Steam & Excursion > Flues

What are flues make out of? Is it just steel? Why are they so hard to procure?

Yes and the size on heated tubes makes them a bit hard to find.

Out

Could dom tubing be used? Or would that be cost prohibited?

bankshotone Wrote:
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> Could dom tubing be used? Or would that be cost
> prohibited?


I sure don't know what THAT is, but there are specific metallurgical requirements, specified by the FRA, for Flue and tube material used in steam locomotive boilers. Plus, documentation of those materials must be submitted to the FRA (just like staybolt material, staybolt cap material, firebox/boiler steel, etc..

I see. Dom stands for drawn over mandrel it is a seamless tube. Some call it bushing stock. It is available in many different sizes.

Posted from Android

Seamless is the preferred material and yes pretty much all of it is DOM.

Out

I don't know why DOM couldn't be used but I thought it was mainly for uses where a precision ID is desirable. Also used to make roll cages. I am not sure if it's available commonly in the lengths needed, 20ft nominal is listed on one website.
http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube

Flues are not hard to procure, with the exception of certain sizes.

There are several suppliers of tubes, and most of the sizes used
in locomotive boilers are in stock in large quantities. Check
the web sites of Anderson Tube or Kilsby-Roberts, just 2 of the
many suppliers.

There are hundreds of thousands of boilers in daily use in the USA.
Everything from huge power plants to the tiny boiler at your local
laundry. And new boilers are being constructed every day.

Locomotive boiler tubes must meet ASTM/ASME specifications. Usually
SA-178 or SA-210. Look them up at the ASTM website. You will find
the recipe for the steel, the cookbook for how to make it and test
it, and how to construct the tube.

There is no room for such things as copper flues, chrome-tubes, stainless
steel tubes, hardware store schedule 80 pipe, used mobile home axles,
or anything else that does not meet the specs and doesn't have the
Material Test Report with it. That is kind of the birth certificate
for that batch of flues and that pour of steel.

There are some tube sizes for which demand is so low it's almost
non-existent, and therefore suppliers don't carry it in stock and few
mills make it, because it will languish on the shelves for years.

This applies to the 5 3/8" diameter, 5 1/2" diameter, and 6" diameter
tubes that usually have superheater units installed in them.

This is just a WAG, but there are probably no more than a dozen or so
operating locomotives that use 5 1/2" flues, and they range from 0-6-0s
all the way up to the biggest things out there. It doesn't take a genius
to figure out that all of these together won't use a full mill-run of
5 1/2" flues (the minimum order) in 30 years.

Changing to a smaller size won't work well because it will drastically
change the heating surface and the volume of hot gasses that can pass
through it and around the superheater unit. Going to a larger size usually
requires new front and back tube sheets, and will also change the gas
flow and drafting characteristics.

All this for machines that will run a few weeks a year. Why bother?

Years ago, one operator that had a need for 5 1/2" flues and hit the wall
trying to find them got the idea to buy a mill run of them from a mill in
Germany that agreed to manufacture them to the proper specs. This led to
contacting other known operators of other locomotives requiring said size.
By combining the needs of those, it was worthwhile to but the mill run
and have it shipped to the USA. That was done. Win-Win all around, thanks
to some operators that don't work in a vacuum and keep secrets and are not
afraid to look ahead.

A few operators didn't bother and are now looking at trying to find flues
as their boilers get close to the 15-year limit for removing the flues.
At least one operator managed to completely screw up a boilerful of nearly
new tubes.

Some of these operators will simply remove, clean, inspect, re-end, and
reinstall their 5 1/2" flues, assuming they have enough pieces to make
the safe-ends. That is perfectly legal, too. The genius who ruined the
flues in his engine doesn't have that option, as there is nothing left
to be reused.

Sooner or later another mill run will have to be secured. Hopefully it will
not be Chinese.

American mills that produce tubing of those diameters, which is in very high
demand (but does not meet the specs for boilers), do not want to shut down
their production lines and change over to make one run of flues that few
people want, then have to change back to the stuff for which there is a ready
market.

IOW, you CAN get them. It just takes a little determination, detective work,
money, and not running down a rabbit hole looking for something "better" that
isn't legal in the first place.



Edited 1 time(s). Last edit at 10/23/14 17:51 by Realist.

....and NW J611's brand new flues just arrived a few days ago on several flat cars to the locomotive!

Realist,

Good responce. You covered the whole question and answered a few questions I have had for years. Thanks,

Nudge

spnudge Wrote:
-------------------------------------------------------
> Realist,
>
> Good responce. You covered the whole question and
> answered a few questions I have had for years.
> Thanks,
>
> Nudge

You are welcome.

No charge!

I expect Wes Camp will have some additions to this subject.

Re: 'Flues'

I'll admit I'm in over my head with being up to speed with current flue requiremwnts and suppliers.
If I was faced with having to replace the boiler's tubes, I'd hire the best LOCO experienced contractor(s) to do the job of removal and replacement.
The grunt-work of cleaning the shell, etc. I'm up for!

But, the ART of proper flue installation utilizes the employment of (current) muscle-memory and multi-loco re-tubing experience.
Its heavy, hot work and you have to do it often enough to become proficient at it ----- those puppies (boiler tubes) may stay in there for a LONG time -and I want the BEST installers that money allow. I'm impressed with the young folks that have taken up the craft of being boilermakers; without those guys, the future for operating steam is dim, indeed.

I'm not a boiler 'artist', but I have gotten to know some of the BEST. The things that they've seen and done during the Glory Days are astounding --I miss their stories and deeds deeply. I'm highly appreciative of skilled boiler/firebox repair folks. The skill of simply looking at firebox sheets and being able to evaluate their true condition is an ART that I deeply admire. I am often awe-struck by the pure art of the craft! Some welds are things of beauty, in their own right!

I remain in a state appreciative humility for the boiler folks that keep my hopes alive!

Wes C.

Thank you, Realist, for the education on flue suppliers. Tossing down another Ale 8 One in your honor...did not realize till now that one of the bigger flue suppliers was just a loud belch from my residence.

Posted from iPhone



Edited 1 time(s). Last edit at 10/23/14 21:44 by Alco251.

I've always admired the sight of a sheet full of properly beaded tubes and flues. A work of art. Rolling and beading ain't easy!