17-4 PH

[metass]

Please explain the significance of the weight percent ratio of noibium to carbon being less than 6.

Nb/C < 6

Thanks.

 

[CoryPad]

This is due to C-Nb-P interactions which lead to phosphorus segregation at grain boundaries, reducing material toughness. High toughness and strength are retained when Nb/C < 6.

You can learn more from the article "Effect of phosphorus segregation on impact toughness variation in 17-4 precipitation hardened stainless steel", Scripta Metallurgica Volume 20, Issue 5 (1986), pages 713-716, available from ScienceDirect:

http://www.sciencedirect.com/scienc...serid=10&md5=44fa4a5d508ee024b4e005f8213c5c86

Regards,

Cory

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