What is p11 and p22 material?

P-11 is a piping material usually used in refinery and petrochemicals industries for services at or around 550 to 600 degree C temp. It is low alloy steel. It contains 1.25 cr and 0.5moly.It resitant to hydrogen attack. It need PWHT(post weld heat treatment).

PWHT to be in the range of 680 to 780 degree C.

P-22 is a piping material usually used in refinery and petrochemicals industries for services at or around 550 to 625 degree C temp. It is low alloy steel. It contains 2.25 cr and 1.moly.It resitant to hydrogen attack. It need PWHT(post weld heat treatment).

PWHT to be in the range of 680 to 780 degree C.