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Pretreatment process for steel which will be powder coated?



I want to know the pretreatment process used in steel for powder coating the detergent and step by step process for also only galvanized steel item. I will be thankful to u.

Mohammed Nizamuddin
lighting company - Riyadh, Central, Saudia Arabia


Hi Mohammed,

You asked about the pretreatment process used in steel for powder coating do you mean organic electrostatic powder . Ok first there are two methods for pretreatment of steel 1- dipping ( mean there are different tanks contains chemicals solution and the steel part put inside these tanks) 2- spray ( mean the steel part is hinged on conveyer and then pass through tunnel which have nozzle to spray the chemicals solution on the surface of the part). So what kind of the two methods you have because the sequence and the chemicals is different in the two methods first dipping method 1- chemical degreasing tank or phosphodegreasing solution 2- chemical degreasing tank 3- hot water rinse tank 4- cold water rinse tank 5- phosphate tank ( zinc phosphate or iron phosphate ) 6- cold water rinse tank 7- passivation tank 8- cold water rinse tank 9- dryer second spray method 1- chemical degreasing tank 2- cold water tank 3- phosphate tank ( zinc phosphate or iron phosphate or phosphodegreasing solution) 4- cold water tank 5- air nozzle finally all these steps depended in your line ? your steel ? The application after pretreatment ? So Mohammed if you need more information please tell us more details about your line, your steel, the application after pretreatment.

Aly Gomaa
cookers - Giza, Cairo, Egypt


Hello Mohammed,

I would be glad to answer your question in such a way that you get the information you obviously need. But........ to do so, I -and any other expert - would need a lot more information about your specific situation. Listing all the different possibilities wouldn't help you, because you still have to determine which system would suit your needs best. See also my answer to letter 21454 in the Powdercoat section. A hint: contact a professional who will help you to make the right decision in a far shorter time then you would need yourself (a number of them are listed in the consultancy section of this site)

Good luck,

Remmelt Bosklopper
- Enschede, The Netherlands



The phosphating is the best pretreatment for steel. Before the powder coatings we recommend that you could use iron phosphate type (phospho-degreasing )which is more common

For short cycle heavy iron phosphate rinse, phosphodegreasing, rinse.

For long cycle alkaline degreaser, rinse, phosphodegreasing, rinse, dim rinse.

Ahmed Fouad Serag Eldin
Ein Shams - Cairo - Egypt


Dear Sir,
I want to know about the detail process steps of 9 Tank process of metal sheet. Please also mention the pH of the solution used for processing.

- Mumbai, Maharashtra, India

August 6, 2008

I would like to application methods and parameters for Zinc/ Phosphate treatment in car assembly line. Information like pH, temperature, line speed, length of time needed car body in the tank. any other information you may have.

What is approximate formula of zinc phosphate system? Is the particle size of deposited material controlled by pH or surfactant or NV? How do they replenish the tank?

This information will be useful to all.

Your comments would be appreciated.


Jonathon jade
employee - Wilmington, Delaware

Phosphating of Metals
by Rausch

Failure Analysis of
Paints and Coatings

January 17, 2009


I would like to start powder coating job, so please tell the pre-treatment procedure and chemical name percentage of chemical to be added. We are only powder coating of HR sheet.

Thanking you,

- Puducherry, INDIA
January 21, 2009

Hi, T. Either iron phosphating or the more expensive zinc phosphating can be done. Please search the site for 'zinc phosphate' or 'iron phosphate' for more info.


Ted Mooney   Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

January 7, 2010


I would like to know the proper pretreatment process for SECC material.(steel Electrolyte cold rolled coil.)

Ashish vyapari.
powder coating shop employee. - Pune,Maharashtra, India

January , 2010

Hi, Ashish. Although the meaning of "SECC" seems to be debated, I believe the "E" stands for "electrogalvanized". I don't think the pretreatment of SECC would be different from galvanized steel, i.e., a zinc phosphate pretreatment. Good luck.


Ted Mooney,   Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

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