... and by "surge" I assume you mean "search"
ASTM/ASME P335 P11 is a low alloy product configured as piping (1.25 Cr - 1.0 Mo) intended for use in moderately high temperature applications
________________________________________________________________________________________________________________________________________
About ASTM A335 P11 Pipe From: -----
Trade Name: 1 ¼ Chrome
Grade: P11
UNS #: K11597
Pipe: A335/SA335
Forged/Bored Pipe: A369/SA369
Chromium and molybdenum are important elements of P11. Chromium, or chrome, improves high-temperature strength, increases oxidation resistance and raises the tensile, yield and hardness at room temperatures. Molybdenum increases the strength, elastic limit, resistance to wear, impact qualities and hardenability. It increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement. Moly is also the most effective additive for increasing high temperature creep strength, or creep resistance. It also enhances the corrosion resistance of steel and inhibits pitting.
___________________________________________________________________________________________________________________________________________
Regarding its use at elevated temperatures:
"The material P11 is especially suited for steam boiler, boiler parts, boiler drum, pressure vessel for the apparatus engineering and similar purposes. It can be used in permanent operation with wall temperatures up to about 590 °C '1094 °F+."
It has been my experience that,over the decades industry has moved away from P11 in favor of it's big brother, A335-P22 ...
The move to the slightly more expensive P22 is because of occasional temperature spikes possible in long-term operation. P11 is considerably more susceptable to creep failure where there are spikes above 590C than P22
There is a long sorry history in thermal power plant operation where P11 Main Steam and Reheat Steam piping has catastropically failed (creep failure) after many years of usage. There were deaths ..... It was most often replaced by P22 (or better) piping materials.
Can you tell us more about your project ???
MJCronin
Sr. Process Engineer