RE: Flanged connections with dissimilar Materials

From: <Steve>
Date: Thu Jul 04 2002 - 01:29:00 EDT

Hi Nirmal Murarka

It is normally more difficult to arrange the welding of two dissimilar metals than it is to arrange a flanged joint. As you have stated that the materials will be dissimilar, a material "break" joint is required somewhere. It will be either mechanical or welded. Mechanical is more common. With RTJ joint with two different flange materials, hardness, elasticity, galvanic/corrosion resistance need to be considered carefully. A good selection of ring material may help. I would talk to your vessel supplier and your flange supplier. Service and temperature cannot be ignored.

Cheers

Steve McKenzie

-----Original Message-----

From: NIRMAL MURARKA [mailto:Nirmal-Murarka@enc.ltindia.com] Sent: Thursday, July 04, 2002 5:00 PM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] Flanged connections with dissimilar Materials

Steve/Mahavir,

Do you tend to say that we should not use different material flanges for RTJ joints with solid metallic gasket?

Can I conclude that if the joint is RTJ go for spec break at weld and otherwise flange face without bothering much about service and temperature?

Any comments?

Nirmal Murarka

                       "Steve McKenzie"
                       <Mechproj@xtra.co        To:
<PipingDesign@yahoogroups.com>
                       .nz>                     cc:
                                                Subject:  RE: [PipingDesign]
Flanged connections with
                       04/07/2002 09:28          dissimilar Materials
                       AM
                       Please respond to
                       PipingDesign

Hi Mahavir

your dilemma occurs sometimes with pumps. One way it is overcome is to have the equipment supplier provide flanged ends on his equipment and also to supply mating flanges (and gasket if necessary) to your pipe material spec.

Cheers

Steve McKenzie

-----Original Message-----

From: Prasad Mahavir/Piping [mailto:jainmp@eil.co.in] Sent: Thursday, July 04, 2002 3:30 PM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] Flanged connections with dissimilar Materials

Hi folks,

I guess that type of flange facing would also play a role. For example if the flange is with RTJ ends and gasket being used is solid octagonal or oval, then I would not like to exercise option 2. Any Comments?

Mahavir

  -----Original Message-----
From: NIRMAL MURARKA [mailto:Nirmal-Murarka@enc.ltindia.com] Sent: Wednesday, July 03, 2002 5:55 PM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Flanged connections with dissimilar Materials

   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 ?

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Received on Thu Jul 04 01:29:00 2002