Product Categories / Metal Treatment / Steel Treatment / Zinc Phosphating

Duraphos 637

Product description

  • Duraphos 637 is a nitrite accelerated dicationic zinc phosphating product. It produces uniform crystalline zinc phosphate coating on steel, iron and zinc substrate.

Feature:

  • Duraphos 637 is especially suitable to give paint adhesion process.
  • Coating weight per unit area is about 2-4 gm/ m2.
  • Duraphos 637 is made for spray application and can be used in dip application.
  • Duraphos 637 contains an additive especially formulated to reduce the sludge in the zinc phosphating tank.

Applications

Duraphos 637 is a specially formulated product most suitable for steel iron, galvanized and electro- galvanized steel.

Physical & Chemical Properties:

Appearance :  Liquid.
Color : light green.
PH (1%)  at   25°C : 2.6 ± 0.2
Sp gr. at   25°C : 1.4 ± 0.1
Free acid point(1%) : 1.7 ± 0.2
Total acid point(1%) : 9 ± 0.3

Operating Parameters:

Concentration (v/v%) : 2.0 to 4.0
Temperature (°C) : 45 to 55
Time (min) : 1 to 3
Nozzle pressure : 1 to 1.5 bars
Free acid point(FAP) : 0.8 to 1.5
Total acid point(TAP) : 15 to 35
Acceleration Point : 3 to 6 (for steel), 2 to 4 (for GI steel)

Equipment:

The main process tank can be fabricated from stainless steel or acid resistance material tank is recommended for durability. Pumps & nozzles must be of SS. Grade 316 or PVC.

Initial Preparation :

  • Add 20 to 40 lit of Duraphos.637 per 1000 lit of operating volume.
  • Add Duradd 14 periodically and slowly while thoroughly mixing, till free acid point adjusted.
  • Free acid point adjusted for different line applications and different type of steel, optimum work Pointage is 0.8 to 1.5.
  • Add 500 to 1500 ml Duradd 13 per 1000 lit of operating volume (To be added just before starting the line)

Process Sequences:

  • Cleaning & Degreasing with Duraclean products.
  • Water Rinse.
  • Water Rinse.
  • Refining and activation with Duradd 5
  • Zinc Phosphating with Duraphos 637
  • Water Rinse.
  • Passivation with Durapass products
  • Drying

Precautions

  • Carry over should be avoided as much as possible
  • Oil should be skimmed regularly from the degreasing tank.
  • Total acid point, free acid point, and accelerator point should be checked at least twice in a shift and especially before replenishment.
  • Rinsing water should be changed frequently.
  • Temperature of Zinc Phosphating tank should be maintained all the time.
DOWNLOAD