Marek Gucwa - Academia.edu (original) (raw)

Papers by Marek Gucwa

Journal of Applied Mathematics and Computational Mechanics, 2021

The calculation results of the temperature field during multi-beads GMAW (Gas Metal Arc Welding) ... more The calculation results of the temperature field during multi-beads GMAW (Gas Metal Arc Welding) cladding of the S355 steel plate are presented in the paper. Numerical simulations were performed using the Sysweld ® program. Two of Goldak's heat source models were chosen for calculating the temperature field for each weld bead. The original article achievement is, by selecting the right heat source model and heat loading of the finite elements, obtaining an irregular shape of the fusion zone. This irregular shape of the fusion zone is very complicated to obtain using other commercial programs for numerical welding simulation. The calculation results were verified by the dimensions (critical temperatures) of the heat affected zones (HAZ) determined in the experiment, obtaining a satisfactory agreement.

IOP Conference Series: Materials Science and Engineering, 2021

This paper presents a comparative analysis of heat input per unit length and per unit volume for ... more This paper presents a comparative analysis of heat input per unit length and per unit volume for selected methods of welding. The purpose of the analysis is to assess the usability of calculating heat input per volume unit. The interpretation of heat input per unit length according to the standards: QW-409.1 of ASME IX, EN ISO 1011-1 is discussed. The concept of calculating heat input per unit volume is described. For exemplary padded welds and spot welded joints, the heat input values were calculated in accordance with the above-mentioned standards and based on the concept of heat input per unit volume. The study showed a lack of consistency between the individual standards in the interpretation of the heat input. In addition, the practical application of the heat input per unit volume method in calculating the actual amount of heat introduced into the weld was justified.

Industry 4.0: Trends in Management of Intelligent Manufacturing Systems, 2019

In stress calculations during the welding processes of metals and their alloys, the interaction o... more In stress calculations during the welding processes of metals and their alloys, the interaction of temperature fields, phase transformations, strains, and stresses is commonly taken into account. The starting point for these calculations is the temperature field, whose changes result in changes in structural component shares (e.g., in steel, cast iron) and changes in the strain fields. Finally, the thermal and structural strains, in conjunction with stress-strain curves, enable the determination of temporary and residual stresses. 9.2 Temperature Field Two methods are mainly used to calculate the temperature in welding processes: analytical (usually based on integral transformations and Green's functions) [1-7] and numerical: (FEM-Finite Element Method) [8-16], as well as methods of elementary balances and finite differences. In this work, the temperature field is described analytically as the summary temperature increase caused by the action of the electric arc Θ a and the heat transferred by the molten metal electrode Θ w [17]:

Proceedings of the 2nd EAI International Conference on Management of Manufacturing Systems, 2018

In work the model of stress calculation and analysis of stress field during single-pass SAW (Subm... more In work the model of stress calculation and analysis of stress field during single-pass SAW (Submerged Arc Welding) surfacing have been presented. In the temperature field solution, influence heat of melted electrode and heat of direct impact of electric arc have been taken into consideration. The phase change kinetics according to the laws of Johnson-Mehl-Avrami-Kolmogorov and Koistinen-Marburger were determined. The temperatures of the beginning and the end of the changes were determined by the A c1 and A c3 temperatures during heating and on the basis of the timetemperature-transformation welding diagram for cooling. The stress state of thermal loaded flat has been described assuming planar section hypothesis and simple Hooke's law and using integral equations of stress equilibrium. The stress-strain curves were modeled as the curves of the mixture of individual material phases depending on temperature. The analysis of stress state has been presented for SAW surfacing S355 steel plate.

Advances in Manufacturing Engineering and Materials, 2018

The wear-resistant layers of the chromium cast iron structure can be made by traditional casting ... more The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.

Lecture Notes in Mechanical Engineering, 2019

The paper presents the results of research on the possibility of shaping the hardfacing structure... more The paper presents the results of research on the possibility of shaping the hardfacing structure by changing the conditions of the surfacing process. The material used in research was high carbon and chromium a self-shielding cored wire giving the hardness 760–840 HV (62–65 HRC) according to the manufacturer. The obtained hardness of the hardfacing was on the same level or was significant higher. The test results show significant differences in the structure and hardness of the deposits, where differences in the amount of carbide precipitations reach 30%, and differences in hardness reach up to 200 HV. The erosion tests showed that impingement angle 30° gives lower erosion rate than angle 60°. It is possible to shape the structure and properties of hardfacing to a certain extent by selecting the appropriate parameters of the surfacing process. In conditions of this experiment the decisive effects on the properties are played by parameters such as heat input and heat dissipation.

The paper presents the results of qualification of produc- tion welding procedures for heat-resis... more The paper presents the results of qualification of produc- tion welding procedures for heat-resistant cast steel in grade GX40NiCrNb35-45 with used filler material in grade WZ 35 45 Zr (PN-EN ISO 14343). Qualification of welding technology was made in accordance to PN-EN ISO 11970. Test welded joint was made using 141 method and non-destructive and destructive testing were performed in order to determine the mechanical properties of the welded joint. Completed tests met the requirements of PN-EN ISO 11970 and were the ba- sis of the welding procedure qualification record. in polish Spawanie produkcyjne odlewu staliwnego zaroodpornego GX40NiCrNb35-45 W pracy przedstawiono przykladowe wyniki badan kwalifikowania technologii spawania produkcyjnego odlewu staliwnego zaroodpornego w gatunku GX40NiCrNb35-45 przy uzyciu materialu dodatkowego w gatunku WZ 35 45 Zr wg PN-EN ISO 14343. Badanie kwalifikowania technologii spawania wykonano zgodnie z PN-EN ISO 11970. Zlącze probne wykonano metod...

Archives of Foundry Engineering, 2014

The paper discusses the effect of the heat input in the case of welding with solid and cored wire... more The paper discusses the effect of the heat input in the case of welding with solid and cored wire, respectively to the quality of the obtained joints. Formulas used for this purpose do not allow for the form of the filler, which, in the authors' opinion, has an effect on the basic parameters characterizing the welded joint. The paper presents the results of research on the geometric sizes of a joint made with a similar heat input, but using the filler in the form of, respectively, solid and cored wire. Investigations were carried out on fillet-weld joints that were subjected to macroscopic metallographic examinations. Studies have shown that the heat input given without allowing for the form of the filler does not reflect the changes that occur in the welded joint due to the thermal welding cycle.

Archives of Foundry Engineering, 2018

Use of welding technology for the repair of steel castings is particularly common in two areas. T... more Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of found...

Archives of Foundry Engineering, 2015

The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium a... more The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium and carbon surfaces. In these studies selfshielded cored wire was used as a material for hardfacing. Pulsed arc is used in welding technologies to better control of transport molten metal in the welding arc and heat input. The correct heat input results in limited dilution surfaces that is very important in wear prevention technologies. The paper presents the results of research on the geometric parameters and hardness of deposited surfaces. The investigation was carried out with various welding parameters that were designed in heat source. The survey was conducted on the specimens that were subjected to metallographic examination hardness test.

Materials, 2021

Wastewater treatment activities in the chemical industry have generated abundant gypsum waste, cl... more Wastewater treatment activities in the chemical industry have generated abundant gypsum waste, classified as scheduled waste (SW205) under the Environmental Quality Regulations 2005. The waste needs to be disposed into a secure landfill due to the high heavy metals content which is becoming a threat to the environment. Hence, an alternative disposal method was evaluated by recycling the waste into fired clay brick. The brick samples were incorporated with different percentages of gypsum waste (0% as control, 10, 20, 30, 40 and 50%) and were fired at 1050 °C using 1 °C per minute heating rate. Shrinkage, dry density, initial rate of suction (IRS) and compressive strength tests were conducted to determine the physical and mechanical properties of the brick, while the synthetic precipitation leaching procedure (SPLP) was performed to scrutinize the leachability of heavy metals from the crushed brick samples. The results showed that the properties would decrease through the incorporatio...

Materials, 2021

This study intended to address the problem of damaged (collapsed, cracked and decreased soil stre... more This study intended to address the problem of damaged (collapsed, cracked and decreased soil strength) road pavement structure built on clay soil due to clay soil properties such as low shear strength, high soil compressibility, low soil permeability, low soil strength, and high soil plasticity. Previous research reported that ground granulated blast slag (GGBS) and fly ash can be used for clay soil stabilizations, but the results of past research indicate that the road pavement construction standards remained unfulfilled, especially in terms of clay’s subgrade soil. Due to this reason, this study is carried out to further investigate soil stabilization using GGBS and fly ash-based geopolymer processes. This study investigates the effects of GGBS and ratios of fly ash (solid) to alkaline activator (liquid) of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1, cured for 1 and 7 days. The molarity of sodium hydroxide (NaOH) and the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) was fixed...

Materials, 2021

This paper clarified the microstructural element distribution and electrical conductivity changes... more This paper clarified the microstructural element distribution and electrical conductivity changes of kaolin, fly ash, and slag geopolymer at 900 °C. The surface microstructure analysis showed the development in surface densification within the geopolymer when in contact with sintering temperature. It was found that the electrical conductivity was majorly influenced by the existence of the crystalline phase within the geopolymer sample. The highest electrical conductivity (8.3 × 10−4 Ωm−1) was delivered by slag geopolymer due to the crystalline mineral of gehlenite (3Ca2Al2SiO7). Using synchrotron radiation X-ray fluorescence, the high concentration Ca boundaries revealed the appearance of gehlenite crystallisation, which was believed to contribute to development of denser microstructure and electrical conductivity.

Welding Technology Review, 2020

Wear resistant welds are used in many industries when it is necessary to protect machine componen... more Wear resistant welds are used in many industries when it is necessary to protect machine components and structures against wear caused by operating conditions. Often the main parameter determining the usefulness of these welds is high hardness reaching about 60HRC. In many cases, after the surfacing process, a mesh of cracks is formed in the surface layer, which can affect the durability of the hard-wearing layers used. The paper presents the analysis of the influence of preheating before welding up to 400 ° C on the properties of welds and its effect on the number of cracks in the surface layer. The use of preheating allowed to reduce the number of cracks in the surfacing to 1. The optimum heating temperature was 200 ° C, for which the number of cracks was reduced and the lowest wear was recorded.

Biuletyn Instytutu Spawalnictwa, 2020

The study presents the geometry as well as results of the peeling, shearing and metallographic te... more The study presents the geometry as well as results of the peeling, shearing and metallographic tests of copper and aluminium welded joints used in the absorber panels of flat solar collectors. The article discusses desired characteristics and mechanical properties of ultrasonic welded joints and compares the latter with laser welded joints. In addition, the study indicates prospective implementation areas of ultrasonic welding technologies.

Biuletyn Instytutu Spawalnictwa, 2018

The article presents test results concerning welded joints made of cast steel GX8CrNi12-1. The ab... more The article presents test results concerning welded joints made of cast steel GX8CrNi12-1. The above-named cast steel has a martensitic microstructure and can be used in pressure equipment operated at ambient and high temperature. The test joints were made in the horizontal position and in the vertical up position. The foregoing was dictated by the fact that the above-named positions are used in industrial conditions, e.g. when welding steel castings. The welding process performed in the above-named positions ensured that specimens were sampled from areas exposed to the lowest and highest arc linear energy. The article describes the process of manual metal arc welding (111) and the post-weld heat treatment. The test joints were subjected to destructive tests including transverse tensile tests, impact strength tests, hardness measurements as well as macro and microscopic tests. The test results revealed differences in properties of joints made in different positions, resulting from various heat inputs to joints during welding.

IOP Conference Series: Materials Science and Engineering, 2018

A chamfering of the joining sheet edges is often used in welding practice. In work, the analysis ... more A chamfering of the joining sheet edges is often used in welding practice. In work, the analysis of groove weld input on residual stress distribution in single-pass butt welded joints with thorough penetration is presented. For this purpose, comparative calculations of instantaneous and residual stresses in two steel flat bars were made. The butt welded joints of S235 steel elements put to the analysis. Numerical simulations were conducted for joint with welding groove and for joint without chamfering of flats. The calculations include strains caused by temperature changes as well as the effect of phase transformations. For calculations are used authors' programs made in Borland Delphi. The results are presented in the form of temperature, volume phase fraction and stress distributions in the element's cross section as well as welding thermal cycles and stress history at selected points. The analysis of the results of the calculations showed slight differences in the stress distributions in the heat-affected zones of the considered flat bars, while it did not show significant differences in stress levels outside these areas.

Przegląd Spawalnictwa - Welding Technology Review, 2015

W pracy przedstawiono wybrane aspekty technologii wykonywania powierzchni grzewczych tj. wężownic... more W pracy przedstawiono wybrane aspekty technologii wykonywania powierzchni grzewczych tj. wężownic przegrzewaczy pary z wykorzystaniem kompleksowego stanowiska do spawania metodą zmechanizowaną TIG. Próby spawania wykonano na rurach ze stali VM12-SHC o średnicy 44,5mm i grubości ścianki 7,1mm. Przedstawiono wyniki badań niszczących oraz nieniszczących oraz wskazano na problemy jakie można spotkać w czasie spawania tego typu stali. Przeprowadzone próby spawania złącza doczołowego dowiodły, iż spawanie orbitalne metodą TIG jest procesem bardzo skutecznym pod względem powtarzalności oraz jakości wykonanych połączeń spawanych. Odpowiednio przygotowane oprogramowanie procesu spawania, czy też bieżąca kontrola stanu technicznego urządzenia, powodują iż wskaźnik wadliwość wykonywanych złącz wynosi poniżej 1%. Z tego względu metoda spawania orbitalnego TIG jest rekomendowana w przypadku, gdy spawane są elementy w gatunkach o utrudnionej spawalności tj. VM12-SHC.

Przegląd Spawalnictwa - Welding Technology Review, 2011

W artykule omówiono problem określenia parametrów istotnych dla napawania drutem rdzeniowym samoo... more W artykule omówiono problem określenia parametrów istotnych dla napawania drutem rdzeniowym samoosłonowym. Metoda SSA jest jedną ze spawalniczych metod, która daje duże możliwości w wytwarzaniu napoin o zróżnicowanym składzie chemicznym i dobrej jakości. Istotne jest określenie, które z parametrów napawania mają znaczący wpływ na właściwości napoiny. Zastosowanie planu Placketta-Burmana umożliwiło statystyczną ocenę istotności wpływu wybranych parametrów napawania na geometrię napoiny.

Journal of Applied Mathematics and Computational Mechanics, 2021

The calculation results of the temperature field during multi-beads GMAW (Gas Metal Arc Welding) ... more The calculation results of the temperature field during multi-beads GMAW (Gas Metal Arc Welding) cladding of the S355 steel plate are presented in the paper. Numerical simulations were performed using the Sysweld ® program. Two of Goldak's heat source models were chosen for calculating the temperature field for each weld bead. The original article achievement is, by selecting the right heat source model and heat loading of the finite elements, obtaining an irregular shape of the fusion zone. This irregular shape of the fusion zone is very complicated to obtain using other commercial programs for numerical welding simulation. The calculation results were verified by the dimensions (critical temperatures) of the heat affected zones (HAZ) determined in the experiment, obtaining a satisfactory agreement.

IOP Conference Series: Materials Science and Engineering, 2021

This paper presents a comparative analysis of heat input per unit length and per unit volume for ... more This paper presents a comparative analysis of heat input per unit length and per unit volume for selected methods of welding. The purpose of the analysis is to assess the usability of calculating heat input per volume unit. The interpretation of heat input per unit length according to the standards: QW-409.1 of ASME IX, EN ISO 1011-1 is discussed. The concept of calculating heat input per unit volume is described. For exemplary padded welds and spot welded joints, the heat input values were calculated in accordance with the above-mentioned standards and based on the concept of heat input per unit volume. The study showed a lack of consistency between the individual standards in the interpretation of the heat input. In addition, the practical application of the heat input per unit volume method in calculating the actual amount of heat introduced into the weld was justified.

Industry 4.0: Trends in Management of Intelligent Manufacturing Systems, 2019

In stress calculations during the welding processes of metals and their alloys, the interaction o... more In stress calculations during the welding processes of metals and their alloys, the interaction of temperature fields, phase transformations, strains, and stresses is commonly taken into account. The starting point for these calculations is the temperature field, whose changes result in changes in structural component shares (e.g., in steel, cast iron) and changes in the strain fields. Finally, the thermal and structural strains, in conjunction with stress-strain curves, enable the determination of temporary and residual stresses. 9.2 Temperature Field Two methods are mainly used to calculate the temperature in welding processes: analytical (usually based on integral transformations and Green's functions) [1-7] and numerical: (FEM-Finite Element Method) [8-16], as well as methods of elementary balances and finite differences. In this work, the temperature field is described analytically as the summary temperature increase caused by the action of the electric arc Θ a and the heat transferred by the molten metal electrode Θ w [17]:

Proceedings of the 2nd EAI International Conference on Management of Manufacturing Systems, 2018

In work the model of stress calculation and analysis of stress field during single-pass SAW (Subm... more In work the model of stress calculation and analysis of stress field during single-pass SAW (Submerged Arc Welding) surfacing have been presented. In the temperature field solution, influence heat of melted electrode and heat of direct impact of electric arc have been taken into consideration. The phase change kinetics according to the laws of Johnson-Mehl-Avrami-Kolmogorov and Koistinen-Marburger were determined. The temperatures of the beginning and the end of the changes were determined by the A c1 and A c3 temperatures during heating and on the basis of the timetemperature-transformation welding diagram for cooling. The stress state of thermal loaded flat has been described assuming planar section hypothesis and simple Hooke's law and using integral equations of stress equilibrium. The stress-strain curves were modeled as the curves of the mixture of individual material phases depending on temperature. The analysis of stress state has been presented for SAW surfacing S355 steel plate.

Advances in Manufacturing Engineering and Materials, 2018

The wear-resistant layers of the chromium cast iron structure can be made by traditional casting ... more The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.

Lecture Notes in Mechanical Engineering, 2019

The paper presents the results of research on the possibility of shaping the hardfacing structure... more The paper presents the results of research on the possibility of shaping the hardfacing structure by changing the conditions of the surfacing process. The material used in research was high carbon and chromium a self-shielding cored wire giving the hardness 760–840 HV (62–65 HRC) according to the manufacturer. The obtained hardness of the hardfacing was on the same level or was significant higher. The test results show significant differences in the structure and hardness of the deposits, where differences in the amount of carbide precipitations reach 30%, and differences in hardness reach up to 200 HV. The erosion tests showed that impingement angle 30° gives lower erosion rate than angle 60°. It is possible to shape the structure and properties of hardfacing to a certain extent by selecting the appropriate parameters of the surfacing process. In conditions of this experiment the decisive effects on the properties are played by parameters such as heat input and heat dissipation.

The paper presents the results of qualification of produc- tion welding procedures for heat-resis... more The paper presents the results of qualification of produc- tion welding procedures for heat-resistant cast steel in grade GX40NiCrNb35-45 with used filler material in grade WZ 35 45 Zr (PN-EN ISO 14343). Qualification of welding technology was made in accordance to PN-EN ISO 11970. Test welded joint was made using 141 method and non-destructive and destructive testing were performed in order to determine the mechanical properties of the welded joint. Completed tests met the requirements of PN-EN ISO 11970 and were the ba- sis of the welding procedure qualification record. in polish Spawanie produkcyjne odlewu staliwnego zaroodpornego GX40NiCrNb35-45 W pracy przedstawiono przykladowe wyniki badan kwalifikowania technologii spawania produkcyjnego odlewu staliwnego zaroodpornego w gatunku GX40NiCrNb35-45 przy uzyciu materialu dodatkowego w gatunku WZ 35 45 Zr wg PN-EN ISO 14343. Badanie kwalifikowania technologii spawania wykonano zgodnie z PN-EN ISO 11970. Zlącze probne wykonano metod...

Archives of Foundry Engineering, 2014

The paper discusses the effect of the heat input in the case of welding with solid and cored wire... more The paper discusses the effect of the heat input in the case of welding with solid and cored wire, respectively to the quality of the obtained joints. Formulas used for this purpose do not allow for the form of the filler, which, in the authors' opinion, has an effect on the basic parameters characterizing the welded joint. The paper presents the results of research on the geometric sizes of a joint made with a similar heat input, but using the filler in the form of, respectively, solid and cored wire. Investigations were carried out on fillet-weld joints that were subjected to macroscopic metallographic examinations. Studies have shown that the heat input given without allowing for the form of the filler does not reflect the changes that occur in the welded joint due to the thermal welding cycle.

Archives of Foundry Engineering, 2018

Use of welding technology for the repair of steel castings is particularly common in two areas. T... more Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of found...

Archives of Foundry Engineering, 2015

The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium a... more The paper discusses the possibility of using pulsed arc hardfacing for depositing high chromium and carbon surfaces. In these studies selfshielded cored wire was used as a material for hardfacing. Pulsed arc is used in welding technologies to better control of transport molten metal in the welding arc and heat input. The correct heat input results in limited dilution surfaces that is very important in wear prevention technologies. The paper presents the results of research on the geometric parameters and hardness of deposited surfaces. The investigation was carried out with various welding parameters that were designed in heat source. The survey was conducted on the specimens that were subjected to metallographic examination hardness test.

Materials, 2021

Wastewater treatment activities in the chemical industry have generated abundant gypsum waste, cl... more Wastewater treatment activities in the chemical industry have generated abundant gypsum waste, classified as scheduled waste (SW205) under the Environmental Quality Regulations 2005. The waste needs to be disposed into a secure landfill due to the high heavy metals content which is becoming a threat to the environment. Hence, an alternative disposal method was evaluated by recycling the waste into fired clay brick. The brick samples were incorporated with different percentages of gypsum waste (0% as control, 10, 20, 30, 40 and 50%) and were fired at 1050 °C using 1 °C per minute heating rate. Shrinkage, dry density, initial rate of suction (IRS) and compressive strength tests were conducted to determine the physical and mechanical properties of the brick, while the synthetic precipitation leaching procedure (SPLP) was performed to scrutinize the leachability of heavy metals from the crushed brick samples. The results showed that the properties would decrease through the incorporatio...

Materials, 2021

This study intended to address the problem of damaged (collapsed, cracked and decreased soil stre... more This study intended to address the problem of damaged (collapsed, cracked and decreased soil strength) road pavement structure built on clay soil due to clay soil properties such as low shear strength, high soil compressibility, low soil permeability, low soil strength, and high soil plasticity. Previous research reported that ground granulated blast slag (GGBS) and fly ash can be used for clay soil stabilizations, but the results of past research indicate that the road pavement construction standards remained unfulfilled, especially in terms of clay’s subgrade soil. Due to this reason, this study is carried out to further investigate soil stabilization using GGBS and fly ash-based geopolymer processes. This study investigates the effects of GGBS and ratios of fly ash (solid) to alkaline activator (liquid) of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1, cured for 1 and 7 days. The molarity of sodium hydroxide (NaOH) and the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) was fixed...

Materials, 2021

This paper clarified the microstructural element distribution and electrical conductivity changes... more This paper clarified the microstructural element distribution and electrical conductivity changes of kaolin, fly ash, and slag geopolymer at 900 °C. The surface microstructure analysis showed the development in surface densification within the geopolymer when in contact with sintering temperature. It was found that the electrical conductivity was majorly influenced by the existence of the crystalline phase within the geopolymer sample. The highest electrical conductivity (8.3 × 10−4 Ωm−1) was delivered by slag geopolymer due to the crystalline mineral of gehlenite (3Ca2Al2SiO7). Using synchrotron radiation X-ray fluorescence, the high concentration Ca boundaries revealed the appearance of gehlenite crystallisation, which was believed to contribute to development of denser microstructure and electrical conductivity.

Welding Technology Review, 2020

Wear resistant welds are used in many industries when it is necessary to protect machine componen... more Wear resistant welds are used in many industries when it is necessary to protect machine components and structures against wear caused by operating conditions. Often the main parameter determining the usefulness of these welds is high hardness reaching about 60HRC. In many cases, after the surfacing process, a mesh of cracks is formed in the surface layer, which can affect the durability of the hard-wearing layers used. The paper presents the analysis of the influence of preheating before welding up to 400 ° C on the properties of welds and its effect on the number of cracks in the surface layer. The use of preheating allowed to reduce the number of cracks in the surfacing to 1. The optimum heating temperature was 200 ° C, for which the number of cracks was reduced and the lowest wear was recorded.

Biuletyn Instytutu Spawalnictwa, 2020

The study presents the geometry as well as results of the peeling, shearing and metallographic te... more The study presents the geometry as well as results of the peeling, shearing and metallographic tests of copper and aluminium welded joints used in the absorber panels of flat solar collectors. The article discusses desired characteristics and mechanical properties of ultrasonic welded joints and compares the latter with laser welded joints. In addition, the study indicates prospective implementation areas of ultrasonic welding technologies.

Biuletyn Instytutu Spawalnictwa, 2018

The article presents test results concerning welded joints made of cast steel GX8CrNi12-1. The ab... more The article presents test results concerning welded joints made of cast steel GX8CrNi12-1. The above-named cast steel has a martensitic microstructure and can be used in pressure equipment operated at ambient and high temperature. The test joints were made in the horizontal position and in the vertical up position. The foregoing was dictated by the fact that the above-named positions are used in industrial conditions, e.g. when welding steel castings. The welding process performed in the above-named positions ensured that specimens were sampled from areas exposed to the lowest and highest arc linear energy. The article describes the process of manual metal arc welding (111) and the post-weld heat treatment. The test joints were subjected to destructive tests including transverse tensile tests, impact strength tests, hardness measurements as well as macro and microscopic tests. The test results revealed differences in properties of joints made in different positions, resulting from various heat inputs to joints during welding.

IOP Conference Series: Materials Science and Engineering, 2018

A chamfering of the joining sheet edges is often used in welding practice. In work, the analysis ... more A chamfering of the joining sheet edges is often used in welding practice. In work, the analysis of groove weld input on residual stress distribution in single-pass butt welded joints with thorough penetration is presented. For this purpose, comparative calculations of instantaneous and residual stresses in two steel flat bars were made. The butt welded joints of S235 steel elements put to the analysis. Numerical simulations were conducted for joint with welding groove and for joint without chamfering of flats. The calculations include strains caused by temperature changes as well as the effect of phase transformations. For calculations are used authors' programs made in Borland Delphi. The results are presented in the form of temperature, volume phase fraction and stress distributions in the element's cross section as well as welding thermal cycles and stress history at selected points. The analysis of the results of the calculations showed slight differences in the stress distributions in the heat-affected zones of the considered flat bars, while it did not show significant differences in stress levels outside these areas.

Przegląd Spawalnictwa - Welding Technology Review, 2015

W pracy przedstawiono wybrane aspekty technologii wykonywania powierzchni grzewczych tj. wężownic... more W pracy przedstawiono wybrane aspekty technologii wykonywania powierzchni grzewczych tj. wężownic przegrzewaczy pary z wykorzystaniem kompleksowego stanowiska do spawania metodą zmechanizowaną TIG. Próby spawania wykonano na rurach ze stali VM12-SHC o średnicy 44,5mm i grubości ścianki 7,1mm. Przedstawiono wyniki badań niszczących oraz nieniszczących oraz wskazano na problemy jakie można spotkać w czasie spawania tego typu stali. Przeprowadzone próby spawania złącza doczołowego dowiodły, iż spawanie orbitalne metodą TIG jest procesem bardzo skutecznym pod względem powtarzalności oraz jakości wykonanych połączeń spawanych. Odpowiednio przygotowane oprogramowanie procesu spawania, czy też bieżąca kontrola stanu technicznego urządzenia, powodują iż wskaźnik wadliwość wykonywanych złącz wynosi poniżej 1%. Z tego względu metoda spawania orbitalnego TIG jest rekomendowana w przypadku, gdy spawane są elementy w gatunkach o utrudnionej spawalności tj. VM12-SHC.

Przegląd Spawalnictwa - Welding Technology Review, 2011

W artykule omówiono problem określenia parametrów istotnych dla napawania drutem rdzeniowym samoo... more W artykule omówiono problem określenia parametrów istotnych dla napawania drutem rdzeniowym samoosłonowym. Metoda SSA jest jedną ze spawalniczych metod, która daje duże możliwości w wytwarzaniu napoin o zróżnicowanym składzie chemicznym i dobrej jakości. Istotne jest określenie, które z parametrów napawania mają znaczący wpływ na właściwości napoiny. Zastosowanie planu Placketta-Burmana umożliwiło statystyczną ocenę istotności wpływu wybranych parametrów napawania na geometrię napoiny.