Can you weld a PM, Cast, Forged Part to Mild Steel....?

[dmc456]

I have a small and expensive weldment that I would like to convert into a cast or PM part. I have seen this done and welded to mild steel but don't know what material or process was used to make the part. Part will be welded to a 1" mild steel shaft.

Looking for suggestions.

Thanks

David

 

[swall]

For steel castings and iron castings, probably--it all depends on specific alloys and desired strength levels. Powder metal? Many potential pitfalls here. Some ferrous pm alloys are copper infiltrated. Some contain free graphite. All, other than high density re-forged pm parts, would have residual binder that would cause welding difficulties.

 

[dgallup]

We tried laser welding a MIM part and had problems with outgassing. Brazing would probably work well though.

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[btrueblood]

Even brazing or soldering a PM part can be difficult, as the part will soak up filler metal like, well a sponge, unless infiltrated like swall suggested.

 

[TVP]

I agree with the others, PM will be difficult to weld and still obtain high quality. A good investment casting with a suitable steel alloy should be weldable. If you want PM, then you will need to look at a different joining method.

 

[arunmrao]

Have you tried vacuum brazing of your parts. Also do you have adequate quantities to justify for the increase in cost by PM or Investment casting routes.

 

[metengr]

A part produced from the PM/HIP method can be welded with no issues. There was a recent ASME B&PV Code Case our committee approved for Grade 91 PM/HIP material with no binder. This was for valve bodies in lieu of traditional castings. The PM/HIP product was superior to traditional castings in terms of soundness, chemical composition and weldability.

 

[tbuelna]

It should be no problem to cast a part in mild (low carbon) steel using any conventional casting process. It would also seem to present no problems welding a mild steel shaft to the mild steel casting using any conventional welding process. It is probably much less expensive to cast/machine the part rather than using PM, for small or medium production quantities.