Immersion Zinc Phosphate Coating for Steel - Freiborne Industries, Inc Immersion Zinc Phosphate Coating for Steel - Freiborne Industries, Inc

Product Type: Formcoat 2

High quality zinc phosphate usd for lubricant retention to facilitate tube drawing and cold forming. Formcoat 2 has lower temperature capabilities and imparts a finer crystal structure than Formcoat 1.


FORMCOAT 2 is a high quality immersion zinc phosphate coating process for steel and steel alloys. FORMCOAT 2 is used primarily to facilitate cold forming when used in conjunction with a FORMLUBE lubricant,or wire drawing when used in conjunction with a FORMATE series drawing compound. FORMCOAT 2
generates less sludge than other traditional zinc phosphating products.

• The process tank should be constructed from stainless steel or an acid and oxidizer resistant
composite material that will withstand the temperature ranges required. Use of mild steel will result in shortened equipment life due to chemical attack.

• Heat transfer surfaces should be constructed of 316 stainless steel, or an acid and oxidizer
resistant high temperature composite, if steam or heat transfer fluid type heat exchangers are used.

• Piping and pumps may be constructed of stainless steel, mild steel, or an appropriate composite material. Use of mild steel will result in shortened equipment life.

Fill the tank to the three-quarter level with water and add the desired amount of FORMCOAT 2A, using the equation below, to the bath.

(Target Total Acid Points) x (0.00289) x (Working Volume in Gallons) = Gallons of FORMCOAT 2A required

With water bring the tank to the operational level and heat to the required temperature, typically 175oF. Once the optimum temperature is determined, it should be maintained within 5oF. Cleaned steel is placed in this solution for 3 to 10 minutes to produce a uniform coating.

Just before any work is processed, add 10 oz. (220 mls.) of FREIDOX 2 or 20 oz. (500 mls. of a 20% solution of Freidox 1) per 1,000 gallons and mix.

The treatment process for FORMCOAT 2 is generally as follows:
1. Cleaning with a FREICLEAN series cleaner
2. Hot water rinse
3. Pickle
4. Cold water spray rinse
5. Cold water rinse
6. Hot water preheat
8. Cold water rinse
9. Hot NEUTRALIZER rinse
10. FORMLUBE soap or polymer series lubricant
11. Forced air dryer (tubing)

When being used on tubing it is recommended to drain and refill the solution from the tubes two to 4 times during application. Proper techniques should be used to avoid contact marks and expel air and gasses in the tube bundles during processing.

To maintain the bath’s performance it should be regularly tested and adjusted to within operating parameters. Normal processing time with FORMCOAT 2 is 3 to 10 minutes. Processing parameters can vary widely based on individual processes and performance requirements. Typical operating parameters are listed below. Your Freiborne epresentative will help develop the proper operating parameters for your specific needs.

Insoluble phosphate sludge will be generated as a natural byproduct of the FORMCOAT 2 reaction with the steel. This sludge must be periodically removed to prevent it from depositing on the surface of the steel being coated, as it is abrasive in nature and therefore very detrimental to forming operation.

Maintaining the temperature of the rinse prior to FORMCOAT 2 as close to the temperature of the Formcoat 2 as possible will reduce both chemical consumption and sludge generation.

If the Formcoat 2 phosphating solution is continually heated when not in used excess free acid will be generated resulting in a low TA/FA ratio. To avoid this situation the tank temperature should be lowered during long periods of inactivity.


Testing and control of a FORMCOAT 2 bath is based on Total Acid and Total Acid/Free Acid ratio (TA/FARatio) according to the following table.

Total Acid: Using a 5ml volumetric pipette, transfer a 5ml sample of the FORMCOAT 2 into a clean 250ml Erlenmeyer flask (adding up to 50ml of DI water to the flask may aid in viewing the endpoint). Add 5 drops of Indicating Solution #3 (Phenolphthalein) and titrate with Testing Solution #11 (0.1 N NaOH) to a slight pink endpoint. Record the buret reading as the Total Acid.

Free Acid: Using a 5ml volumetric pipette, transfer a 5ml sample of the FORMCOAT 2 into a clean 250ml Erlenmeyer flask (adding up to 50ml of DI water to the flask may aid in viewing the endpoint). Add 5 drops of Indicating Solution #11 (Bromophenol Blue) and titrate with Testing Solution #11 (0.1 N NaOH) to a blue-green endpoint. Record the buret reading as the Free Acid.

TA/FA Ratio: Divide the total acid reading by the free acid reading to obtain the TA/FA ratio

TA/FA Ratio: For a fresh bath this is normally in the 10.0-15.0 range. If this ratio drops below 10.0, discontinue using FORMCOAT 2B replenishing chemical and use FORMCOAT 2A until the ratio is above 10.5. If, even with proper testing and control, your TA/FA ratio is routinely out contact your Freiborne representative about using a modified replenisher.

An addition of 33 lbs. (2.5 gallons) of FORMCOAT 2B per 1000 gallons of solution will raise the Total Acid 1.0 point.

An addition of 41 lbs. (3.25 gallons) of FORMCOAT 2A per 1000 gallons of solution will raise the Total Acid by 1.0 point.

FREIDOX TESTING: (recommended after bath is idle for more than 4 hours.)

Dip a strip of Indicator Paper 17 into the working solution. If it turns pink FREIDOX must be added, as above, until a fresh piece of paper does not change color. If it should turn pink the bath is on the “iron side” and further work should not be processed until sufficient “Freidox” is added to kick out the iron from the solution. This can be done using the same quantities, in increments, as with a new bath.

Additional Information

Temp Range



Carbon Steel


Extrusion, Drawing

Product Type

Conversion Coatings

Product Line




Ordering Information

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