bagnamento
Nuclear
- Feb 23, 2005
- 30
Hi everybody,
we are about to start with the fabrication of a 21/4Cr-1Mo pressure vessel for the petrochemical industry.
Customer's technical specification gives acceptance criteria for delta-ferrite content in stainless steel overlay: the limits in PWHT condition are 3-10% for type 308 or 316 weld metal and 6-10% for 347 weld metal.
Why is the minimum limit higher when 347 SS is used?
I remember hearing that 347 has a hiogher tendency to hot cracking than other SS because of low-melting components formed by Nb(Cb); is this the reason for the higher required delta-ferrite content?
we are about to start with the fabrication of a 21/4Cr-1Mo pressure vessel for the petrochemical industry.
Customer's technical specification gives acceptance criteria for delta-ferrite content in stainless steel overlay: the limits in PWHT condition are 3-10% for type 308 or 316 weld metal and 6-10% for 347 weld metal.
Why is the minimum limit higher when 347 SS is used?
I remember hearing that 347 has a hiogher tendency to hot cracking than other SS because of low-melting components formed by Nb(Cb); is this the reason for the higher required delta-ferrite content?
