It was all I wanted to know.
Final conclusion is heat treatment at 850°C rises elongation. Duclility is inchanged or lower. YS & UTS are much lower. Thank you very much indeed.
Thank, you or your answer.
I was told that ITN is number of norm. File I get from client is named itn06710_023. I kow quite well standard heat treatment and behaviour of 17 4PH.
But heat treatment in 850°C is so mysterious for me I had to ask.
It seems you get the right answer. Due to this...
In ITN I foud stabilization after annealing and before aging.
Stabilization
fixture introduction in to the furnace at a temperature not higher than 300 °C, ris e
up to 850 °C, hold for 2 hours , cooling in still air (till T<200°C) and subse quent
cooling in water fo r 2 hours t o guarantee...
