Re:(PipingDesign) Flanged connections with dissimilar Materi

the effect of the temp is not much of concern assuming the rating is ok. using option no. 1, is acceptable as long as the the weld procedure has been qualified and the matereil is comptaible with the service.
my preference is option no. 2 since it simplify the wps and this is the most accepted practice in breaking the piping spec.

• In PipingDesign@y..., "Tushar, Zope " <zope_tushar@f...> wrote:
  > Nirmal,
  >
  > Please clarify the design conditions of vessels & piping and the
  fluid being
  > handled.
  >
  > Dissimilar weld are not prefered. And I think this is very rare
  case that the
  > piping matl & vessel matl are different. They both handle the same
  fluid and
  > will have same operating conditions. Some consultants do have
  higher flange
  > rating for nozzles.
  >
  > Either of the flange joint or the weld joint will not avoid the
  unequal
  > (vertical) thermal expansion.
  > Proper installation / tightening of flange joint avoids the
  possibility of
  > leakage. The dissimillar weld in fact will be the place of stress
  > intesification. The thickness may be different at this weld. This
  will create
  > more pr. drop & turbulance and to avoid this a inside tapered peace
  of (higher
  > quality material) with thk matching on either side shall be used.
  >
  > Hence if the vessel spec says that nozzle is flanged then go for
  option 2.
  >
  > Tushar Zope
  > Piping Engineer
  > Foster Wheeler Eastern Pte. Ltd, Singapore
  > Ph: 6890 0774 Fax: 6223 2989
  >
  > Disclaimer
  > 'The information contained in this email and the files transmitted
  with it are
  > confidential and intended only for the use of the individual or
  entity to whom
  > they are addressed. If you have received this message in error,
  please
  > immediately notify the sender and delete the mail. The views or
  opinions
  > presented in this email are those of the author and do not
  necessarily represent
  > those of the company. The recipient should check this email and any
  attachments
  > for the presence of viruses. Foster Wheeler Eastern Pte Ltd accepts
  no liability
  > for any damage caused by any virus transmitted by this email.'
  >
  >
  >
  > ____________________Reply Separator____________________
  > Subject: (PipingDesign) Flanged connections with dissimilar
  Materials
  > Author: "NIRMAL MURARKA" <SMTP:Nirmal-Murarka@e...>
  > Date: 7/3/02 8:25 AM
  >
  > For a spec break with change in material near a flanged joint (may
  be
  > equipment flange and piping flange) what should be the correct
  approach:
  >
  > 1. Have spec break at flange-pipe joint (with dissimilar welding at
  the
  > flange-pipe joint) and avoid leakage because of unequal thermal
  expansion.
  > 2. Have spec break at the gasket (face of flange) and avoid
  dissimilar
  > material welding.
  >
  > May be temperature and type of materials will play a key role. When
  can we
  > go with option # 2 safely ?
  >
  >
  >
  >
  > Yahoo! Groups Sponsor
  >
  >
  <http://rd.yahoo.com/M=229641.2166546.3626727.1829184/D=egroupweb/S=17 05083319:H
  > M/A=1142327/R=0/*http://promo.yahoo.com/debtscape/>
  >
  > _____________________________________________________
  > Unsubscribe: PipingDesign-unsubscribe@y...
  >
  > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service
  > <http://docs.yahoo.com/info/terms/> .