Galvanised & cast components

As is also the case with cast metals, hot-dip or spray galvanised components exhibit a porous surface and therefore tend to outgas during the curing procedure. When dealing with conventional powder coatings, this can lead to increased formation of small blisters beneath the coating surface. The powder coating systems presented below reduce the gas pressure that occurs when the workpieces are heated and can prevent the formation of gas/air blisters.

Duplex procedure
So-called “duplex systems” combine galvanisation with powder coating. In addition to the decorative effect, the advantage of this procedure is that the galvanisation is protected against weather-related wear and chemical attacks. The zinc corrosion may be greater than 8 μm each year if galvanised steel components are frequently exposed to salty air or moist soil. When dealing with high corrosion protection requirements, the zinc cover should therefore be protected with a powder coating (Duplex process). This increases the duration of corrosion protection by between 1.2 and 2.5-fold. Duplex systems that consist of hot-dip galvanisation and powder coating are now also regulated by a standard thanks to the introduction of DIN 55633*.

Coat structure
Specially developed outgassing-friendly powder coatings from the IGP-DURA®vent range are particularly suited to single layer powder coat structures on porous metal substrates such as hot-dip galvanised steels. In addition to good adhesive strength and weathering ability, they also offer a proven corrosive resistance that corresponds to corrosion category C4-H in accordance with DIN EN 12944.
The Qualisteelcoat approvals of all IGP-DURAvent product groups support the metal constructors and the coaters in providing proof of permanent component protection according to DIN EN 1090-2 on supporting components manufactured from galvanised steel. 

In contrast, two-coat powder corrosion systems permit a freer selection of the top coat system (such as IGP DURA®face or IGP-HWF products in addition to IGP DURA®vent) on the one hand and, on the other hand, they significantly increase the protective effect.
According to the classification of DIN 55633, Annex A, the top corrosion category C5 I/M with a duration of protection of up to 15 years can be achieved with corresponding coating thicknesses.

The IGP-KORROPRIMER 10V primer is ideally suited for two-coat application system structures on galvanised steel and cast components. Powder coating primers with IGP-KORROPRIMER 10V prevent problems such as surface flaws caused by outgassing substrates and support a blister-free surface. Certificates are available here. Please also see Product Information: IGP-KORROPRIMER.

* DIN 55633: Paints and varnishes – Corrosion protection of steel structures by powder coating systems – Assessment of powder coating systems and execution of coating

 

  • IGP-DURA®vent 51

    Weather-resistant coating system for application on exhalating substrates.

  • IGP-DURA®face 80

    Weather-resistant powder coating for metal facades and structural components in exterior environments with particular suitability for exhalating substrates.

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