ABSTRACT A theoretical analysis is presented for the time-dependent vertical motion of spherical ... more ABSTRACT A theoretical analysis is presented for the time-dependent vertical motion of spherical particles in a gas stream. Laminar, transitional and turbulent flows are considered, and equations are developed to predict particle velocity and distance travelled as functions of time in both stagnant and slowly-moving gases. In both cases the equations are shown not to be universally applicable, and algorithms for estimating the limits within which they remain valid are briefly presented.
... and control. Wear, 19 (1972) 163-168. 2 AV Sreenath and N. Raman, Running-in wear of a compre... more ... and control. Wear, 19 (1972) 163-168. 2 AV Sreenath and N. Raman, Running-in wear of a compres-sion ignition engine; factors influencing the conformance between cylinder liner and piston ring. Wear, 36 ( 1976) 271-290. 3 ...
The development of gas nitriding and the systematic expansion of its scope of application in prac... more The development of gas nitriding and the systematic expansion of its scope of application in practice means that the issue of the production of nitrided layers on steels is still in the center of interest of industry and research centers from both a cognitive and application point of view. Research mainly focuses on determining the relationship between the construction of the nitrided layer and its production parameters. The condition of full control of the nitriding process effect is the control of the nitrogen availability of the nitriding atmosphere, which depends on the value of the nitrogen potential (Np) and the degree of ammonia dissociation (α). Shaping of these parameters is carried out by controlling and regulating the composition of the inlet atmosphere. Control and regulation of the inlet atmosphere composition is important in controlling the nitrogen availability of the nitriding atmosphere and, consequently, the kinetics of nitrided layer thickness increase. The articl...
In industrial applications of thermo-chemical treatments, gas nitriding is a widespread method of... more In industrial applications of thermo-chemical treatments, gas nitriding is a widespread method of nitriding. Machine parts and tools of various shapes and sizes are nitrided, including drills, cutters, dies, shafts, rings, bearing balls, etc. often characterized by a complicated shape. The nitrided layers should have a controlled thickness not only of the diffusion zone, but also the surface layer of iron nitrides to have good exploitation properties. With a properly prepared surface on low alloy steels, we obtain a uniform nitrided layer after nitriding. It may happen that the structure of the nitrided layer is heterogeneous or even completely lacking in the nitrided parts having a complicated shape, and especially thin inner openings, where it is difficult to properly prepare the surface. Therefore, the nitriding problem is not the external surface of the workpieces but the internal one. The aim of the work was to assess the possibility of nitriding deep holes with small diameter....
W artykule porównano dwuskładnikowe atmosfery wlotowe rozcieńczane zdysocjowanym amoniakiem (NH3/... more W artykule porównano dwuskładnikowe atmosfery wlotowe rozcieńczane zdysocjowanym amoniakiem (NH3/NH3zd) oraz azotem (NH3/N2). W atmosferach NH3/NH3zd rozporządzalność azotu regulowano zmieniając stopień rozcieńczenia atmosfery wlotowej zdysocjowanym amoniakiem. W atmosferach wlotowych NH3/N2 rozporządzalność azotu regulowano również zmieniając stopień rozcieńczenia azotem atmosfery wlotowej. W artykule wykazano między innymi, jeżeli w pierwszym stopniu procesu wartość potencjału przyjmuje wartości z obszaru trwałości fazy γ’, towarzyszy temu ograniczenie kinetyki wzrostu warstwy azotowanej. Ograniczenie to występuje również po wzroście potencjału do wartości z obszaru trwałości fazy ε. W odróżnieniu od atmosfery rozcieńczanej zdysocjowanym amoniakiem, nie ma znaczenia, czy w pierwszym stopniu procesu rozporządzalność azotu jest niska a w drugim stopniu wysoka czy też odwrotnie, końcowy efekt procesu pod względem parametrów warstwy azotowanej jak i pod względem kinetyki wzrostu grubo...
W artykule omówiono wyniki badań realizowanych w projekcie „TANGO”, „Innowacyjne warstwy azotowan... more W artykule omówiono wyniki badań realizowanych w projekcie „TANGO”, „Innowacyjne warstwy azotowane nowej generacji o podwyższonej odporności korozyjnej wytwarzane na elementach maszyn”. Celem projektu było m.in. opracowanie technologii azotowania antykorozyjnego części maszyn wykonanych ze stali 41CrAlMo7. Fragmenty części i próbki kontrolne azotowano w dwustopniowych procesach regulowanego azotowania gazowego. W wyniku procesu uzyskano warstwy azotowane z przypowierzchniową warstwą azotków żelaza + ’. W artykule wykazano, że warstwa azotków żelaza o grubości 15 µm będąca mieszaniną faz + ’ skutecznie zabezpiecza stal przed korozją atmosferyczną oraz podwyższa jej odporność na zużycie przez tarcie.
Archives of Mechanical Technology and Materials, 2016
In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding pr... more In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding process has many advantageous properties. Controlled gas nitriding was carried out on 42CrMo
A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable n... more A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser tr...
A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable n... more A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser tr...
Purpose: The article presents the application of the duplex technology (nitriding plus PVD) to mo... more Purpose: The article presents the application of the duplex technology (nitriding plus PVD) to modification of the surface of pressure casting dies made of steel WCL (EN: X37CrMoV51). In this technology, there are clearly defined expectations regarding the properties of the surface layer of the dies obtained in the nitriding process. The main part of the article is presentation a complex system of designing, in-situ visualization and control of the gas nitriding process.Design/methodology/approach: In the conception of computer designing, analytical mathematical models and artificial intelligence methods were used.Findings: As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers.Practical implications: Computer procedures make it possible to co...
Introduction. The anticorrosion nitriding, or nitrocarburizing, often combined with post-oxidatio... more Introduction. The anticorrosion nitriding, or nitrocarburizing, often combined with post-oxidation, represents in the last two decades an attractive treatment, widely applied to all kinds of machine parts exposed to corrosion in service. It has been a subject of numerous publications [1-4], among others referring to new variants of this process, involving the impregnation of the nitrided surface with special compounds [5-7]. This category includes anticorrosion nitriding followed by impregnation with corrosion inhibitors [8], which is the subject of this paper. We describe the application of this kind of nitriding with subsequent oxidation and inhibitor impregnation to hydraulic actuator rods, exposed in service to an aggressive corrosive environment and, at the same time to mechanical wear. These actuators represent the basic component of hydraulic systems, mainly in mining equipment (loaders) subjected to elevated temperatures of about 35 o C in the presence of brine. They are als...
ABSTRACT A theoretical analysis is presented for the time-dependent vertical motion of spherical ... more ABSTRACT A theoretical analysis is presented for the time-dependent vertical motion of spherical particles in a gas stream. Laminar, transitional and turbulent flows are considered, and equations are developed to predict particle velocity and distance travelled as functions of time in both stagnant and slowly-moving gases. In both cases the equations are shown not to be universally applicable, and algorithms for estimating the limits within which they remain valid are briefly presented.
... and control. Wear, 19 (1972) 163-168. 2 AV Sreenath and N. Raman, Running-in wear of a compre... more ... and control. Wear, 19 (1972) 163-168. 2 AV Sreenath and N. Raman, Running-in wear of a compres-sion ignition engine; factors influencing the conformance between cylinder liner and piston ring. Wear, 36 ( 1976) 271-290. 3 ...
The development of gas nitriding and the systematic expansion of its scope of application in prac... more The development of gas nitriding and the systematic expansion of its scope of application in practice means that the issue of the production of nitrided layers on steels is still in the center of interest of industry and research centers from both a cognitive and application point of view. Research mainly focuses on determining the relationship between the construction of the nitrided layer and its production parameters. The condition of full control of the nitriding process effect is the control of the nitrogen availability of the nitriding atmosphere, which depends on the value of the nitrogen potential (Np) and the degree of ammonia dissociation (α). Shaping of these parameters is carried out by controlling and regulating the composition of the inlet atmosphere. Control and regulation of the inlet atmosphere composition is important in controlling the nitrogen availability of the nitriding atmosphere and, consequently, the kinetics of nitrided layer thickness increase. The articl...
In industrial applications of thermo-chemical treatments, gas nitriding is a widespread method of... more In industrial applications of thermo-chemical treatments, gas nitriding is a widespread method of nitriding. Machine parts and tools of various shapes and sizes are nitrided, including drills, cutters, dies, shafts, rings, bearing balls, etc. often characterized by a complicated shape. The nitrided layers should have a controlled thickness not only of the diffusion zone, but also the surface layer of iron nitrides to have good exploitation properties. With a properly prepared surface on low alloy steels, we obtain a uniform nitrided layer after nitriding. It may happen that the structure of the nitrided layer is heterogeneous or even completely lacking in the nitrided parts having a complicated shape, and especially thin inner openings, where it is difficult to properly prepare the surface. Therefore, the nitriding problem is not the external surface of the workpieces but the internal one. The aim of the work was to assess the possibility of nitriding deep holes with small diameter....
W artykule porównano dwuskładnikowe atmosfery wlotowe rozcieńczane zdysocjowanym amoniakiem (NH3/... more W artykule porównano dwuskładnikowe atmosfery wlotowe rozcieńczane zdysocjowanym amoniakiem (NH3/NH3zd) oraz azotem (NH3/N2). W atmosferach NH3/NH3zd rozporządzalność azotu regulowano zmieniając stopień rozcieńczenia atmosfery wlotowej zdysocjowanym amoniakiem. W atmosferach wlotowych NH3/N2 rozporządzalność azotu regulowano również zmieniając stopień rozcieńczenia azotem atmosfery wlotowej. W artykule wykazano między innymi, jeżeli w pierwszym stopniu procesu wartość potencjału przyjmuje wartości z obszaru trwałości fazy γ’, towarzyszy temu ograniczenie kinetyki wzrostu warstwy azotowanej. Ograniczenie to występuje również po wzroście potencjału do wartości z obszaru trwałości fazy ε. W odróżnieniu od atmosfery rozcieńczanej zdysocjowanym amoniakiem, nie ma znaczenia, czy w pierwszym stopniu procesu rozporządzalność azotu jest niska a w drugim stopniu wysoka czy też odwrotnie, końcowy efekt procesu pod względem parametrów warstwy azotowanej jak i pod względem kinetyki wzrostu grubo...
W artykule omówiono wyniki badań realizowanych w projekcie „TANGO”, „Innowacyjne warstwy azotowan... more W artykule omówiono wyniki badań realizowanych w projekcie „TANGO”, „Innowacyjne warstwy azotowane nowej generacji o podwyższonej odporności korozyjnej wytwarzane na elementach maszyn”. Celem projektu było m.in. opracowanie technologii azotowania antykorozyjnego części maszyn wykonanych ze stali 41CrAlMo7. Fragmenty części i próbki kontrolne azotowano w dwustopniowych procesach regulowanego azotowania gazowego. W wyniku procesu uzyskano warstwy azotowane z przypowierzchniową warstwą azotków żelaza + ’. W artykule wykazano, że warstwa azotków żelaza o grubości 15 µm będąca mieszaniną faz + ’ skutecznie zabezpiecza stal przed korozją atmosferyczną oraz podwyższa jej odporność na zużycie przez tarcie.
Archives of Mechanical Technology and Materials, 2016
In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding pr... more In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding process has many advantageous properties. Controlled gas nitriding was carried out on 42CrMo
A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable n... more A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser tr...
A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable n... more A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser tr...
Purpose: The article presents the application of the duplex technology (nitriding plus PVD) to mo... more Purpose: The article presents the application of the duplex technology (nitriding plus PVD) to modification of the surface of pressure casting dies made of steel WCL (EN: X37CrMoV51). In this technology, there are clearly defined expectations regarding the properties of the surface layer of the dies obtained in the nitriding process. The main part of the article is presentation a complex system of designing, in-situ visualization and control of the gas nitriding process.Design/methodology/approach: In the conception of computer designing, analytical mathematical models and artificial intelligence methods were used.Findings: As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers.Practical implications: Computer procedures make it possible to co...
Introduction. The anticorrosion nitriding, or nitrocarburizing, often combined with post-oxidatio... more Introduction. The anticorrosion nitriding, or nitrocarburizing, often combined with post-oxidation, represents in the last two decades an attractive treatment, widely applied to all kinds of machine parts exposed to corrosion in service. It has been a subject of numerous publications [1-4], among others referring to new variants of this process, involving the impregnation of the nitrided surface with special compounds [5-7]. This category includes anticorrosion nitriding followed by impregnation with corrosion inhibitors [8], which is the subject of this paper. We describe the application of this kind of nitriding with subsequent oxidation and inhibitor impregnation to hydraulic actuator rods, exposed in service to an aggressive corrosive environment and, at the same time to mechanical wear. These actuators represent the basic component of hydraulic systems, mainly in mining equipment (loaders) subjected to elevated temperatures of about 35 o C in the presence of brine. They are als...
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Papers by Jerzy Michalski