FORMCOAT 48 is designed to deposit a tight-grained, dense, high quality zinc phosphate coating on steel surfaces with smaller crystal sizes and less sludge generation than typical cold forming phosphates. Lower sludge generation rates translate into less downtime, labor, and disposal expenses from desludging phosphate tanks.
FORMCOAT 48 may be used in cold forming, cold heading, tube drawing, wire drawing and impact extrusion when used in conjunction with a FORMLUBE lubricant or a FORMATE series drawing compound. FORMCOAT 48 is particularly suited for use under our Polymer series of lubricants due to the refined crystal structure and the lower film weights associated with Polymer lubricants.
• 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 71 gallons (925 LBS) of FORMCOAT 48A 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°CF. Once the optimum temperature is determined, it should be maintained within 5°CF. A processing bath built up according to these recommendations will result in 24 points of Total Acid, or what is referred to as a 24 point bath. 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 48 is generally as follows:
1. Cleaning with a FREICLEAN series cleaner
2. Hot water rinse
4. Cold water spray rinse
5. Cold water rinse
6. Hot water preheat
7. FORMCOAT 48
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 48 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 48 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 48 as close to the temperature of the FORMCOAT 48 as possible will reduce both chemical consumption and sludge generation.
If the FORMCOAT 48 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°CF or lower.
Testing and control of a FORMCOAT 48 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 10-12 range. If this ratio drops below 10.0 discontinue using Formcoat 48C replenishing chemical and use Formcoat 48A until the ratio is above 11.0. If, even with proper testing and control, your TA/FA ratio is routinely outside of the recommended range contact your Freiborne representative about using a modified replenisher.
An addition of 30 lbs. (2.3 gallons) of Formcoat 48C per 1000 gallons of solution will raise the Total Acid 1.0 point.
An addition of 39 lbs. (3 gallons) of Formcoat 48A 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.
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