Use of Low Temp Carbon Steel piping material for 4500 kPa Super Heater Steam
Use of Low Temp Carbon Steel piping material for 4500 kPa Super Heater Steam
(OP)
I need help from Piping Design Folks on this issue, please
For 14" 4500 kPa(g) super heated steam system, based on design conditions, the wall thickness required is 0.75" for NPS 14. Piping Material is A-106 Gr B
MDMT is -29 Degree C
Based on ASME B31.3 Figure 323.2.2A & combination of nominal thickness 0.75” (19.05 mm) & MDMT of -29 C comes below the Curve B, therefore, impact testing is required for A-106 Gr. B Material or I have to use low temp carbon steel A 333 Gr. 6 as per client specification.
I never heard of use of LTCS material for super heated steam line. At the same time the pipe will never be subjected to -29 C in service. This line is also insulated.
Yes if the line is out of service for considerable duration of time during extreme cold of -29 C, the pipe material can see this temperature but the line will not be pressurized at that point.
For impact testing, do we need to consider pressure as well extreme cold temperature of -29 C at the same time? How can I justify that the use of LTCS for superheated line is overkill.
Would highly appreciate your feedback.
Thanks,
For 14" 4500 kPa(g) super heated steam system, based on design conditions, the wall thickness required is 0.75" for NPS 14. Piping Material is A-106 Gr B
MDMT is -29 Degree C
Based on ASME B31.3 Figure 323.2.2A & combination of nominal thickness 0.75” (19.05 mm) & MDMT of -29 C comes below the Curve B, therefore, impact testing is required for A-106 Gr. B Material or I have to use low temp carbon steel A 333 Gr. 6 as per client specification.
I never heard of use of LTCS material for super heated steam line. At the same time the pipe will never be subjected to -29 C in service. This line is also insulated.
Yes if the line is out of service for considerable duration of time during extreme cold of -29 C, the pipe material can see this temperature but the line will not be pressurized at that point.
For impact testing, do we need to consider pressure as well extreme cold temperature of -29 C at the same time? How can I justify that the use of LTCS for superheated line is overkill.
Would highly appreciate your feedback.
Thanks,





RE: Use of Low Temp Carbon Steel piping material for 4500 kPa Super Heater Steam
RE: Use of Low Temp Carbon Steel piping material for 4500 kPa Super Heater Steam
Thanks for your reply and rest of the folks on my same post at Metal and Metallurgy forum. But the discussion was without any result. And it seems that piping engineering seems to be the relevant forum. Please accommodate.
RE: Use of Low Temp Carbon Steel piping material for 4500 kPa Super Heater Steam
Furthermore, selection of A-333 Gr 6 to replace A-106 should not be done because of its decreased high temperature Creep properties and greater susceptibility to graphitization at the operating steam temperatures.