First-class results in corrosion protection thanks to deburring process

Dec. 17, 2012 - PRLog -- The best rust protection for tough requirements
In the field of agricultural and construction machinery in particular, components need to meet the harshest demands. They are not only constantly exposed to wind and weather, but stone chips and other problems are also commonplace in the use of heavy equipment. Reliable rust protection for components is an important fundamental prerequisite. So it is with the Multicar M27 all-rounder, which is fitted with a cooler grille from

metal component specialist, Solvaro. The cooler grille, supplied by Solvaro and including frame and hinges, is equipped with HV 2–2.25 perforation and achieves an air passage of around 70% thanks to its undulating shape. Great for air intake, but a challenge for corrosion protection. With stamped and lasered plates, CDP coating can get very thin on the punch burr, thus compromising the rust protection.

The salt spray test says, ‘Wow!’
Effective rust protection with CDP coating can be achieved with special deburring technology. ‘The grilles are treated with this technology. This rounds off the edges in the ideal way for the subsequent coating process,’ explains Gerhard Bullinger, managing director of Solvaro. In order to find the optimum coating for the Multicar cooler grille, five coating variants were sent through the salt spray test in accordance with DIN ISO 9227. During the test, the cooler grilles were in a chamber at a temperature of 35°C which was continuously nebulised with a 5% saline solution at a controlled pH value. The spray condensed on the cooler grilles and coated them with a corrosive salt water film. The test took 528 hours. As, in this case, the focus was on testing the coating, this latter was scored down to the base metal. During the test, the base metal corroded along the score lines. The coating was eroded to a greater or lesser degree during the test due to the corrosion process. The resistance of the coating on the test cooler grille was determined by the degree of erosion. The erosion around the scoring was very good (0.16 mm–0.23 mm). However, the differing results with regard to rust formation on the surface and adhesion of the paint coating on the sheet were surprising. The cooler grille treated by Solvaro, which had a subsequent cathodic dip painting and powder coating, showed the best results. This combination even beat the galvanised cooler grille by a mile, as the paint didn’t adhere very well to the grille bars.