Welding dissimilar materials

[andysf]

I have a Norwegian customer who wishes to weld a mild steel plate onto the front of a 25/12 casting.
Does anyone have any idea what type of consumable they should be using?
My first instincts would be to go for something as close to the 25/12, such as a 309, but i am not sure what effect, if any, this will have on the mild steel plate.

Thanks

 

[metengr]

Yes, the 309 would be an acceptable filler metal for joining the dissimilar materials.

 

[andysf]

Thanks kindly metengr, always good to have a second opinion

 

[wegm]

Andysf,
I agree with metengr that E309 welding consumable is a good choice for such a welding though I would like to highlight that it is recommended only for standard temperature service (SFA-5.4, A7.10, E309 states: "Embrittlement or cracking can occur if these dissimilar steel welds are subjected to a post weld heat treatment or to service above 370 degree C"). So, since the "casting Chromium-Nickel-Iron alloy 25/12 class" is intended to be used for high-temperature service, if your construction is for such service then a nickel based consumable (e.g. AWS 5.14, ErNiCr-3) is recommended. Please have a look at this link:

http://www.weldinguide.com/gdanastasiadis/viewtopic.php?f=5&t=32

regards
wegm

 

[metengr]

wegm;
Keep in mind that the 25/12 is a wrought version of 309.

 

[wegm]

Metengr,
Since andysf wrote "25/12 casting", I suppose it is in accordance with ASTM A 447 (standard specification for steel castings, Chromium-Nickel-Iron Alloy, 25-12 Class, for high-temperature service) and even though the chemical composition of E309 is closer to that steel than the ErNiCr-3, the ErNiCr-3 is highly recommended for high temperature service because of the reason that I gave in my past post.
Why do you have objection regarding ErNiCr-3 in case of high temperature service?
regards
wegm

 

[metengr]

wegm;
I don't have any objection with using the nickel-base filler, I was merely pointing out the fact that the 25/12 is a wrought version of 309, and use of 309 filler metal would be considered appropriate. Having carbon steel joined to 309 for elevated temperature service is not typical, considering carbon steel will be the weak link from a design standpoint.

 

[MagBen]

If parts' geometry permitted, one may try inertia friction welding in which no filler mateiral is needed.

 

[andysf]

I will have to ask the question as to what kind of service these parts will be performing. I don't think friction welding would be a viable option for them however. With mild steel being involved I am also of the thought that maybe it is not high temperature environment. This customer does however have areas where high temperature castings are required.

 

[pandithan]

309 is best choice

 

[Ripz]

When in doubt, Inco it out!

 

[weldstan]

Ripz,
Not always. In some environments the nickel base filler will preferentially corrode.