hi group,
is there is any one working on any of the tools mentioned. if so shall we have a small conversation on some of the topics. ok waiting for replay.
nice day.
--- PipingDesign@yahoogroups.com <firreza@yahoo.com>
wrote:
> Dear Ranjiit
>
> As far as I know the clad thickness is not brought
into the strenght calculation of the cladded vessel ,
therefore all the pressure parts should be welded to
the base metal , your case carbon steel.
> The other reason which crosses my mind is that , in
cladded vessels the internal fluid in contact with the
clad is very corrosive for the outer layer (cs) ,
therefore , if there happens a leak through the clad
it will corrode the carbon steel very fast.For example
in Urea Plant the rate of corrosion of carbon steel in
the vicinity of carbamate is 1000 mm per year , so
suppose a time this occurs in your cladded vessel
round the tray support attached to the clad , it would
cause support and consequently tray failure.
> The welding procedure is also very important while
welding the support to the vessel considering the
buttering which is required round the support area
which will be embeded in the stainless steel clad and
also PWHT which might be required.
> Therefore I recommend you to follow your client
spec.
>
> Hope the above would help
>
> Cheers
> Reza
>
>
> ramanan ranjit <ranjitperu@yahoo.com> wrote:
> Dear All,
> My question may be classified as an irrelevant one
to
> this group as it is more or less related to pressure
> vessel fabrication rather than piping.However as I
> have not find any alternative at present but to ask
> this question in this forum. Please forgive me and
> allow me to ask this question.
> We have a carbon steel vessel which is cladded
> internally with stainless steel( the cladding was
done
> by explosion bonding).Our client specification
states
> that anything welded to the inside of a cladded
vessel
> shall be attached to the base metal(carbon
steel)after
> peeling off the cladding and the area from where the
> cladding has been removed shall be filled with weld
> deposit.My question is that "is it really necessary
to
> weld the relative light weight components like tray
> support ring to the base metal after peeling off the
> cladding which has been integrally bonded to the
base
> metal by executing a metallic bonding during
cladding
> operation?Also the bond shear strength of the clad
> metal has been established by bond shear test and
the
> same is many times greater than that required to
hold
> the tray support ring together with the trays and
the
> entrained fluid as can be demonstrated by
calculation.
> On the contrary removal of clad metal will lead to
an
> area prone to more corrosion in addition to the
> undesierable chemistryand hardness produced at the
> weld deposited area.
> I hope the experienced engineers in this forum will
> give more insight to elaborate my above explanation
> and in turn help me to convince our client in this
> matter.
>
> thanking You in advance.
> regards,
> ranjit.
>
>
>
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