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To clean austenitic stainless steel tanks by acid pickling and passivation

2007

Dear Sir,
We are manufacturing Stainless Steel Tanks,Reactors and various CHEMICAL PROCESS EQUIPMENTS in our Engineering Factory at Ambernath,near Mumbai, India and wish to know the exact proportion of ACID to be used to carry out ACID PICKLING and PASSIVATION of the SS TANKS and SS Vessels.
We are presently carrying out with HF Acid and Nitric Acid but not getting the desired results.To improve the QUALITY of Surface after acid pickling, we request you to let us know more about ACID CLEANING

Sincerely yours

Narendra Hari Attarde
engineering company - Addl.Ambernath, Maharashtra, India

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First of two simultaneous responses -- 2007

Your request is vague.
What needs cleaning � weld scale & heat tint, tooling marks, other?
What 'HF Acid and Nitric Acid' composition are you using? What is unsatisfactory about the results?

Start with ASTM A380 , 'Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems.'

For bright, highly sanitary surfaces, start with good material, grind and polish welds, then electropolish.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.

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Second of two simultaneous responses --

Try www.nickelinstitute.org webpages- there you can find many useful free infos about SS technology.Good luck!

Goran Budija
- Zagreb, Croatia
2007

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This is common problem now a days. This can cause uneven & patchy surface look, pitting corrosion or sometimes total blackening of whole SS tank which is sometimes impossible to repair.And, hence it becomes very problematic to pass during inspection.

You should use jelly as it don't attack SS surface directly and gives excellent Satin ( silvery white ) finish required by customers.

Vinay Golwala
- Dahisar, Mumbai, India
2007