17-4 PH Straightening

[boo1]

I have questions on the straightening of 17-4 PH H1150. Im confused on what temps can be to rework machined parts when I read AKSteel note on transformation to martensite.
1. What temps can be used for straighting H1150?
2. What is the stress relieving process to be use?

AMS 2759/3
3.4.6 Straightening
"When approved by the cognizant engineering organization, straightening shall be accomplished at either ambient temperature, during aging, or by heating to not higher than 50 °F (28 °C) below the aging temperature. Ambient temperature straightening and hot or warm straightening after aging shall be followed by stress relieving. It is permissible to stress relieve after straightening during aging."

http://www.aksteel.com/markets_products/stainless_precipitation.aspx

Data Product Bulletine 17-4 PH page 18
"When fabricating AK Steel 17-4 PH Stainless Steel, it is
important to keep in mind the low temperatures at which
the start of transformation to martensite (Ms) and the
completion of the martensite transformation (Mf) occur.
These temperatures are approximately 270°F (132°C)
and 90°F (32°C) respectively.

Because of this characteristic, it is necessary to cool
parts in process at least to 90°F (32°C) prior to applying
subsequent heat treatments if normal final properties
are to be obtained. This practice is essential to assure
grain refinement and to assure good ductility."

 

[boo1]

Correction should have been 17-4 PH condition A

 

[unclesyd]

I would not straighten 17/4 PH SS in Condition A. Applying heat is problematic as 17/4 does strange things when you get above 600°F. All our PH SS shafts are straightened cold. I checked with a local shipyard on their method and it was the same, cold. Straightening a shaft of any kind requires a skilled mechanic and a good setup. We do all our straightening of the PH alloys H1130 on 17/4 and similar hardness on others.

http://www.wbmetals.com/about.asp