water pipe vs DOM

I've got a project where i need over a hundred feet of 1.38 ID by 1.625 OD DOM tubing.
Turns out this is almost exactly the same size as 1 1/4 water pipe,
MUCH less expenisve.
Need to do a lot of machining and some bending of a small tab. Will water pipe work as well?
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If it matters, recently purchased water pipe may not be particularly round, especially at the weld. I have to adjust its position in a 3-jaw chuck to get it close to centered.
I made some half round stone splitting shims from it, involving a lot of cold bending before and after welding, and it didn't crack. It seems quite soft as steel goes, but doesn't tear when turning it. My untested SWAG of its yield strength would be at the 25 KSI low end for steel. It's easy to weld.
--jsw
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http://lists.contesting.com/pipermail/towertalk/2000-May/030631.html "The most common, and lowest grade of pipe is ASTM grade A120, welded or seamless pipe, back or galvanized. It's material composition *is not controlled at all* !!!!"
I don't trust my amateur engineering calculations or welds and proof-test the final assembly, currently with this: http://tinyurl.com/h4krwg9
--jsw
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On Fri, 15 Apr 2016 06:01:39 -0500, Karl Townsend

My experience with it is that it's pretty gummy to turn, but that's because it's usually made of something like AISI 1010. DOM typically is 1020 or 1030.
When I say "like" 1010, I'm talking only about carbon content. As far as I know, it's not graded material, or it's a special spec just for water pipe. It is very low in carbon, however.
--
Ed Huntress

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wrote:

I just filed and Scotch-Brited an old work-holding fixture turned from black pipe. It's smooth and shiny but on the low end of the samples I'd show an interviewer to prove I can run a lathe. --jsw
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One thing to consider: US made Gav pipe and Black pipe is not the cheap crap we get from China. Simple as that.
I bronzed some fittings to a plate for a lady. She bought them from a BOX store. The metal flowed easier than the bronze! It was like solder. So I went to the hardware store that buys USA. Those worked just fine and I could even weld them.
So quality depends on the supplier.
Martin
On 4/15/2016 11:51 AM, Jim Wilkins wrote:

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On Sat, 16 Apr 2016 22:37:16 -0500, Martin Eastburn

Sadly you can't depend on any supplier having the same product this month as they had last month. The next batch your hardware store gets might not be the quality US stuff either, Depends on availability and price.
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On Fri, 15 Apr 2016 11:57:23 -0400, Ed Huntress

It's "nonspecific remelt" sourced from common "shred" - which contains old washers and driers and refrigerators as well as 45 gallon drums and other low-grade scrap.
If DOM is specified it likely has some strength requirements., or possibly some dimensional requirements that water/gas pipe would never come close to meeting.
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On Fri, 15 Apr 2016 13:42:02 -0400, snipped-for-privacy@snyder.on.ca wrote:

Oh. Like Chinese "M60 equivalent" high-speed steel. d8-)

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On Fri, 15 Apr 2016 06:01:39 -0500, Karl Townsend

I'd seen the term "DOM" mentioned a few times recently, and finally decided to find out what it was. Here are some of the sites I visited in my research which might be of interest to you, Karl.
http://tubular.arcelormittal.com/images/ArcelorMittal_DOMSpecs.pdf
https://www.rme4x4.com/showthread.php?64334-Pipe-vs-D-O-M-tubing
http://metalsupermarkets.com/blog/difference-between-erw-dom-and-seamless-tube/

https://www.youtube.com/watch?v=buu3Ytubp1s

http://www.jalopyjournal.com/forum/threads/4130-moly-versus-dom-race-car-tubing.286487/
http://products.anssteel.com/item/steel-pipes/sch-40-bare-black-standard-steel-pipe/un-1-1-4-2272? http://products.anssteel.com/item/steel-pipes/galvanized-standard-steel-pipe/g-1-1-4-2272?&bc 0|1002|1016|1047|1049
http://www.industrialgroupco.com/assets/files/common-pipe-specifications.pdf
Pipe seems to be made from a mutt steel; whatever they find. If I were making a simple bench or something for intermittent use or of a light-duty nature, I'd use pipe, the cheapest.
If I wanted a chassis for a vehicle of some sort, I'd definitely want to go with DOM. It has a much higher safety factor. 1020 seems to be the standard the 4-wheelers use.
I'd also avoid 4130. Chromoly is nice, but is way too expensive and too finicky for proper welds.
--
If you want to make your dreams come true,
the first thing you have to do is wake up!
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On Fri, 15 Apr 2016 12:35:08 -0700, Larry Jaques

Not really. It's easy to weld with O/A or TIG. You just have to know how it behaves, and if you won't learn that, I wouldn't want to ride in anything you welded, anyway.
1020 is (or was) used on NASCAR racers, for two reasons: The weight restrictions allow(ed) you to use tubing so heavy that you're at the limit of practical strength anyway, even with 1020; and if (scratch that -- "when") you crash it, you can cut out old tubes and replace them without worrying about it.
--
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wrote:

I didn't have any trouble welding 4130 aircraft tubing tees for practice.
Wasn't there a problem with chrome-moly frames so strong and stiff they overstressed and killed the driver instead of progressively absorbing energy?
--jsw
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On Fri, 15 Apr 2016 16:14:43 -0400, "Jim Wilkins"

No, it's just somebody's old tale. I've heard it before, too.
First, the stiffness of 4130 and 1020 are almost exactly the same (as is true of all steels, except for the slightly less-stiff stainless). Second, there isn't *that* much difference in strength. (yield is around 65 ksi for normalized 4130; 54 ksi for DOM 1020). The ductility, elongation and ultimate tensile strength are better for 4130 than for 1020 in the hard-drawn condition. 4130 tubing is almost always used in the normalized condition; 1020 in the hard-drawn condition.
So you get some more strength and a lot more ductility with 4130. Your welds can be somewhat stronger because hard-drawn 1020 loses a lot of its strength from heating at the weld. 4130 is very slow-quenching -- on the verge of air-hardening, and, in thin sections (like the light-gauge tubing used on aircraft and smaller race cars), it *is* air-hardening. Strength *at the weld* is pretty good.
It can get tricky with thicker sections. There is a lot of voodoo surrounding 4130, but the major welding equipment suppliers can clear that up for you if you ask. They also have info about it on their websites.
BTW, the Brits, including Lotus, Cooper, Vanwall, etc., used 1020 or its equivalent for race cars through the '60s, and they performed as well as 4130 cars. They bronze-brazed their chassis joints, for the most part. Chassis stiffness is the issue, unless you care about the safety of your drivers, which some didn't. <g> 1020 is just as stiff.
--
Ed Huntress

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On Fri, 15 Apr 2016 17:02:48 -0400, Ed Huntress

If I remember correctly Norton built some of their racing frames using "bronze-welding" and claimed that the brazed joints were an advantage as they were less stiff then welded joints and didn't break as often :-)
--

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John B.
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wrote:

Oh, yeah, that was another source of voodoo. <g> Many or most of the one-off and low-volume Brit race cars were, supposedly, bronze "welded" during the '50s and into the '60s. Bronze "welding" in that parlance was brazing with a weld-like buildup of filler metal at the joint.
The old authorities said there was no meaningful difference in strength between that method and fusion welding. I think it was treated in the classic chassis book:
(Amazon.com product link shortened)
--
Ed Huntress

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On Sat, 16 Apr 2016 07:21:30 -0400, Ed Huntress

That's a great book and every time I read it I get all enthusiastic about building my own single seater car. I was surprised to learn from some local race car builders that the book is still used a lot by builders. The issue of 4130 as opposed to mild steel is covered in the book and from the the book's point of view the chrome-moly steels should only be used where the extra strength is needed, for example in some suspension components, and not in the frames because there is not enough advantage in rigidity and crashworthiness and a big disadvantage when it comes to joining with heat. Eric
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On Sat, 16 Apr 2016 10:09:18 -0700, snipped-for-privacy@whidbey.com wrote:

A good friend of mine has built and rebuilt a LOT of Lotus 7 chassis, and a LOT of motorcycle frames. "fillet brazing:" is the "british" way of joining steel tubing. The flux is applied with the gas by bubbling (im not sure if it's the O2 or the Acetelene) through a bottle of flux so no flux paste or flux coating on the rod is required. It's a different brazing alloy than used for normal "flow" frazing.
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On Sat, 16 Apr 2016 10:09:18 -0700, snipped-for-privacy@whidbey.com wrote:

Me too. And I got my copy in 1965.

Costin and Phipps wrote a great book, but take anything they say about welding or 4130 with a fat grain of salt. In fact, take anything said about it by anyone in 1962 with a grain of salt.
For some reason, the Brits were slow to accept fusion welding -- O/A or TIG -- for tube frames. They were slow to accept TIG, in fact. And they were slow to adopt 4130.
They may have had some good reasons, but my feeling, having studied a great deal about it over the past 50 years, is that they were a bit caught up in popular misconceptions. There are some such misconceptions floating around in the US, too, such as a need to pre-heat even thin tubing before TIG-welding it, and the supposed "grain opening" of 4130 if you braze it. These stories have been debunked.
Note that Brit homebuilt-aircraft builders aren't allowed to weld their own tube frames unless they're CAA certified welders. In the US, our EAA runs classes in welding 4130 with O/A and with TIG, and hundreds of aircraft have been built that way. I think we have a more extensive experience base with both the materials and the processes.
But I don't really know. I hope to get out to Jay Leno's garage again next year, and I'd like to ask Bernard, the garage manager, about it. He ought to know the whole story on the Brits. Also, the motorsports instructors at Lincoln and Miller should know very well what works and what doesn't.
BTW, we have an article coming up on when and where you can use lift-start TIG, later this year in Fab Shop. I think it will contain some discussion about 4130.
--
Ed Huntress

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"Ed Huntress" wrote in message wrote:

Me too. And I got my copy in 1965.

Costin and Phipps wrote a great book, but take anything they say about welding or 4130 with a fat grain of salt. In fact, take anything said about it by anyone in 1962 with a grain of salt.
For some reason, the Brits were slow to accept fusion welding -- O/A or TIG -- for tube frames. They were slow to accept TIG, in fact. And they were slow to adopt 4130.
They may have had some good reasons, but my feeling, having studied a great deal about it over the past 50 years, is that they were a bit caught up in popular misconceptions. There are some such misconceptions floating around in the US, too, such as a need to pre-heat even thin tubing before TIG-welding it, and the supposed "grain opening" of 4130 if you braze it. These stories have been debunked.
Note that Brit homebuilt-aircraft builders aren't allowed to weld their own tube frames unless they're CAA certified welders. In the US, our EAA runs classes in welding 4130 with O/A and with TIG, and hundreds of aircraft have been built that way. I think we have a more extensive experience base with both the materials and the processes.
But I don't really know. I hope to get out to Jay Leno's garage again next year, and I'd like to ask Bernard, the garage manager, about it. He ought to know the whole story on the Brits. Also, the motorsports instructors at Lincoln and Miller should know very well what works and what doesn't.
BTW, we have an article coming up on when and where you can use lift-start TIG, later this year in Fab Shop. I think it will contain some discussion about 4130. =============================================================For five/six point roll bars and 10 point roll cages that get installed into production vehicles to augment the factory structures the NHRA requires 1-3/4" OD tubing with minimum 0.118" wall thickness for mild steel and minimum 0.083" wall thickness for 4130 chrome moly tubing. Mild steel welding must be "approved MIG wire feed or approved TIG heliarc process" and 4130 chrome moly welding by "approved TIG heliarc process". No grinding on welds permitted. Welds must be free of slag and porosity. For full tube frame vehicles there are more rules on OD and wall thickness depending on where in the frame the tube is installed. So for the five and six point bars and 10 point cages mild steel is most common, and if you want to save 75-100 lbs you can step up to 4130 for an extra $500-1000. Unlike roundy-round cars (NASCAR and dirt tracks) it is extremely rare for a drag racing car to hit anything so repairability isn't really a concern.
----- Regards, Carl Ijames
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On Sun, 17 Apr 2016 01:27:49 -0400, "Carl Ijames"

That's kind of interesting. I'd like to know how NHRA arrived at their rules for thickness and acceptable welding techniques.
There's a lot of talk about the problem with "cold starts" when welding 4130, which refers to MIG, primarily. But some kit planes have MIG-welded 4130 frames.
Over the years I've seen lots of comments and conclusions from people who build frames, but they rarely do any actual testing. I have a connection with a guy who works for a major welding-equipment company who supposedly has lots of testing data on tube frames for aircraft and cars. I have too much on my plate now to pursue it for an article, but I hope to get to it eventually.
--
Ed Huntress

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