Dela Ferrite in Martensite steels
Dela Ferrite in Martensite steels
(OP)
Dear members,
delta-ferrite is deleterious to the creep properties and toughness of Martensite steels ,such as P91 and P92. delta-ferrite is often observed in weld metal and at fusion line. If the PWHT temerature exceed the transformation temperature and with normal cooling rate (such as 80-150 centidgree per hour), will delta ferrite form?
and to what level of the ferrite content, it will be unaceptable to use the material? 1%, 3% or 5% and so on, it has no exact advice about this in ASME A 335.
thanks!
delta-ferrite is deleterious to the creep properties and toughness of Martensite steels ,such as P91 and P92. delta-ferrite is often observed in weld metal and at fusion line. If the PWHT temerature exceed the transformation temperature and with normal cooling rate (such as 80-150 centidgree per hour), will delta ferrite form?
and to what level of the ferrite content, it will be unaceptable to use the material? 1%, 3% or 5% and so on, it has no exact advice about this in ASME A 335.
thanks!





RE: Dela Ferrite in Martensite steels
IF the AC1 is exceeded during PWHT, fresh martensite will form, can we just re-PWHT the weld, replacing the NT followed by tempering?