am i stupid on hydrogen embrittlement ? 6

[dho]

we clean oily parts in some solvent which has a pH value around 10.5. so, this solvent is no way acidic. to me, there will be no free hydrogen atoms. but army tells me it will cause high strength steel hydrogen embrittlement. am i out of my mind?
thanks.

 

[weldstan]

High strength steels are subject to caustic cracking. At your stated pH levels and at ambient temperature conditions, you will be safe.

 

[EdStainless]

Either too high or too low of pH can lead to trouble with high strength steels.

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Plymouth Tube

 

[dho]

"Either too high or too low of pH can lead to trouble with high strength steels", elaborate?
thanks.

 

[dho]

"High strength steels are subject to caustic cracking. At your stated pH levels and at ambient temperature conditions, you will be safe." temperature other than room will have any impact at this pH level?
thanks.

 

[swall]

There is a test, ASTM F519, for hydrogen embrittlement prospensity of cleaning/maintenance solutions that may come in contact with high strength steel components. You expose 4340 notched test bars to the chemical in question for the same exposure time and temp that would be used when clelaning. The test bars are then subjected to a sustained load test for 200 hours. If the bar is intact at the end of the test, the solution is considered non embrittling.

 

[metengr]

swall is correct, and provides good advice to ensure no issues.

 

[dho]

"There is a test, ASTM F519 ... " yes, there is a astm test to verify hydrogen embrittlement. BUT, if the solution has a pH number of 10.5, why army suspecting hydrogen embrittlement. there is no hydrogen atoms. why need to test. that is my question. i do not understand the thinking behind. or i just do not know that even at pH of 10.5, there is free hydrogen atoms there.
thanks to all.

 

[weldstan]

Hydrogen can be a byproduct of the chemical reaction of NaOH with iron.

 

[dho]

"NaOH with iron". chemical equation?
thanks.

 

[weldstan]

Fe + 2NaOH = Na2FeO2 + H2

 

[EdStainless]

Any corrosion will result in hydrogen ions at the surface of the metal.
In some cases even reactions in the solution that do not result in corrosion (where the metal may be a catalyst) will generate H.

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Plymouth Tube

 

[dho]

http://answers.yahoo.com/question/index?qid=20081006090116AA4gulH

 

[dho]

"Fe + 2NaOH = Na2FeO2 + H2", conditions?

 

[CoryPad]

Try Corrosion and Corrosion Control by Revie, page 122:

http://books.google.com/books?id=HJ...A&ved=0CDgQ6AEwAA#v=snippet&q=Na2FeO2&f=false

 

[tbuelna]

Halogenated solvents and cutting fluids can also create corrosion issues with titanium alloys at RT.

 

[weldstan]

dho,
Conditions are temperature, concentration, exposure time and other chemicals used in the cleaning solution. In general, you should experience no cracking at temperatures below approximately 150 F. You need to be more forthcoming in divulging just what is in your cleaning solution, the time and temperature of exposure, and the alloy steel and its mechanical properties (based on heat treatment) in order to receive meaningful info.

 

[dho]

Omegaclean (by Omegasonics), use ultrasound machine, set to 140F and 10 minutes.
to clean oily parts made from 4340 (Chrome plated), 17-4ph, and 440C. (all >150 kpsi)
sorry, i thought at pH 10.5, those not matter too much.
thanks.