Microstructure and microhardness of Ti6Al4V alloy treated by GTAW SiC alloying

In this work, the change of the structure and microhardness of Ti6Al4V titanium alloy after remelting and remelting with SiC alloing by electric arc welding (GTAW method) was studied. The current intensity equal 100 A and fixed scan speed rate equal 0,2 m/min has been used to remelting surface of the alloy. Change of structure were investigated by optical and scanning electron microscopy. Microhardness test showed, that the remelting of the surface does not change the hardness of the alloy. Treated by GTAW SiC alloying leads to the formation of hard (570 HV0,1) surface layer with a thickness of 2 mm. The resulting surface layer is characterized by diverse morphology alloyed zone. The fracture of alloy after conventional heat treatment, similarly to fracture after remelting with GTAW is characterized by extremely fine dimples of plastic deformation. In the alloyed specimens the intergranular and crystalline fracture was identified

The Quality of Welded Connections Elements from the Steel 30HGS and Titanium Alloy Ti6Al4V

The aim of that work was the evaluation of the quality of welded connections elements (welds) from the 30HGS steel and titanium alloy Ti6Al4V. The metallographic, factographic tests were used, and measurements of microhardness with the Vickers method. In the head weld of the 30HGS steel there were non-metallic partial division and bubbles observed. The average microhardness in the head connection was 320 HV0.1. There was no significant increase/decrease observed of microhardness in the head influence zone of the weld. There was a good condition of head connections observed, in accordance with the standard EN12517 and EN25817. In the head weld of Ti6Al4V titanium alloy there were single, occasional non-metallic interjections and bubbles observed. There were no cracks both on the weld, and on the border of the heat influence zone. The value of microhardness in head connection was in the range 300÷445 HV0.1. Reveal a very good condition of the head connections in accordance with the standard EN12517 and EN25817. The factographic tests prove the correctness of welded connections done and then heat treatment in case of steel and titanium alloy

Characterization Of Oxide Layers Produced On The AISI 321 Stainless Steel After Annealing

In this study, the structure, chemical composition and topography of oxide layers produced on the surface of the AISI 321 austenitic steel in the annealing process were analyzed. Heat treatment was done at 980°C temperature for 1 hour time in different conditions. The annealing was done in a ceramic furnace in oxidation atmosphere and in vacuum furnaces with cylindrical molybdenum and graphite chambers. The analysis was carried out using the following methods: a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDX), a transmission electron microscope (TEM) equipped with an energy-dispersive X-ray spectrometer (EDX), an X-ray diffractometer (XRD), a secondary ion mass spectrometer with time-of-flight mass analyzer (TOF SIMS) and an atomic force microscope (AFM). The oxide layer formed during annealing of the AISI 321 steel at 980°C consisted of sub-layers, diversified in the chemical composition. The thickness of the oxidized layer is depended on the annealing conditions. In a ceramic furnace in oxidation atmosphere, the thickness of the oxide layer was of 300-500 nm, in a vacuum furnace with molybdenum and graphite heating chambers, it ranged from 40 to 300 nm and from a few to 50 nm, respectively. TOF SIMS method allows to get average (for the surface of 100 μm × 100 μm) depth profiles of concentration of particular elements and elements combined with oxygen. In oxide layers formed in vacuum furnaces there are no iron oxides. Titanium, apart from being bounded with carbon in carbides, is a component of the oxide layer formed on the surface of the AISI 321 steel

Charakterystyka warstw tlenkowych powstałych na stali nierdzewnej AISI 321 po wyżarzaniu

In this study, the structure, chemical composition and topography of oxide layers produced on the surface of the AISI 321 austenitic steel in the annealing process were analyzed. Heat treatment was done at 980°C temperature for 1 hour time in different conditions. The annealing was done in a ceramic furnace in oxidation atmosphere and in vacuum furnaces with cylindrical molybdenum and graphite chambers. The analysis was carried out using the following methods: a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDX), a transmission electron microscope (TEM) equipped with an energy-dispersive X-ray spectrometer (EDX), an X-ray diffractometer (XRD), a secondary ion mass spectrometer with time-of-flight mass analyzer (TOF SIMS) and an atomic force microscope (AFM). The oxide layer formed during annealing of the AISI 321 steel at 980°C consisted of sub-layers, diversified in the chemical composition. The thickness of the oxidized layer is depended on the annealing conditions. In a ceramic furnace in oxidation atmosphere, the thickness of the oxide layer was of 300-500 nm, in a vacuum furnace with molybdenum and graphite heating chambers, it ranged from 40 to 300 nm and from a few to 50 nm, respectively. TOF SIMS method allows to get average (for the surface of 100 μm × 100 μm) depth profiles of concentration of particular elements and elements combined with oxygen. In oxide layers formed in vacuum furnaces there are no iron oxides. Titanium, apart from being bounded with carbon in carbides, is a component of the oxide layer formed on the surface of the AISI 321 steel.W pracy analizowano strukturę, skład chemiczny oraz topografię warstwy tlenków powstałych na powierzchni stali austenitycznej AISI 321 w procesie wyżarzania. Obróbkę cieplną prowadzono w temperaturze 980°C w czasie 1 godziny w zróżnicowanych warunkach. Wyżarzanie prowadzono w piecu ceramicznym w atmosferze powietrza oraz w piecach próżniowych z cylindryczną komorą molibdenową i grafitową. W prowadzonej analizie wykorzystano skaningowy mikroskop elektronowy (SEM) wyposażony w spektrometr promieniowania X (EDX), transmisyjny mikroskop elektronowy (TEM) wyposażony w spektrometr promieniowania X (EDX), dyfraktometr rentgenowski (XRD X-Ray Diffraction), spektrometr mas jonów wtórnych z analizatorem czasu przelotu (TOF SIMS) oraz mikroskop sił atomowych (AFM). Warstwa tlenków powstała w wyniku wyżarzania stali AISI 321 w temperaturze 980°C składała się z podwarstw różniących się składem chemicznym. O grubości warstwy utlenionej w decydowały warunki wyżarzania. W piecu ceramicznym z atmosferą powietrza grubość warstwy tlenków wynosiła 300-500 μm, w piecu próżniowym z grafitową i molibdenową komorą grzejną grubości wynosiły odpowiednio od 40 nm do 300 nm oraz kilka nm do 50 nm. Badania TOF SIMS pozwalają otrzymać uśrednione profile koncentracji pierwiastków metalicznych oraz profile koncentracji pierwiastków metalicznych będących w kontakcie z tlenem. W warstwach tlenków powstałych w piecach próżniowych nie obserwowano tlenków żelaza. Tytan oprócz roli związania węgla w węglikach, wchodzi w skład warstwy tlenków tworzonych w piecu próżniowym na powierzchni stali AISI 321

Structure of X5CrNi18-10 and S355NL Steels after Remelting with the Electric Arc

The work presents the results of the research and tests of the surface machining of the S355NL and X5CrNi18-10 steels with the concentraded stream of heat with the usage of the GTAW method. The surface layers of the tested steels were remelted with the electric arc using the current of the electric arc 50, 100, 150 and 200A.The machining was done in the atmosphere of argon with the constant speed of the welding head. A microscope examination was performed of the obtained structure and measurements of depth, width and hardness of the received surface layer were performed. Moreover the relation between the current of the electric arc and geometry of the remelted layers with their microhardeness was examined