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[Akhil subahash]

Is it any strength difference between alloy steel p22 and p11

[sgkim]

Minimum tensile- and yield- strengths are the same 60 and 30 ksi(kilo psi) respectively for the both grades, but the maximum allowable stresses(MAS's) are different.   The MAS's for grade p22 (2.25Cr-1Mo)are slightly higher than p11(1.25Cr-0.5Mo) for the temperature range 700~1200℉; see the table below (ASME/ASTM SA335). 

Temp(℉)   MAS, p11//p22, (ksi)

-20~700    15.0//15.0

750           14.8//15.0

800           14.4//15.0

900           13.6//13.6

1000           6.3//8.0

1100           2.8//3.8

1200           1.2//1.4

 

It seems that slightly higher contents of Cr and Mo make the higher MAS and resistance to oxydation at higher service temperatures. 

 

~Stefano G Kim

Edited by sgkim, 06 February 2017 - 03:42 AM.