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| steam delivery welding question ? https://www.rypn.org/forums/viewtopic.php?f=1&t=24449 |
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| Author: | John Risley [ Thu Dec 13, 2007 12:56 pm ] |
| Post subject: | steam delivery welding question ? |
In a thread below Mike Tillger mentioned parts being fabricated for the #1361 project. My question just how tricky of a job is this. I have looked at quite a few locos dry/steam delivery pipes and thought these would be expensive to cast up. I always wondered if it wouldn't be much easier to fab something up. So, just how tricky is it to get them to seal up tight and is there a problem of expansion/contraction effecting the joints. I know there are flexable joints available for other applications. Haven't gotten to the point where I have helped out on that paticular project yet, but I see it coming down the pike. Thanks in advance for the thoughts on this. John. |
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| Author: | Dave [ Thu Dec 13, 2007 1:30 pm ] |
| Post subject: | Re: steam delivery welding question ? |
High pressure steam - at pressures that make ours look inconsequential - lines have been fabricated with welding for decades now. The challengs it to make them fit without compromising draft and tube access. Those sleek, smooth compound curves are easier to cast than fabricate. Spherical ground in ring joints can be used with either welded or fabricated piping in this application. I recently was responsible for a boiler that had the FTS drypipe to T joint made with a commercial flanged fitting with a gasket - it did not like to stay tight, and frequent tightening was inconvenient but very necessary. I'd keep using ground in rings if it was up to me. dave |
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| Author: | tomgears [ Thu Dec 13, 2007 2:25 pm ] |
| Post subject: | Re: steam delivery welding question ? |
The problem is that 80 years ago there were dozens of places that could cast anything you wanted. Today there are few places here in the US that are able to cast anything more complicated than a manhole cover. If it could be done the cost would be ten times that of fabricating a welded assembly. Then try and find a patternmaker for such a task. Our manufacturing capabilities are a shadow of what they once were. |
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| Author: | jasonsobczynski [ Thu Dec 13, 2007 8:33 pm ] |
| Post subject: | Re: steam delivery welding question ? |
They can be cast, in fact a foundry exists in PA that does a wonderful job of them. Cast of a proper iron they cost 1,200 each...for a 1913 baldwin 2-4-2. I have long been a fan of weldments. But trying to find a welder that is capable of laying out all of the slices of the pie to come out for the required shape would not be an easy task either. |
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| Author: | Mike Tillger [ Thu Dec 13, 2007 8:52 pm ] |
| Post subject: | Re: steam delivery welding question ? |
If my memory serves me correctly the pattern quotes for the K4 were around $9500.00 for each delivery pipe, 1 left, 1 right for a total of $19,000 and the casting was around $950 per side. For a total cost of $20,900. This was back in 2003 dollars. You can do a lot of jig making and layout work and welding for that amount of money. Mike Tillger |
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| Author: | Robert Yuill [ Fri Dec 14, 2007 12:13 am ] |
| Post subject: | Re: steam delivery welding question ? |
Fabricated steam pipes, drifting valves, and telescoping pipes for the foward engine were all installed in the N&W 1218 during the initial rebuild. All joints were spherical/flat joint ring style and work just fine at 300 psi. Nothing better than a well fitted and lapped ground joint! The SP 786 is going to receive new fabricated steam pipes, and the dry pipe will be a fabrication, (retaining the throttle elbow casting). Certainly cast parts will work, but so will faricated ones. It may come down to what resources are available in your area. Robert Yuill |
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| Author: | John Risley [ Fri Dec 14, 2007 2:13 am ] |
| Post subject: | Re: steam delivery welding question ? |
I appreciate the collective thoughts on this. When replacing old boilers with new ones I can see some problems arising when using the old ones if still useable. I have also seen some castings that have one of the two eyes broken off down by the lower joint. So obviously some folks will be needing to address these problems soon {I hope}. When I was a welder we made a number of different cranes and winches for the US Navy. I remember one style that had a hydraulic tank with a motor/pump mounted topside. We had to use cast couplings tack welded together {for fitting} to make a snake like piece that bolted up on both ends. The pressure was #1000s of pounds, don't recall exactly, doesn't matter, but the point was that it had to hold pressure and not leak obviously. I don't know if you can picture what I am trying to describe, but it was a smaller scale but similar arrangement. I am sure hyd and steam welding have many different characterists. With the heating and eventual cooling that goes on I would think cast would be best, but technology has come a long way too. I know old technology oftens works best on steam locos, but sometimes technology works too. Was just curious how professional steam mechanics would address this problem. Another time we had some huge elbos come in that like boiler parts had to meet some pretty strict guidelines, we machined the chamfer on either end for welding on some jobsite somewhere else. These Elbos were about 4ft in dia and were to "thin" in a few places. Had to build them up with 7018 and then grind them down, blending it so you couldn't tell it had been welded. Kind of like pad welding, but without the paperwork! Thanks again for sharing your thoughts, John. |
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