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6304 |
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Friday, June 12, 2020, Hall G2 11:00 AM Laser Cladding |
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Perspectives for hard chrome replacement by high-speed laser cladding |
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Sabrina Vogt / TRUMPF Laser- und Systemtechnik GmbH, Germany Svenja Müller / TRUMPF Laser- und Systemtechnik GmbH, Germany Marco Göbel*/ TRUMPF Laser- und Systemtechnik GmbH, Germnay |
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Hard Chrome plating is still an often-used coating technology for applying thin hard layers on even very complex workpieces which must achieve high surface quality. But this coating technology has limits. It is difficult or even technically not feasible to coat very big or long components, to vary the layer thickness locally or to apply diffusion tight, corrosion resistant coatings. Additionally, hard Chrome plating is prone to constantly increasing restrictions in Germany, the European Union and in the Asian market. One technology which is currently under investigation for replacing hard Chrome plating in these instances is the High-Speed Laser Cladding or EHLA. Using High-Speed Laser Cladding, a laser beam is melting powder particles, which are fed coaxially into the laser beam, before these particles hit the substrate. Using a laser as heat source, heat input into workpiece can be minimized and fast thermo cycles can be achieved. This allows for a very low dilution of additive into workpiece typically < 10µm and high feed rates between 100-500 m/min. Layers generated by this process can be locally adjusted in thickness between 50-300 µm per layer. Since each layer is metallurgically bonded to the substrate or the layer before, multi layers or multi-material approaches are feasible. This feature can be used to achieve functionally graded material or to apply metallurgically bond coatings on hard-to-weld alloys such as cast iron. By use of the afore mentioned unique process features, new and in properties tailored coating systems become feasible. High-Speed Laser Cladding is already used for a broad range of applications: wear resistant layers on small valves, enhancement of brake discs, corrosion resistant coatings for very long shafts used in hydraulic systems, etc. Even additive manufacturing of rotational symmetric geometries such as seal lips or a shoulder on a shaft is feasible. |