Waspaloy Heat Treat Procedures 2

[COKA]

Hello All,

I was going through our heat treating procedures for superalloys, and I found two different procedures for waspaloy:

Procedure 1. Increase to 1850F and hold 1 hour, cool to room temperature (???), increase to 1550F and hold 4 hours, cool to 1400F and hold 16 hours, cool to room temperature.

Procedure 2: Increase to 1850F and hold 1 hour, cool to 1550F and hold 4 hours, cool to 1400F and hold 16 hours, cool to room temperature.

Can somebody explain to me the drop to room temperature in the first procedure? I was told that both procedures were found in literature, although I do not know where.

Thank you.


Coka

 

[unclesyd]

This alloy has a different HT for every application. Case in point we have a turbine that has three different components made from Waspaloy and all three have different HT procedures. This piece of equipment was designed by ex P&W engineers.

If my mind is still on track the different HT's are dictated by the end use and is mainly concerned by the stress rupture properties desired.
I have no notes on the interrupted quench you mention. All our procedures (3) are solution treat with air cool then the aging treatments.

I do know there is HT procedure that has water quench from the higher ranges of solution treating temperatures then an additional one at the lower end of the solution treating range with an air cool. Then a 2 step aging with air cool.

If you can get a hold of the AMS 5544 spec and see if they give any explanation of the difference. Haynes Alloys may be able to give additional information as they supplied some of our material.

I tried to contact an expert on Waspaloy but regretfully he has gone on to work on the big turbine in the sky.

 

[metengr]

COKA;
Here is some information on waspaloy from Carpenter. It contains some interesting information on various heat treatment conditions and associated high temperature properties. I will see if I can find any additional info from a superalloys reference book that I have at home.

http://carpenter.idesinc.com/datasheet.asp?i=3&e=135&c=TechArt

 

[metengr]

COKA;
As a follow-up to my previous post, I looked thru several references regarding nickel-base superalloys and specifically, Waspaloy. I could not find any information regarding heat treatment method #2. Air cooling to room temperature is typical and required for solution treatments and stabilization treatments to provide the necessary driving force for precipitation of a particular phase during aging.

For heat treatment #2 , I do not see any benefit of enhancing precipitation other than affecting grain size and coarsening of existing carbides.

 

[COKA]

Thank you both! This actually helps a lot.
Have a good weekend!

Coka