[SEL] electrolysis

Peter Scales peter at loud-n-clear.net
Fri May 19 12:32:00 PDT 2006


I'd have to say that in my experience, there isn't a great deal of chance of
hydrogen embrittlement at room temperatures.  As far as my understanding
goes, hydrogen embrittlement is caused by the presence of dissolved atomic
hydrogen in solid iron, and the solubility of atomic hydrogen in solid iron
below about 200 degrees Centigrade is virtually negligible.  The gas
produced during electrolysis is molecular hydrogen (H2) and as such has
effectively zero solubility in steel at room temperature.  The thinner the
section, the less the effect of hydrogen on it, as the time taken for
hydrogen to diffuse out of the section falls with the reduction in
thickness.

I worked in welding inspection for fifteen years, until 1989, and unless
there has been a great new body of experience since then, the rule of thumb
was to post-heat thick sections (> 1" or 25mm) (or at least to control
cooling) for 24 hours per inch of thickness at 200 Centigrade, to allow time
for any entrained hydrogen to diffuse out of the material.  Under an inch of
thickness, there usually wasn't much done other than to throw a blanket over
the weld, maybe.

If you have a critical component, such as a gun barrel or high pressure
vessel or receiver, then maybe there is a need to pay more attention to
this, but in my opinion, for thin low-stress items, at low temperature,
there isn't a great deal of cause for concern.

Regards

     Pete
-- 
Peter Scales  

> -----Original Message-----
> From: sel-bounces at lists.stationary-engine.com 
> [mailto:sel-bounces at lists.stationary-engine.com] On Behalf Of 
> Andy Glines
> Sent: 19 May 2006 19:42
> To: sel at lists.stationary-engine.com
> Subject: [SEL] electrolysis
> 
> I know that electrolysis is a popular method for cleaninig up 
> rustry iron 
> among the ATIS crowd.  I have used it a couple of times and I 
> am a big fan.  
> Someone on another list asked about using electrolysis on a 
> small steam 
> boiler.  What permanent or chemical effects does electrolysis 
> have on the 
> base metal?  Someone on the other list mentioned hydrogen 
> embrittelment?  
> I'm asking here because I know that there is some knowledge 
> of the subject 
> on the SEL.  Thanks
> 
> 
> 
> _______________________________________________
> SEL mailing list
> SEL at lists.stationary-engine.com
> http://www.stationary-engine.com/mailman/listinfo/sel
> 






More information about the sel mailing list