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EN
The microstructure and mechanical properties of hot-rolled Fe-9Mn-0.2C medium-manganese steels with different Al, Cu, and Ni contents were investigated in this study. Based on the SEM, XRD, and EBSD analysis results, the microstructure was composed of martensite, band-type delta ferrite, and retained austenite phases depending on the Al, Cu, and Ni additions. The tensile and Charpy impact test results showed that the sole addition of Al reduced significantly impact toughness by the presence of delta-ferrite and the decrease of austenite stability although it increased yield strength. However, the combined addition of Al and Cu or Ni provided the best combination of high yield strength and good impact toughness because of solid solution strengthening and increased austenite stability.
PL
W artykule zaprezentowano wyniki badań mikrostruktury, wybranych własności mechanicznych (twardość, odporność na pękanie w warunkach dynamicznych), użytkowych (odporność na ścieranie) i fizycznych (współczynnik rozszerzalności liniowej) próbek pobranych z dyfuzora kompresora silnika samolotu, wykonanego ze stali martenzytycznej odpornej na korozję. Postawowe wskaźniki własności mechanicznych stali, z której wykonano dyfuzor kompresora wynoszą: HRC = 48, KV = 15,7 J (dla przekroju 0,4 cm2), współczynnik tarcia w zakresie 0,38 ÷ 0,57 (zależnie od czasu trwania próby), średni współczynnik rozszerzalności liniowej 14,7 ∙ 10-6 K-1 (dla zakresu przed przemianą fazową) i 22,8 ∙ 10-6 K-1 (dla zakresu po przemianie). Mikrostrukturę elementu dyfuzora w stanie obrobionym cieplnie stanowi martenzyt odpuszczony. Obserwacje fraktograficzne wskazują na mieszany charakter przełomów próbek dyfuzora użytych do badań odporności na pękanie, tj. charakter quasi - kuchy z przewagą przełomu transkrystalicznego i pewnym udziałem przełomu międzykrystalicznego.
EN
The results of microstructural studies, mechanical examinations (hardness, impact toughness), utility (resistance to wear) as well as physical (coefficient of linear thermal expansion) properties of samples taken from jet engine diffuser are presented in this paper. The diffuser was made of martensitic corrosion resistant steel. The steel is characterised by the following mechanical and physical parameters: HRC = 48, KV = 15.7 J (for cross-section of 0.4 cm2), friction coefficient 0.38 - 0.57 (depending of a test duration), average coefficient of linear thermal expansion 14.7 · 10-6 K-1and 22.8 · 10-6 K-1 for temperatures below and above phase transformation, respectively. The microstructure of the heat treated part consists of a tempered martensite. Fractographic studies has proved that a fracture of the specimen has a mixed, quasi-brittle character where transcrystalline fracture dominates over intercrystalline one.
PL
Inżynierskie kompozyty cementowe [IKC] n z dodatkiem włókien należą do grupy wysokowartościowych fibrokompozytów. Zawierają one drobnoziarniste składniki: cement, drobny piasek i popiół lotny, natomiast nie zawierają kruszywa grubego. Zawartość cementu w typowym inżynierskim kompozycie cementowym wynosi około 1000 kg/m3, co sprawia, że jest to materiał niezgodny z koncepcją zrównoważonego rozwoju. Popiół lotny w mieszankach IKC poprawia właściwości mechaniczne i trwałość, a optymalna ilość popiołu zastępującego cement mieści się w granicach od 30% do 40%. W przeprowadzonych badaniach podjęto próbę dodania do IKC granulowanego żużla wielkopiecowego zastępującego cement, wraz z popiołem lotnym. Przygotowano pięć mieszanek, jedną kontrolną i cztery o różnej zawartości żużla od 10% do 50%, w odstępach co 10%. Zawartość granulowanego żużla wielkopiecowego w takiej zaprawie ma korzystny wpływ na właściwości mechaniczne oraz odporność na udar.
EN
Engineered Cementitious Composites are belonging to the ultrahigh performance fiber reinforced composites. Engineered Cementitious Composites are composed of fine grained ingredients like cement, fine sand, fly ash, but don’t coarse aggregate. Presence of cement in the typical Engineered Cementitious Composites mix is nearly 1000 kilograms per cubic meter, which make this material to keep far from the sustainability. The content of fly ash in the mix improves the performance of mechanical properties and durability, however, the percentage of replacement of cement has the optimum up to 30 to 40 %. In this study, an attempt is made to add granulated blast furnace slag to Engineered Cementitious Composites mix replacing the cement, along with fly ash. Five different mix proportions are used in this investigation, from 10%, to 50%, at 10% intervals of the granulated blastfurnace slag, replacing cement. The content of granulated blast-furnace slag exhibit remarkable achievement in the mechanical parameters and impact toughness.
EN
Weld metal deposit (WMD) was carried out for standard MMA welding process. This welding method is still promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (self-tempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with good impact toughness of welds at low temperature. Separate effect of these elements on the mechanical properties of welds is well known, but the combined effect of these alloy additions has not been analyzed so far. It was decided to check the total influence of nickel with a content between 1% to 3% and molybdenum with content from 0.1% up to 0.5%.
EN
The paper offers mathematical equations of the influence of micro-jet cooling on structure and impact toughness properties of metal weld deposit. Weld metal deposit (WMD) was carried out for standard MIG welding and for MIG welding with micro-jet cooling. This new method is very promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (selftempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with very good mechanical properties ie. good impact toughness of welds at low temperature. Micro-jet cooling after welding can find serious application in automotive industry very soon. Until that moment only argon, helium, nitrogen and gas mixtures of argon were tested for micro-jet cooling after welding. The best results of mechanical properties of WMD in presented welding method correspond with micro-jet argon cooling.
EN
The paper describes influence of rare earth metals (REMs) on G20Mn5 cast steel microstructure and mechanical properties. The cerium mixture of the following composition was used to modify cast steel: 49.8% Ce, 21.8% La, 17.1% Nd, 5,5% Pr and 5.35% of REMs. Cast steel was melted in industrial conditions. Two melts of non-modified and modified cast steel were made. Test ingots were subject to heat treatment by hardening (920°C/water) and tempering (720°C/air). Heat treatment processes were also performed in industrial conditions. After cutting flashes off samples of cast steel were collected with purpose to analyze chemical composition, a tensile test and impact toughness tests were conducted and microstructure was subject to observations. Modification with use of mischmetal did not cause significant changes in cast steel tensile strength and yield strength, while higher values were detected for fractures in the Charpy impact test, as they were twice as high as values for the data included in the PN-EN 10213:2008 standard. Observations performed by means of light and scanning microscopy proved occurrence of significant differences in grain dimensions and morphology of non-metallic inclusions. Adding REMs resulted in grain fragmentation and transformed inclusion shapes to rounded ones. Chemical composition analyses indicated that round inclusions in modified cast steel were generally oxysulphides containing cerium and lanthanum. In the paper the author proved positive influence of modification on G20Mn5 cast steel mechanical properties.
PL
W artykule przedstawiono nową technologię spawania stalowych konstrukcji z wykorzystaniem chłodzenia mikrojetowego. Podwyż- szono własności użytkowe spawanych konstrukcji, w tym udarność złączy spawanych w ujemnej temperaturze. Istotną zaletą spawalniczego procesu z chłodzeniem mikrojetowym jest zmniejszenie spawalniczych naprężeń cieplnych w przestrzennych konstrukcjach stalowych i pomniejszenie w nich strzałki ugięcia.
EN
A new technology of steel structures welding using microjet cooling has been presented. The usability of welded structures has increased, including the impact toughness of welded joints at negative temperatures. An important advantage of the micro-jet cooling process is the reduction of welding stresses in spatial steel structures and the reduction of their deflection.
EN
The material selected for this investigation was low alloy weld metal deposit after MAG welding with micro-jet cooling. The present investigation was aimed as the following tasks: obtained WMD with various amount of acicular ferrite in WMD in terms of helium percentage in micro-jet gas mixture. Paper focuses on low alloy steel weld properties after innovate welding method with micro-jet cooling. Weld metal deposit (WMD) for micrograph analyses and impact toughness was carried out for MAG. Until that moment only argon, helium and nitrogen were seriously tested as micro-jet gases. In that paper various gas mixtures (Ar-He) were tested for micro-jet cooling after welding. The influence of oxygen and nitrogen included in gas mixtures based on Ar-He couple on properties of WMD was also tested.
PL
Materiałem wybranym do tego badania było stopiwo uzyskane po spawaniu niestopowej stali procesem MAG z chłodzeniem mikro-jetowym. Badanie miało na celu: otrzymanie stopiwa z różną ilością drobnoziarnistego ferrytu (acicular ferrite) w zależności od zawartości helu w mieszance z argonem stosowanej do schładzania mikro-jetowego. W artykule skoncentrowano się na właściwościach złącza ze stali niestopowej po wprowadzeniu innowacyjnej metody spawania z wykorzystaniem chłodzenia mikro-jetowego. Stopiwo do badań mikrostruktury i udarności było uzyskane po spawaniu procesem MAG. Do tej pory do schładzania mikro-jetowego były dokładnie testowane tylko takie gazy jak argon, hel i azot. W tym artykule badano różne mieszanki gazowe (Ar-He) jako gazy mikro-jetowe. Na własności stopiwa badano również dodatkowy wpływ tlenu i azotu zawartego w mieszankach gazowych opartych na Ar-He.
EN
The paper focuses on low alloy steel after innovate welding method with micro-jet cooling. Weld metal deposit (WMD) was carried out for welding and for MIG and MAG welding with micro-jet cooling. This method is very promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (self-tempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with very good mechanical properties, ie. high impact toughness of welds at low temperature. Micro-jet cooling after welding can find serious application in automotive industry very soon. Until that moment only argon, helium and nitrogen were tested as micro-jet gases. In that paper first time various gas mixtures (gas mixtures Ar-CO2) were tested for micro-jet cooling after welding.
10
Content available Impact Toughness of Steel WMD after TIG Welding
EN
The material selected for this investigation was low alloy weld metal deposit after TIG welding with various amount of oxygen in weld metal deposit (WMD). After TIG process it is difficult to get proper amount of oxygen in WMD on the level much lower than 350 ppm. The highest impact toughness of low alloy WMD corresponds with the amount of oxygen in WMD above 350 ppm. In the paper focuses on low alloy steel after innovate welding method with micro-jet cooling that could be treated as a chance on rising amount of oxygen in weld. Weld metal deposit (WMD) was carried out for TIG welding with micro-jet cooling with various amount of oxygen in WMD. In that paper various gas mixtures (gas mixtures Ar-O2 and Ar-CO2) were tested for micro-jet cooling after TIG welding. An important role in the interpretation of the results can give methods of artificial intelligence.
EN
This study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-β grain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment, α and β phase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.
EN
The present work, presented the study of effect of different inoculants on impact toughness in High Chromium Cast Iron. The molds were pouring in industrial conditions and samples were tested in laboratory in Faculty of Foundry Engineering at AGH. Seven samples were tested - one reference sample, three with different addition of Fe-Ti, and three with different addition of Al. The samples were subjected to impact toughness on Charpy hammer and the hardness test. The presented investigations indicate that for the each inoculant there is an optimal addition at which the sample obtained the highest value of impact toughness. For the Fe-Ti it is 0.66% and for Al is 0.17%. Of all the examined inoculants best results were obtained at a dose of 0.66% Fe-Ti. Titanium is a well-known as a good modifier but very interesting results gives the aluminum. Comparing the results obtained for the Fe-Ti and Al can be seen that in the case of aluminum hardness is more stable. The hardness of all samples is around 40-45 HRC, which is not high for this type of cast iron. Therefore, in future studies it is planned to carry out the heat treatment procedure that may improves hardness.
EN
The material selected for this investigation was low alloy steel weld metal deposit (WMD) after MIG welding with micro-jet cooling. The present investigation w*as aimed as the following tasks: obtained WMD with various amount of acicular ferrite and further analyze impact toughness of WMD in terms of acicular ferrite amount in it. Weld metal deposit (WMD) was first time carried out for MIG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen were tested as micro-jet gases for MIG/MAG processes. An important role in the interpretation of the results can give methods of artificial intelligence.
EN
Low carbon steel weld structures generally exhibit a very linear stress-strain relationship. In the study of strength of materials, the compressive strength is the capacity of a material or structure to withstand loads tending to reduce size of structure. It is mainly measured by plotting applied force against deformation in a testing machine. Compressive strength is a main key value for design of welded structures.The main goal of that paper was analysing of plastic properties of frame welds which were made with various parameters of micro-jet cooling. New technology of micro-jet welding could be regarded as a new way to improve plastic properties of welds. It allows to obtain welds with better mechanical properties in comparison to ordinary welding method. Furthermore it is possible to steering of weld structure and properties of the weld. There were given main information about influence of various micro-jet gases on metallographic and properties of structure steel welds.
15
EN
The material selected for this investigation was low alloy steel weld metal deposit (WMD) after MAG welding with micro-jet cooling. The present investigation was aimed as the following tasks: analyze impact toughness of WMD in terms of micro-jet cooling parameters. Weld metal deposit (WMD) was first time carried out for MAG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen and its gas mixture were tested for micro-jet cooling.
EN
An attempt is made to establish empirical relationships to predict the properties of friction stir welded stainless steel joints. The process parameters namely, rotational speed, welding speed and shoulder diameter and the properties such as tensile strength, notch tensile strength, impact toughness and degree of sensitization are considered. The investigated properties are correlated with the macrostructure and microstructural characteristics of different zones of FSW joints to understand the influence of process parameters. Multi-criteria optimization is used to obtain optimum welding conditions that can yield enhanced properties of FSW joints. The optimized results indicated that, the properties can be enhanced with the use of rotational speed of 441 rpm, welding speed of 118 mm/min, and shoulder diameter of 17.5 mm. This is mainly due to very fine stir zone grain structure in the order of 5.5 μm and the presence of thin layer of banded structure at the advancing side of fabricated joints under optimum parameters.
EN
By example of steel 17G1S, the regularities in the impact fracture of Charpy specimens at normal and low temperatures are described. The relationship between the energy parameters of fracture (impact toughness) and the deformation response of the material (the height of shear lips) of the specimens from the pipe steel is established. The micromechanisms of impact fracture of the material are described. At 20 °C and –30 °C, focal splitting of the material was observed on the fracture surface of specimens; at –60 °C, the material failed in a brittle manner by the mechanism of cleavage.
18
Content available remote CrMoV steel welding in the narrow gap using of SAW technology
EN
Purpose: of this paper is the verification of multi-layer SAW welding the raw material “1.6946” by different welding consumables (TOPCORE 838 B, Thermatit MTS 616) in the „ultra” narrow gap using the prescribed temperature cycle and subsequent heat treatment. Design/methodology/approach: An evaluation of the mechanical properties of the test for both types welding consumables. The measured values of yield strength and the tensile strength exhibit comparable properties to the RAW material “Inspection Certificate” for welding consumable “TOPCORE 838 B”. Findings: Thermatit MTS 616” was found falling below the specified values of impact energy, ductility. The welding consumable TOPCORE 838 B shows less susceptibility to the brittleness. Based on the results will be verified by the existence of internal structures arising using the microstructure analysis & ARA diagram of the base material 1.6496. Research limitations/implications: Obtained results will be subsequently verified the existence of internal generated microstructures using the ARA chart of the base material (W Nr. 1.6496) for the future design of the new temperature cycles in all phases of the production. Originality/value: The welding consumable “TOPCORE 838 B” showed the low tendency to embrittlement in the heat-affected zone using the defined heat treatment. On the basic of the examination the welding consumable “TOPCORE 838 B” can be recommended to be used for the welding process, thermal cycle and heat treatment.
PL
W artykule zamieszczono wyniki badań wpływu szybkości chłodzenia stopu Ti6Al4V z zakresu jednofazowego [beta] na jego mikrostrukturę, twardość i udarność. Wykazano, że ze zmniejszeniem szybkości chłodzenia od 23,1 do 0,012 [stopni]C/s, twardość próbek stopu maleje od 334 do 286 jednostek Vickersa, natomiast udarność wzrasta, osiągając 37 J - dla najwolniejszej szybkości chłodzenia - 0,012 [stopni]C/s. Wyniki badań uzyskane w próbie udarności uzupełniono dokumentacją fraktograficzną przełomów. Cechy charakterystyczne przełomów próbek udarnościowych nie wykazują istotnych różnic w zależności od warunków chłodzenia i twardości materiału.
EN
The assessment of a cooling rate on the structure, hardness and impact toughness of a Ti6Al4V alloy cooled from the single phase ([beta]) range was presented in the paper. Samples cooled from 1020 [degrees]C at cooling rate of 23.1 [degrees]C/s and 0.012 [degrees]C/s are characterized by the Vickers hardness 334 HV and 286 HV respectively. Impact toughness increases with reduced cooling rate achieving 37 J for 0.012 [degrees]C/s. Fracture surface observations were also performed for tested samples. However, any noticeable effect of cooling conditions on the fracture features were found.
EN
Structure, safety and exploitation conditions of welding steel in car body depend on many factors. The main role of that conditions is connected with car body material, welding technology, state of stress and temperature. Because of that, a good selection of steel and welding method is very important for proper steel structure. Low alloy steel is used for car body structure, very often with small amount of carbon and the amount of alloy elements such as Ni, Mn, Mo, Cr and V in car body and welded joints. Depending on the kind of steel which is used, a proper welding method and adequate filler materials should be applied. The present paper describes the influence of Mn, Ni, Mo, Cr, V in WMD (Weld Metal Deposit) on the behaviour of steel structure especially for low temperature service.
PL
Struktura, bezpieczeństwo i warunki spawania stali karoserii samochodowych są zależne od wielu czynników. Główną rolę odgrywają warunki związane z materiałem, metodą spawania, stanem naprężenia oraz temperaturą. Jednakże za najistotniejszy czynnik uważany jest odpowiedni dobór metody spawania. Do konstrukcji karoserii używana jest stal niskostopowa, bardzo często z małą ilością węgla i pierwiastków stopowych, takich jak Ni, Mn, Mo, ??Cr i V. W zależności od rodzaju stali należy użyć właściwej metody spawania oraz odpowiednich materiałów dodatkowych. W niniejszej pracy przedstawiono wyniki badań wpływu Mn, Ni, Mo, Cr, V w stopiwie (WMD) na zachowanie konstrukcji stalowej szczególnie podczas niskich temperatur pracy.
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