Wyniki wyszukiwania - BazTech

1

Quantitative X-Ray Diffraction Analysis of Zn-Al Based Alloys

Gogola P., Gabalcová Z., Suchánek H., Babinec M., Bonek M., Kusý M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

959--966

EN

The paper describes modification to Fm3 ̅m (space group no. 225) lattice of aluminium based α-solid solution observed in Zn-Al alloys required to properly correlate quantitative data from X-ray diffraction analysis with results obtained from quantitative scanning electron microscopy image analysis and those predicted from Zn-Al binary phase diagram. Results suggests that 14 at.% of Zn as a solute atom should be introduced in crystal lattice of aluminium to obtain correct estimation of phase quantities determined by quantitative X-ray diffraction analysis. It was shown that this modification holds for Cu mould cast as well as annealed and water-cooled samples of Zn-3wt.%. Al and Zn-5wt.% Al.

2

Corrosion Behaviour Correlation of the Secondary Aluminium Casts in Natural Atmosphere and Laboratory Conditions

Kuchariková L., Liptáková T., Tillová E., Bonek M., Medvecká D.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1455--1462

EN

The secondary aluminium alloys are very important material in actual industry from economic and ecological point of view. The secondary aluminium used for production of casts, however, contains some elements, i.e. iron, – affecting physical, chemical and mechanical behaviour. The subject of our investigation has been corrosion behaviour in natural atmosphere of the hypoeutectic AlSi7Mg0.3 cast alloys with various content of iron, because the Fe content affects not only mechanical properties but corrosion resistance, as well. Three types of the AlSi7Mg0.3 cast alloys were exposed for 9 months in natural atmosphere and the measure of their degradation by corrosion was found by determination of the weight loss and the light microscopy. In addition, a scanning electron microscopy (SEM) analyses and evaluation of surface changes were used. The corrosion behaviour in natural atmosphere was compared to results of the carried out electrochemical and exposure laboratory experiments in chloride solutions.

3

Badania trybologiczne materiałów inżynierskich

Pakieła W., Bonek M., Pakieła K.

LAB Laboratoria, Aparatura, Badania

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2018

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R. 23, nr 3

26--30

4

The Investigation of Properties of High-Speed Steel After Laser Surface Treatment

Bonek M.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

227--233

EN

The aim of this research paper is to present laser surface treatment technologies, investigation of properties of the HS6-5-3-8 high-speed steel \ alloying with ceramic particles using High Power Diode Laser. Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, wear resistant. Remelting of the steel with introducing into liquid molten pool the alloying additions in the form of ceramic powders, causes significant increase of properties of surface layer of investigated steel in comparison to its analogical properties obtained through conventional heat treatment, depending on the laser beam power implemented for remelting. The increase of hardness of surface layer obtained throughout remelting and alloying with carbides by high power diode laser is accompanied by increase of tribological properties, when comparing to the steel processed with conventional heat treatment.

5

Formation of Hard Composite Layer on Tool Steel by Laser Alloying

Bonek M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

719--724

EN

Investigations include alloying the PMHSS6-5-3 steel surface layer with carbide and ceramic powders WC, VC, TiC, SiC, Si3N4 and Al2O3, using the high power diode laser (HPDL). Laser treatment is especially promising for solving contemporary surface engineering problems making it possible to focus precisely the delivered energy in the form of heat in the surface layer. The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, method on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its abrasive wear resistance. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. The tribological wear relationships were determined for laser treated surface layers, determining friction coefficient, and wear trace shape developed due to the abrasive wear of the investigated surfaces. Comparison of the laser treatment parameters and tribological properties of surface layer after remelting and alloying with hard particles of the PMHSS6-5-3 steel using the high power diode laser to obtain the optimum service properties is the outcome of the investigations carried out.

6

Finite Element Prediction for the Internal Stresses of (Ti,Al)N Coatings

Żukowska L. W., Śliwa A., Mikuła J., Bonek M., Kwaśny W., Sroka M., Pakuła D.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

149--152

EN

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.

7

Computer Simulation of the Relationship between Selected Properties of PVD Coatings

Śliwa A., Kwaśny W., Sitek W., Bonek M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

481--484

EN

The possibility to apply the Finite Element Method to calculate internal stresses which occur in Ti+TiN, Ti+Ti(CxN1-x) and Ti+TiC coatings obtained in the magnetron PVD process on the sintered high-speed steel of the PM HS6-5-3-8 type. For the purpose of computer simulation of internal stresses in coatings with the use of MES, the correct model of analyzed specimens was worked out and then it was experimentally verified by comparison of calculation results with the results of computer simulation. Accurate analysis of correlations indicated especially strong dependence between internal stresses and microhardness and between microhardness and erosion resistance what created conditions for establishing the dependence between internal stresses obtained in the result of computer simulation and erosion resistance as basic functional quality of coating. It has essential practical meaning because it allows to estimate predictable erosion resistance of coating exclusively on the base of the results of computer simulation for used parameters in the process of coating manufacturing.

8

Improving open toothed weels

Kaplun P., Gonchar V., Shalapko Y., Bonek M.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 71, nr 1

28--33

EN

Purpose: Investigations include results of research opportunities of improving the quality of open toothed wheels using advanced technologies of surface by ion nitriding in hydrogen-saturating media and subsequent heat treatment with the creation of the material in the surface layer of optimal residual compressive stresses. Design/methodology/approach: Researches on high-cycle bending fatigue were performed on the smooth cylindrical samples with a diameter of 5 mm using IMA-5 engine in pure bending with rotation (50 Hz) in the 3% NaCl solution and midair. Findings: The analysis of the operating conditions and the stress-strain state of open toothed weels showed that different portions of the surface of the teeth take different in size and type of stress. The most dangerous areas of the surface have a leg and depression between the teeth. Practical implications: Experience of operating gears indicates that the vast majority of failing of open gears occurs as a result of breakage of teeth from bending. Currently, there are many ways to improve the wear resistance and durability of the gears, but the problem is not solved until the end and it is urgent. Originality/value: In order to improving the quality of open toothed wheels by hardening the surface of the toothed wheels and especially in hazardous areas due to the deposition of hardening coatings with a gradient structure in depth, authors create a surface layer of residual compressive stress with optimal value and strengthening the core of the toothed wheel.

9

FEM modeling of lean duplex stainless steel welding

Brytan Z., Niagaj J., Pakieła W., Bonek M.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 70, nr 1

36--44

EN

Purpose: Investigations include finite element model FEM of the various weld test performed on lean duplex stainless steels (TIG, MIG) and study calculated heat thermal cycle and deriving parameters. Design/methodology/approach: The FEM model was also applied to evaluate residual stress on the weld surface. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. Findings: Obtained result can be correlated to measured ferrite content in the weld, thus providing a simple prediction of phase balance in weld microstructure dependent on introducing heat input. Comparative analysis of the numerical FEM calculations and residual stress measurements made by X-ray diffraction showed good correlation. Practical implications: Numerical calculations allow to quick selection of the optimal welding process parameters. Analysis of the thermal cycles curves has enabled to determine the basic parameters such as maximum temperature, heating time and cooling down and the rate of temperature is reached maximum and intermediate temperature ranges important for phase transformations. Originality/value: A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method.

10

The investigation of Microstructures and Properties of High Speed Steel HS6-5-2-5 after Laser Alloying

Bonek M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1647--1651

EN

This paper presents the results of the influence of laser alloying on structure and properties of the surface of HS6-5-2-5 high speed steel, carried out using a high power diode laser (HPDL). WC, VC, TiC, SiC, Si3N4 and Al2O3 particles powder was used for alloying. It was found out that remelting and laser alloying with hard particles result in structure refinement across the entire investigated laser power range. Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, EDX, X-ray microanalysis results. Fine grained, dendritic structures occur in the remelted and alloyed zone with the crystallization direction related to the dynamical heat movement from the laser beam influence zone. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. Micro-hardness changes depend up in the effects of the laser beam on the treated surface, and especially in the alloyed layer. The outcome of the research provides better understanding of the structural mechanisms accompanying laser remelting and alloying. Laser technique features the especially promising tool for solving the contemporary surface engineering problems thanks to the physical properties of the laser beam, making it possible to focus precisely the delivered energy in the form of heat in the surface layer.

PL

W pracy przedstawiono wyniki badań laserowego stopowania na strukturę i własności warstwy wierzchniej stali szybkotnącej HS6-5-2-5, przetapianej za pomocą lasera diodowego dużej mocy (HPDL). Jako materiał stopujący użyto proszków WC, VC, TiC, SiC, Si3N4 i AI2O3. Stwierdzono, że do przetopienia i stopowanie laserowe twardymi cząstkami powoduje poprawę własności warstwy wierzchniej w całym zakresie mocy lasera. Odpowiedni dobór warunków pracy lasera jak również jakość wiązki ma wpływ na wyniki przetopienia co potwierdzono badaniami twardości, mikrotwardości, mikroanalizy rentgenowskiej i rentgenowskie analizy fazowej. W strefie przetopionej i stopowanej stwierdzono występowanie drobnoziarnistej oraz dendrytycznej struktury z kierunkiem krystalizacji związanym z dynamicznym przepływem ciepła ze strefy oddziaływania wiązki laserowej. Drobnoziarnista struktura martenzytu jest odpowiedzialna za wzrost twardości warstwy stopowanej. Zmiany mikrotwardości ściśle zależą od efektów oddziaływania wiązki laserowej na obrabianą powierzchnię. Wyniki badań pozwalają na lepsze zrozumienie mechanizmów strukturalnych towarzyszących przetapianiu i stopowaniu laserowemu. Laserowa obróbka powierzchniowa stanowi szczególnie obiecujące narzędzie do rozwiązywania problemów inżynierii powierzchni dzięki wykorzystaniu własności fizycznych wiązki lasera umożliwiających precyzyjną obróbkę cieplną w warstwie wierzchniej.

11

Effect of high power diode laser surface alloying on wear resistance of high speed steel

Bonek M.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

349--359

EN

Purpose: The following paper presents the results of the influence of laser alloying on structure and properties of the surface of HS6-5-2-5 high speed steel, carried out using a high power diode laser (HPDL). WC, VC, TiC, SiC, Si3N4 and Al2O3 particles powder was used for alloying. Design/methodology/approach: Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, wear resistant, EDX and X-ray microanalysis results. Findings: Selection of laser operating conditions is discussed, as well as beam face quality after remelting, hardness, micro hardness test, wear resistant, EDX and X-ray microanalysis results. Fine grained, dendritic structures occur in the remelted and alloyed zone with the crystallization direction related to the dynamical heat movement from the laser beam influence zone. The remelted zone structure is characterized by significant martensite dispersion with its laths several times shorter than of those developed during conventional quenching. The fine grained martensite structure is responsible for hardness increase of the alloyed layer. Micro-hardness changes depend up in the effects of the laser beam on the treated surface, and especially in the alloyed layer. Practical implications: Laser technique features the especially promising tool for solving the contemporary surface engineering problems thanks to the physical properties of the laser beam, making it possible to focus precisely the delivered energy in the form of heat in the surface layer. Originality/value: The outcome of the research provides better understanding of the structural mechanisms accompanying laser remelting and alloying.

12

Mechanizm tworzenia laserów modyfikowanej warstwy wierzchniej stali szybkotnącej

Bonek M.

Spajanie Materiałów Konstrukcyjnych

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2012

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Nr 3 (17)

54--56

PL

Stale szybkotnące pomimo swojej ponad wiekowej tradycji stosowania nadal cieszą się dużym zainteresowaniem. Są one jedynie niewielką częścią ogólnej produkcji materiałów metalowych, lecz nadal stanowią silną pozycję w stosunkowo małej grupie materiałów narzędziowych, ze względu na ich pożądaną ciągliwość.

13

Characterization and performance of laser alloyed commercial tool steels

Bonek M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

623--628

EN

Purpose: The purpose of this research paper is investigated influence of carbides particle on the functional properties of surface layers. Design/methodology/approach: The experiments were made on specimens made from the HS6-5-3-8 high speed steel remelted and alloyed. The technological part of this work was made using the HPDL Rofin DL 020. Therefore all experiments were made at the constant remelting rate, varying the laser beam power in the range from 0.7 to 2.5 kW. It was established experimentally that the argon blow-in with the flow rate of 20 l/ min through the 12 mm circular nozzle oppositely directed in respect to the remelting direction provides full remelting zone protection. Findings: The structure of the solidified material after the laser remelting is characterized by the diversified morphology connected with the multiple changes of the crystal growth direction from little dendrites to tiny equiaxed grains in the near-surface zone. The main axes of the dendrites are directed according to the heat abstraction directions on the border of the solid and liquid phases with the carbides’ clusters arranged according to the whirls caused by a convectional movement in the pool of the metallic liquid as well as partly unremelted conglomerates WC as a melting material in the middle area of the remelted zone. 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 WC particles using the high power diode laser for manufacturing and regeneration of various tools from the HS6-5-3-8 high speed steel. Originality/value: The laser treatment as a part of the new generation techniques applied in metal surface technology.

14

Formation of gradient surface layers on high speed steel by laser surface alloying process

Bonek M.

Archives of Materials Science and Engineering

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2012

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Vol. 58, nr 2

182--189

EN

Purpose: The purpose of this research paper is focused on the high speed steel HS6-5-3-8 surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with the WC, VC, TiC, SiC, Si3N4 and Al2O3 particles using high power diode laser HPDL. Design/methodology/approach: Investigation indicate the influence of the alloying elements on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides, oxides, nitrides and power implemented laser (HPDL). Findings: Laser alloying of surface layer of investigated steel without introducing alloying additions into liquid molten metal pool, in the whole range of used laser power, causes size reduction of dendritic microstructure with the direction of crystallization consistent with the direction of heat carrying away from the zone of impact of laser beam. In the effect of laser alloying with powder of the WC, VC, TiC, SiC, Si3N4 and Al2O3 particles occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved particles and consolidation through enrichment of surface layer in alloying additions coming from dissolving elements. Introduced particles of carbides, oxides, nitrides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. In effect of convection movements of material in the liquid state, conglomerates of carbides arrange themselves in the characteristic of swirl. Practical implications: Laser surface modification has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones. Originality/value: The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and method of applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness and microhardness.

15

Structural analysis of heat treated automotive cast alloy

Tillová E., Chalupová M., Hurtalová L., Bonek M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 47, nr 1

19--25

EN

Purpose: The present study is conducted to investigate and to provide a better understanding of the heat treatment T4 (solution treatment at 505, 515 and 525°C, holding time 2, 4, 8,16 and 32 hours, then quenching in warm water in the range from 40°C and natural aging at room temperature during 24 hours) on the microstructure (morphology of eutectic Si, morphology of intermetallic Fe- and Cu-rich phases) and on mechanical properties (tensile strength and Brinell hardness) of recycled (secondary) AlSi9Cu3 cast alloy. Design/methodology/approach: Metallographic samples were selected from tensile specimens (after testing) and prepared by standard metallographic procedures (wet ground, polished with diamond pastes, finally polished with commercial fine silica slurry (STRUERS OP-U) and etched by Dix-Keller, HNO3 or H2SO4 (standard etching) or HCl (deep etching in order to reveal the three-dimensional morphology of phases). The microstructure was studied using an optical microscope Neophot 32 and SEM observation with EDX analysis using scanning electron microscope VEGA LMU II linked to the energy dispersive X-ray spectroscopy (EDX analyser Brucker Quantax). Hardness measurement was performed by a Brinell hardness tester with a load of 62.5 kp (1 kp = 9.807 N), 2.5 mm diameter ball and a dwell time of 15 s. Findings: The results indicate that increasing solution treatment temperature results in spheroidization of eutectic Si, gradual disintegration of iron rich intermetallic phases on base Al15(FeMn)3Si2, dissolution but also melting of intermetallic phases on base Al-Al2Cu-Si. Optimal solution treatment (515°C/4 hours) most improves mechanical properties. Further increases of solution time, leads to alloy elongations, while both, the tensile strength continuously drop. Practical implications: The present study is a part of larger research project, which was conducted to investigate and to provide a better understanding microstructure, heat treatment and mechanical properties of recycled (secondary) Al-Si cast alloy. Originality/value: The paper contributes to better understanding effect of the T4 heat treatment on the microstructure (morphology of eutectic silicon and intermetallic phases) and mechanical properties (tensile strength and Brinell hardness) of recycled cast alloy.

16

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.

17

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.

18

Microstructure analysis of the modified casting magnesium alloys after heat and laser treatment

Dobrzański L. A., Tański T., Domagała J., Bonek M., Klimpel A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 32, nr 1

7-12

EN

Purpose: In this paper there is presented the structure of the modeling cast magnesium alloy EN-MCMgAl6Zn1 as cast state, after heat treatment and laser treatment. Design/methodology/approach: The presented results concern X-ray qualitative and quantitative microanalysis as well as qualitative and quantitative X-ray diffraction method, light and scanning microscope. A casting cycle of alloys has been carried out in an induction crucible furnace using a protective salt bath Flux 12 equipped with two ceramic filters at the melting temperature of 750š10 °C, suitable for the manufactured material. The heat treatment involve the solution heat treatment (warming material in temperature 375° C by 3 hour, it elevation temperature to 430°C, warming by 10 hours) and cooling in different cooling mediums as well water, air and furnace. Laser surface melting was carried out with a high power diode laser (HDPL). Findings: The results of the metallographic examinations confirm the fact that the magnesium cast alloy MCMgAl6Zn1 is characterized by a microstructure of the . solid solution constituting the alloy matrix as well as the ß – Mg17Al12 discontinuous intermetallic phase in the forms of plates located mostly at grain boundaries. The results indicate that laser-melted layer contains the fine dendrites. The substrate grains are significantly coarses than in the laser surface remelting zone. Research limitations/implications: According to the alloys characteristic, the applied cooling rate and alloy additions seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and aging process. This investigation presents different speed rates feed by one process laser power and in this research was used one powder with the particle size over 5žm. Practical implications: This work helps to use the new developed laser treatment technique for alloying and remelting of magnesium cast alloys for new application. Originality/value: The originality of this work is based on applying of High Power Diode Laser for improvement of properties of the magnesium alloys.

19

The study of properties of laser modified hot-work tool steel surface layer

Bonek M., Piec M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 28, nr 1

75-78

EN

Purpose: The following paper is a synopsis of the fundamentals of laser remelting and alloying, outlining some of its benefits compared with conventional heat treatment techniques of hot-work tool steel X40CrMoV5-1. Design/methodology/approach: A selective review of the experimental research carried out in this area is presented. The aim of such treatment was to harden and alloy the steel surface which had been previously coated with the paste consisting of the tungsten carbide and the inorganic binder. Findings: Development of the surface layer was observed in which one can distinguish the remelted zone, heat-affected zone and the transient zone. Occurrences of the un-melted tungsten carbide grains were observed in the structure and the increased tungsten content compared to the native material, whose variable concentration is connected with the molten metal fluctuation in the pool during alloying. The fine grained, dendritic structure occurs in the remelted and alloyed zone with the crystallization direction connected with the dynamical heat abstraction from the laser beam influence zone. Practical implications: It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones. Originality/value: The outcome of the research is an investigation showing the structural mechanisms accompanying laser alloying.

20

Structure and properties of laser alloyed gradient surface layers of the hot-work tool steels

Dobrzański L., Bonek M., Hajduczek E., Labisz K., Piec M., Jonda E., Polok A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

148-169

EN

Purpose: The purpose of this research paper is focused on the 55NiCrMoV7, 32CrMoV12-28, X40CrMoV5-1, X38CrMoV5-3 hot work tool steels surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the hot work tool steels alloying with ceramic particles using high power diode laser HPDL. Design/methodology/approach: Investigation indicate the influence of the alloying carbides on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides and power implemented laser (HPDL). Laser alloying of surface layer of investigated steel without introducing alloying additions into liquid molten metal pool, in the whole range of used laser power, causes size reduction of dendritic microstructure with the direction of crystallization consistent with the direction of heat carrying away from the zone of impact of laser beam. Findings: In the effect of laser alloying with powders of carbides NbC, TaC, TiC, WC and VC occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved carbides and consolidation through enrichment of surface layer in alloying additions coming from dissolving carbides. Introduced particles of carbides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. In effect of convection movements of material in the liquid state, conglomerates of carbides arrange themselves in the characteristic of swirl. Remelting of the steel without introducing into liquid molten pool the alloying additions in the form of carbide powders, causes slight increase of properties of surface layer of investigated steel in comparison to its analogical properties obtained through conventional heat treatment, depending on the laser beam power implemented for remelting. Practical implications: It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones. The increase of hardness of surface layer obtained throughout remelting and alloying with carbides by high power diode laser is accompanied by increase of tribological properties, when comparing to the steel processed with conventional heat treatment. Originality/value: The outcome of the research is an investigation and proving the structural mechanisms accompanying laser remelting and alloying. The artificial neural networks were used to determine the effect of the technological effect of laser alloying on hardness and resistance wear abrasion of the hot work tool steels.