Steam Boiler

Hi

Can anyone tell me if inconel 740 steel can be used to build a boiler for a 5ich gauge loco

Most states in Australia accepts model boilers made from "Duplex" stainless steel. Have you contacted your club boiler inspector about using Inconel steel, you may have trouble getting it certified.

Thor

Not in England you can't if you want to go the club testing route as the code specifically precludes stainless as a generic and I imagine NI is the same, not sure about the South though. You might be OK with a commercial test and a commercial insurer as long as you can do the numbers and get a design approved. Could be complicated and expensive though!

I can see the logic precluding stainless as a material given its propensity for cracking and sudden failure but other places in the world as well as Europe allow it, maybe we are stuck in the dark ages.

Paul.

With a maximum Fe content of 3%, Inconel 740 is hardly a steel! It is designed for the superheater section of a coal-fired boiler in a power station, but does its cost not make it less attractive, even given the probable difficulties in trying to get a boiler certificate.

Has anyone read the code that the Australians use for stainless steel boilers?

Bri

I only found these on the Internet, seems you have to buy a copy, others may be able to find it.

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Thor

" You might be OK with a commercial test and a commercial insurer as long as you can do the numbers and get a design approved. Could be complicated and expensive though! "

I have just completed that route for a conventional steel vertical firetube boiler. 18 pages of calculations, many pages of risk assessments, installation and operation instructions etc. etc. later, plus over £1500 lighter in the wallet department just for design approval and independant testing. I cover some of this in an article coming up in the next issue of EIM.

In short, that sort of money will buy you a hell of a lot of copper and silver solder.

Martin

There has been a concerted effort by some senior people to have the Australian codes put on the net for all, but the AMBSC reckons they can't afford to forego the money from selling them. There was an article in AME on the testing of a Duplex boiler, for a 7-1/4 Darjeeling B, a few years back.

I would imagine that machining the inconel would be challenging, we used to machine it at one company I worked for and I know that inconel castings were a real pain. We were using machining centres that could use the correct speeds and feeds and had plenty of power.

Dave W