A234 WP11 Class 2 microstructure

[abramb]

Good morning to all,

We are manufacturing a red tee, the dimensions are OD 508x20.62WT and OD 457.2x19.05 WT.
The material is ASTM A234 WP11 Class 2

The heat treatment is normalize and temper, with air cooling, as per Code.
The heat treatment parameters are:

-normalization, soaking temperature 920 °C, soaking time 2 minutes/mm, rapid air cooling
-tempering, soaking temperature 650 °C, soaking time 2 minutes/mm, still air cooling

The microstructure obtained is the following:

http://files.engineering.com/getfile.aspx?folder=f15f3255-7e43-4919-8e59-fa31d903a717&file=12_25.jpg

http://files.engineering.com/getfile.aspx?folder=492d96fd-f5b1-4092-87dc-1131484feb21&file=12_26.jpg

Can anyone tell me if the microstructure is conforming, please?

Thank you,
A.

 

[stanweld]

Your microstructure is not considered atypical for a rapidly air cooled (air quenched) and tempered heat treatment. Why the rapid air cooling? Cooling in still air will provide the desired microstructure.

 

[metengr]

Agree with stanweld. The higher rate of cooling may have been selected to ensure CL2 properties.

 

[abramb]

Thank you for your answers, stanweld and metengr.