SA 312-Tp316 Instead of SA335-P91 Material

banu.....

Yes,

According to ASME Boiler and Power Piping Codes, TP316 stainless steel piping can be used at that temperature range, but......

The SA335 -P91 material was developed for high temperaturere AND high pressure piping applications (such as main steam and hot reheat systems). P91 retains more strength than TP316 at high temperature.

Based on that elementary question, I do sincerely hope that you are not working on expensive and dangerous high energy piping systems.....

Dear Lahane82

Greeting to you

the temperature range in power plant usually in the high temperature range not in the normal range

in ASME sec I para. PG- 5.5 : The use of austenitic alloy steel is permitted for boiler pressure parts that are steam touched in normal operation. Except as specifically provided in PG-9.1.1, PG-12, and PEB-5.3, the use of such austenitic alloys for boiler pressure parts that are water wetted in normal service is prohibited.1

IN THE FOOTNOTE :

Austenitic alloys are susceptible to intergranular corrosion and stresscorrosion cracking when used in boiler applications in water wetted service. Factors that affect the sensitivity to these metallurgical phenomenaare applied or residual stress and water chemistry. Susceptibility to attack is usually enhanced by using the material in a stressed condition with a concentration of corrosive agents (e.g., chlorides, caustic, or reduced sulfer species). For successful operation in water environments, residual and applied stresses must be minimized and careful attention must be paid to continuous control of water chemistry.

if we read the main title of material SA-312 we will find

SPECIFICATION FOR SEAMLESS AND WELDED AUSTENITIC STAINLESS STEEL PIPES

but for material SA- 335

SPECIFICATION FOR SEAMLESS FERRITIC ALLOYSTEEL PIPE FOR HIGH-TEMPERATURE SERVICE

that the main reason

i hope it help you