Wyniki wyszukiwania - Biblioteka Nauki

1

Analiza zjawisk cieplnych procesu obróbki laserowej w warunkach kriogenicznych

100%

Lisiecki A. , Ślizak D. , Kukofka A. , Waląg G.

Spajanie Materiałów Konstrukcyjnych

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2018

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tom Nr 2 (40)

16--18

PL

Bardzo wysoka gęstość mocy wiązki laserowej jako źródła energii cieplnej jest powodem, dla którego technologie laserowe często znajdują zastosowanie do modyfikacji lub regeneracji warstw powierzchniowych części maszyn i mechanizmów. Umożliwiają one wytworzenie warstw o wymaganych właściwościach mechanicznych, odpornych na zużycie ścierne bądź działanie szkodliwych mediów, również w wysokich temperaturach. Techniki laserowe stosowane przy obróbce powierzchni dzieli się na przetopieniowe, bezprzetopieniowe, natapianie oraz technologie wykorzystujące proces odparowania.

2

Zautomatyzowane spawanie laserowe blach karoseryjnych

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Lisiecki A. , Kurc-Lisiecka A. , Kukofka A.

Stal, Metale & Nowe Technologie

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2018

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tom nr 1-2

70--77

PL

W artykule opisano wyniki badań wpływu podstawowych parametrów spawania laserowego (tj.: mocy wiązki laserowej i prędkości spawania oraz energii liniowej spawania) blach karoseryjnych ocynkowanych ze stali DC04 o grubości 0,8 mm na jakość i właściwości złączy doczołowych. Próby spawania wykonano za pomocą lasera dyskowego Yb:YAG TruDisk 3302 firmy TRUMPF, o mocy maksymalnej 3,3 kW, z głowicą ogniskującą wiązkę do średnicy 200 μm, techniką bez materiału dodatkowego. Stwierdzono, że konfiguracja złącza doczołowego stwarza dogodne warunki do ujścia par cynku, bez ryzyka porowatości spoin. Mikrostruktura, mikrotwardość i własności mechaniczne złączy zależą wyraźnie od warunków spawania.

EN

The article describes the results of the research on the influence of the basic parameters of laser welding (i.e. laser beam power and welding speed, and also energy input) of 0.8 mm thick car body electro-galvanized steel DC04 sheets on the quality and properties of butt joints. The tests of welding were conducted by the means of a TRUMPF Yb:YAG TruDisk 3302 disk laser with the maximum output power of 3.3 kW and the beam spot diameter of 200 μm, applying the autogenous technique, i.e. with no additional material. The keyhole laser welding of zinc coated steel sheets in butt configuration was found to provide excellent conditions for zinc vapours to escape, with no risk of porosity. The microstructure, microhardness and mechanical properties of the butt joints depend on laser welding conditions.

3

Laser cladding of Co-based metallic powder at cryogenic conditions

100%

Lisiecki A. , Ślizak D. , Kukofka A.

Journal of Achievements in Materials and Manufacturing Engineering

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2019

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tom Vol. 95, nr 1

20--31

EN

Purpose: of this paper was demonstration a novel technique of laser cladding by experimentally composed Co-based metallic powder and forced cooling of the substrate by liquid nitrogen under cryogenic conditions, at the temperature -190°C, for producing clad layers with enhanced microstructure characteristic and properties. Design/methodology/approach: Technological tests of laser cladding were conducted by means of a high power fibre laser HPFL with maximum output power 3.0 kW, and six-axis robot. The experimental Co-based powder was composed for providing high abrasive wear resistance, high resistance for impact load, and also for corrosion resistance at elevated temperature. The unique and novel technique of forced cooling of the substrate was provided by immersing the specimens in the liquid nitrogen bath. The three coaxial nozzle head was designed and custom made to provide precise deposition of the powder delivered into the laser beam irradiation region. The scope of the study included tests of conventional laser cladding at free cooling in ambient air in a wide range of processing parameters, and also trials of laser cladding under cryogenic conditions. The test clad layers produced by conventional laser cladding and by the novel technique of laser powder deposition under cryogenic conditions were investigated and compared. Findings: The obtained results indicate that the novel technique of forced cooling the substrate by liquid nitrogen bath provides lower penetration depth, as well as low dilution of the clad, and also provides higher hardness of the clads. Additionally, it is possible shaping the geometry of the individual bead, providing high reinforcement and low width. Research limitations/implications: The presented results are based just on preliminary test of the novel technique of laser cladding under cryogenic conditions. Therefore, further study and detailed analyse of the influence of the cooling rate on the quality, microstructure, and properties of the deposited coatings are required. Practical implications: The study is focused on practical application of the novel technique for manufacturing of wear resistance coatings characterised with enhanced performance compared to conventional range of application of the laser cladding. Originality/value: Novel technique of laser cladding at forced cooling under cryogenic conditions was demonstrated. The powder used for cladding trials was experimentally composed (not commercially available). The experimental stand custom made was used with custom made powder feeding rate, and also with custom made coaxial nozzle head.