17-7 HP microstructure

[Tania Matsuo]

Hi, I would like to know some literature about 17-7 alloy. We have a 17-7 HP spring that failed due to cracks. I am not sure if the heat treatment done was correct because I can visualize the inclusions using optical microscope (x100). The composition inclusion is Al end Fe and their shape are angulars. I am not sure if these kind of precipitation is regular.

 

[EdStainless]

Yes, those are the regular ones, Al intermetallics.
There is a handbook for 17-7PH published by Armco back in the day.
It only has a few micros, but it should be helpful.
One thing to do is check for surface damage. There are a number of things that can cause this (Heat treat gases, cleanliness, secondary treatments).
Get me your email and I'll send a scan of the handbook.


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P.E. Metallurgy, Plymouth Tube

 

[metengr]

thread330-357285

Follow the thread, the Armco 17-7 PH handbook can be downloaded.