Troubleshooting guide to iron phosphatizing

Posted by: FEIHONG Powders |on July 3, 2018

Problem, Cause and Remedy

PROBLEM	CAUSE	REMEDY
Poor Coating	pH not in range. See “Poor Cleaning.”	Adjust pH down with acid, up with caustic.
Poor Cleaning	Temperatures too low	Raise temperature
	Concentration too low	Increase concentration
	Poor exposure to cleaner	Check racking. Check nozzles. Check pressure, 15-25 psi.
Spotty Coating/ Streaking	Contaminated rinses Poor cleaning	Check rinse tanks. See“Poor Cleaning.”
	Contaminated rinses	Check rinse tanks
	Poor exposure	Check racking. Check nozzles.
Rusting	Coating weight too low	Raise temperatures. Lengthen time. Increase concentration
	Dry-off too slow	Increase temperature in final rinse.
	Drying between stages	Run at lower temps. Better placement of nozzles. Use fog nozzles
Solutions Foaming	Temperature too low	Raise temperature
	Pressure too high	Check for plugged nozzles
	Pump picking up air	Check pump packing. Check water level.
Poor Paint Adhesion	Coating too heavy	Lower temperature. Lower concentration.
	Poor cleaning	See “Poor Cleaning.”
	Contamination	Look for source of silicone near washer.
	Bad steel	Check raw material for excessive soil.