ss to iron

[Tony Goodson]

Hi ,I need to weld a half inch dia 316 stainless tube through a hole drilled in a 2inch plumbing fitting. The fitting I think is malleable iron ,can this be migged or should it be brazed ? Thanks

 

[Omniata]

Brazing would perhaps be easier or perhaps bronze welding?

If welding is a must, "dissimilar" electrodes would maybe be better but then that limits you to arc only IIRC...

 

[gavuk]

can you post some pics of the job? ,maybe there is a way of designing out the need to weld it ?......what gear have you available ,and what is the job going to be used for ?.....

 

[Delgado]

Without seeing the job it's a bit hard to say, but I would imagine that your plumbing fitting is either mild steel or galvanised steel. If its galvanised then grind the surface off until you don't see any silver fleks, and if its not then just clean it up a bit. The correct way to weld it would be with a 309L filler material, what process you use is up to you (personally I'd use TIG), although buying a roll of 309L mig wire might be an expensive option for just one small job. If you've already got some 316L filler and it's not for anything critical, then you could probably get away with just using that.

 

[Chris Stevens]

Hi ,I need to weld a half inch dia 316 stainless tube through a hole drilled in a 2inch plumbing fitting. The fitting I think is malleable iron ,can this be migged or should it be brazed ? Thanks

You should be able to MIG this using MS wire no problem at all.............only issue would be that the MS weld wouldnt be as corrosion resistant as the other parts.

A very easy way to join many dissimilar ferrous metals is TIG brazing using SIF No 8, and this has the added advantage of very little distortion from heat.

 

[mike os]

Maliable iron plumbing is usually mig-ed or mma, assuming the connection is not critical from a corrosion perspective using normal mig or mma rods would be fine (will obviously affect the corrosive resistance of the HAZ on the stainless component)

otherwise TIG using the same grade wire as the stainless part or higher, or braze.

At the end of the day it is part of a mal iron fitting so I would guess it would not need to excede those design restrictions.????

I guess it is a fitting for a control sensor or similar? cant think of any other reason to use st/st into mal iron......

 

[Tony Goodson]

Many thanks to all of you for taking the time to reply ,the stainless tube is to inject water into a marine exhaust not ideal but they last about ten years ,that's why I couldn't remember if they were welded or brazed. I have now found someone to braze them for me thanks.