Wyniki wyszukiwania - BazTech

1

Laser welding of stainless steel

Kurc-Lisiecka A., Lisiecki A.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 98, nr 1

32--40

EN

Purpose: of this paper 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. Design/methodology/approach: The preliminary trials 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 - heat affected zone) 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 investigations included the macrostructure and microstructure observations by light microscopy, researches of mechanical properties in a static tensile test and also microhardness measurements made by Vickers method. Findings: The results have shown that it is possible to provide a proper shape of the weld of fine-grained structure and narrow heat affected zone, but it requires careful selection of the welding parameters, especially a low energy input. The microhardness measurements showed that the in case of welding the butt joints using the high-power diode laser in HAZ area a slight increase in microhardness to approx. 185HV0.2 compared to base material (160-169HV0.2) and a decrease in microhardness in the fusion zone (FZ) to approx. 140- 150HV0.2 have been observed. All welded sample broke from the joint during the testing at tensile stress between 585 MPa and 605 MPa with corresponding percentage elongation in the range of 45-57%. It can be found that the joints strength is not less than the strength of the base metal of 2.0 mm thick AISI 304 austenitic stainless steel sheet. Research limitations/implications: Studies of the weldability of stainless steels indicate that the basic influence on the quality of welded joints and reduction of thermal distortions has the heat input of welding, moreover the highest quality of welded joints of austenitic stainless steel sheets are ensured only by laser welding. Practical implications: The laser welding technology can be directly applied for welding of austenitic steel AISI 304 sheets 2.0 mm thick. Originality/value: Application of high power diode laser for welding of austenitic stainless steel AISI 304.

2

Napawanie laserowe tarcz zderzaków kolejowych brązem aluminiowym

Sitarz M., Kurc-Lisiecka A., Gamon W.

Stal, Metale & Nowe Technologie

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2017

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nr 9-10

80--84

PL

W artykule opisano wyniki badań procesu napawania laserowego powierzchni tarcz zderzaków kolejowych ze stali S355J2 proszkiem na bazie brązu aluminiowego. Próby napawania wykonano za pomocą lasera diodowego dużej mocy (HPDL) LDF 4000-30 firmy LaserLine o mocy maksymalnej 4,0 kW. Badania obejmowały również obserwacje metalograficzne wytworzonych warstw, badania ich odporności na zużycie ścierne i pomiary twardości. Stwierdzono, że w wyniku napawania laserowego tarcz zderzaków kolejowych ze stali S355J2 proszkiem brązu CuAl9Fe3 i laserem diodowym HPDL możliwe jest wykonanie wysokiej jakości napoin bez nieciągłości strukturalnych i o korzystnej, drobnoziarnistej strukturze dendrytycznej w obszarze napoiny. Wykazano również, że napawanie laserowe brązem aluminiowym zapewnia znaczący wzrost odporności na zużycie ścierne powierzchni czołowych tarcz zderzaków kolejowych i pozwala na wyeliminowanie konieczności okresowego ich smarowania.

EN

The paper presents the results of the study of the laser powder cladding of railway buffers heads made of the S355J2 steel by aluminium bronze-based powder. The high power diode laser (HPDL) LDF 4000-30, produced by LaserLine, with the maximum output power of 4.0 kW, was used for the cladding trials. The investigations included also the metallographic observations of the clad layers, wear behaviour and hardness measurements. It was found that it is possible to produce high-quality clad layers of the aluminium bronze CuAl9Fe3 on the steel substrate, without any internal imperfections, such as voids or structural discontinuities, and characterized by fine-grained dendritic structure in the fusion zone of the clad. It was also shown that the laser cladding of aluminium bronze provides a significant increase of wear resistance of buffer working surfaces and can also eliminate the need of periodical greasing of these surfaces.

3

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.

4

Influence of the HPDL surface treatment of the X40CrMoV5-1 and 32CrMoV12-28 tool steels on wear resistance

Jonda E., Labisz K., Pakieła W.

Archives of Materials Science and Engineering

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2013

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Vol. 64, nr 2

152--159

EN

Purpose: This paper presents the results of laser remelting influence on structure and properties of the surface of the X40CrMoV5-1 and 32CrMoV12-28 hot work tool steels, carried out using the high power diode laser (HPDL). Structure changes were determined in the work, especially structure fragmentation. Also hardness investigation of the different remelting areas was performed. The purpose of this work was also to determine technological and technical parameters for a right performed HPDL remelting process. Boron nitride powder was used for alloying. The goal of this work was also to determine technical and technological conditions for remelting the surface layer with HPDL. Design/methodology/approach: Here are discusses the new methodology ways which can be applied in case of improving of the surface layer properties. A new laser treatment techniques applied in metal surface technology is here the most important feature. Also the influence of ceramic powders to the structure in all zones is investigated. Optical and scanning electron microscopy, EDS point wise and area microanalysis was used to characterize the microstructure and to investigate the intermetallic phases occurred. Findings: The most important factor is the zone structure of the surface layer which was coming into existence without cracks and defects as well as has a considerably higher hardness value compared to the non remelted material. It was find out, that the hardness of the alloyed surface layer increases according to the applied laser power. The highest power applied gives the highest hardness value in the remelted layer mostly in all user ceramic powders. Practical implications: The reason of this work was also to determine the laser treatment parameters, particularly the laser power, to achieve a good layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant for work extreme conditions. The most important practical implication investigated in this work improves the appliance of HPDL laser for alloying and remelting of hot work tool steel. Originality/value: The originality of this work is assured through the using of an high-level up-to-date laser device for improvement of steel surface layer mechanical properties.

5

HPDL laser alloying of Al-Si-Cu alloy with Al2O3 powder

Labisz K., Tański T., Dobrzański L.A., Janicki D., Korcina K

Archives of Materials Science and Engineering

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2013

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Vol. 63, nr 1

36--45

EN

Purpose: This article presents results of investigation of laser alloyed cast aluminium alloys after standard heat treatment. In general into the aluminium matrix there are fed different types of ceramic particles including aluminium oxide. The purpose of this work was also to determine the laser treatment conditions for surface hardening of the investigation alloys, like laser power, as well the laser scan rate. Design/methodology/approach: The investigations were performed using light and electron microscopy (SEM) for structure determination, using EDS microanalysis it was also possible to determine the chemical composition changes. The morphology and size of the ceramic powder particles was also possible to determine. Findings: Concerning the laser treatment conditions for surface hardening the scan rate as well as the laser power influence was studied. The structure of the surface laser tray changes in a way, that there are very high roughness of the surface zone and the flatness or geometry changes. Research limitations/implications: The aluminium samples were examined metallographically using optical microscope with different image techniques as well as scanning electron microscope. Practical implications: Developing of new technology with appliance of Al alloys, High Power Diode Laser and diverse ceramic powders can be possible to obtain, based in findings from this research project. Some other investigation should be performed in the future, but the knowledge found in this research concerning the proper process parameters for each type of alloy shows an interesting investigation direction. Originality/value: The combination of metallographic investigation, including electron microscope investigation and High Power Diode Laser (HPDL) treatment parameters makes the investigation very attractive especially for automobile industry, and transportation where parts manufactured of aluminium alloys are a very important because of its surface properties.

6

Comparison of the abrasion wear resistance of the laser alloyed hot work tool steels

Dobrzański L., Jonda E., Labisz K.

Archives of Materials Science and Engineering

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2012

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Vol. 55, nr 2

85-92

EN

Purpose: The paper presents the comparison of the abrasion wear resistance of the laser alloyed hot work tool steels X40CrMoV5-1 and 32CrMoV12-28. Design/methodology/approach: The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determining the friction coefficient, and mass loss of the investigated surfaces. Findings: The performed investigations leads to the conclusions that for both types of steels - X40CrMoV5-1 and 32CrMoV12-28 the wear resistance measured using pin-on-disc, wear resistance test in the metal - metal arrangement, and wear resistance test in the metal - ceramic material arrangement, the wear resistance increases together with the hardness of the surface layer. This relationship is valid for all types of ceramic powders used. It is characteristic for the obtained surface layers, that the high roughness, multiple pores, irregularity, and flashes at the borders increases also together with the increasing of the laser power. Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers. Practical implications: The alloyed layers which were formed on the surface of the hot work steels have shown significant improvement concerning properties. Good properties of the laser treatment make these layers suitable for various technical and industrial applications. Originality/value: A modification of tool steels surface using a laser beam radiation, as well as coating them with special pastes containing carbide particles 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.

7

Technology of laser repair welding of nickel superalloy inner flaps of jet engine

Klimpel A., Rzeźnikiewicz A.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 47, nr 1

66--74

EN

Purpose: of this paper: work out laser welding repair technology of cracked MIG 29 jet engine inner flaps made of cast nickel superalloy ŻS-3DK(ЖС-3ДК, Russian designation). Design/methodology/approach: The study were based on the analysis of laser HPDL powder INCONEL 625 welding of nickel superalloy using wide range of welding parameters to provide highest quality repair welds. Findings: Study of automatic welding technologies GTA, PTA and laser HPDL has shown that just laser welding can provide high quality repair welds. In order to establish the properties of welded joints repair cracks in the inner flap HPDL laser, studied the hardness, mechanical properties and erosive wear resistance. Research limitations/implications: It was found that only laser HPDL welding can provide high quality repair welds. Practical implications: The technology can be applied for repair cracked MIG 29 jet engine inner flaps. Originality/value: Repairing cracked MIG 29 jet engine inner flaps.

8

Sintered stainless steel surface alloyed with Si3N4 powder

Brytan Z., Dobrzański L., Pakieła W.

Archives of Materials Science and Engineering

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2011

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Vol. 50, nr 1

43-55

EN

Purpose: The goal of this study was to investigate effects of laser surface alloying with Si3N4 powder on the microstructural changes and properties of vacuum sintered stainless steels, both austenitic X2CrNi17-12-2, ferritic X6Cr13 and duplex X2CrNiMo22-8-2. Design/methodology/approach: High power diode laser (HPDL) was applied to surface modification of sintered stainless steels with Si3N4 powder. The influence of laser alloying conditions on the width, penetration depth of alloyed surface layer were studied and analysed via FEM simulation. The microstructure of alloyed layers was examined using light and scanning electron microscopy as well as X-ray diffraction. The microhardness and wear resistance of studied surface layers were also evaluated. Findings: The hardness increased with addition of Si3N4 due to strong solution hardening effect of nitrogen and silicon that dissolved in the steel matrix during laser alloying. The strong austenite stabilizer effect of nitrogen was observed in ferritic stainless steel that revealed duplex microstructure. The hardness increased with addition of Si3N4 due to strong solution hardening effect of nitrogen and silicon dissolved in the steel matrix during laser alloying. The hardening effect of Si3N4 was strongest in case of ferritic stainless steel where microhardness increased to 450 HV0.1 for 2.1 kW of laser beam power. The duplex stainless steel shows the regular microhardness on the whole penetration depth. Laser surface alloying with Si3N4 improved wear resistance of sintered stainless steels compared to not processed stainless steel as well as comparing layers prepared as machined grooves and surface with pre-coated paste. Practical implications: Laser surface alloying with Si3N4 powder can be an efficient method of surface layer hardening of sintered stainless steels and produce improvement of surface layer properties in terms of hardness and wear resistance. Moreover, application of high power diode laser HPDL and surface prepared as machined grooves can guarantee uniform heating of treated surface, thus uniform thermal cycle across processed area and uniform penetration depth of alloyed surface layer. Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus uniform thermal cycle across processed area and uniform penetration depth of alloyed surface layer.

9

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.

10

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.

11

Structure changes and mechanical properties of laser alloyed magnesium cast alloys

Dobrzański L., Domagała J., Malara S., Tański T., Kwaśny W.

Archives of Materials Science and Engineering

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2009

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Vol. 35, nr 2

77-82

EN

Purpose: The aim of this work was to investigate structure and mechanical properties of the MCMgAl12Zn1 casting magnesium alloys after laser treatment. The laser treatment was carried out using a high power diode laser (HPDL). Design/methodology/approach: The laser processing of TiC, WC, SiC particles in MCMgAl12Zn1 and the resulted microstructures and properties are discussed in this paper. The resulting microstructure in the modified surface layer was examined. Phase composition was determined by the X-ray diffraction method using XPert device. The measurements of hardness after laser melt injection was also studied. Findings: Structure of the solidyifying material after laser alloying is characteristic with occurrences of areas with the diversified morphology, dependent on solidification rate of the magnesium alloys, is characteristic of structure of the solidified material after laser alloying. The MCMgAl12Zn1 casting magnesium alloys after laser alloying demonstrate similar hardness tests results, in reference to hardness of the alloys before their laser treatment. Research limitations/implications: In this research three powders (titanium carbide, tungsten carbide and silicon carbide) were used to reinforcing the surface of the MCMgAl12Zn1 casting magnesium alloys. Practical implications: High power diode laser can be used as an economical substitute for CO₂ and Nd:YAG lasers to modify the surface magnesium alloy by feeding the carbide particles. Originality/value: The originality of this work is applying of High Power Diode Laser for laser treatment of cast magnesium alloy consisting in fusion penetration of the hard particles of titanium, tungsten, and silicon carbides into the remelted surface layer of the alloy.

12

Laser surface treatment of cast magnesium alloys

Dobrzański L., Domagała J., Tański T., Klimpel A., Janicki D.

Archives of Materials Science and Engineering

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2009

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Vol. 35, nr 2

101-106

EN

Purpose: The goal of this work was to investigate influence of laser treatment on structure and properties MCMgAl3Zn1, MCMgAl6Zn1, MCMgAl9Zn1 and MCMgAl12Zn1 cast magnesium alloys. Design/methodology/approach: Tests were made on the experimental MCMgAl3Zn1 MCMgAl6Zn1 MCMgAl9Zn1 and MCMgAl12Zn1 casting magnesium alloys. Laser treatment was made using the Rofin DL020 HPDL high power diode laser in the argon shield gas cover with the technique of the continuous powder supply to the remelted pool area. Findings: Investigations of the surface layers carried out confirm that laser treatment of the surface layer of the Mg-Al-Zn casting magnesium alloys is feasible using the HPDL high power diode laser ensuring better properties compared to alloys properties after the regular heat treatment after employing the relevant process parameters. Occurrences were found based on the metallographic examinations of the remelted zone (RZ) and the heat affected zone (HAZ) in alloyed surface layer of the investigated casting magnesium alloy. Research limitations/implications: This investigation presents different laser power and in this research was used two powders, namely tungsten-, and titanium carbide. Practical implications: Reinforcing the surface of cast magnesium alloys by adding TiC and WC particles is such a possible way to achieve the possibilities of the laser melt injection process, which is a potential technique to produce a Metal-Matrix Composite (MMC) layer in the top layer of a metal workpiece. 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 carbide.

13

Laser surface treatment of magnesium alloy with WC and TiC powders using HPDL

Dobrzański L., Domagała J., Tański T., Klimpel A., Janicki D.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 28, nr 2

179-186

EN

Purpose: The aim of this work was to improve the surface layer cast magnesium alloy EN-MCMgAl6Zn1 by laser surface treatment. The purpose of this work was also to determine the laser treatment parameter. Design/methodology/approach: The laser treatment of an EN-MCMgAl6Zn1 magnesium alloy with alloying WC and also TiC powders was carried out using a high power diode laser (HPDL). The resulting microstructure in the modified surface layer was examinated using scanning electron microscopy. Phase composition was determined by the X-ray diffraction method using the XPert device. The measurements of microhardness of the modified surface layer was also studied. Findings: The alloyed region has a fine microstructure with hard carbide particles. Microhardness of laser surface alloyed layer with both TiC and WC particles was significantly 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 µm This investigation presents different speed rates feed by one process laser power. Practical implications: The results obtained in this investigation were promising to 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 carbide and titanium carbide.

14

Laser welding of butt joints of austenitic stainless steel AISI 321

Klimpel A., Lisiecki A.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 1

63-66

EN

Purpose: of this paper: A study of an automated laser autogenous welding process of butt joints of austenitic stainless steel AISI 321 sheets 0.5 [mm] and 1.0 [mm] thick using a high power diode laser HPDL has been carried out. Design/methodology/approach: Influence of basic parameters of laser welding on shape and quality of the butt joints and the range of optimal parameters of welding were determined. Findings: It was showed that there is a wide range of laser autogenous welding parameters which ensures high quality joints of mechanical strength not lower than the strength of the base material (BM). The butt joints of austenitic steel AISI 321 sheets welded by the HPDL diode laser at optimal parameters are very high quality, without any internal imperfections and the structure and grain size of weld metal and HAZ is very small and also the HAZ is very narrow and the fusion zone is very regular. Research limitations/implications: Studies of the weldability of stainless steels indicate that the basic influence on the quality of welded joints and reduction of thermal distortions has the heat input of welding, moreover the highest quality of welded joints of austenitic stainless steel sheets are ensured only by laser welding. Practical implications: The technology of laser welding can be directly applied for welding of butt joints of austenitic steel AISI 321 sheets 0.5 and 1.0 [mm] thick. Originality/value: Application of high power diode laser for welding of austenitic stainless steel AISI 321.

15

Structure and tribological behavior of surface layer of laser modified X40CrMoV5-1 steel

Dobrzański L. A., Jonda E., Lukaszkowicz K., Križ A.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

343--346

EN

Purpose: The paper presents the effect of alloying with WC, TaC and TiC on structure and mechanical properties of the X40CrMoV5-1 steel surface layer using the HPDL (High Power Diode Laser). Design/methodology/approach: The microstructure of the alloyed layers which were formed on the surface of the investigated hot work steel was examined using optical microscope. The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determining the friction coefficient, and mass loss of the investigated surfaces. X-ray diffraction (XRD) technique was used to investigate crystalline structure and phases in the layers. Findings: The metallographic investigations on light microscope show that during alloying the X40CrMoV5-1 hot work tool steel with the WC, TaC and TiC powder layer the obtained run face is characteristic of the high roughness, multiple pores, irregularity, and flashes at the borders. The changes of the surface layers hardness formed as a result of remelting and alloying with ceramic powders containing carbides are accompanied with the increased tribological properties. Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers. 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.

16

Structure and properties of surface layers obtained by alloying of the hot work tool steels

Dobrzański L. A., Polok A., Jonda E.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

329--332

EN

Purpose: The aim of the present work was to study the microstructure and properties produced after laser alloying of the 55NiCrMoV7 and X40CrMoV5-1 an alloy hot-work tool steels. Design/methodology/approach: Structure investigation was performed using the light microscope Leica MEF4A supplied by Zeiss. Phase composition and crystallographic structure were determined by the X-ray diffraction method using the DRON 2.0. The measurements of microhardness have been performed using Shimadzu microhardness intender equipped with electronic sensor that allows the direct readout of the hardness values. Findings: The metallographic investigations on light microscope show that steel after laser remelting can be characterized by a dendrite structure. Metallographic examinations on the scanning microscope with the EDX attachment confirm the occurrence of the niobium carbides in the surface layer of the investigated steels. Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers. Practical implications: The surface layer of the hot work steel alloyed with ceramic powder have good properties and make possibility for uses it in various technical and industrial applications. Originality/value: The microstructure and properties of the surface layer of the 55NiCrMoV7 and X40CrMoV5-1 hot-work tool steels alloying with ceramic powder were compared.

17

Comparison of the abrasion wear resistance of the X40CrMoV5-1 and 55NiCrMoV7 hot work tool steels with their surface layer enriched with the ceramic powders

Dobrzański L. A., Jonda E., Polok A.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 15, nr 1-2

32--38

EN

Purpose: In the paper there are presented the results of the influence of laser remelting parameters on the properties of the surface layer of the X40CrMoV5-1 and 55NiCrMoV7 hot work steel, using the high power diode laser (HPDL). The aim of this work was to compare the abrasion wear resistance of the X40CrMoV5-1 and 55NiCrMoV7 hot work tool steel surface layers enriched with the TiC, WC and VC ceramic powders. The surface layers of hot work tool steel remelted with a diode laser beam have been metallographically examined and analyzed with the use of a hardness testing machine. Design/methodology/approach: The high power diode laser (HPDL) and ceramic powders WC, VC and TiC were used. Remelting and alloying processes were carried out at the constant remelting rate and focus shape, varying the laser beam power for the alloyed test pieces in the range from 1,2 – 2,3 kW. Findings: On the basis of the wear abrasion tests carried out on 55NiCrMoV7 and X40CrMoV5-1 steels it could be ascertained that each of those steels is characterized by different resistance for the same powders and the power of the laser beam. In the case of employing 1,2 kW laser, the surface layer formed using the majority of the investigated portions undergoes a total wear during the wear-rate test which also causes the wear of the initial material. When 2,3 kW is employed, the surface layers have crack and microcrack defections which decrease the resistance to the abrasion. The smallest mass loss for 55NiCrMoV7 steel among all the analyzed cases has been observed for the surface layers alloyed with TiC powder, at the of the laser beam power of 2,3 kW and for WC powder at 1,2 kW laser beam power. For the X40CrMoV5-1 steel the smallest mass decrement has been observed forthe steel alloyed with WC powder at 1,2 kW laser beam power and VC powder at 1,6 kW laser beam power. Practical implications:The investigations showed that as a result of the applied laser processing there is the increase in the hardness and resistance to abrasion of the surface layers in relation to the output material. Originality/value: Wear resistance and hardness of two hot work tool steels were compared.