Summary for 17-7ph condition a Discussion
17-7PH condition A heat treatment is discussed with a focus on whether it can be brought to CH900 or RH950. Lee Gearhart explains that CH900 applies to 17-7 PH (Type 631) wire that has already been solution annealed and cold drawn, then aged 1 hour at 900 °F; if the part was not cold drawn, CH900 cannot be done. He says RH950 is a different sequence: solution anneal, austenite condition at 1750 °F with air cool, then cool to -90 °F within 1 hour for 8-9 hours, warm to ambient, and age 1 hour at 950 °F. Toby Padfield disagrees in part, saying annealed 17-7 can only reach a maximum yield at RH900 and that CH900 is tied to condition C, though he adds that Solar Heat can reportedly achieve CH900 from condition A using an extra aging technique. The thread also includes later questions about 17-4PH and other 17-7PH conditions, but no further answers.
Q. Can 17-7 PH condition A be heat treated to CH900/RH950?
Everardo Hernandez
Sierra Pacific Engineering and Products – Los Angeles, California
2004
 | A. Yes to the RH950 condition, no to the CH900 condition. The CH900 requires that the starting material be in the heavily cold worked condition, called condition C, and not the annealed or solution treated condition called A.
A. It may be possible to heat treat your article to RH950 or CH900, depending on exactly what you have. CH900 applies to 17-7 PH (Type 631) wire that has been previously solution annealed and then cold drawn, which is then aged for 1 hour at 900 °F (482 °C). If your article has not been cold drawn, then CH900 cannot be performed. RH950 is performed as follows: after solution annealing the article is heated for austenite conditioning, which consists of heating to 1750 °F (954 °C) then air cooling. Within 1 hour the article must be cooled to -90 °F (-68 °C) for 8-9 hours, then air warmed to ambient. The article is then aged for 1 hour at 950 °F (510 °C). Toby Padfield |
A. 17-7PH Cond. A- You guys are wrong. Rules dictate that 17-7 in the annealed state can only attain a maximum yield at RH900. Condition C.- which is attained by cold reduction is supposedly the only way to reach CH900.
Due to the fact that mills thumb their noses at “small buys” of 17-7PH sheet, bar etc.- only condition A is available. However, through an extra aging technique CH900 is attainable from condition A — there is a group called Solar Heat who are able to achieve this feat.
William Rudolph
– Toronto, Ontario, Canada
2006
Q. Can 17-4PH condition A be heat treated to CH900/RH950? I have a job that requires this process, I want to know if this is possible.
Felipe Gutierrez
Sheet metal Shop – Oxnard, California
2006
RFQ: Hi Guy’s, Hi Girl’s,
On the subject of 17-7PH I’m looking for very nice etched cross sectional micrographs or SEM’s in longitudinal direction and at
90° to this. If possible of thin strip in condition A, Condition TH 1050 and RH 950.
I need them for educational purpose.
Thanks for your help.
Andy Blatter
– Rothenburg, Luzern, Switzerland
2007
Ed. note: This RFQ is outdated, but technical replies are welcome, and readers are encouraged to post their own RFQs. But no public commercial suggestions please ( huh? why?).
Q. IS 17-7 CONDITION C AND ANNEALED CONDITION THE SAME?
IF NOT, CAN YOU HEAT TREAT FROM ANNEALED CONDITION TO CONDITION C?
Carole Delacroix
alloys – Orange, California
July 15, 2008
Q. Hello,
I need the detailed steps of cold work of 17-7 steel. It is very work hardening alloy and it needs intermediate annealing processes. I don’t know how it is possible to anneal this steel but it’s final strength is not reduced.
zahede farzan
student – Tehran, Iran
May 12, 2009
Q. Does anyone have data on the resultant drop in hardness/tensile strength if 17-7 PH CH900 is overaged at 900 °F for periods greater than normal, say 6 or 12 or 24 hours? I am putting together some educational materials and this data would be helpful as a cautionary note.
Jim Kobrinetz
– Chicago Illinois USA
July 20, 2011
Q. Re: Heat Treating of Annealed 17-7PH sheet:
I have a request to harden a part to RH1020. Is this possible ?
JEFF MILLER
METAL PRODUCTS – Gardena, California
August 22, 2012
July 6, 2015
Q. Hi everyone.
I have a problem with the magnetic properties of 17-7PH wire springs.
Is there someone who can give me a clue about the main factor of magnetic properties in 17-7PH SS?
My wire condition is CH900 finished with 90% drawing ratio.
Due to a very small size of sample, I couldn’t measure the martensite or delta ferrite volume fraction.
Regards,
SIHOTANG
Restu Sihotang
Wire Manufacture – Busan,Korea
Ed. note — That’s 7 unanswered questions in a row, folks. If you know enough about the subject to be able to post a reasonable question, you probably know enough to be able to help.