×
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

Changing of microstructure after fire
2

Changing of microstructure after fire

Changing of microstructure after fire

(OP)
Hello,

Could you give me some advice?

Now I examine structural steel (S235) sample from fired construction.

As I can see there is shperoidisation of perlite and some carbides along grain boundaries. Band structure is disappeared.

Is it really possible this changing after fire (Unfortunately I don't know time, but I think it wasn't too long)?

Thank you in advance.

RE: Changing of microstructure after fire

There are books (and consultants) that address this subject.
Yes, structural steels can be damaged (microstructure and properties) in a fire.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Changing of microstructure after fire

(OP)
Thanks a lot!

We have performed only hardness test (due to sample size). Hardness is around 125 HV10. Conversion in Rm (UTS) give acceptable result for steel S235, but as I understand in this case value of Rp0.2 (YS offset 0,2%) would be more significant...

N.B. Could you please give some reference if it is possible?

RE: Changing of microstructure after fire

I'm not really sure what to say regarding the hardness test since you provided no details. Damage likely extended from the surface beyond visible changes in microstructure. You can get a good feel for this by taking a microhardness survey starting at the surface and also obtaining core microhardness so you can identify the extent of damaged material.

RE: Changing of microstructure after fire

Agree with EdS, this is a specialized field and the investigation should involve a specialist who is trained to look for visible evidence at the scene as well as metallurgical. What you actually want is a fitness-for-service assessment to determine how much material must be condemned.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

RE: Changing of microstructure after fire

Hello,

Yes, you can see a microstructural change like that after a exposure of the steel to high temperatures (ie. fire). I suggest you to read this article.

http://www.ommi.co.uk/etd/eccc/advancedcreep/V6i1x...

Good Luck!

RE: Changing of microstructure after fire

Hardness testing should always be done in concert with in situ metallography.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

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