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1
Modyfikacja warstwy wierzchniej stopów magnezu za pomocą metody GTAW
100%
Szafarska M. , Iwaszko J. , Kudła K.
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tom Vol. 32, nr 4
747-750
PL
Głównym celem pracy była próba zaadaptowania metody spawalniczej GTAW (Gas Tungsten Arc Welding) na potrzeby powierzchniowej obróbki przetopieniowej. Materiał badawczy stanowiły komercyjne stopy magnezu AZ91 i AM60. Ze względu na własności fizykochemiczne charakterystyczne dla wybranych materiałów, użycie metody GTAW wiązało się z wieloma problemami technologicznymi, m.in. ryzykiem utraty stabilności łuku elektrycznego oraz szybkim nagrzewaniem się elektrody, prowadzącymi do braku przetopienia materiału bądź do wystąpienia niekorzystnych zmian w geometrii powierzchni. Zaistniałe trudności wymusiły potrzebę przebudowy i doposażenia standardowego stanowiska spawalniczego. Efektem podjętych działań było opracowanie nowatorskiego zestawu dwupalnikowego z palnikami pracującymi w układzie tandem. Rolą palnika prowadzącego było katodowe oczyszczanie powierzchni materiału ze ściśle przylegającej warstwy tlenków, a drugiego palnika przetopienie oczyszczonej powierzchni. Efektywność zmian generowanych w wyniku przetapiania weryfikowano na podstawie obserwacji makroskopowych połączonych ze wstępnymi badaniami strukturalnymi. Zaproponowana metodyka obróbki pozwoliła na osiągnięcie zamierzonego celu i skuteczną modyfikację warstwy wierzchniej stopów magnezu bez konieczności uprzedniego oczyszczania mechanicznego, bądź chemicznego powierzchni materiałów. Opracowane rozwiązanie może stanowić cenną alternatywę dla technik laserowych, dominujących obecnie w inżynierii powierzchni stopów magnezu.
EN
The main objective of the study was to try to adapt the GTAW welding method to the surface remelting treatment needs. The study materials were the commercial alloys of magnesium AZ91 and AM60. Due to the physical and chemical properties characteristic for the selected material, the use of the GTAW method involved many technological problems, among other things the risk of loss of the electric arc stability and quick electrode heating in turn leading to a failure in the material remelting or the occurrence of an adverse alternation in the surface geometry. The arisen difficulties forced us to rebuild the welding station and fit it with additional equipment. The effect of the taken action was the development of an inventive double-burner set with the burners operating in tandem. The leading burner role was the cathodic cleaning of the material surface and the removal of the layer of oxides firmly adhered to it, whereas the role of the second burner was to remelt the cleaned surface. The effectiveness of the alternations caused by the remelting proces was verified on the basis of macroscopic observation along with preliminary structural investigations. The proposed treatment method has made it possible to obtain the intended aim and the effective modification of the outer layer of magnesium alloys without the necessity of the previous mechanical or chemical cleaning of the surface of materials. The developed solution can be a valuable alternative for the laser techniques that are presently dominating in magnesium alloy surface engineering.
2
Content available remote The remelting of C90U steel with using GTAW method
84%
Adamiak S.
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2007
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tom Vol. 7, iss. 3
7-10
EN
This work presents results of investigation the C90U steel surface remelting with a concentrated energy beam, using the GTAW method. The top surface layer of the C90U steel was partially remelted at the welding head feed rate of 200 mm/min, and the electric arc current of 50 through 300A. Microscopic inspection of resulting structure, as well as remelted layers' geometry and hardness measurements were conducted. The correlation between electric arc current and the remelted layers' geometry, microstructure and micro-hardness was derived. In the remelted zone, numerous inter-crystalline cracks were found with the current intensity of 200 and 300A.
3
Content available remote The microstructure of HS 6-5-2 steel in the areas overlapping remelting obtained by the use of GTAW method
84%
Dziedzic A.
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2008
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tom Vol. 8, iss. 3
47-52
EN
The work presents microstructures of HS 6-5-2 high-speed steel from the areas overlapping remelting. The surface layer of the steel was remelted using the GTAW method. The microstructure photos were taken with LM and SEM microscopes. On microstructure photos there are visible results of heat effect overlapping remelting. The conclusions of the work show that as a result of crystallization in the zone of first remelting a system of crystals is formed which is forced the direction of heat removal from the front of the crystallization through the solid phase. With overlapping the second remelting on the first one, as a result of retreating crystallization on the border of the second and the first remelting the direction of crystals packing changes. Additionally, the heat influence zone of the second remelting changes the structure of the first remelting significantly. Aforementioned factors determine the decrease of the microhardness value of the surface layer within the areas overlapping remelting.
4
Content available remote Microhardness changes of surface layer of HS 6-5-2 steel in the areas overlapping remelting obtained with the use of GTAW method
84%
Bylica A. , Dziedzic A.
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2008
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tom Vol. 8, iss. 3
25-28
EN
The work presents test results of microhardness of surface layer of HS 6-5-2 high-speed steel from areas overlapping remelting. The surface layer of the steel was remelted using the GTAW method. The microhardness was measured using the Vickers method. The work shows that the area, where the heat influence zone of the second remelting overlapping on the first remelting zone is characterizes by the microhardness lower about approx. 200 HV0,065.
5
Content available remote The remelting of the surface layer of C15 steel with an electric arc
84%
Adamiak S.
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2008
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tom Vol. 8, iss. 3
5-10
EN
This study presents results of a research on enhancing properties of the surface layer of C15 steel by treating it with a concentrated heat stream utilizing the GTAW method. Remelting of the surface layer of C15 steel was performed by a welding head moving with a constant speed of 200 mm/min and varying current intensity of the electric arc ranging from 50A to 300A as well as with a constant current intensity of the electric arc and a varying speed of the welding head ranging from 200 mm/min to 800 mm/min. Metallographic evaluations (LM and SEM) of the resulting structure were performed as well as measurement of the hardness of the remelted layers. Correlation between current intensity of the electric arc and its speed in relation to the treated material sample and the geometry of the remelted layers and their microhardness was established.
6
Content available remote Structure of carbon steels after remelting of the surface layer with the electric arc
84%
Adamiak S.
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2009
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tom Vol. 9, iss. 2
181-184
EN
This study presents results of a research on the enhancement of properties of the surface layer of carbon steels by treating it with a concentrated heat stream utilizing the GTAW method. Remelting of the surface layer of studied steels was performed by a welding head moving at a constant speed of 200 mm/min and varying current intensity of the electric arc ranging from 50A to 300A as well as with a constant current intensity of the electric arc and a varying speed of the welding head ranging from 200 mm/min to 800 mm/min. Metallographic evaluations (LM and SEM) of the resulting structure were performed. Correlation between the current intensity of the electric arc and its speed in relation to the treated material sample and the geometry of the remelted layers and their structure was established.
7
Content available remote Friction wear cast iron casting surface hardened by concentrated source of heat
84%
Orłowicz W. , Trytek A.
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2009
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tom Vol. 9, iss. 2
189-192
EN
In this study surface fusion by the GTAW (in argon atmosphere) surfacing process on plate of cast iron with electric arc advance speeds from 200 to 800 mm/min and current range I=300A were performed. The geometry, microstructure, hardness, friction wear intensity were measured. A stepwise regression method was used to develop relationships between the electric arc advance speed, parameters of fusion geometry, microhardness and friction wear intensity.
8
Content available remote Structural studies of partial meltings of casting surfaces made of cobalt alloy MAR-M509
84%
Opiekun Z. , Chruściel K.
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2009
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tom Vol. 9, iss. 2
197-200
EN
The results of structural studies of partial meltings of casting surfaces of plates made of cobalt alloy MAR-M509 have been presented. The partial meltings were formed with argon or helium plasma beam generated in electric arc. Observations of microstructure revealed presence of phase y and carbides. X-ray diffraction has shown phase y, carbide types MC and M23C6 and scanty amount of hexagonal phase [...].
9
Content available remote Microhardness and tribological wear of the steels remelted with an electric arc
67%
Adamiak S.
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2009
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tom Vol. 9, iss. 2
177-180
EN
This study presents results of a research on the surface strengthening of the C15, C45 and C90U steels by application of concentrated heat stream with the GTAW methodology. Utilizing the GTAW methodology remelting of the surface layer of the sampled steels was performed by a welding head moving at a speed ranging from 200 mm/min to 800 mm/min and the current intensity of the electric arc ranging from 50A to 300A. Measurements of hardness, frictional coefficient and intensity of tribological wear were performed in the remelted surface layer. Correlation between the intensity of the electric arc versus microhardness and tribological wear resistance under conditions of dry-friction was established. Following the treatment an increase in hardness as well as increase in the tribological wear resistance could be observed in steel samples. The best results were achieved during remelting of the surface layer with electric arc at 100A intensity and the speed of the welding head in relation to treated sample of 200 mm/min.
10
Content available remote Effect of the concentrated heat flow treatment on the structure and the antiwear properties of cast iron
67%
Orłowicz W. , Shevelya V. , Trytek A. , Kirilkov V.
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2009
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tom Vol. 9, iss. 2
185-188
EN
The influence of modes of surface fusion by electric arc plasma (GTAW method) on the hardness and wear-resistance of plain cast iron was studied. A possible mechanism of structural rearrangement in the processed material during the friction was analyzed. This mechanism is determined by specific behaviour of hardened martensitic structure under dynamic load. This martensitic structure forms a metal basis of cementite eutectic under conditions of fast crystallisation.
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