Typical Cleaning and Passivation Systems for Stainless
Steel parts
1. Emulsifier Cleaning System:
- Cleaning tank:
- Emulsifying alkaline cleaner, warm for best cleaning. Follow manufacturer's directions.
- Circulating pump in tank if possible, Ultrasonic unit optimum.
- Drain Board:
- Angled to allow draining of cleaning solution back into Cleaning Tank to save cost of cleaners.
- Rinse tank:
- Room temperature tap water, circulating optimum.
- Passivation tank:
- 8-10% CitriSurf at 70-160 degrees F.
- Circulating pump in tank if possible.
- Drain Board:
- Angled to drain back into Passivation Tank to conserve CitriSurf.
- Rinse tanks:
- Room temperature tap water, circulating optimum.
- Cycle time:
- 2-30 minutes depending on product, tank temperature, circulation, ultrasonics, etc.
- Drying:
- Depending on parts, spin drying or convection oven air drying is optimum; room temperature air drying to passivate the
surface with an oxide coating takes 24 hours minimum per industry standards.
2. Oil Splitter System:
- Cleaning Tank:
- Splitting alkaline cleaner, warm for best cleaning.
- Circulating pump in tank; optimum results using ultrasonic tank.
- Proper skimming and oil reclamation equipment required.
- Drain Board:
- as above.
- Rinse Tank:
- as above.
- 2nd Cleaning Tank: (Optional)
- A second emulsifier cleaning tank can be used where difficult cleaning situations occur.
- Same as Cleaning Tank in Example #1 above.
- Drain Board:
- as above.
- Rinse tank:
- as above.
- Passivation Tank:
- as in Example #1 above.
- Drain Board:
- as above.
- Rinse tank:
- as above.
- Drying:
- as in Example #1 above.
Proper ventilation by means of a hood to exhaust any fumes is always recommended, but usually not necessary with
CitriSurf.
See MSDS for proper handling off all chemicals.
3. Line with no Cleaning System:
This setup is used by some companies who have very simple systems and requirements.
Although the CitriSurf 2050 system is a good cleaner for some materials, it is designed primarily as an agent to remove free iron
from the surface of stainless steel. Where only light cleaning is required, it may be possible to use only the CitriSurf solution to clean
and passivate. You should test to see if this meets your requirements before using it in production!
- Cleaning:
- Proper cleaning before heat treating prevents stubborn smut on parts.
- Heat Treating (if required):
- Heat treat at proper temperature to relieve stress and remove oils from surface.
- Passivation:
- If only light cleaning is required prior to passivation, stainless steel parts can be placed directly into the passivation tank.
- 8-10 % CitriSurf at 150 degrees F.
- Circulating pump in tank recommended.
Steps after the passivation tank should be the same as in above examples.
Example Cleaning and Passivation Line
(All tanks 40" deep to meet OSHA guidelines)
- Station #1 - Cleaner
- 36" x 36" x 40" deep with 18" x 36" drainboard (polypropylene, 316 ss or equiv.)
- 2.5" top rim
- Girthed as required
- Bottom drain
- Heated to 150 degrees F. in 4 hours using stainless steel heaters (faster available if desired)
- Digital indicating control with over-temperature protection
- (Options: Ultrasonics, Oil splitting, Multiple cleaning tanks)
- Station #2 - Rinse
- 18" x 36" x 40" deep
- Dam with drain, bottom drain
- Girthed as required
- Station #3 - Passivation Solution
- 36" x 36" x 40" deep CitriSurf tank
- same specifications as Station #1
- Station #4 - Rinse
- 18" x 36" x 40" deep
- same specifications as Station #2
- Station #5 - Rinse
- 18" x 36" x 40" deep
- same specifications as Station #2
- pH control for effluent
- (Option: heated rinse to accelerate drying and improve rinse)
- Item #6 - Ventilation System (Optional)
- 6750 cfm #22JVA all plastic exhauster complete with 3 HP T.E. motor, V-belt drive and weather cover, two hoods,
duct work and automatic damper.
