Can I weld to a CF8M casting?

[KernOily]

Guys I need some way to attach some type of a 304L/316L stainless forged pipe fitting, e.g. a weldolet or coupling, to a cast part. The part in question is the volute of a centrifugal pump.

Can I weld directly to the cast volute? I would like to use a SMAW stick procedure, position weld in the field, but I can TIG them on if I have to. What about some other method of attachment, e.g. brazing or silver solder? (Don't suggest J-B weld ;-) )

Thanks for your help and ideas! Pete

Thanks!
Pete

 

[metengr]

Yes, you can weld either 304L or 316L to the CF8M cast volute. The CF8M is a cast version of 316 stainless steel. I would use the GTAW process to minize heat input with an ER316 filler material. Before welding, I would perform a Liquid penetrant inspection of the area you will be welding on to make sure you have no surface defects.

No preheat, and keep the interpass temperature below 400 deg F. When you have finished welding, perform a Liquid penetrant test of the weld and surrounding base material.

 

[KernOily]

metengr - Thanks for your reply and information. I will go ahead with that plan. Thanks! Pete

Thanks!
Pete

 

[sayee1]

If my memory is correct, CF8M is not classified in ASME Section IX. Preferable to weld it to ss with an inconel type electrode/filler wire. I remember that CF8M was used in the coils of a furnace for a refinery and we faced some problems in procedure qualification, especially since the low ductility of the CF8M did not allow for full 180 Degree bends. So we had to do some base metal bends and then carry out bends of the welde3d joint to a greater angle to demonstrate greater ductlity of the welded joints.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

 

[GRoberts]

Sayee,
Actually, CF8M only runs into ductility problems if the ferrite is too high and it has been exposed to high temperatures, changing the ferrite into sigma. Otherwise, it is very ductile. In most normal circumstances, it is very weldable and an austenitic stainless filler should work excellent. Are you sure you weren't working with a higher carbon/high temperature cast stainless steel?

 

[sayee1]

Sorry Guys
GRoberts is correct, the problems we faced were with HK40 and not CF8M. CF8M is ductile and no weldability isuues.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!