Does Acid Washing Cause Hydrogen Embrittlement?

[LarryG]

I’ve read that acid washing a blade will cause hydrogen embrittlement. Is there evidence that that is true? If so, how deep does it go and does it affect a sharpened edge?

 

[Bill DeShivs]

If it does, a few minutes at 300 degrees should take care of it.

 

[FortyTwoBlades]

It can. Most acids have hydrogen, and hydrogen-based acids will release a certain amount of it that can infiltrate the steel. Temperature over time will release the hydrogen, so either waiting a long time or warming it for a period (referred to as "baking" in the fastener and steel finishing world) can relieve it faster. The degree of embrittlement will depend on the nature of the specific treatment process but a combination of heat and/or time will relieve the embrittlement. It's just important to make sure you don't hit temps that damage the heat treatment in the process, which also is a function of temperature over time.