Corrosion Protection for Auma Actuators

Previous tests had already proved the high corrosion resistance of the advanced two-layer powder coating AUMA introduced a few years ago. The latest certificate confirms that the fully-assembled actuators, including all non-powder-coated metallic parts such as shafts and screws, withstand corrosion equally well.

“Excellent corrosion protection is a key concern for us as an actuator manufacturer,” says Gert Wetzel, Product Manager at Auma. “Rust is not only ugly but can also cause considerable costs as it reduces plant availability and performance. Most of our actuators are installed in harsh environments, whether indoors or outdoors. We have invested continuously in product and materials design, and we are proud that these challenging tests confirm our products have the best corrosion protection on the market.”

Standard Auma SA and SQ actuators with AC or AM integrated controls meet the requirements of corrosivity category C5-M long, without any extra measures and cost. C5-I long is available as an option.

To achieve this C5-M certification, the products had to undergo a salt mist test (EN ISO 9227:2012) for 1,500 hours and a constant humidity test with condensation (EN ISO 6270-2:2005) for 720 hours. For C5-I certification, the devices had to additionally withstand 30 cycles of a condensation alternating climate test containing sulfur dioxide (EN ISO 3231). Following the tests the Auma products showed no signs of rust.

Key to the excellent corrosion resistance is a two-layer powder coating applied to the individual housing parts before assembly. As a feature unique to Auma actuators, the coating also includes the output flange and goes beyond the sealing edge of the joints. This means that the coating remains intact even if the actuator is removed from the valve or if the housing is opened during installation or commissioning.