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Two new topcoats at the O&S






Two new topcoats at the O&S


Delta-Protekt® VH 301.1 GZ offers optimised fastening properties for assembling with aluminium components or against e-coat surfaces. / Delta-Lube® 10 was developed as a lubricant for large-dimension threaded components assembled with automatic screw fastening systems.

Two new top coats for specific applications were presented at the O&S - International Trade Fair for Surface Treatments and Coatings in Stuttgart by Dörken MKS-Systeme GmbH & Co. KG, Herdecke. With Delta-Protekt® VH 301.1 GZ the company presented a further development of the silicon sealing with integrated lubricant. This offers optimised fastening properties for assembling with aluminium components or against e-coat surfaces and sets new standards as far as the fulfilment of the highest requirements of German automobile manufacturers for the surfaces of screws in car body and engine construction is concerned. Also presented in Stuttgart, Delta-Lube® 10 is a lubricant specially tailored to the MKS system with multifunctional properties for large dimension threaded components in commercial vehicle construction.

No chance for stick-slip effect

In the past, the change from chromium(VI)-based to chromium (VI)-free surfaces led to problems when installed against e-coat surfaces, as documented in test specification VDA 235-203 and the surfaces approved therein. These so-called stick-slip effects can currently only be observed in particularly difficult applications. These include, for example, fastening elements with extreme outer supports. A further problem is caused by the increasing demand for weight reduction in vehicle construction. This results in increasing amounts of lightweight metals such as aluminium and magnesium being utilised. For under-head plates for screwed fasteners the range extends from milled to polished backings. In the thread area screwing depths in tapped holes with triple diameter can be accommodated. Here high coefficients of friction at torque/angle of rotation tightening lead to high tightening torque levels, which exceed the control limits and even the capacity of the power screwdriver employed. The new topcoat Delta-Protekt® VH 301.1 GZ was developed specifically for these scenarios. In particularly difficult applications sealing with integrated lubricant prevents stick-slip effects when installing chromium(VI)-free surfaces against e-coat surfaces and also satisfies requirements for loosening under high temperatures.

The new topcoat can also be screwed against aluminium without problems and satisfies the requirements of the new VW standard 1131-1/2, such as double tightening in the yield point against aluminium or five times fastening with e-coat surfaces. The new surface has been employed in various installation areas with both lightweight constructions and the difficult applications stated and has proved itself capable of solving the installation problems there.

Smooth as silk

With Delta-Lube® 10 Dörken MKS-Systeme also presented a new lubricant with multifunctional properties at the O&S. The water-based inorganic material was designed specifically for large-dimensioned threaded components assembled with automatic screwing systems. The main area of use is in the field of commercial vehicles and here it was soon specified in plant standard 183 by MAN Truck & Bus AG. Relubrication provides for a dry, non-slip lubricating layer and permits consistent overall coefficients of friction µg with a VDA-based value between 0.09 and 0.14. For the user, this means: calculable fitting results with reproducible tightening torque and clamping force, with shorter fitting times. The topcoat is applied using dip spin or spin coating methods and then dried for 15 to 20 minutes at 50°C to 60°C.