The chemcoater is used to apply chemical substances to galvanized flat carbon steel. These substances, which are water-based media, contain additives that pretreat the steel and increase the corrosion protection of subsequent paint and film coatings. The chemcoater carries out chemical pretreatment processes required for the subsequent painting process. A total of three different chemicals can be applied to the sheet via rolls.

The new unit operates on the basis of a reuse process so that no wastewater is produced except in the subsequent rinsing operation. “This six million euro investment virtually eliminates the need for chromium-based corrosion-protection pretreatments for organically coated parts,” said team coordinator Ralf Wittkowski. “By using zinc-magnesium hot-dip coated starting material, we achieve better corrosion protection results with thinner zinc coatings.

“Water consumption is also reduced,” added Wittkowski; “By using two five-stage cascade rinses we have reduced the amount of water we need by 8,000 liters per hour”.

The company began planning some three years ago for the extensive modernization of coil-coating line 3, and the project was finally implemented last fiscal year. During the three-week shutdown when the chemcoater was installed, the company also carried out maintenance and cleaning work that would ensure defect-free operation of the line.

The paint- and film-coated steel produced on coil-coating line 3 is supplied in the form of coil, slit strip and cut-to-length sheets for use in the construction, appliance, garage door and auto industries.