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REMELTING AND SUBSEQUENT APPLICATION WELDING AND COMPONENT

20170304936 ยท 2017-10-26

    Inventors

    Cpc classification

    International classification

    Abstract

    After remelting in a suitable mold for reducing grain boundaries, an oxidation-resistant material is epitaxially grown so that the oxidation resistance of a repaired material or also of a new part is improved.

    Claims

    1. A method for surface treatment of a metallic substrate, in which the surface of the metallic substrate first undergoes remelting in order to remove cracks and to reduce grain boundaries, followed by deposition welding of a more oxidation-resistant material at least partially onto the remelted region.

    2. The method as claimed in claim 1, in which deposition welding of the oxidation-resistant material is conducted epitaxially.

    3. The method as claimed in claim 1, in which the more oxidation-resistant material is a NiCoCrAlX alloy, X being in particular rhenium, silicon, yttrium, tantalum and/or iron.

    4. The method as claimed in claim 1, in which the remelting and the deposition welding are carried out in the same device.

    5. The method as claimed in claim 1, in which the substrate is a nickel-based or cobalt-based alloy.

    6. The method as claimed in claim 1, in which the material of the oxidation-resistant material is different from the material of the substrate.

    7. A metallic component, comprising: on a remelt region of a substrate of the component, a more oxidation-resistant material of an epitaxially grown material.

    8. The component as claimed in claim 7, in which the substrate is a nickel-based or cobalt-based alloy.

    9. The component as claimed in claim 1, in which the material of the oxidation-resistant material is different from the material of the substrate.

    10. The component as claimed in claim 1, in which the more oxidation-resistant material is a NiCoCrAlX alloy, X being in particular rhenium, silicon, yttrium, tantalum and/or iron.

    Description

    DETAILED DESCRIPTION

    [0006] The description shows merely an exemplary embodiment of the invention.

    [0007] What is proposed is a method having two steps:

    [0008] Step 1: [0009] Processing a surface of a substrate by remelting. Remelting, in particular using a laser beam, can be used to create long grains along the remelted track, thus removing grain boundaries at the surface. [0010] Step 2: [0011] An oxidation-resistant layer, in particular consisting of NiCoCrAlY, can be deposition-welded onto the remelted zone by epitaxial deposition welding, in particular using a laser, such that this layer grows in particular epitaxially onto the substrate (identical crystallographic orientation as the base material) with few or no grain boundaries. [0012] This improves the oxidation resistance at the surfaces of polycrystalline components made of nickel-based superalloys, in particular because by virtue of the epitaxy fewer grain boundaries are available for oxidation damage, and additionally because a coating provides additional oxidation protection. [0013] The material of the oxidation-resistant layer is different from the material of the substrate of the metallic component. Different means that there is 15% more or less of at least one alloy element, or that at least one alloy element is or is not present.