RYPN'ers;

What is to stop someone from putting in brass (rather than bronze) or stainless on a boiler?

I have been looking for something relating to the use (or, hopefully, banning the use) of these materials.

Any pointers to documents pertaining to materials for use on items under pressure? For example, would SS piping "pass"?

Let me state that this is just for interest only; I'm certainly not planning on making a SS boiler, or attaching SS to anything other than as decoration. I'm just trying to research what materials are specified in certain places. The side-rod discussion below started this train of thought.



john.stewart@crc.ca

John:

I do not know what the standards are in Canada.

However; in the US the controlling document for materials would be the ASME B&PV Code Section II Materials.

> RYPN'ers;

> What is to stop someone from putting in
> brass (rather than bronze) or stainless on a
> boiler?

> I have been looking for something relating
> to the use (or, hopefully, banning the use)
> of these materials.

> Any pointers to documents pertaining to
> materials for use on items under pressure?
> For example, would SS piping
> "pass"?

> Let me state that this is just for interest
> only; I'm certainly not planning on making a
> SS boiler, or attaching SS to anything other
> than as decoration. I'm just trying to
> research what materials are specified in
> certain places. The side-rod discussion
> below started this train of thought.


pkurilecz@yahoo.com

I have been told that at least some grades of stainless react badly in a steam environment when used to construct model welded boilers. The only use of stainless I have seen in traditional full size locomotives is decorative.

Dave

irondave@bellsouth.net

Stainless Steel is a poor conductor of heat so it would not make the best material for a boiler.

Paul D

pfdx@aol.com

The 4449 has stainless poppet valves in the throttle and blow downs. This was done because of the long periods of no activity and the pitting that can occur during this time. I have heard that the conversion works well. I believe that the 844 has stainless valves in her throttle as well but I don't know for sure. I also don't know what grade of stainless was used but if I guessed I would guess on 316.

Robert@trainorders.com

> Stainless Steel is a poor conductor of heat
> so it would not make the best material for a
> boiler.

Having worked on many shipboard steam systems, I can't recall any SS piping, 304, 316, or 400 grade. Mostly carbon steel pipe, from 1/2" IPS to 20". Valves were steel too, as I recall. I would guess that the RR's used mostly carbon steel as well. Anyone?

Russell Underwood

Jay611@home.com

The UP did specify a stainless for some water gage fittings (the nipple which threaded into the backhead and extended into the water space).

I made one a while back, but can't remember the exact alloy off hand. I'm pretty sure it was a 400 series. I'll see if I can find it.

Speaking from a modeller's perspective (don't laugh, they've probably tried just about everything).
Stainless and brass are both no-nos in boiler construction itself. Stainless, as was pointed out is a rather poor conductor of heat. It was also shown to develop pinhole leaks at the welded joints after it had been in service a relatively short while (Stainless feedwater heaters have been successfully done though, as have stainless pistons and rods.). Brass, being rather more brittle than copper, has been shown to crack when used for sheets.

As for fittings, I have seen commercial brass fittings used successfully on many models, but you still need to make sure not to exceed the manufacturer's temperature and pressure recommendations. Stainless fittings were not traditionally used that often, at least in models, due to the higher material costs and harder machining. However, some things, like stainless tubing, inserts, seats, and check balls are growing much more popular, especially in places where corrosion or wear become important.

Bottom line is,it might be do-able depending on you specific application, but it's probably still best to ask your supplier about specific applications (and your friendly neighborhood inspector if he will accept it) first.