engineering fundamentals Discussion Forum
Directory | Career | News | Industrial
Home Membership Magazines Forum Search Member Calculators

Materials

Design

Processes

Units

Formulas

Math
List Recent Topics | Start a New Topic
 

<< Previous Message No. 20983 Next >>
Author: gearloose
Time: 01/28/10 20:04 PST
This is a reply to message no. 20974 by bzcc
Reply | Original Message | New Topic | List Topics | List Messages on This Topic
Current Topic:
help..tensile fracture behaviour on tempered steel

No, I would not expect a quench delay to be the cause of the strange results you describe.  What a tempering delay could do is give time for quench cracks to form.  If the stress within the part is high enough, untempered martensite will crack, and the stress to cause cracking will be less if you have more time.  (I've had a load of cutting tools crack because they sat overnight without tempering.  You really remember your mistakes!)

 

Does the fracture surface of the one tempered at the lowest temperature look brittle?  That is, lots of flat fracture, perhaps a granular appearance?  If so, then perhaps cracking while waiting played a role, although I would have expected it to show up in all the test samples.

[ List Replies to This Message Only ]

Home  Membership  About Us  Privacy  Disclaimer  Contact  Advertise

Copyright © 2018 eFunda, Inc.