FATIGUE-APPEARANCE-TRANSITION TEMPERATURE (FATT) 2

[ATsampalas]

1) Can someone explain how to calculate FATT for a given metal ?
2) Is it a link with a Charpy-V Transition Curve Temperature ? Please explain ...
3) Any reference documentation about FATT will be appreciated .

Sincerely,

A_Tsampalas

 

[metengr]

You are referring to the fracture appearance transition temperature (FATT). This is a value that is selected from Charpy impact testing of steels that exhibit a ductile to brittle transition temperature.

Your question is too board for this forum. There are various web sites that can explain further;

http://www.key-to-steel.com/Articles.htm

Scroll to the article of interest regarding brittle fracture.

 

[arto]

J.F.Harvey's "Pressure Component Construction" has a good info [sections 5.22-5.26 in 1980 edition] on fracture, Charpy's etc.
also:
J.A.Collins "Failure of Materials in Mechanical Design" par 3.7

Ashby & Jones "Engrg Mat'ls" p.150

"L.R.Hurst "Brittle Fracture of a Brick-lined P.V." Mat'l Perf. March 86 pp.24-26

 

[ATsampalas]

Dear MM Metengr and Arto,

Thanks for your answers.
I know how to obtain CV ductile-to-brittle transition temperature curves .
I have never used FATT .
In found documentation, the writer suggests :
" After CV specimens were tested...From the fractured surfaces of the specimens, the FRACTURE-APPEARANCE-TRANSITION TEMPERATURE at 50 % cleavage (FATT 50) can be determined ".
As I am not acquainted with FATT, the subject (previous affirmation) seems unclear .
Can you please clarify ?

Sincerely,

A_Tsampalas

 

[JoeTank]

I believe that you may find illustrations of % cleavage of CVN specimens in ASTM A20 or A370.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[metengr]

The FATT is a value based on a visual percentage of flat (cleavage) fracture on the broken impact specimen. Typically, percent flat fracture is a variable that is plotted on a Charpy impact energy graph as a function of test temperature. At the temperature where 50% of the fracture surface is flat and the remainder is shear, this is the FATT @50%.