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7265 |
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Friday, May 06, 2022, Hall D 11:40 AM Metal Coatings II |
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Thermal spraying of a novel nickel-free high strength and corrosion resistant austenitic steel |
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Philipp Kluge / Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany Andreas Mohr* / Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany Horst Hill/ Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany Kerstin Ernst/ Putzier Oberflächentechnik GmbH, Germany Olga Schwabe/ Putzier Oberflächentechnik GmbH, Germany |
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Stainless austenitic steels like the 316L (1.4404) are widely applied in various applications and were also used for surface protection using thermal spraying. The reason for this is the easy processability and the high corrosion resistance. Stainless austenitic steels contain typically the following alloying elements: The formation of an austenitic microstructure is achieved by nickel (Ni). The addition of chromium (Cr) leads to the good corrosion resistance due to the formation of an oxid layer. For resistance against pitting corrosion, molybdenum (Mo) can be added. Also, stainless austenites usually exhibit very low carbon and nitrogen contents to prevent chromium carbides and nitrides which reduces the corrosion resistance. However, both alloying elements cannot be classified as being detrimental in stainless austenites in general. In contrast high nitrogen contents can also be used to improve the chemical properties, especially the resistance against pitting corrosion. And finally, carbon and nitrogen lead to an increase in hardness of the thermal sprayed layer. Based on this knowledge, a high-strength austenite for thermal spraying was developed. The new high strength austenite was processed by HVAF spraying with different particle distributions and parameter variations. Resulting coatings were investigated regarding the microstructure, elemental composition, hardness and corrosion properties in comparison to the standard coating material 316L. |