It’s worth its weight in gold.
Federntechnik Knörzer counteracts corrosion with a highly effective surface seal. Unlike metallic coatings, such as chrome, zinc or nickel, it is highly compatible with high-tensile steels and a base thickness of only 7 μm is enough to for a highly effective barrier against corrosion with this zinc flake coating.
Development clearly shows that this is an existential subject: increased performance with less mass and reduced installation space can be achieved in spring production only with high-tensile and thus extremely flexible steels. But these steels are extremely sensitive on their highly stressed surfaces and very susceptible to corrosion.
“We just can’t escape facts, because the higher the strength, the more sensitive the reaction of the surface of a tensed structure. And high-tensile steels of more than 2000 N/mm2 are in precisely this range. Therefore—loosely speaking—only wrapping helps because these high-performance springs are practically unusable without the right protection” – says Thomas Knörzer, Managing Director for the Pfullingen-based company, which has more than 7,000 products in its repertoire, and custom-made solutions for all requirements.
With the Basecoat “Delta Tone silver”, the springs are protected against corrosion at Knörzer in a matt-silvery paint in accordance with DIN 50021 SS (salt spray test) or ISO 9227 so that the minimum resistance is 240 – 480 hours (coat thickness 7 – 13 μm) in this extreme stress. With an organic top coat in black and a coat thickness of 18 μm, these values can be increased to up to 1,000 hours. The number of coats can be matched to the spring stress, resulting in corresponding graduations between the minimum and maximum values.
The cathodic long-distance effect of the stratified, multi-layer barricading seal is another advantage, because an effective protection remains on the surface, even with forceful damage. Under high stresses, this seal is vastly superior to a plastic coating or pure metallic coatings.
With this efficient protection, signs of stress and corrosion are counteracted and the service life is maximised.
Coatings used by Federntechnik Knörzer are Cr6-free and thus more environmentally friendly than comparable alternatives.