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Welding of titanium alloy by different types of lasers

Lisiecki A.

Archives of Materials Science and Engineering

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2012

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Vol. 58, nr 2

209--218

EN

Purpose: of this paper was focused on comparing the welding modes during laser welding of butt joints of titanium alloy Ti6Al4V sheets 1.5 and 2.0 mm thick with direct diode laser and Disk solid state laser. Design/methodology/approach: Bead-on-plate welds were produced at different parameters of laser welding, different welding speed, different output laser power resulted in different heat input of laser welding process. The test welds were investigated by visual test, metallographic observations including macro and microstructure analysis. Additionally mechanical test were carried out such as tensile tests and technological bending test of the joints. The influence of basic laser welding parameters on the penetration depth, shape of fusion zone, width of welds and width of heat affected zones were studied. Additionally the phenomena of laser heating and melting of the welded sheets were analyzed. Findings: It was found that the mechanism of HPDL laser welding of titanium alloy differs distinctly from the mechanism of Disk laser welding. The test welds produced by HPDL laser were high quality. Welds produced by the Disk laser are characterized by a columnar shape of fusion zones, very narrow with narrow and fine structure heat affected zone. Research limitations/implications: In further investigations of laser welding of titanium alloys applying the key-hole welding mode a special care must be taken to the shielding of the weld zone and protection the weld pool and weld metal against the harmful gases from air atmosphere. Practical implications: Results of investigations presented in this paper may be applied directly for welding high quality butt joints of titanium alloy with the HPDL laser. In a case of laser welding with the Disk laser practical application requires further study, especially concentrated on the effectiveness of gas protection of the welding area including the key-hole, weld pool and surrounding regions of metal. Originality/value: This paper describes results of investigation concerning laser welding of the most common used titanium alloy Ti6Al4V by two unique and modern lasers. The investigations were carried out using the high power diode laser with a rectangular laser beam spot and also using a new generation of Disk laser characterised very high power density of the laser beam spot.

2

HPDL Remelting of Anodised Al-Si-Cu Cast Alloys Surfaces

Labisz K., Tański T., Janicki D.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 2s

45--48

EN

The results of the investigations of the laser remelting of the AlSi9Cu4 cast aluminium alloy with the anodised and non-anodised surface layer and hardness changes have been presented in this paper. The surface layer of the tested aluminium samples was remelted with the laser of a continuous work. The power density was from 8,17•103 W/cm2 to 1,63•104 W/cm2. The metallographic tests were conducted in form of light microscope investigations of the received surface layer. The main goal of the investigation was to find the relation between the laser beam power and its power density falling on a material, evaluating the shape and geometry of the remelted layers and their hardness. As the substrate material two types of surfaces of the casted AlSi9Cu4 alloy were applied – the non–treated as cast surface as well the anodized surface. As a device for this type of surface laser treatment the High Power Diode Laser was applied with a maximum power of 2.2 kW and the dimensions of the laser beam focus of 1.8 x 6.8 mm. By mind of such treatment it is also possible to increase hardness as well eliminate porosity and develop metallurgical bonding at the coating-substrate interface. Suitable operating conditions for HPDL laser treatment were finally determined, ranging from 1.0 to 2.0 kW. Under such conditions, taking into account the absorption value, the effects of laser remelting on the surface shape and roughness were studied. The results show that surface roughness is reduced with increasing laser power by the remelting process only for the non-anodised samples, and high porosity can be found in the with high power remelted areas. The laser influence increases with the heat input of the laser processing as well with the anodisation of the surface, because of the absorption enhancement ensured through the obtained alumina layer.

3

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.

4

Laser surface treatment of the hot work tool steel alloyed with TaC and VC carbide powders

Dobrzański L. A., Jonda E., Klimpel A.

Archives of Materials Science and Engineering

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2009

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Vol. 37, nr 1

53-60

EN

Purpose: The paper presents investigation results of the structure and properties of alloying surface layer of the X40CrMoV5-1 hot work tool steel, using the high power diode laser HPDL. Tantalum and vanadium carbides powders were used for alloying and the X40CrMoV5-1 conventionally heat treated steel was used as reference material. Design/methodology/approach: Metallographic examinations of the material structures after laser alloying surface layer were made on light microscope and transmission electron microscope. The resistance research has been done with the use of the pin-on-disc method. Hardness tests were made with Rockwell method in C scale. Findings: It was found out in examinations of the surface layer that it can be possible to obtain high quality top layer with better properties compared to material after a standard heat treatment. Research limitations/implications: In this research two powders (TaC and VC) were used for alloying of the surface layer of investigated steel. Practical implications: The structure as well as improvement of mechanical properties is a practical aim of this work as well as improvement of hardness as a very important properties for practical use. 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

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.

6

Characteristic of Mg-Al-Zn alloys after laser treatment

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

Archives of Materials Science and Engineering

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2008

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Vol. 34, nr 2

69-74

EN

Purpose: The structure and the properties of casting magnesium alloy EN-MCMgAl3Zn1, EN-MCMgAl6Zn1, EN-MCMgAl9Zn1 and EN-MCMgAl12Zn1 after laser surface treatment are presented in this paper. The aim of this work was to improve the surface layer cast magnesium Mg-Al-Zn by melting and feeding of TiC particle on the surface. The purpose of this work was to determine the laser treatment parameter. Design/methodology/approach: The experiments were performed using high power diode laser. The laser treatment of an EN-MCMgAl3Zn1, EN-MCMgAl6Zn1, EN-MCMgAl9Zn1, EN-MCMgAl12Zn1 magnesium alloy with alloying 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 hardness of the modified surface layer was also studied. Findings: The alloyed region has a fine microstructure with hard carbide particles. Hardness of laser surface alloyed layer with TiC particles was significantly improved as compared to alloy without laser treatment for EN-MCMgAl3Zn1 and EN-MCMgAl6Zn1 alloys. Research limitations/implications: In this research one powder - TiC was used with the particle size over 6 µm. This investigation presents different speed rates feed and different laser power value for four type of magnesium alloys. Practical implications: The results obtained in this investigation were promising compared to 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 titanium carbide.

7

Thermal analysis of nozzle for powder feeding in High Power Diode Laser (HPDL) powder surfacing

Klimpel A., Janicki D., Lisiecki A.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

463-466

EN

Purpose: Purpose of these researches was to determine the influence of High Power Diode Laser (HPDL) powder surfacing parameters, material type and shape of the nozzle for powder feeding on the temperature field of the nozzle. Design/methodology/approach: Different materials for manufacturing of the nozzle for powder feeding during HPDL powder surfacing and different shapes of the nozzle were tested to establish the optimum shape and select the material that ensure lowest heating of the nozzle. Reflection coefficient of the infared laser radiation of 808 nm for the tested materials were determined as a function of a temperature. Temperature of the nozzle tip was measured and determined as a function of surfacing parameters. Life time of the different nozzles was determined. Findings: It was shown that the nozzle made of copper body and thin-walled tube made of austenitic stainless steel ensures much higher life time of the nozzle and also higher process efficiency compared with nozzle made of copper. Research limitations/implications: It was found that decreasing the distance from the nozzle tip of thin-walled tube made of austenitic stainless steel to the weld pool surface resulted in increasing of the process efficiency but too short distance is the reason of extensive heating of the nozzle. Originality/value: The optimized shape of the powder feeding nozzle made of thin-walled tube made of austenitic stainless steel guarantee unlimited lifetime of the nozzle and high surfacing efficiency over 95%.

8

Study of laser welding of copper sheets

Klimpel A., Rzeźnikiewicz A., Janik Ł.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

467-470

EN

Purpose: Purpose of this research is to study laser autogeneous welding process of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1.0 [mm] thick. On the bases of results of quality assessment it was proved that high power diode laser (HPDL) welded lap joints of copper sheet provide mechanical properties on the level of parent material. Design/methodology/approach: Short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1,0 [mm] thick were tested, to establish the optimum parameters of high power diode laser autogeneous welding process. Findings: It was shown that there is very narrow range of optimum HPDL autogeneous welding parameters of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1,0 [mm] parameters. It was proved that high power diode laser (HPDL) autogeneous welded lap joints provide mechanical properties on the level of parent material. Practical implications: It is possible to produce high quality short seam bead and fillet weld lap joints of oxygen-free copper sheets 1.0 [mm] thick. It was proved that high power diode laser (HPDL) autogeneous welded lap joints provide mechanical properties on the level of parent material. Originality/value: The optimum HPDL autogeneous welding parameters of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1.0 [mm] parameters makes possible to produce high quality laser autogeneous welded lap joints of copper sheets 1.0 [mm] thick.

9

Mechanical and tribological properties of the laser alloyed surface coatings

Dobrzański L. A., Piec M., Bonek M., Jonda E., Klimpel A.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

235-238

EN

Purpose: Improvement of surface properties of X38CrMoV5-3 is one of the goals set to the research institutions active in this paper. Design/methodology/approach: Remelting and alloying of surface layers were made using the HPDL high power diode laser Rofin DL 020 in the laser power range of 1.2-2.3 kW. Abrasion wear resistance tests were made in the metal-ceramic material arrangement (ASTM-G65), and also in the metal-metal one. Findings: All employed carbides cause hardness and microhardness increase of the surface layer of the investigated steel, and in most cases abrasion wear resistance increase. The investigations carried out indicate that the best mechanical properties are displayed by the surface layers of steel alloyed with carbides: TaC, NbC, and VC; whereas, the best tribological properties are displayed by surface layers allowed with vanadium carbide, compared to the conventionally heat treated steel. Improvement of mechanical properties and abrasion wear resistance grow with the increase of the laser power. Research limitations/implications: The material behavior for the HPDL processing has been found to be different from the other high-power lasers in the following aspects: fewer cracks and less spallation for surface glazing/sealing, more uniform melt/heating zones, smoother surface, better beam absorption for metallic materials, more consistent and repeatable. Practical implications: The research results indicate to the feasibility and purposefulness of the practical use of remelting and alloying with the tungsten carbide using the high power diode laser for manufacturing and regeneration of various tools from the X38CrMoV5-3 hot-work tool steel. Originality/value: Possibilities of increasing the functional properties of hot-work alloy tool steels by modification of their chemical composition additional of ceramic particles in a conventional way are very limited already.

10

Computer aided structure prediction of OH18N9 and S235JR steels laser welded joints

Klimpel A., Kik T., Górka J.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 1

83-86

EN

Purpose: of these researches was to investigate possibilities of joining materials with different chemical composition and properties. CAW software to prediction of joints structure was used. Design/methodology/approach: the quality of single- and double sided joints was assessed by metallographic examinations, hardness tests, tensile and bending tests. Findings: a computer aided structure prediction was tested by metallographic examinations and hardness tests. Because of possibility of use these type of joints in medical equipment production tensile and bending tests and also corrosion resistance tests were performed. Research limitations/implications: for complete information about tested different chemical composition and properties materials joints it is needed to check others materials in place of S235JR carbon steel. Practical implications: result of this paper is an information that is possible to join materials with different chemical composition and properties materials with different chemical composition and properties. It also possible to precise predict structure of weld using computer software. Originality/value: the researches were provided for welding materials used in medical equipment producing. Welded joints were tested for a corrosion resistance in typical disinfectants used in medical conditions. At the beginning computer prediction was used.

11

Mechanical and tribological properties of the surface layer of the hot work tool steel obtained by laser alloying

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

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 7

389-396

EN

Purpose: The paper presents results on the mechanical and tribological properties examinations of the X40CRMoV5-1 hot work alloy tool steel alloyed with carbide powders using the high power diode laser (HPDL). Design/methodology/approach: Metallographic examinations of the material structures after laser alloying of their surface layer were made on light 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. Hardness tests were made with Rockwell method in C scale on specimens subjected to the standard heat treatment and alloyed using the high power diode laser at various parameters. X-ray diffraction (XRD) technique was used to investigate crystalline structure and phases in the layers. Findings: Metallographic examinations carried out on the light microscope confirm that the structure of the material solidifying after laser remelting is diversified, which is dependant on the solidification rate of the investigated steels. The investigations carried out made it possible to state that due to the heat treatment and remelting of the X40CrMoV5-1tool steel with the WC, TaC or TiC powders it is possible to obtain the high quality surface layer with no cracks and defects and with hardness significantly higher than the substrate metal. 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: A modification of tool steels surface using a laser beam radiation, as well as coating them with special pastes containing carbides particles such as tungsten, tantalum and titanium allows the essential improvement of the surface layer properties-their quality and abrasion resistance, decreasing at the same time the surface quality.

12

Mechanizm napawania proszkowego laserem HPDL

Klimpel A., Janicki D., Lisiecki A.

Przegląd Spawalnictwa

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2005

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R. 77, nr 4-5

17-23