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P2 Locomotive Company and related matters

Discussion in 'Steam Traction' started by class8mikado, Sep 13, 2013.

  1. W.Williams

    W.Williams Well-Known Member

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    Lots of incredible progress!
    One question I have, why are the areas in yellow not welded? (Excuse the markup, it was done on the phone!)
     

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  2. Richard Roper

    Richard Roper Member

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  3. Kylchap

    Kylchap Member

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    The fabricated cylinder block is like a 3-dimensional jigsaw which requires welding bits together in a very precise sequence so that the welder can gain access as required. I'm guessing that the current image of the block only shows the welds for which the sequence has been worked out.
     
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  4. Richard Roper

    Richard Roper Member

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    Purely out of interest, what is the life expectancy of a fabricated & welded cylinder, as compared with a cast iron one? Obviously the P2 Group have the CAD and assembly / welding drawings to hand if another block is required, but I'd be interested to know - Manufacturing another block wouldn't probably be as difficult as say manufacturing another V2 monobloc, but it certainly wouldn't be a small job either...

    Richard.
     
  5. W.Williams

    W.Williams Well-Known Member

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    I’d be surprised if it’s not being made as a life of engine component in the same way a cast one would. I presume the fabrication will still have liners in the bores and these are the components (together with valve seals) that see the most wear and are regularly serviced and replaced.

    Its getting a full PWHT so to me nothing suggests it’s going to be coming out of the frames any sooner than a cast component.

    In the days of yore large castings of this size were entirely the norm. Nowadays fabrication is the norm. It’s a sign of the times more than anything in my book.

    Castings aren’t perfect. They often live life with significant residual stresses in them that given enough use and time will initiate cracks as has happened to the V2.

    I think the P2 group in using the more standard (nowadays) fabrication method and aiming to get all the residual stresses from welding out in a post weld heat treat are creating a superior cylinder assembly
    to a cast one.

    All that being said, the method by which that heat treat is conducted is important. An electric oven is the ideal, there must be some big ones in the country somewhere? Sheffield? Port Talbot?

    Failing that heat blankets could be used in abundance inside (or outside) a fabricated box, an ISO container could actually be bricked up on the inside in theory if you wanted a makeshift oven.... Did someone say Heath Robinson....?

    600/650degrees or so for 6 hours. The precise parameters are set by the welding engineer but that’s roughly what I’d expect to see.
     
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  6. Richard Roper

    Richard Roper Member

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    Thank You for your input Sir! Very much appreciated... I was wondering if it would be a lifetime assembly, or whether it would require renewal more frequently... I was basing this on my very limited knowledge that cast iron does not rust away as quickly as steel, but I appreciate that we are talking heavy section components, not thin platework.

    Richard. :)
     
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  7. Kylchap

    Kylchap Member

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    I think A1slt did enquire about having a cast cylinder block made but their supplier looked at the complexity of the casting and declined.
     
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  8. guycarr360

    guycarr360 Member

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    Think the company that did Tornado's looked at it and laughed, have seen the footage on a roadshow somewhere on YouTube, presented by Mark Allatt.
     
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  9. Steve

    Steve Part of the furniture Friend

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    I started to type something similar but then abandoned it. Steel will definitely corrode faster than iron and anyone with an inside cylindered locomotive will know that corrosion of the cylinder block is its achilles heel, even as an iron casting. At least with steel there is more chance of a repair.
     
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  10. 8126

    8126 Member

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    Thermofax in Dudley will put 10 tonnes of steel over 1000 deg C in a 4x3x2m electric furnace for you, if you want it and can cover the electricity bill, I'm sure there are others. Also a couple of big vacuum and inert gas ovens out there, although I doubt anybody with a nice clean vacuum oven is going to want a nasty carbon steel fabrication in it.
     
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