Pickling and Passivation
Agrawal Sunil (Mumbai -Stequ)
Regard to Process Static Equipments, when it is necessary to carry out Pickling and passivation. If we don’t do pickling and passivation, how it is going to effect the product when put in service?
Sometime, only pickling and passivation is carried out only for weld portion, why it is so? Also sometime only pickling is carried out.
Request to for guidance on above.
Thank you,
Sunil Agrawal
Tecnimont ICB/ STEQU
Bathula Raghuram (Mumbai - PIPING)
Done mostly for hygienic/aesthetic reasons, however a fine surface finish is also crucial to corrosion resistance. SS is protected by a thin chromium oxide layer mainly taking O2 from atmosphere. But during fabrication this self healing layer is disturbed due to mechanical work (grinding, welding, cutting etc.) and reduce resistance to local corrosion.
The after treatment (pickling/passivation) will be determined on various factors, corrosion resistance of steel grade, corrossivity of the atm, hygienic condition aesthetic appearance etc.
Scale or heat tint formed during welding required to be removed, hence recommended mostly for welds only; assuming the rest of base material passive layer is intact. Pickling is de scaling, cleaning process before passivation.
Salvador, Camilo
inspection?
What's the best method of cleaning post passivation?
Most part of procedures are based on ASTM A-380, but this standard
doesn't give us details about the "accept criteria" of passivation.
Regards,
On Nov 24, 4:43 am, "Bathula Raghuram (Mumbai - PIPING)"
Biswajit Mukherjee
Visit the AvestaPolarit welding website and download the free 20 page Pickling Handbook (dont worry; it also includes Passivation & Post cleaning). You will have no questions unanswered.
Regards,
|
To post to this group, send email to material...@googlegroups.com
To unsubscribe from this group, send email to materials-weld...@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
GOPU NAIR
Dear Mr. Salvador
It is essential to clean the pickled and passivated (Acid cleaned) surface thoroughly by flushing with water. Thereafter you may check the presence of acid using litmus paper. The suface should be clean and free from any embedments and rust.
Regards
|
|
The INTERNET now has a personality. YOURS! See your Yahoo! Homepage.
M S R K S Prasad
Flushing with abundant DM water is essential for cleaning after pickling and passivation.The presence of acid stains can be tested with litmus paper.
regards
M.S.R.K.Srinivasa Prasad
Sr. Manager( Mech. Maint PP-1)
Nagarjuna Fertilizers And Chemicals
Nagarjuna Road
KAKINADA-533003
Ph: 0884-2360212(O)
2379302(R)
PEMMARAJU RAGHAVENDRA
Dear All,
As you all know that TOFD needs a scanner. Can you pl.help me in identifying the best automatic motorized scanner for the same. We are using Veritech Sonomatic make Microplus 2 model TOFD machine. I believe that the scanners can be made compatible for any machine.
Regards,
Raghavendra
Larsen & Toubro Limited
www.larsentoubro.com
This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system.