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Wyniki wyszukiwania dla: HEAT TRANSFER, NANOFLUIDS, CATTANEO-CHRISTOV HEAT FLOW MODEL
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Modeling of natural convection with Smoothed Particle Hydrodynamics: Non-Boussinesq formulation
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Nanostructure and dielectric behavior of vanadate glasses containing BaTiO3
PublikacjaThe ac and dc electrical conductivity of barium titanate doped bismuth-vanadate as-quenched and heat-treated materials was measured in the frequency range from 1 mHz to 1 MHz and in the temperature range from 153 K to 423 K with the impedance spectroscopy method. The microstructure was investigated by means of XRD, scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal microscopy. The obtained results showed...
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The effect of cable duct diameter on the ampacity of high-voltage power cables
PublikacjaThe ampacity of power cables depends, among others, on the conditions of heat dissipation from the cable to the environment. Cables are usually laid directly in the ground, but in some sections, they may be placed in ducts, which adversely affects the ampacity of the cable line. The paper presents heat transfer phenomena for cables installed in pipe-type ducts filled with air. The effect of cable duct diameter on this ampacity...
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Application of the fluid–structure interaction technique for the analysis of hydrodynamic lubrication problems.
PublikacjaFluid–structure interaction technique seems to be one of the most promising possibilities for theoretical analysis of lubrication problems. It allows coupling of different physical fields in one computational task, taking into account the interaction between them. In this article, two sets of fluid–structure interaction analyses focusing on the bearing performance evaluation are presented. One analysis was applied to a water-lubricated...
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Funkcjonowanie zespołów napędu hydraulicznego maszyn w niskich temperaturach otoczenia
PublikacjaW pracy przedstawiono cztery warianty klasyfikacji rozruchów oziębionego napędu hydraulicznego. Pierwsza sytuacja dotyczy zagadnienia, w którym wszystkie zespoły układu napędowego wraz z olejem mają taką samą niską temperaturę podczas rozruchu. Pozostałe warianty odnoszą się do rozruchu w warunkach szoku termicznego wywołanych zasilaniem ciepłym czynnikiem roboczym oziębionych zespołów hydraulicznych. Rozruch zespołów...
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Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
PublikacjaThe study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of...
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Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublikacjaThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
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LCT, PIV and IR Imaging Detection in Selected Technical and Biomedical Applications
PublikacjaPaper presents the brief summary of the history of Thermochromic liquid crystals (TLC), Particle Image Velocimetry (PIV) and Infrared Imaging Themography (IR). Principal methods and tools are described and some examples are presented. With this objective, a new experimental technique have been developed and applied to the study of heat and mass transfer and for biomedical diagnosis. Selected results of experiments using these methods...
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Experimental Investigations on the Influence of Coil Arrangement on Melting/Solidification Processes
PublikacjaThe latent heat thermal energy storage units are very popular because of their high energy density and almost close to constant temperature during the charging/discharging. In the present study has been proposed new shell-and-coil geometry with a shifted coil position to enhance the performance of phase change thermal magazine. The experimental investigations have been performed both for the melting and solidification process of...
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A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
PublikacjaThe Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling...
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Application of Stirling Engine Type Alpha Powered by the Recovery Energy on Vessels
PublikacjaThe Stirling engine is a device, in which thermal energy is transformed into mechanical without a contact between the heat carrier, and the working gas closed in the engine. Mentioned feature makes this type of engine very attractive for the use of the recovery energy, taken from other heat devices. One of the potential applications of Stirling engines is the use of thermal energy generated in the ship's engine room for producing...
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Wioletta Gorczewska-Langner dr inż.
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Impact of surface skin temperature change on blood flow characteristics in palm
PublikacjaHeating a human palm during 3 minutes period causes changes in superficial skin temperature and leads to thermoregulation system response. The response time and level of flow characteristics change depend on the subject hand size and health of his vascular tree. A solution of Pennes bioheat propagation model was analyzed in order to see how much heat has to be transferred into the tissue to extort the observable reaction. The reflective...
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Nuclear Co-generation: The Analysis of Technical Capabilities and Cost Estimates
PublikacjaThis paper presents a concept of the parallel connection of a nuclear power plant fitted to provide heat for district heating application, with the CHP and heat plants existing in the supply region, in this case with the heating systems of Wejherowo and Gdynia. Presented variant proposes to add heat to a nuclear power plant’s total output by supplying heat exchangers with the steam from bleeders of low pressure (LP) turbine stage...
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Analytical and reliability data from the real-time simulator biogas plant
Dane BadawczeThe dataset represents the results of biogas plant simulation. The described plant is an agricultural biogas system, which can produce electrical energy with power estimated up to 1070 kW and heat energy that can reach 1200 kW simultaneously.
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White light thermoplasmonic activated gold nanorod arrays enable the photo-thermal disinfection of medical tools from bacterial contamination
PublikacjaThe outspread of bacterial pathogens causing severe infections and spreading rapidly, especially among hospitalized patients, is worrying and represents a global public health issue. Current disinfection techniques are becoming insufficient to counteract the spread of these pathogens because they carry multiple antibiotic-resistance genes. For this reason, a constant need exists for new technological solutions that rely on physical...
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Design analysis of Tesla micro-turbine operating on a low-boiling medium
PublikacjaThis paper presents results of the design analysis of a Tesla bladeless turbine intended for a co-generating micro-power plantof heat capacity 20 kW, which operates in an organic Rankine cycle on a low-boiling medium. Numerical calculations of flowin several Tesla turbine models were performed for a range of design parameters. Results of investigations exhibit interestingfeatures in the distribution of flow parameters within the...
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EPR of TiO2 hydrogenated at 500 and 600oC
Dane BadawczeData contain EPR spectra of TiO2 (anatase phase) heat treated in H2 at 500 and 600oC. Sample heated at 500oC contained 4 wt% of rutile and that at 600oC 8 wt% of rutile.
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On the differential effect of temperature on the Nusselt-Rayleigh relationship in free convection
PublikacjaThe aim of and inspiration behind this paper was to explain the reasons, also observed by other researchers, of the discrepancy in the results of experimental free convection, which for small Rayleigh and Nusselt numbers in the initial phase of research can sometimes reach several hundred percent. These discrepancies decrease with increasing heating power and plate surface temperature, in proportion to the increase in Ra and Nu,...
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Neural Modelling of Steam Turbine Control Stage
PublikacjaThe paper describes possibility of steam turbine control stage neural model creation. It is of great importance because wider application of green energy causes severe conditions for control of energy generation systems operation Results of chosen steam turbine of 200 MW power measurements are applied as an example showing way of neural model creation. They serve as training and testing data of such neural model. Relatively simple...
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Comparison of soil models in the thermodynamic analysis of a submarine pipeline buried in seabed sediments
PublikacjaThis paper deals with mathematical modelling of a seabed layer in the thermodynamic analysis of a submarine pipeline buried in seabed sediments. The existing seabed soil models: a “soil ring” and a semi-infinite soil layer are discussed in a comparative analysis of the shape factor of a surrounding soil layer. The meaning of differences in the heat transfer coefficient of a soil layer is illustrated based on a computational example...
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XPS-TiO2 heated in H2
Dane BadawczeThese XPS spectra were recorded for TiO2 heat-treated at 450-600oC in H2. Surface oxygen groups were determined. Deconvolution of Ti 2p peak allowed to determine Ti3+ on the titania surface.
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SEM of TiO2 heated at 400-600oC in Ar or H2
Dane BadawczeData contain some SEM images of TiO2 taken after its heat treatment in Ar or H2 at 400-600oC. Treated TiO2 was crystalline anatase phase with 3-4 % of rutile nclei.
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Comparative study of operation of condensing and traditional boilers equipped with the ORC module for electricity generation
PublikacjaCondensing technology applied to boilers is to make full use of thermal energy contained in the fuel. That means that additionaly the heat from condensation of exhaust gases can be used for the purposes of heating the domestic hot water and to cover the demand for central heating. The study analyzed the operation of the "traditional" boiler equipped with the ORC module as the similar arrangement but with the condensing boiler....
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Areas of updraft air motion from WRF model simulations.
Dane BadawczePresented dataset is a part of numerical modelling study focusing on the analysis of sea ice floes size distribution (FSD) influence on the horizontal and vertical structure of convection in the atmosphere. The total area and spatial arrangement of the updrafts indicates that the FSD affects the total moisture content and the values of area averaged...
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Phase change thermal energy storage – the experience of the materials preparation for the specific applications.
PublikacjaThermal energy storage and temperature stabilization is very important in many engineering applications. There are three kinds of thermal energy storage: sensible heat, latent heat and reversible chemical reaction heat. Phase change materials (PCM) absorb, store and release large amounts of energy in the form of latent heat, at constant temperature, called the transition temperature. Many innovative applications could be found...
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Active management of equipment cooling in hoteling data centers
PublikacjaHoteling data centers are designated for housing computing and storage units of many, usually small customers, as opposed to traditional data centers supporting own computing and storage resources of a bigger company. One of the services to be provided to consumer’s equipment is cooling. Cooling in data centers is prevalently achieved by circulating air in computer room. Efficient cooling requires delivering cold air from central...
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Adapting the pinch point analysis to improve the ORC design process
PublikacjaPinch point analysis can be adapted so as to assist in the early stages of designing the ORC systems. Typically used in determining the working parameters of heat exchangers, it can be employed to improve the heat fitting between the source of heat and the working fluids of the ORC system. To attain the parametric match, an algorithm was built enabling quick estimation of the possible heat reception by the specific working fluid....
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FTIR-TiO2 heated at 400-600oC in Ar or H2
Dane BadawczeData contain FTIR diffuse eflectance spectra of TiO2, which was heat-treated at 400-600oC in Ar or H2. Hydrogen reduced TiO2 revealed new bands due to the adsorption of some species on the titania oxygen vacancy sites.
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A multistage turbine for a micro power plant
PublikacjaThis paper presents results of a design analysis of a multi-stage turbine for the cogeneration micro-power plant working in accordance with Organic Rankine Cycle (ORC). The heat power of the plant is assumed equal to 20 kW and the corresponding available electric output is estimated to be of about 3 kW. Different variants of the radial and axial-flow turbines have been considered, while the detailed results of the calculations...
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Profitability criteria of partial cogeneration in nuclear power plant.
PublikacjaIn this paper, profitability criteria and calculation methodology of profitability conditions for partial cogeneration in nuclear power plant (NPP) was presented. Considered NPP supplies electricity to consumers through public power system, whereas heat is expected to be supplied to consumption regions via long-distance heat transport line. First proposed profitability criterion was total annual costs of electricity and heat delivered...
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Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
PublikacjaEffective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat...
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Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
PublikacjaEffective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat supply...
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Effect of annealing temperature on slurry erosion resistance of ferritic X10CrAlSi18 steel
PublikacjaIn the present work, the slurry erosion tests were carried out to investigate the influence of heat treatment on slurry erosion process of ferritic X10CrAlSi18 stainless steel using a slurry pot test rig. X10CrAlSi18 stainless steel was tested in as-received condition and after annealing at three different temperatures: 600°C, 800°C and 1000°C. Degradation of materials due to slurry erosion depends on many factors connected with...
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Numerical simulation of cold flow and combustion in a swirl stabilized combustor
PublikacjaA numerical simulation model was developed to investigate the cold flow and combustion using Ansys FLUENT 2021R1. The governing equations were solved using the pressure-based method, and pressure–velocity coupling was performed using the SIMPLE method. To model the turbulent process, the RSM model was used. Non-premixed model is chosen to solve the chemical kinetics between fuel and oxigen. Radiation heat transfer was calculated...
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Effect of the North Atlantic Thermohaline Circulation on changes in climatic conditions and river flow in Poland
Publikacja: The purpose of this study is to find connections between the North Atlantic Thermohaline Circulation (NA THC), climate elements, such as cloud cover, precipitation, air temperature, sunshine duration, and relative humidity, and flow of rivers in Poland. The intensity of NA THC was characterized by the DG3L index, which was established to assess changes in the amount of heat transported by NA THC along with the transport of water...
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Structure, luminescent properties and FDTD simulation of TeO2-BaO-Bi2O3-Ag:Ln3+ glass-ceramics system
PublikacjaTeO2-BaO-Bi2O3-Ag glass systems (TBB) co-doped with terbium and europium ions have been successfully synthesized through conventional melt-quenching technique. Heat treatment procedure at 350 °C has been conducted in order to synthesize silver nanoparticles embedded in TBB glass matrix. Structural measurements involved XRD studies that revealed no crystallization of glass structure after heat treatment at elevated temperatures....
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Thermomagnetic behavior of a semiconductor material heated by pulsed excitation based on the fourth-order MGT photothermal model
PublikacjaThis article proposes a photothermal model to reveal the thermo-magneto-mechanical properties of semiconductor materials, including coupled diffusion equations for thermal conductivity, elasticity, and excess carrier density. The proposed model is developed to account for the optical heating that occurs through the semiconductor medium. The Moore–Gibson–Thompson (MGT) equation of the fourth-order serves as the theoretical framework...
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Bead-on-Plate Underwater Wet Welding on S700MC Steel
PublikacjaThe participation of high strength steels in marine and offshore structures is increasing, which makes it necessary to develop recommendations for underwater repair welding works. The article presents the results of bead-on-plate welded specimens made of S700MC high strength steel in underwater wet welding conditions by covered elec- trodes. Three specimens with heat input values in the range 0.91-1.05 kJ/mm were made. The specimens...
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Combined operation of 900MW power plant with the ORC through the bleed steam extraction point and CO2 recovery system
PublikacjaThe work presented here is aimed at utylisation of waste heat in the reference supercritical power plant in the manner to produce electricity in ORC installation. The waste heat is available in the form of a stream of hot water at 90 C, recovered from the exhaust gases in the amount of 200MW. Such low enthalpy heat source is rather insufficient to produce a good quality vapour to feed the ORC turbine. Therefore an original approach...
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Experimental and theoretical study of a vertical tube in shell storage unit with biodegradable PCM for low temperature thermal energy storage applications
PublikacjaThis article presents the experimental investigations of the coconut oil-based TES module for HVAC applications in the ambient and-sub ambient temperature range. To properly study this problem modular experimental module and test loop were developed. Special attention has been paid to study the physical mechanism of the melting/solidification process for natural substance (coconut oil) which has perspectives to be used in thermal...
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Analysis of the selection of low-temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublikacjaThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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THERMODYNAMIC ANALYSIS OF A GENERATION IV SCWR NUCLEAR POWER PLANT CYCLE
PublikacjaThis article presents a flow and thermodynamic analysis of a Generation IV nuclear cycle. An SCWR (Supercritical water reactor) is a high temperature and high pressure reactor that uses water at a temperature above its thermodynamic critical point as the working fluid. The cycle used for the calculations consists of one interstage superheater and 7 regenerative heat exchangers. Division pressure was optimized in view of the cycle efficiency,...
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Analysis of the selection of low temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublikacjaThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Integrated plant-wide modelling for evaluation of the energy balance and greenhouse gas footprint in large wastewater treatment plants
PublikacjaModern wastewater treatment plants (WWTPs) should maintain a balance between three combined sustainability criteria, including effluent quality, energy performance and greenhouse gas (GHG) emissions. All of these criteria were considered in the integrated plant-wide model developed in this study. The proposed model incorporates new features, including: (i) the addition of associated facilities to the overall energy balance and...
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The structure of vanadate glass-ceramics containing BaTiO3 measured with X-ray diffraction method
Dane BadawczeThe structure of vanadate glass-ceramics doped with BaTiO3 was measured by XRD. Samples of the composition of x[BaO,TiO2]–(80 − x)V2O5–20Bi2O3 where x = 5, 10 and 15 in mol% were prepared by a conventional melt quenching technique. The melting was performed in alumina crucibles at the temperature of 1273 K–1373 K. The melts were poured on a preheated...
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Photoluminescence spectra of TiO2
Dane BadawczeThese data contain photoluminescence spectra of TiO2 measured at the temperature of liquid nitrogen. There is a comparison of the photoluminescence spectra of TiO2 heat treated at 400-600oC in the ambient (Ar) and reduced (H2) atmospheres. These emission spectra were recorded after TiO2 excitation with a wavelength of 290 nm
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Determination of benzo(a)pyrene content in PM10 using regression methods
PublikacjaThe paper presents an attempt of application of multidimensional linear regression to estimation of an empirical model describing the factors influencing on B(a)P content in suspended dust PM10 in Olsztyn and Elbląg city regions between 2010 and 2013. During this period annual average concentration of B(a)P in PM10 exceeded the admissible level 1.5-3 times. Conducted investigations confirm that the reasons of B(a)P concentration...
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Cooperation of ORC installation with a gas boiler as a perspective co-generation system for households
PublikacjaThis paper reports tests of an innovative micro-CHP unit prototype, consisting of a traditional gas boiler and organic Rankine cycle (ORC), which incorporates original system components such as an axial vapour microturbine, evaporator and condenser. The system co-generates heat and electricity for a single household or a group of households. Electricity is only a by-product during production of heat. While testing the prototype,...
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The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints
PublikacjaThe tests results of superduplex stainless steel welded joints made with a different heat input, using automatic submerged arc welding (SAW) and semi-automatic flux-cored arc welding (FCAW) have been presented. Metallographic examinations, the measurements of the ferrite content, the width of the heat affected zone (HAZ) and the hardness of the welds in characteristic areas have been performed. Significant differences in the amount of...