Uniform Zinc Phosphate Coating - Freiborne Industries, Inc Uniform Zinc Phosphate Coating - Freiborne Industries, Inc

Product Type: Formcoat 12

High quality uniform zinc phosphate coating used in conjunction with Formlube series lubricants for cold forming. Similar to Formcoat 1 but produces slightly “fluffier” sludge for ease of tank wash-out.


FORMCOAT 12 is an immersion zinc phosphate coating process for use in the cold forming industry. FORMCOAT 12 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.

• 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 90 gallons (1100 LBS) of FORMCOAT 12A chemical for each 1,000 gallons of working solution required. With water bring the tank to the operational level and heat to the required temperature,typically 180°F. Once the optimum temperature is determined, it should be maintained within ±5°F. A processing bath built up according to these recommendations will result in 24 points of Total Acid, or what is referred to as a 25 point bath. Cleaned steel is placed in this solution for 3 to 10 minutes to produce a uniform coating.

To calculate the amount of FORMCOAT 12A necessary to build up a bath use the following equation:(Working Volume) x (Total Acid Points Desired) x (0.0035) = Volume of FORMCOAT 12A Required

Example: To build up a 5000 gallon working volume bath at 25 points of total acid (5000 gallons) x (25 points) x (0.00304) = 438 gallons of FORMCOAT 12A required

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 12 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

To maintain the bath’s performance it should be regularly tested and adjusted to within operating parameters. Normal processing time with FORMCOAT 12 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 representative will help develop the proper operating parameters for your specific needs.

Insoluble phosphate sludge will be generated as a natural byproduct of the FORMCOAT 12 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. The frequency of sludge removal will depend on the processing parameters and the type and surface area of steel being processed.

Maintaining the temperature of the rinse prior to FORMCOAT 12 as close to the temperature of the FORMCOAT 12 as possible will reduce both chemical consumption and sludge generation.

If the FORMCOAT 12 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, preferably to 160°F or lower.

Testing and control of a FORMCOAT 12 bath is based on Total Acid and Total Acid/Free Acid ratio (TA/FA Ratio) according to the following table.

TA/FA Ratio: For a fresh bath this is normally in the 5.5-7.5 range. If this ratio drops below 5.8, discontinue using FORMCOAT 12B replenishing chemical and use FORMCOAT 12A until the ratio is above 6.0. If, even with proper testing and control, your TA/FA ratio is routinely out of the recommended control
parameters contact your Freiborne representative about using a modified replenisher.

TA/FA Ratio 5.8-7.5

An addition of 0.23% v/v FORMCOAT 12B will raise the Total Acid 1.0 point. (Target TA – Actual TA) x Tank Volume x 0.0023 = Amount of FORMCOAT 12B to add (25.0 – 22.4) x 5000 gallons x 0.0023 = 28.6 gallons Replenisher (FORMCOAT 12B)

TA/FA Ratio <5.8

An addition of 0.35% v/v FORMCOAT 12A will raise the Total Acid by 1.0 point. (Target TA – Actual TA) x Tank Volume x 0.003 = Amount of FORMCOAT 12A to add (25.0 – 22.4) x 5000 gallons x 0.0035 = 39 gallons Makeup (FORMCOAT 12A)

Depending on the specific operation – including the load factor in the process tank, the quantity of production, the level of high carbon verses low carbon stock processed – variations in the above replenishing schedule may be required for optimum performance. The final recommendations are best left
to Freiborne service personnel during initial operation.

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


Drawing, Extrusion

Product Type

Conversion Coatings

Product Line




Ordering Information

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