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1

Spawanie laserowe złączy doczołowych z austenitycznej stali nierdzewnej AISI 304

Kurc-Lisiecka A.

Stal, Metale & Nowe Technologie

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2016

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nr 11-12

40--44

PL

Przedmiotem badań była analiza wpływu podstawowych parametrów spawania laserowego (tj. mocy wiązki laserowej i prędkości spawania oraz energii liniowej spawania) złączy doczołowych blach ze stali nierdzewnej AISI 304 o grubości 2,0 mm na kształt i jakość złączy. Wstępne próby symulowanego spawania laserowego poprzez przetapianie blach ze stali austenitycznej (ang. bead-on-plate welding), jak i spawania właściwych złączy próbnych wykonano przy użyciu lasera diodowego dużej mocy firmy ROFIN DL 020, techniką bez materiału dodatkowego. Krytycznym parametrem decydującym zarówno o własnościach mechanicznych, ale również odporności korozyjnej złącza (obszar spoiny oraz SWC) w przypadku stali nierdzewnych o strukturze austenitycznej jest energia liniowa spawania, która powinna być ograniczona do minimum, przy zapewnieniu pełnego przetopienia blach oraz poprawnego kształtu spoiny. Badania wykazały, że możliwe jest wykonanie laserem diodowym złączy doczołowych blach ze stali AISI 304 o grubości 2,0 mm o poprawnym kształcie i wysokiej jakości.

EN

The subject of the study was to analyze the influence of the basic parameters of laser welding (i.e. laser beam power and welding speed, as well as energy input) of butt joints of the 2.0 mm thick stainless steel AISI 304 sheets on the weld shape and joint quality. The preliminary tri-als of simulated laser welding by melting the austenitic stainless steel sheets (the so called bead-on-plate welding), as well as the welding of the test butt joints, were carried out using the high-power diode laser (HPDL) ROFIN DL 020, without the additional material (the technique of autogenous welding). A crucial parameter that determines both the mechanical properties and the corrosive resistance of a joint (the region of a weld and HAZ) in the case of stainless steels with austenitic structure is energy input, which should be kept at a minimum, and at the same time full penetration and a proper shape of the fusion zone should be ensured. The study have shown that it is possible to produce high quality butt joints of the 2.0 mm thick austenitic stainless steel AISI 304 sheets by means of diode laser.

2

The comparision of tribological properties of the surface layer of the hot work tool steels obtained by laser alloying

Dobrzański L. A., Jonda E., Labisz K., Bonek M., Klimpel A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

142-147

EN

Purpose: The paper presents the investigation results of the influence of laser remelting or alloying on the abrasive wear resistance of the X40CrMoV5-1 and 32CrMoV12-28 hot work tool steels surface, using the high power diode laser (High Power Diode Laser). Design/methodology/approach: The main goal of this work was to compare the abrasion wear resistance of those two steels before and after laser treatment consisting on remelting or alloying with carbide powders. The reason of this work was also to determine the laser treatment parameters, particularly the laser power, to achieve surface layer with better properties for example hardness which is connected with abrasive wear resistance of surface layers. Findings: A modification of tool steels surface using a laser beam radiation, as well as coating them with special pastes containing particles such as vanadium allows the essential improvement of the surface layer properties – their quality and abrasion resistance, decreasing at the same time the surface quality, what is dependent on the processing parameters such as energy of impulse and the time of its work. Surface layer obtained due to laser modification is characteristic of different properties than the native material. Research limitations/implications: The results present only four selected laser powers by one process speed rate. Also carbide powders were used for alloying with the particle size in a chosen range. Practical implications: The alloyed layers which were formed on the surface of the hot work steel have shown significant improvement. Good properties of the laser treatment make these layers suitable for various technical and industrial applications. Originality/value: Structural and tribological behaviour of surface layer achieved by alloying and remelting using high diode power laser and selected ceramic powders were compared.

3

Microstructure and properties of laser surface alloyed PM austenitic stainless steel

Brytan Z., Bonek M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 40, nr 1

70-78

EN

Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404). Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL). The influence of laser alloying conditions, both laser beam power (between 0.7 and 2.0 kW) and powder feed rate (1.0-4.5 g/min) at constant scanning rate of 0.5m/min on the width of alloyed surface layer, penetration depth, microstructure evaluated by LOM, SEM x-ray analysis, surface roughness and microhardness were presented. Findings: The microstructures of Cr laser alloyed surface consist of different zones, starting from the superficial zone rich in alloying powder particles embedded in the surface; these particles protrude from the surface and thus considerably increase the surface roughness. Next is alloyed zone enriched in alloying element where ferrite and austenite coexists. The following transient zone is located between properly alloyed material and the base metal and can be considered as a very narrow HAZ zone. The optimal microstructure homogeneity of Cr alloyed austenitic stainless steel was obtained for powder feed rate of 2.0 and 4.5 g/min and laser beam power of 1.4 kW and 2 kW. Practical implications: Laser surface alloying can be an efficient method of surface layer modification of sintered stainless steel and by this way the surface chromium enrichment can produce microstructural changes affecting mechanical properties. Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus uniform thermal cycle across treated area and uniform penetration depth of chromium alloyed surface layer.

4

Structure and properties of surface layer of hot-work tool steels alloyed using high power diode laser

Dobrzański L. A., Jonda E., Labisz K.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

617-621

EN

Purpose: In this paper the results of remelting and alloying laser parameters on the structure and properties of the surface layer of the X40CrMoV5-1 and 32CrMoV12-28 hot work tool steels, using the high power diode laser (HPDL) are presented. Design/methodology/approach: The effect was determined of the main alloying parameters on hardness, abrasive wear resistance and roughness. The hot work tool steels conventionally heat treated were used as reference material and the tantalum carbide was used as an alloying material. The remelted layers which were formed in the surface of investigated hot work tool steels were metallographically examined and analyzed using a hardness testing machine. Findings: It was found out in examinations of the surface layer that it can be possible to obtain high quality top layer with higher hardness and abrasive wear resistance compared to material after conventional heat treatment. Research limitations/implications: The surface layer and its properties are elements which are critical for lifetime of tools and parts of machines and also for lifetime of whole technical equipment. If the working surface of a tool or its part is exposed to rough friction, an intensive mass and volume loss occurs. In this case it is reasonable to produce a surface layer which is extremely wear resistant to avoid the mass and volume loss. Originality/value: The research results of this type of heat treatment show that there is a possibility of applying the worked out technology to manufacturing or regeneration of chosen hot working tools.

5

Effect of laser treatment on micro-structure and properties of cast magnesium alloys

Dobrzański L. A., Domagała-Dubiel J., Labisz K., Hajduczek E., Klimpel A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 1

57-64

EN

Purpose: The goal of this paper is to present the structure and properties of the cast magnesium alloy after laser treatment. Design/methodology/approach: The laser treatment of magnesium alloys with TiC, WC powders was carried out using a high power diode laser (HDPL). The resulting microstructure in the modified surface layer was examined using optical microscopy, scanning electron microscopy and transmission electron microscope. Phase composition was determined by the X-ray diffraction method using the XPert device. The measurements of hardness and wear resistance of the modified surface layer were also studied. Findings: The region after laser treatment has a fine microstructure with hard carbide particles. Hardness of laser surface layer with both TiC and WC particles was improved as compared to alloy without laser treatment. Research limitations/implications: In this research two powders (WC and TiC) were used with the particle size over 5 ěm. This investigation presents different laser power by one process speed rates. Practical implications: The results obtained in this investigation were promising towards compared other conventional processes. High Power Diode Laser can be used as an economical substitute of Nd:YAG and CO2 to improve the surface magnesium alloy by feeding the carbide particles. Originality/value: The originality of this work is applying of High Power Diode Laser for alloying of magnesium alloy using hard particles like tungsten and titanium carbides.