RE: Tray support rings welded to the inside of an integally stainless stell cladded vessel.

I am a bit familiar with the predicament faced by you.

In such a situation, both the practices are feasible, i.e., welding the TSR straight on the cladding or on the base material. I know some cases where the TSR was directly welded to the cladding & it worked satisfactorily.

However, (you can say it as recommended good practices), it is always advisable to weld the TSR on the base material. The basic reasons cited in support of this argument are like :

a)The mechanical rigidity of cladding will be less than the base (obvious, isn't it?)
b) In case you are going for welding TSR to the cladding, the bonding strenght of the cladding with base material may deteriorate at that location during welding of TSR. This is a real possibility.

Regarding the question of localized corrosion, if you check the procedure of fixing the TSRs, it will be clear to you.

Generally, the cladding is first removed at the location where TSRs will be fixed, may be a 100-150 mm band. Then the TSRs are welded with inconel/E309 Mo electrode (I assume TSRs are of SS metallurgy). The gap between TSR and edge of cladding is then weld overlayed with same electrode. This ensures that no CS parent metal is exposed to the corrosive media.

I hope this is of some use to you.

regards Received on Wed Aug 03 08:06:00 2005