 10' a drop so goes by the pound. You might check to see if you have one near you.

MikeB

Reply to
BQ340

I guess I'm lucky that I've got a local steel merchant (

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) with a "no minimum order" policy. Really friendly, and they're always happy to get me whatever I need, even when they are busy supplying large orders for the big guys.

Jon

Reply to
Jon Danniken

That's what comes of living "out in the sticks" where your suppliers are limitted, largely because their market is limitted.

Try the same in, say, Vancouver, or Calgary, Edmonton, Toronto, Kitchener, Montreal, etc, where many diverse industries use the materials in question.

Luckily you DID have a Home Hardware store - what they stock and sell out of the huge warehouse in the little town of St Jacobs Ontario is staggering!!!! And their prices are pretty fair, on the whole.

Reply to
clare

I'm pretty sure the days of 30 cents/pound are long gone.

I purchased three beams for the house I'm building, new material, that cost me right at 33 cents/pound---but that was a few years ago. I expect that you're going to pay no less than 50 cents/pound now, and probably more.

Harold

Reply to
Harold & Susan Vordos

I bought angle and channel for several projects from a place "out in the sticks" that sells recycled pallet racks.

jsw

Reply to
Jim Wilkins

That might be shaped hot, via bending rollers. (like metal roofing)

Given the same alloy, absolutely. Look at the crosssection. Extruded is much thicker at the root of the V.

Only in the Borgs or retail stores. In real metalmonger stores, it's cheapest in 20' lengths.

Reply to
Larry Jaques

Angle iron (steel) is not extruded. The standard structural product is hot roll-formed. Cold-roll-formed angle has uniform thickness throughout, but the hot-rolled shapes are squeezed in their plastic state so they're thicker at the bend and thin out at the edges.

It is possible to extrude steel, and it's done, for more complex shapes. I've never heard of it being done for simple angles. It involves using molten glass as a lubricant and it's fairly involved, unlike aluminum extrusion.

Cold-formed steel is inherently stronger because of the effect of work-strengthening, but the shape of the hot-rolled product is superior in structural terms. Pound-for-pound, there is a tradeoff, but I think the hot-rolled comes out with a strength advantage due to shape, over the strength advantage of cold-rolled due to work-strengthening.

Reply to
Ed Huntress

I'm pretty sure the days of 30 cents/pound are long gone.

I purchased three beams for the house I'm building, new material, that cost me right at 33 cents/pound---but that was a few years ago. I expect that you're going to pay no less than 50 cents/pound now, and probably more.

Harold

Reply: Go to Goodwill or other thrift stores. Lots have bed frames, that they will give you or sell for a buck or less. Good source of angle iron.

Reply to
Califbill

Bed rails are good strong steel, somewhat like 1045. I think they are recycled manganese-steel railroad track. They are more difficult to saw, drill and weld than hot-rolled mild steel.

jsw

Reply to
Jim Wilkins

They're bastards to weld. The HAZ ends up large and very brittle. If you do weld a bedframe, then normalize around the weld for at least a few inches - preferably more.

Don't ask how I know. :-)

-- Jeff R.

Reply to
Jeff R.

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