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EN
This study concerns the wear behaviour of metal couples used in industry, particularly in mechanical sliding systems (numerically controlled machine tools). In general, the nature of the materials of the parts of these systems which are in contact and move relatively, are medium carbon steels, thanks to their good mechanical and tribological properties. The present work aims to study, the dry sliding wear of the contact surface of the pin (machine slide) against the contact surface of a disc (machine groove) and the damage induced on the worn track. The pin is AISI 1038 and AISI 1045 steel, the disc is AISI 1055 steel. The tribological tests were carried out on a pin-disc tribometer, in an atmospheric environment. The wear of the pins being evaluated by weighing and studied according to the hardness of the pin with the variation of the normal load applied. The discussion of the results is based on SEM observations and EDS analyzes of worn surfaces and interfacial phenomena produced by dynamic contact. The results obtained indicated the influence of the applied load and the hardness on the wear of the pin and therefore on the tribological behaviour of the worn surfaces.
EN
The application of hardfacing is one of the ways to restore the functional properties of worn elements. The possibility of using filler materials rich in chrome allows for better wear resistance than base materials used so far. The paper presents the results of research on the use of 3 different grades of covered electrodes for the regeneration of worn track staves. The content of the carbon in the covered electrodes was from 0,5% to 7% and the chromium from 5% to 33%. The microscopic and hardness tests revealed large differences in the structure and properties of the welds. The differences in the hardness of the welds between the materials used were up to 150 HV units. The difference in wear resistance, in the ASTM G65 test, between the best and worst materials was almost 12 times big.
EN
The paper presents the problem which concerning the technology of bimetallic castings in materials configuration: high-chromium steel as the working layer and grey cast iron as the base part. The aim of the studies was integrate the process of manufacturing of bimetallic casting with the heat treatment of hardening type of X46Cr13 steel insert by applying the mould with sandmix on a matrix of chromite sand. Range of studies included the chemical composition analysis, non-destructive ultrasonic tests to examine the quality of the permanent bond between the working layer (steel insert) and the base part (grey cast iron) of the bimetallic castings, hardness measurements as well as metallographic examinations performed on the optical and scanning electron microscopes. On the basis of obtained results was concluded that the self-hardening process occurred in the X46Cr13 steel working layer and in result of this the hardness on its surface equalled approx. 45HRC in case of the bimetallic castings with full permanent bond between both parts.
EN
This paper investigates the influence of 1%, 2% and 3% zirconia (ZrO2) nanoparticles to the melting, microstructural and mechanical properties of the Sn58Bi solder. Melting temperatures of 145.11°C, 140.89°C and 143.84°C were attained correspondingly for the 1%, 2% and 3% ZrO2 reinforced Sn58Bi solder. The microstructures especially the spacing between the lamellar structures of the Sn58Bi solder alloy was narrower for 1% ZrO2 added with Sn58Bi solder alloy. The highest and lowest hardness value of 32.28 HV and 27.62 HV was recorded for 1% and 2% ZrO2 additions respectively. Highest shear strength value was noted for the 3% ZrO2 added SnBi/Copper joint with 0.8712 kN, while the lowest value of 0.4380 kN noted for the 1% ZrO2 added SnBi/Copper joint. The presence of small-sized ZrO2 nanoparticles can be seen to be properly dispersed at the solder joint to increase the shear load at maximum joint stress.
EN
The article presents an analysis of the Cold Metal Transfer (CMT) method, including the process, advantages and application of the method. The joints made with low energy CMT method and classic MAG method were also compared. The paper presents the results of non-destructive penetrant tests of welded joints made of steel in the S235JR grade. Microscopic observations were made using optical microscopy and the hardness was measured in accordance with PN-EN ISO 6507-1:2007. The test results confirmed that the CMT process allows for the production of high-quality joints and a narrow heat-affected zone compared to the classic MAG welding method, and also provides good mechanical properties and elimination of spatter.
PL
W artykule scharakteryzowano metodę spawania MAG w odmianie Cold Metal Transfer (CMT), uwzględniając proces technologiczny, zalety i przydatność technologiczną, a także porównano złącza wykonane niskoenergetyczną metodą CMToraz klasyczną metodą MAG. W pracy przedstawiono wyniki nieniszczących badań penetracyjnych złączy spawanych wykonanych ze stali gatunku S235JR. Przeprowadzono obserwacje mikroskopowe za pomocą mikroskopu optycznego oraz wykonano pomiar twardości zgodnie z PN-EN ISO 6507-1:2007. Wyniki badań potwierdziły, że proces CMT pozwala na wytworzenie złączy o wysokiej jakości i wąskiej strefie wpływu ciepła w porównaniu do klasycznej metody spawania MAG, a także zapewnia dobre właściwości mechaniczne i eliminację rozprysku.
EN
The article analysis the effect of exposure to ultraviolet light on the hardening process of the model made in the SLA technology. Research samples were created with the SLA additive technique using a 10s exposure time. In this experiment, the change in item hardness and density over a 96-hour period was analysed. Light exposure time for details of an item made in SLA technology results in an increase in hardness. At the same time are observed, changes in density and stabilization of both parameters with increasing exposure time to UV light.
EN
The use of cast aluminium has still increased, so have the mechanical property requirements. By casting and also in other metallurgical processes, the inclusions enter to the molten aluminium alloy and it exhibits poor ductility or toughness. It can cause a variety of problems in the manufacture of aluminium alloy castings. Therefore, the purification of the molten aluminium alloy is one of the most important processes for improving the quality of Al-products. Filters have been used for many years in order to improve the quality of castings. The inclusions in molten secondary AlSi7Mg0.3 cast were removed using depth filtration by ceramic foam filters of 20 ppi porosity. Were used 4 types of ceramic filters in 2 thicknesses (15 and 22 mm); Brinell hardness and porosity were measured. Quality of microstructure (occurrence of oxidic particles and larger non-metallic inclusions) was observed. Experimental results show that the insertion of ceramic filters into the inlet system has contributed primarily to a decrease in porosity. On the microstructure, the inclusion of filters was not significantly reflected.
EN
The subject of the research presented in this article are viscoelastic polyurethane foams (VPF) made using a fillers from coffee grounds. The foams were made with varying content of coffee fillers. Foams and fillers were characterized by means of techniques such as infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and cone calorimeter. The changes in the microstructure of the foams were analyzed using a scanning electron microscope. Foam properties in the compression test was assessed. As a result, it was concluded that the use filler from coffee grounds causes a significant reduction in compression set of foams after compression by 75% and by 90% of the height of the samples. It was shown that these changes are caused by changes in the chemical structure of the macromolecules of these foams but also in their structure. After addition the filler, all foams have permanent deformations with a value below the permissible limit of 10%. Addition of 20% by mass of filler caused by a decrease in the rate of heat release and the rate of smoke release during foam combustion.
PL
Przedstawiono wyniki badań lepkosprężystych pianek poliuretanowych (VPF) wytworzonych z dodatkiem różnych ilości fusów kawy. Pianki i napełniacz scharakteryzowano z zastosowaniem spektroskopii w podczerwieni, analizy termograwimetrycznej, różnicowej kalorymetrii skaningowej i kalorymetru stożkowego. Zmiany w strukturze pianek obserwowano metodą skaningowej mikroskopii elektronowej. Oceniono właściwości pianek w próbie ściskania. Stwierdzono, że napełniacz w postaci fusów kawy powoduje zmniejszenie odkształcenia trwałego pianek w próbie ściskania o 75% i zmniejszenie o 90% wysokości próbek, co jest wynikiem zmian w budowie makrocząsteczek pianek i w ich strukturze. Wprowadzenie 20% mas. napełniacza spowodowało zmniejszenie szybkości wydzielania ciepła i dymu w trakcie spalania pianek.
EN
This article describes the growth and characterization of 4-sulfobenzenaminium potassium hydrogen phosphate (SPH) sulphanilic acid with potassium dihydrogen phosphate (KDP) doped semi-organic single crystals. The crystal was grown by the slow evaporation method. Examination of the crystalline nature of the sample was carried out by single crystal X-ray diffraction and it confirmed that the sample crystallizes in orthorhombic structure in the centrosymmetric space group P212121. The optical transmittance behavior was tested by UV-Vis spectral analysis. FT-IR spectral investigations have been carried out to indicate the presence of functional groups. The chemical structure of the compound was established by 1H and 13C NMR spectra. The SHG efficiency of the powdered SPH crystal is around 1.7 times that of pure KDP. The grown crystal was stable up to 270 °C as observed from TGA and DTA curves. The microhardness test was carried out to study the load dependency of hardness. The result of this study indicates that SPH crystal is a malleable material. From the hardness values, the stiffness constant and yield strength were calculated. The dielectric response of the novel crystal was studied in the frequency range of 50 Hz to 5 MHz at various temperatures. By employing FE-SEM, the surface morphology and the particle size of the crystal were assessed.
EN
This paper presents a new welding quality evaluation approach depending on the analysis by the fuzzy logic and controlling the process capability of the friction stir welding of pipes (FSWoP). This technique has been applied in an experimental work developed by alternating the FSW of pipes process major parameters: rotation speed, pipe wall thickness and travel speed. variable samples were friction stir welded of pipes using from 485 to 1800 rpm, 4–10 mm/min and 2–4 mm for the rotation speed, the travel speed, and the pipe wall thickness respectively. DMAIC methodology (Defining, Measuring, Analyzing, Improving, Control) has been used as an approach to analyze the FSW of pipes, it depends on the attachment potency and technical commonplace demand of the FSW of pipes process. The analysis controlled the Al 6061 friction stir welded joints’ tensile strength. To obtain the best tensile strength, the study determined the optimum values for the parameters from the corresponding range.
EN
The paper presented research results of the impact of short-term overheating of samples collected from the outer bearing ring suitable for the operation at elevated temperature installed in the turbine engine on the microstructure and hardness of the material. The samples were annealed at the following temperatures: 500, 600, 700, 800, 900 and 1000°C; and then cooled in still air. Microstructure examinations were conducted under metallographic microscope and transmission electron microscope.
PL
W publikacji przedstawiono wyniki badań wpływu krótkotrwałego nagrzewania próbek pobranych z pierścienia zewnętrznego łożyska przeznaczonego do pracy w podwyższonej temperaturze z silnika turbinowego na mikrostrukturę oraz twardość jego materiału. Próbki wygrzewano w temperaturach: 500, 600, 700, 800, 900 i 1000°C, następnie studzono na spokojnym powietrzu. Badania mikrostruktury przeprowadzono, wykorzystując mikroskop metalograficzny oraz transmisyjny mikroskop elektronowy.
EN
The aim of this work was to study the impact of various fabrication methods used to prepare high entropy alloys based on the AlFeMnNbNiTi system. Chemical composition was customized to ensure a solid solution structure with precipitation of the Laves phase. The three manufactured alloys were prepared by melting, but with the use of various input materials and different furnaces in protective atmospheres. After the melting process, heat treatment was carried out. Structures of obtained materials were analyzed by means of a Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) mapping. Mechanical properties were represented by Vickers hardness. In this paper, impact of the use of low purity input materials is shown, as well as differences in structure resulting from the utilization of different melting furnaces.
EN
Purpose: This research examined the effects of artificial-aging temperature and time on tensile strength, hardness, microstructure, and fault morphology in AlSiMg. Design/methodology/approach: This research was conducted using aluminium alloy at 120°C, 150°C, and 180°C artificial-aging temperature and 6 hours holding time. The tensile test used ASTM B211-03 standard and hardness test adapted to ALCOA 6061 standard. Findings: Tensile test results indicated the highest tenacity on aluminium alloy at a 150ºC temperature that was 47.263% strain level. In addition to the strain level, this research also obtained the highest tensile strength level at 180ºC that was 62.267 kgf/mm2 and the highest hardness value that was 110 HV. The increase in tensile strength and hardness at 180°C was caused by the increase in Mg, Si, and Al. Based on the microstructure test, the highest tenacity was obtained at 150°C temperature as the result of closed and gathered Mg2Si precipitates; while at 180°C temperature, the precipitates appeared to be more distributed, causing a rise in hardness value and tensile strength. AlSiMg tenacity also exhibited from the number of dimples compared to cleavages at 150°C temperature. Research limitations/implications: The limitation that found in this research was conducted using AlSiMg aluminium Al6061 specimen with an artificial-aging treatment at 120ºC, 150°C, and 180°C temperature for 6 hours and then compared to the raw material. AlSiMg tensile specimen was made according to ASTM E8-E8M standard. Practical implications: This research can be applied in industrial manufacture process to find tensile strength, hardness, microstructure, and fault morphology of Al6061 alloy. Originality/value: According to research result, can be understood that by conducting these experiments, Artificial-aging treatment temperature variations in AlSiMg aluminium alloy could increase hardness.
PL
W pracy badano możliwość zastosowania azotu technicznego do aktywacji powierzchni stali stopowych z dużą zawartością chromu, zwłaszcza stali nierdzewnej X20Cr13, w procesach azotowania i węgloazotowania. Badano twardość i mikrostrukturę azotowanych i węgloazotowanych warstw. Stwierdzono możliwość zastosowania azotu technicznego zawierającego ok. 0,2%O2 do aktywacji powierzchni stali nierdzewnej X20Cr13 w procesach azotowania i węgloazotowania oraz ustalono warunki aktywacji dla badanych stali stopowych.
EN
In the present work technical nitrogen application for surface activation of alloyed steels with chrome, particularly stainless steel X20Cr13 during nitriding and carbonitriding was investigated .Hardness and microstructure of nitrided layers were examined. Possibility of using technical nitrogen containing 0,2%O2 for surface activation of X20Cr13 stainless steel was confirmed and activation conditions for investigated alloyed steels were determined.
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.
EN
The presented publication discusses the test results regarding samples of a prosthetic alloy from the Co-Cr-Mo system. The test samples were obtained by means of two different methods applied in prosthetics laboratories to compare their properties and microstructure. To obtain the samples via the traditional lost wax casting method, the cast alloy Co-Cr-Mo was used, commercially known as Wironit LA. In the case of the modern technique DMLS (Direct Metal Laser Sintering), metallic powder Co-Cr-Mo, called EOS Cobalt Chrome MP1, was used. The samples of both Co-Cr-Mo alloys obtained via the two methods were prepared for metallographic tests; they also underwent microstructural observations with the use of light microscopy (LM) and scanning electron microscopy (SEM), and next they were subjected to hardness tests. The obtained samples demonstrated a dendritic structure. In the samples cast with the lost wax casting method, a segregation of the chemical composition was revealed. The samples obtained by means of the DLMS method were characterized by chemical composition homogeneity. The hardness measurements with the statistical analysis of the measurement results showed a difference between the examined alloys. On the basis of the performed studies, it was stated that the applied methods of manufacturing prosthetic elements make it possible to obtain diversified microstructural and mechanical properties of the alloys. The hardness value significantly affects the subsequent mechanical and finishing treatment of prosthetic elements, such as metal bases of crown caps, bridges, mobile prostheses or other retention elements.
EN
Beech (Fagus sylvatica L.), oak (Quercus robur L.) and pine (Pinus sylvestris L.) wood were volume-densified by means of thermo-mechanical modification. At first stage the wood was heated in a hydraulic press at temperature 100°C for 720 s, and then one-step densified in order to obtain the target thickness. The wood was cooled in a hydraulic press with unheated plates. Density profiles parallel and perpendicular to the grain were examined. The analysis of the density profiles was carried out on the basis of the following parameters: mean density, minimum to mean density ratio, maximum density, and the distance between the maximum density area and the wood surface. Wood hardness was determined according to the Brinell method. Volume-densified pine wood was characterized by considerably lower susceptibility to densification than beech or oak wood. Densified beech wood had the highest mean density 921 ±7 kg/m3, and the highest maximum density 968 ±12 kg/m3. The Brinell hardness of densified beech, oak and pine wood was twice as high as before the densification. The greatest hardness after the densification 78.60 ±10.56 N/mm2 was observed in beech wood.
18
Content available remote The assessment of selected properties of welded joints in high-strength steels
EN
The use of technologically advanced structural materials entails the necessity of adjusting typical welding processes to special requirements resulting from the limited weldability of certain material groups. Difficulties obtaining high-quality joints may be the consequence of deteriorated mechanical properties and structural changes in materials (beyond requirements of related standards). One of the aforementioned materials is steel characterised by a guaranteed yield point of 1300 MPa, where high strength is obtained through the addition of slight amounts of carbide-forming elements and the application of complex heat treatment processes. A heat input during welding may worsen the aforesaid properties not only in the weld but also in the adjacent material. The tests discussed in the article revealed that the crucial area was that heated below a temperature of 600°C, where the hardness of the material decreased from approximately 520 HV to 330 HV.
PL
Wykorzystanie nowoczesnych materiałów konstrukcyjnych niesie za sobą konieczność dostosowania typowych procesów spawalniczych do specjalnych wymagań wynikających z ograniczonej ich spawalności. Trudności w uzyskaniu złączy spawanych o wysokiej jakości mogą być konsekwencją zmniejszonych właściwości mechanicznych lub zmian w strukturze materiału, co wykracza poza wymagania norm przedmiotowych. Przykładem takiej stali jest stal o gwarantowanej granicy plastyczności 1300 MPa, gdzie wysoką wytrzymałość uzyskuje się przez dodatek niewielkich ilości pierwiastków węglikotwórczych i złożonych procesów obróbki cieplnej. Powoduje to, że wprowadzenie ciepła podczas spawania może pogarszać te właściwości nie tylko w samej spoinie, ale i w materiale przyległym. Wykonane badania wykazały, że krytycznym miejscem jest obszar nagrzewany poniżej 600°C, gdzie następuje zmniejszenie twardości materiału z ok. 520 HV do 330 HV.
EN
In this research, Co-30 mass% Cr alloys were fabricated by a vacuum hot-press sintering process. Different amounts of submicron cobalt and chromium (the mean grain size is 800 and 700 nm, respectively) powders were mixed by ball milling. Furthermore, this study imposed various hot-press sintering temperatures (1100, 1150, 1200 and 1250°C) and pressures (20, 35 and 50 MPa), while maintaining the sintering time at 1 h, respectively. The experimental results show that the optimum parameters of hot-press sintered Co-30 mass% Cr alloys are 1150°C at 35 MPa for 1 h. Mean while, the sintered density reaches 7.92 g·cm-3, the closed porosity decreases to 0.46%, and the hardness and transverse rupture strength (TRS) values increase to 77.2 HRA and 997.1 MPa, respectively. While the hot-press sintered Co-30 mass% Cr alloys at 1150°C and 20 MPa for 1 h, the electrical conductivity was slightly enhanced to 1.79 × 104 S·cm-1, and the phase transformation (FCC → HCP) of cobalt displayed a slight effect on sintering behaviors of Co-30 mass% Cr alloys. All these results confirm that the mechanical and electrical properties of Co-30 mass% Cr alloys are effectively improved by using the hot-press sintering technique.
EN
Owing to the excellent properties, graphene nanoplatelets (GNPs) show great reinforcing ability to improve the mechanical and tribological properties of Al nanocomposites for many automotive applications. In this work, the GNPs dispersion and reinforcing effect in Al nanocomposite was tested. Solvent dispersion via tip sonication and facile low energy ball milling (tumbling milling) using two milling speeds 200 and 300 rpm were employed to develop GNPs/Al powders. Sintering response of the GNPs/Al sintered samples wasgauged at two temperatures (550°C and 620°C). The effects of GNPs content, milling rotation speed and sintering temperature on the density, hardness and wear properties of the nanocomposite were examined. The results indicate that relative density % decreases with increasing GNPs content due to possible reagglomeration. The highest hardness of 35.6% and wear rate of 76.68% is achieved in 0.3 wt.% GNPs/Al nanocomposite processed at 300 rpm and 620°C as compared to pure Al due to uniform dispersion, higher diffusion rate at a higher temperature and effective lubrication effect.
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