×
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

what's blue and brittle?

what's blue and brittle?

what's blue and brittle?

(OP)
actually, what's "blue brittle" testing (something to do with steel)?   I'd ask my favorite metallurgist, but he's away from his desk.

RE: what's blue and brittle?

Quoting Bethlehem Steel.

"Blue Brittleness: Brittleness occurring in steel when in the temperature range of 400F to 700F, or when cold after being worked within this temperature range."

RE: what's blue and brittle?

Often you should test for blue-brittle on parts that are potentially workhardened.

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

RE: what's blue and brittle?

(OP)
I think I was already that far along based on the context (which I didn't provide)... but how is the test actually done?

RE: what's blue and brittle?

Other than knowing which materials that are subject to the phenomena the only way I know is to do a metallurgical analysis.  A microscopic analysis will reveal pretty severe grain distortion, greatly elongated grains. This can occur in very discrete bands.

RE: what's blue and brittle?

Not sure what you are looking to do, but a nital etch test is useful for identifying grinding burn, surface damage due to abusive milling, etc. And it is non-destructive.

RE: what's blue and brittle?

Thanks for callin me out there Mike. I guess I should have "thought" about my previous answer (even) a little bit. Did you get your answer?

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

RE: what's blue and brittle?

(OP)
Wes, your answer was still helpful.  It was very similar, in fact, to the answer provided by the guy who told me his parts had passed a blue-brittle test.  Haven't run into anyone yet who can give me the details of the test, nor what the pass/fail criteria would be (including the guy who assured me his parts passed).  Unclesyd suggests looking at the grain structure, and swall suggest nital etch... I had the impression that there was some sort of destructive test done.  I guess I may have to dig deeper around here to figure out what really happened (if anything).

RE: what's blue and brittle?

Mike,

I remember doing some down and dirty tests for work hardening; this is years ago though. I don't remember the specifics but the process goes something like this.

Work Hardening produces a martensitic(?) condition, and that has a specific hardness, so perform a hardness test. If the parts fail (are determined to be blue-brittle / dynamic-strain hardened / work hardened) they undergo a strain relief heat treatment (or scrapped as the case may be.

Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

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