Thread: Hydrogen Embrittlement during Rust Removal

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There have been a couple of recent threads which mention that hydrogen embrittlement can occur during electroplating and electrolysis.
I have been using electrolytic rust removal (so far not on suspension pieces) but am now concerned that there could also be a problem in this process.
Has anyone seen any indication of hydrogen embrittlement during this method of rust removal?
It would seem that baking the part might be good insurance against failure.

Depends a lot on what steel the parts are made out of. Quenched and tempered steels (chrome moly) are fairly susceptable especially at hardnesses over 30 HRc while mild alloy steels are not. Most suspension parts are probably not that hard and even in chrome moly would not be that susceptable.

I believe the baking must be performed within 4 hours of metal exposure to hydrogen.

Kitz

Thanks for your response, Kitz.

From what I read, it is necessary to heat the part to approx. 400F to remove the hydrogen, but I can find no indication of how long the "bake" should last. Is it only necessary to raise the temp of the item to that level or does it have to be kept at that temperature for a specific period?

One of the links I attached to the other thread essentially said, the longer the better for bake time. There are probably practical considerations such as size of plated piece, density of material, thickness of plating, and so on.

Ok, looks like it's a judgment call. I think I will bake any item that I have removed the rust from by electrolysis just as a precaution if there is any chance of it being stressed and certainly any suspension part.
Thanks again.

Hydrogen embrittlement will only happen in the top layers of the parts unless it they are porous, and is generated at the surface of the metal where the electricity is making contact with the electrolyte. Industrial furnaces where hydrogen removal is practiced, operate up to 800 degrees C for 12 to 24 hours.

The cleaning process you talk about did not deposit metal did it?? If it did not then hydrogen embritlement would not be a real issue i dont think.

I am a metallurgist but dont specialise in this field of metallurgy so I can be corrected. One thing I do know is that corrosion can be an issue with electrolytic processes, so check any cracks or imperfections carefully before painting etc, as this would probably cause failure before hydrogen embrittlement.

Originally Posted by JL350

Hydrogen embrittlement will only happen in the top layers of the parts unless it they are porous, and is generated at the surface of the metal where the electricity is making contact with the electrolyte. Industrial furnaces where hydrogen removal is practiced, operate up to 800 degrees C for 12 to 24 hours.

The cleaning process you talk about did not deposit metal did it?? If it did not then hydrogen embritlement would not be a real issue i dont think.

I am a metallurgist but dont specialise in this field of metallurgy so I can be corrected. One thing I do know is that corrosion can be an issue with electrolytic processes, so check any cracks or imperfections carefully before painting etc, as this would probably cause failure before hydrogen embrittlement.

No. The rust is removed from the part being cleaned and ends up on the sacrificial anode (rebar,) but nothing is deposited on the part.