Weld overlay on RTJ grooves - profile of flange face before WO

[jbesson]

Dear Engineers,
In continuation to the thread794-422928 I would like your advice regarding the profile of flange face to be considered before WO (Weld Overlay) deposit.
In this configuration the WO deposit shall be 8.5mm after machining
-if we start with a standard flange the original groove shall be re-machined to allow 8.5mm WO deposit and the machining will reduce the flange thk which is not acceptable, so we have to increase the RF height
-if we start with a flat face flange we have to put enough WO to machine the groove + 8.5mm thk between bottom of groove and interface with flange base material -> ~25mm in this case

I consider that both options are acceptable, does anyone have experience/advise on this subject ?

Thanks in advance

 

[Some Curious Guy]

Ordering Standard RTJ flange with a higher raised face, machining the groove to make room for weld overlay deposit and then machining the weld overlaid groove to have the final dimensions seems like a better proposition.
I say this because I have had bad experience with a weld overlay deposit warping the flatness of a tubesheet. Depositing 25 mm weld overlay to a Flat face flange looks a lot to me but that also depends on the thickness of the base metal and skill of the welder and fabricator doing the job. Usually we Engineers sitting in a office do not get a feel of weld warpage and shrinkage. If you can also take the opinion of the welder ( not the production engineer ). You would get better insights.

 

[jbesson]

Hi "Some Curious Guy"

Thanks for your reply.
In my case there is only WN flange + blind flange so wrapping of the blind is not a concern and the final machining after WO deposit will clear the problems of deformation.
But I agree that for a tubesheet it's a concern and that to "get a feel of weld warpage and shrinkage" is important

 

[Some Curious Guy]

@Jbesson
In my experience I have seen the former method being widely used. I think buying standard RTJ flange, Modifying groove , applying weld overlay and final machining is more convenient, faster and comparatively cheap. However both methods are acceptable. It boils down to comparative cost and manufacturing feasibility analysis. You should think about the machining and finishing capacity of your machine shop, the cost of weld consumables locally , the skill of your welder and machinist, any subcontracting needs etc. All this varies in every part of the world