A Question for our Welder's/Fabricator's Options

[76-914]

I've been trying to figure out how you guy's deal with shrinkage. Not for body panels but just general welding. (And no, I did not shrink my car when I installed the Engman Kit) As an example, let's say I'm welding on a 10' piece of pipe that will become a stair rail. Of course it turns 90' on each end and will have flanged ends that screw to the wall. If the 90' elbows are welded on then the length of the rail will shorten "x" inches. Can this be prevented with pre heating. If so, do you apply heat to the entire piece or just where the weld will be? Do you accept that shrinkage will occur and just do not drill any matching holes until after the weld? Is there a formula that adjusts for this shrinkage? Do you bolt it in place then weld to prevent shrinkage? Also, I don't remember this being a problem with gas welding but that was years ago. My imagination or not? TIA, Kent (IMG:style_emoticons/default/beerchug.gif)

[veekry9]

https://www.youtube.com/watch?v=RPgb77Ruz7g

https://www.youtube.com/results?search_query=welder+tig
Of note is the discussion of 'brown sugar',the heat induced precipitation out of the chromolly.
Due diligence,not the hearsay of 'self-proclaimed normalizers'.
The John Force crash is illuminating,the failure mode,discovered by micrography.
https://www.youtube.com/watch?v=wVrdST1pXRk
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https://www.google.ca/webhp?sourceid=chrome...eel&tbm=vid
With the heavy Pressure Vessel welds of 4-6" wide,the effect you describe is significant.
Training and experience circumvents the natural phenomena,the cooling and becoming smaller,delta T.
In fact,it is standard welding training to understand the 'shrinkage' of materials.
https://www.google.ca/search?q=pressure+ves...aPZDOEQ_AUIBigB
The welds I've seen in machines trade were/are awesome works of fusion art,and like any endeavor requires talent and practice.
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