Where the
world gathers for metal finishing
Q&As since 1989


-----

Hydrogen embrittlement in quenched steel

Dear Srs,
I am student of Material Engineering, and I have to do a work related to hydrogen embrittlement. I am very interesting in the issue of quench cracking in steel as consequence of hydrogen embrittlement.
Can somebody guide me on this subject.
Thank you
Best regards

Diego Del
engineering student - Buenos Aires, Argentina
October 23, 2008

---

It absolutely is not hydrogen embrittlement!
Cracking is do to an improper quench or an improper design of the part (IE: you must have a generous radius on inside corners). I had one of 8 pins crack because I put it into the quench oil level vs a quick drop vertically. Huge crack. It appears to have something to do with the asymmetrical phase structure change causing huge internal stresses.

James Watts
- Navarre, Florida
October 24, 2008

I agree with Jim. If you already brought the part up to a quenching temperature, long ago the hydrogen must have escaped. So, most surely the cracks are due to a temperature gradient (an exterior surface that is shrinking because it is being cooled while the core is still hot). The thicker the object, the higher the risk.

Guillermo Marrufo
Monterrey, NL, Mexico
October 27, 2008