plz answer to my querry

Are you sure of that design temperature (or did you mean Fahrenheit 'F')?

ASME VIII does not provide that much guidance/restriction as to the use of joint design (single-V, double-V); that is covered within Section IX and your qualified weld procedures.

Typically on thicker sections, approximately 3/4" (19 mm) the double-V is used to avoid having excess filler required; the opening on a single-V is that much greater. BUT THIS DEPENDS ON YOUR WELD PROCEDURE (and to a smaller degree the accessibility/orientation of the weld, ease of welding, and welders preference). The question of backing will also be addressed with the WPS.

I gather from your question that you are referring to category B welds as per figure UW-3. Accordingly, as per Table UW-12 you must determine the level of radiography required (assuming this isn't an unfired steam boiler in which according to UW-11(3) you would automatically require 100%). If you don't have the original calculations/design, you will have to perform new calculations to determine the efficiency (E) for that shell thickness. (you didn't provide the material spec for me to guess for you).

I don't fully understand what you are asking about the cladding, that should be covered in Part UCL of Sec VIII (it's a short section so you should probably read it all)

Please see UW-9 and UW-13 for weld details as well, particularly concerning transitions for different thicknesses of material.

Also please check that your locale is not governed by the National Board of Boiler and Pressure Vessel Inspectors (NBIC) which is more relevant to rebuilding rather than Sec VIII new construction. (or any other code/standard as enforced by the law of your land)

Second lastly - please get your authorized inspector involved as soon as possible to make the process for you that much easier.

Lastly, I must reinforce the point, you questions are more applicable to ASME sec IX and welding procedures than they are to sec VIII.

sir thanks for yr answer

i m now summarizing the whole point . basicaly its crude fractional distilation column ( tower). it has three zone zone A, B, C highest temp is in lower portion tht is Zone C and it is 775C ( design temp) how ever the zone A has max temp limit of 300C and Zone B has 300-600 C temp range where Zone C has upto 725, its internal dia is 5.761m from where the shell (shell thickness is 19 mm) to shell weld joint has been cut we just want to re join it. Zone C material is SS410, zone A and B material is Carbon Steel for tht purpose wht sort of weld grrove should we make, plz quote from relevant standard and code yr supporting ans or suggestion

thanks again for yr ans plz do suggest in this regard.

Thanks alot

I think you missed the point:

ASME does not prescribe a weld detail such as this - it is left open to allow the designer freedom to choose.

But if you want an opinion: I suggest going with a double-V weld on any plate that is unclad. It is a little trickier to prep than a single-V but you save in welding time/cost and you don't require a backing strip that needs to be removed and could potentially damage your used material.

The standard you should be quoting is your qualified weld procedures.

(if you have a WPS for a U-groove, J-groove, single-V, double-V: ask your welders which they would prefer to use)

plz also i want to mention that shell to shell weld is b/w CS material. the material is 1501-151-grade B ( it has been taken out of past drawing of CRUDE COLUMN of the built year 1966)

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thanks alot sir for your kind response...

Sorry to not provide an answer, but who has drawings of fractionating towers built prior to 1967? Is it possible to get copies?

sir i cannt give u drawing ...the problem is that we now dont have any drawings of welding joints..... the material is CS 1501-151- Gr B which is present in 1967 year drawongs... its thickness is 19 mm, i dont know its equivalent in todays time, now we want to weld it again so do we need any pre/post Heat weld treatment ..wht kind of electrode should we use to incorporate this material's welding.