×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

RA in Ovako 146s

RA in Ovako 146s

RA in Ovako 146s

(OP)
Hi All,

I have attached a micrograph of Ovako 146s case hardened steel, I am estimating around 10% RA in the case (independent lab from H/T company state "No RA") I am also achieving hardness results to support the level of RA agains independent lab results of >800Hv! Is there a more accurate way of determining without the use of XRD etc?

Thanks

RE: RA in Ovako 146s

(OP)
http://imageshack.us/g/252/52862252.jpg/

The above link is of the samples from the HT comapany and from an independent lab (supposedly from the same sacrificial test piece). Microstructures look very different and a difference in hardness of approx 200Hv.  

RE: RA in Ovako 146s

As you already know, x-ray diffraction is the most accurate method for determination of residual austenite content in steels.  However, microscopy techniques are frequently used, and some of them are more accurate than conventional nital etching.  If you have access to a Scanning Electron Microscope, this can be particularly helpful when observing etched microstructures.  Here are some links with good information on this subject:

Color tint-etching for multiphase steels
http://www.asminternational.org/static/Static%20Files/IP/Magazine/AMP/V161/I02/amp16102p027.pdf?authtoken=8c9476e7ea64b012de742a841f74961b0c6e5f6a&bcsi_scan_7a2556acdb9b1410=0&bcsi_scan_filename=amp16102p027.pdf

Imaging of Phases in Steels
http://www.georgevandervoort.com/met_papers/IronandSteel/imaging_phases_in_steels.pdf

Martensite and Retained Austenite
http://www.georgevandervoort.com/met_papers/IronandSteel/Martensite_RetainedAustenite.pdf

Etching Techniques for the Microstructural Characterization of Complex Phase Steels by Light Microscopy
http://www.mtf.stuba.sk/docs/internetovy_casopis/2008/4mimorc/hairer.pdf
 

RE: RA in Ovako 146s

(OP)
Thanks, some interesting info.Klemm's tint etch could be worth trying as an alternative. Any idea on the claimed >800Hv? As no carbide network is visible and the material has been tempered I would have thought this would be near impossible to achieve?
 

RE: RA in Ovako 146s

Agreed, I have only seen 800 HV in cast iron that has been exposed to extremely rapid cooling.

RE: RA in Ovako 146s

(OP)
Thanks TVP,I'm awaiting response on these claimed results.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources