A-213 T5 vs A-335 P5

[25362]

Would anyone kindly tell us the advantages of either metallurgy for tubes in process fired heaters in oil petroleum refineries, in particular with regard to creep fatigue ?

 

[metengr]

Yes, however, my spin will be on the metallurgy aspect of comparing between these two ASME Section II, Part D, material specifications;

SA-213 T5 - this is a standard specification for seamless ferritic and austenitic alloy steel superheater, and heat-exchanger tubes. This is strictly a tubing specification,

SA-335 P5 - this is a standard specification for seamless ferritic alloy steel pipe for elevated temperature service. This specification is for nominal wall, seamless pipe for high temperature service.

The chemical composition between the P5 Grade in SA-335 and T5 Grade in SA-213 are identical, the melting practice and heat treatments are similar.

Mechanical properties are also identical for those that can be compared. Because SA-335 is a pipe specification, additional properties (specifically elongation) in the transverse orientation are specified.

Based on nearly identical chemical, mechanical properties and comparable heat treatments (in other words both Grades are specified with the same heat treatment), I would expect no differences between these two material specifications regarding creep rupture or fatigue strength in service.

Please review each specification carefully regarding ordering requirements and any supplemental test requirements that you may want to specify.

 

[25362]

To metengr, thanks. I've seen both used in process tube coils in fired heaters SA-335 in a PDA heater, SA-213 in a lube hydrofinisher both in the radiant zone. The same heaters had type SS 316, austenitic, for steam superheating. Could you add something regarding HTHA ?

 

[ijzer]

For fired heater the tube material selection shall be based on the operating metal temperature and the corrosivity of the proces fluid .(e.g. S , H2S, H2, Naphtenic Acid, Polythionic Acid during shut down )

 

[25362]

To ijzer, thanks. What about also considering the corrosivity on the firebox side ?

 

[ijzer]

Fire side corrosion could happen if you have oil firing and high contents of V , Na and S.