The influence of mechanical vibrations on properties of Ni-based coatings

This article reports on research work that was undertaken on Ni-based thermally- sprayed and fused coating deposited on steel substrate. Mechanical vibrations were introduced during fusing process and the impact of vibrations on the properties and microstructure of coatings was investigated. Microstructures of sprayed and sprayed–fused coatings were compared including evaluation of porosity. The microstructure of sprayed coating consists of partly melted and unmelted particles. A lot of voids are present between the splats. The assprayed coating is bonded to the substrate mechanically or by adhesion. The porosity was significantly reduced and strong metallurgical bond between the fused coating and substrate was formed after fusing operation. The hardness and microhardness of different zones of coatings as well as wear resistance were assesse

The influence of mechanical vibrations on properties of Ni-based coatings

This article reports on research work that was undertaken on Ni-based thermally- sprayed and fused coating deposited on steel substrate. Mechanical vibrations were introduced during fusing process and the impact of vibrations on the properties and microstructure of coatings was investigated. Microstructures of sprayed and sprayed–fused coatings were compared including evaluation of porosity. The microstructure of sprayed coating consists of partly melted and unmelted particles. A lot of voids are present between the splats. The assprayed coating is bonded to the substrate mechanically or by adhesion. The porosity was significantly reduced and strong metallurgical bond between the fused coating and substrate was formed after fusing operation. The hardness and microhardness of different zones of coatings as well as wear resistance were assesse

The influence of mechanical vibrations on properties of Ni-based coatings

This article reports on research work that was undertaken on Ni-based thermally- sprayed and fused coating deposited on steel substrate. Mechanical vibrations were introduced during fusing process and the impact of vibrations on the properties and microstructure of coatings was investigated. Microstructures of sprayed and sprayed–fused coatings were compared including evaluation of porosity. The microstructure of sprayed coating consists of partly melted and unmelted particles. A lot of voids are present between the splats. The assprayed coating is bonded to the substrate mechanically or by adhesion. The porosity was significantly reduced and strong metallurgical bond between the fused coating and substrate was formed after fusing operation. The hardness and microhardness of different zones of coatings as well as wear resistance were assesse

Surface Laser Processing of Additive Manufactured 1.2709 Steel Parts: Preliminary Study

Recently, metal selective laser sintering (SLS) techniques have attracted lively interest as a promising technology, which offers a number of unique applications in manufacturing of metal parts with complex internal structure and geometry. However, unsatisfactory surface properties of as-manufactured SLS parts cause high cost of finish processing and restrict wider application of SLS products. The paper presents results of the study, which was taken to evaluate capability of laser processing to improve surface quality of SLS parts manufactured from powder maraging steel 1.2709 (X3NiCoMoTi 18-9-5). The properties of processed surfaces were assessed, and the main dependencies of the roughness, hardness, wear resistance, and phase composition on the main parameters of laser processing—scanning speed, laser power, and number of processing times—were determined. The roughness of surfaces was diminished up to ∼41%, the hardness was increased up to ∼88%, and the wear resistance was improved up to almost 4 times, as compared with surface of as-manufactured SLS part. The preliminary study has demonstrated that laser processing has considerable potential for improvement of surface conditions of steel additive manufactured parts

INVESTIGATION OF CHARACTERISTICS OF SPRAYED NI-CR AND NI-CR-WC COATINGS / PURKŠTINIŲ NI-CR IR NI-CR-WC DANGŲ SAVYBIŲ TYRIMAS

The article deals with the flame sprayed Ni-Cr and Ni-Cr-WC coatings on construction S235 steel substrates. Before spraying, the surfaces of substrates were treated mechanically. Using the different chemical composition of Ni-Cr and Ni-Cr-WC spraying powder and additional substrate heating till 250–290 °C, were sprayed coatings. The microstructure, porosity, hardness, elastic modulus, wear resistance of the Ni-Cr and Ni-Cr-WC coatings were investigated in the work. The influence of the chemical composition and WC content of the coatings on the various physical and tribological properties of the coatings were evaluated. Also the dependence of these coatings characteristics was investigated. Santrauka  Straipsnyje nagrinėjamos liepsninio purškimo būdu ant konstrukcinio S235 plieno substrato užpurkštos Ni-Cr dangos. Substrato paviršiai prieš purškiant buvo apdoroti mechaniniu būdu. Naudojant skirtingos cheminės sudėties Ni-Cr ir Ni-Cr-WC purškimo miltelius ir papildomai pakaitinus substratą iki 250–290 °C temperatūros, buvo užpurkštos dangos. Darbe ištirta gautų Ni-Cr ir Ni-Cr-WC dangų mikrostruktūra, akytumas, kietumas, tamprumo modulis ir atsparumas dilimui. Įvertinta dangų cheminės sudėties ir WC karbidų įtaka įvairioms dangų fizikinėms, tribologinėms savybėms, nustatytos šių dangų charakteristikų priklausomybės. Reikšminiai žodžiai: konstrukcinis plienas, Ni-Cr ir Ni-Cr-WC dangos, liepsninis purškimas, akytumas, atsparumas dilimui