vesselguy
Petroleum
- Feb 25, 2002
- 386
Hi All,
This has already been posted in metal section but I thought you equipment guys might have some experience with this.
I would like to hear some opinions and advise on doing solution annealing of Type 304H aust. S.S. in the field.
I have a 43" ID x 3/4" thk. pipe section (line) in an FCCU operation. 50 psi design pressure, 1385 F design temp. Portions of the line has an elbow made from 304 material piping dating back to 1970 and some 304H piping from the 1990 & 1993 refitting.
It is known the aged elbow from 1970 has suffered from sigmatization and thus is embrittled. No metallograph was done for the newer stuff so I don't know. I'm sure they have been senitized, but it does not matter since this service is only flue gas.
I susgested to cut away the stuff from 1970 and some parts from the 1990 and weld on new replacements for other mechanical reasons which I don't need to discuss here. All the future field weld joints will be at the newer materials (1990 and onward).
The questions is, after cutting off the piping parts must I do field solution annealing to bring back the mechanical properties of the S.S. (to almost like new condition) before I weld on the new parts?
A study done before my work suggests it needs to be done otherwise, the welder will be "chasing cracks" after welding. I say, we don't have to solution anneal for the joints at the "newer" (1990 onward) materials. I have my reason for that but I will keep it to myself for now until I hear any respondent.
Thanks for reading and hope to hear some expert opinion and past experiences.
This has already been posted in metal section but I thought you equipment guys might have some experience with this.
I would like to hear some opinions and advise on doing solution annealing of Type 304H aust. S.S. in the field.
I have a 43" ID x 3/4" thk. pipe section (line) in an FCCU operation. 50 psi design pressure, 1385 F design temp. Portions of the line has an elbow made from 304 material piping dating back to 1970 and some 304H piping from the 1990 & 1993 refitting.
It is known the aged elbow from 1970 has suffered from sigmatization and thus is embrittled. No metallograph was done for the newer stuff so I don't know. I'm sure they have been senitized, but it does not matter since this service is only flue gas.
I susgested to cut away the stuff from 1970 and some parts from the 1990 and weld on new replacements for other mechanical reasons which I don't need to discuss here. All the future field weld joints will be at the newer materials (1990 and onward).
The questions is, after cutting off the piping parts must I do field solution annealing to bring back the mechanical properties of the S.S. (to almost like new condition) before I weld on the new parts?
A study done before my work suggests it needs to be done otherwise, the welder will be "chasing cracks" after welding. I say, we don't have to solution anneal for the joints at the "newer" (1990 onward) materials. I have my reason for that but I will keep it to myself for now until I hear any respondent.
Thanks for reading and hope to hear some expert opinion and past experiences.