Using steel for 5" guage locomotive boilers

Dear All,

I will soon be at the stage in my loco build (GWR45) to start thinking of the boiler. I have the copper and will soon start the flange plates. However I have been interested in the various international reports especially from down under about the highly successful use of Duplex steels for boiler making. I am relatively competent at TIG welding so may use Duplex on another loco build at some stage if I know it can be approved?

There are also a number of posts on ME forums about the successful use of steel for boilers. However I am very unsure about the UK legislation on the use and approval of steel boilers.

Can anyone clarify in layman's terms as to what needs to be inspected and how, for the full approval of a steel boiler weather it be in Duplex stainless or another steel. Making the boiler is the easier part but getting it approved for track use seems the unknown 'black art'.

I am looking forward to your replies.

Thankyou all in advance.

The use of stainless steel for boilers is not permitted within the NAME/S Fed/7.1/4"G rulebook. You only have a choice of copper or mild steel. Steel boilers must be welded by a coded welder, or else you must submit test pieces for inspection by a boiler inspector. Full traceability of all ferrous materials used is required. Hence before you even make a decision on what material to use, you must discuss the matter with your boiler inspector. If you are not a member of a model engineering society, then you will need to take out insurance cover via an approved Insurance Company if you wish to run the engine in public. (Were you thinking of re-mortgaging your house to pay for this?)

Many club boiler inspectors will not test steel boilers - and can quite legitimately refuse to do so if it is beyond their experience. Essentially, the decision of what material to use is what your club boiler tester is prepared to test.

Edited By Nigel Bennett on 01/03/2018 09:14:56

Hi Nigel,

Many thanks for the reply. I think I will put that idea to bed then and get cracking on the flange plates this weekend!

I am a member of the local model engineering society and did discuss this with them but they to were not fully aware of what the latest situation was as the green book was last published 6 years ago, 2012.

Perhaps things will develop over the coming years so I can get my TIG welder doing something exciting!

Best regards,

David.

A lot will depend on the attitude and ability of the club inspector if you go down the club route.

Non destructive testing of your welds should only cost £100, Club inspector may accept that.

Independant boiler inspector if you don't want the club to do it about £200

Insurance from a specialist if your club won't cover you will not be too bad from someone like Walker Midgely.

Hopefully Fizzy will be along later, have a look for his post "steel boiler for £200" to see it can be done at very reasonable cost if your welding is up to the job and you have an agreeable club inspector.

Clubs and insurance companies in the UK seem to be very much behind the times. Stainless steel boilers have been in use in continental Europe for many years with no problems!

Russell (in France)

Biggest problem is the age old attitude towards steel boilers in the UK, get the inspecter on side first. Next is the irrefutable fact that unless you are up there with the very best welders it will leak like a sieve. If your welds are good enough to pass X-ray analysis you will be able to make it leak free, if not then I guarantee it will leak on a stop start lap. Best is to coax a qualified pressure vessel welder to do it for 'free' as technically speaking paying him makes it a commercial boiler, again speak to your inspecter first. There is very little welding on a boiler and if its prepped and tacked up correctly it can be completed very quickly. Best of luck.

" I am relatively competent at TIG welding "

earwigoagain.

Regards Ian.