Funktionale Oberflächen auf Duplex‐Stahl durch Laserfeinbeschichten

Abstract

Während der An-und Abfahrvorgänge mehrstufiger Hochdruckpumpen durchlaufen mediumgeschmierte Axial-und The product-lubricated axial and radial bearings installed in multistage high-pressure pumps inevitably encounter severe mixed friction conditions as the pumps start and stop. This leads to extremely high tribological loads on the bearing components, compounded by the effects of a highly corrosive pumped fluid. The present paper describes a laser cladding process which produces nearnet-shape coatings of new, highly corrosion and wear resistant functional layers which can be deposited directly on high-alloy stainless steels without requiring additional buffer layers and without affecting the mechanical properties and corrosion resistance of the substrate. The results cover the solidification behaviour of the coatings as well as the microstructure resulting from various heat treatment conditions. In addition, the technological properties of the coatings and the resulting composites are discussed. The coating systems are tested as to their corrosion resistance and tribological characterization in a pump-specific tribological system.

Microstructural Analysis of Electron Beam Cladded Surface Layers Using Co‐ and Fe‐Enriched Additives

“…3.1.2). The increase in hardness in the cladding layer could be explained by the formation of carbides as well as martensite as described in literature . But both phases could not be detected by X‐ray measurements.…”

Functional Surface Layers on Stainless Steels Generated by Means of EB Cladding and Nitrocarburizing

“…A different technology for the specific surface modification of stainless steels with respect to the improvement of surface hardness and wear resistance is the surface cladding by means of built‐up welding processes, e.g., shielded metal arc (SMA) welding or metal inert gas (MIG) welding, plasma transferred arc (PTA) welding as well as laser cladding or electron beam cladding . A range of additional materials that exhibit specific properties, especially with respect to highly abrasively stressed areas of components, can be locally cladded.…”

“…A range of additional materials that exhibit specific properties, especially with respect to highly abrasively stressed areas of components, can be locally cladded. The main surface cladding methods reported in the literature are those for applying additive materials based on Fe or Co to corrosion‐resistant steels . The application of Fe‐based additives leads to surface claddings whose thicknesses are in the range of 0.6 to 2 mm, with high hardness and improved wear resistance compared to the untreated base material .…”

“…The main surface cladding methods reported in the literature are those for applying additive materials based on Fe or Co to corrosion‐resistant steels . The application of Fe‐based additives leads to surface claddings whose thicknesses are in the range of 0.6 to 2 mm, with high hardness and improved wear resistance compared to the untreated base material . At the same time the formation of carbides of the type M 7 C 3 , M 3 C, M 5 C 2 results in hardness values between 420 and 1100 HV .…”

“…The application of Fe‐based additives leads to surface claddings whose thicknesses are in the range of 0.6 to 2 mm, with high hardness and improved wear resistance compared to the untreated base material . At the same time the formation of carbides of the type M 7 C 3 , M 3 C, M 5 C 2 results in hardness values between 420 and 1100 HV . The increase in hardness values within the surface claddings correlates with a significant improvement in abrasive wear behavior .…”