Differentiate between 15-5PH and 17-4PH

[metalhoosier]

What is the best way to differentiate between 17-4PH and 15-5PH material? My arc/spark machine results say the Cr content is lower than 17-4 range in the 15-5 Cr content range. Is there an appreciable difference in the amount of ferrite in 15-5 verses 17-4? What etchant will best show this difference? Fry’s? Villella’s?
Any guidance is appreciated.

Thank you,
Metalhoo

 

[metengr]

Your best bet would be to have a complete chemical analysis performed by a chem lab to differentiate between the two PH materials. There are other alloying elements, nickel and copper, besides chromium.

 

[metalhoosier]

Metengr,

The alloy analyzer was able to pickup the Ni, Cu etc. and the alloying ranges fell into the overlap of the 15-5 and 17-4 material chemistry ranges. Hardness was not helpful either. Is there any tell tale etchant I can use?

Thank you,
Metalhoo

 

[mrfailure]

Why bother to differentiate? You can say composition is consistent with both 15-5 and 17-4. Look for the applicable specification for your product form if you need further identification. As precipitation hardening steels, pay attention to the heat treatment specifications if you really are looking for mechanical properties.

Aaron Tanzer

http://www.lehightesting.com