Welding 2205 to 304l;2205 SS/2205 SS 1

[unclesyd]

Ihave a local shop that is haing severe welding problems while welding 2205 SS/2205 SS and 2205 SS/340lSS. The welds are supposed to be strenght welds, no code. The equipment has been in use several years and is very dirty and coated with polymer. Best effort cleaning
appears to have no effect on the welding problems. I am trying to get the welding spec and what has been tried. I made some welds on this equipment some 20 yrs ago using Cronotron 3880 and they are still holding. The question is has anyone tried any different consumable for this type weld and maybe a little on procedure.
Thanks

 

[Goahead]

Did you see the older thread?

http://www.eng-tips.com/viewthread.cfm?qid=223752

http://www.welding-advisers.com/

 

[metengr]

unclesyd;
What are the severe problems you can describe?

 

[unclesyd]

Goahead,
this scre is alightly older model that the previous post. The design is very close but the perating conditions are a lot tighter that the newer one in the old post. One big difference is the metal chemistry is slightly different, I di d make some repairs on this screw many years ago, probably more luck than skill.

Meteng,
The normal operation is is right on top of the design condition, if not over. One big problem I see with this design is that the screw is excessively long for the operating load. There is a noticalbe dog leg in the screw and I'm trying to get it in a lathe to check the T.I.R. The construction, along with being welded will not allow very little if any straightness adjustm.e Was hoping to get the screw annealed, No Joy. Will strees releive prior to welding and possibly after repairs. There were some majors problems with the welding procedure used to make the previous repairs, it left out interpass temperature and getting it clean. If stressed releived prior to repair this will also remove the polymer.

 

[metengr]

unclesyd;
Why in the world was a duplex stainless steel used in this service? Any type of stress relieving is going to destroy the corrosion properties of the duplex and even equally or more important will result in possible formation of intermetallic compounds that would effect strength/ ductility in service.

 

[unclesyd]

METENG,
This screw was originally used with water high in chlorides, it is now on low Chloridew Water. If I recall this was the big selling point as the very first screws were 316 SS. The switch was made when the screws got longer where addition strength and ?corrosion resistance? was needed. I have just found out that the screw tries to plug with polymer (Nylon) during upset coditions. If this is true, it would put tremendous torque on the screw trying to extrude the Nylon Polymer. Looking at the screw the the worst area is near the discharge end, I was looking at the reducing the stresss in the screw caused by operating with the dogleg, giving up some corrosion resistance and strength. It will be out of the building in morning and I hope to get a better look at. I asked for a print of the process Historian just prior to the failure, maybe able to see the events leading up to the failure.

 

[metengr]

unclesyd:
I would stay use E2209 filler metal for the 2205 to the 304 or 2205/2205, and use and use no preheat, and as low of an interpass temperature you can provide.

 

[unclesyd]

Meteng
Thanks for the reply and suggestion. I was already looking for an older welder, one that welds stringers as originally called out for SS welding. We used to call thm dabbers for the method they used, slow but the heat input was extremely low. Most of the local local welders are of the cup walking variety so the heat input goes up very fast.
We may have the "Dead Man Walking Syndrome" as I've now heard that the screw has been through the Pyrolysis Furnace several time. This is a six hour cycle five up to 770°F then one hour at 900°F.. There is supposedly a redesign in the works, take some length out by making it a two stage process