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1

Effects of thermo-chemical treatment and grinding process of external cylindrical surfaces on residual stresses in 13CrMo4-5 steel

Wójcik R., Sawicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 120, nr 1

10--21

EN

Purpose This paper presents a study aimed at determining the effect of the carburizing treatment process and the subsequent grinding process on the residual stresses occurring in ring-shaped specimens made of 13CrMo4-5 steel. Design/methodology/approach During the tests, vacuum carburizing was used, achieving an effective case depth ECD = 0.5 mm. Subsequently, the cylindrical outer surfaces of the samples were ground by conventional plunge grinding and with innovative kinematics using a test stand based on a conventional flat-surface grinding machine. As part of the study, microhardness and residual stresses were measured before and after grinding. Measurements were carried out to a depth of 1 mm. The main component of the stand is an original special device that allows the cylindrical specimen to be clamped. Then the angle between its axis of rotation and the axis of rotation of the grinding wheel is set with respect to the plane of the grinding machine’s magnetic table. In the described tests, the axis of rotation of the cylindrical specimen was deviated from its original position by 15° and set at an angle of 75° to the axis of rotation of the grinding wheel. The specimens were ground with a grinding wheel of noble electro-corundum marked 38A60K8V. In both kinematic cases of the grinding process, a machining allowance of 0.01 mm was removed. Findings Grinding using innovative kinematics did not cause any significant changes in the microhardness distribution, either for vacuum or conventional carburizing. In addition, residual stress measurements using the Dawidenkov-Sachs method showed that innovative grinding enables a more favourable distribution than those obtained after conventional plunge grinding. Research limitations/implications Further research will focus on, among others, selecting the angular settings of the workpiece axes relative to the grinding wheel axes depending on their dimensions. Grinding guidelines should include coverage ratio, infeed value, grinding time, and peripheral speeds. In addition, the plan for future research includes measuring the components of the grinding force and the geometric structure of the surface. Practical implications Grinding process is a crucial stage of steel treatment in almost every industrial branch. In sustainable manufacturing, it is extremely important to produce high-quality items while reducing the cost of manufacturing and taking care of the environment and workers’ health. Originality/value The proposed test stand, together with the authors’ device, makes it possible to conduct machining of the external surfaces of cylindrical workpieces on a flat surface grinder. In this case, the innovation of the grinding process consists of the non-parallel alignment of the cylindrical rotational axis of the specimen and the rotational axis of the grinding wheel with respect to the plane of the magnetic grinding table.

2

The Influence of Changes in Roll Pass Design on the State of Residual Stresses in Railway Rails - Summary

Żak Sylwester, Woźniak Dariusz

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

439--446

EN

The article presents the results of the last stage of work on the impact of changes in the roll pass design on the state of residual stresses in railway rails. The discussed stage includes the summary of industrial experiments of rolling 60E1 rails with a length of 120 meters using a modified pass design of roll grooves. The rolling technology has been deeply modified, ranging from the finishing stand, through the pre-finishing stand, to the semi-finishing stand. The rails in this experiment were cooled using standard cooling technology and then straightened using innovative vertical straightener shaped rollers. Residual stresses were tested using the strain gauge method and the hole-drilling strain gauge method by drilling a hole in the rail axis and at a distance of 14 millimetres from its axis. The resulting tensile stresses in the rail foot were reduced to an average level of less than 43% in relation to the requirements of the EN13674-1 standard.

3

Controlling the State of Residual Stresses in Railway Rails by Modifying Pass Design of Straightening Rollers

Żak Sylwester, Woźniak Dariusz

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

57--70

EN

The paper presents a summary of research on the possibility of influencing the state of residual stresses in railway rails by changing the pass design of vertical and horizontal straightener rollers and optimising their distribution on the rail perimeter. The presented results are devoted to the influence of profiled rollers on the level of residual stresses. A wide range of theoretical considerations were carried out based on the use of the finite element method using the commercial Forge software package. In order to verify the results of the theoretical considerations most reliably, a series of “in situ” experiments were conducted in industrial conditions on an existing production line. The tests were carried out on 120 meters long 60E1 railway rails. A significant reduction in the level of residual stresses compared to the standard requirements was achieved.

4

Influence of Surface Laser Treatment on Mechanical Properties and Residual Stresses of Titanium and its Alloys

Jażdżewska Magdalena, Majkowska-Marzec Beata, Ostrowski Roman, Olive Jean-Marc

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

27--38

EN

Surface modification of the titanium and its alloys used in implantology with a long-pulse laser can change the surface topography, but it also leads to changes in the stress sign and magnitude in the resulting subsurface layer. The presented research was aimed at evaluating the state of stress after laser remelting with the Nd:YAG laser of pre-etched titanium alloys Ti6Al4V and Ti13Nb13Zr and pure titanium. The obtained surface layers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), optical profilography, and nanoindentation studies. Based on the results obtained after the nanoindentation tests, the character of the stresses generated in the melted layers was calculated and determined. Laser processing resulted in surface layer thicknesses between 191-320 µm and surface roughness Ra between 2.89-5.40 µm. Laser processing caused increasing hardness, and its highest value was observed for the titanium alloy Ti13Nb13Zr - 5.18 GPa. The tensile stresses appeared following laser treatment and increased with elevating laser power up to the highest value for titanium.

5

Zastosowanie rentgenowskiej metody pomiaru naprężeń w diagnostyce przyczyny pękania elementu spawanego turbiny gazowej

Szymański Wojciech

Badania Nieniszczące i Diagnostyka

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2022

|

1-4

8--12

PL

W pracy przedstawiono metodykę diagnostyki przyczyn pękania detalu turbiny gazowej w miejscu połączenia spawanego dwóch stopów żarowytrzymałych. Wykonano rozkład naprężeń w okolicy złącza spawanego po wykonaniu elementu, co pozwoliło określić przyczynę pękania. Próby wyżarzania i odprężania wibracyjnego, nie przyniosły spodziewanych efektów. W dalszej części pracy przeprowadzono pomiary naprężeń łączonych spoiną elementów detalu na kolejnych etapach jego wytwarzania, co pozwoliło na określenie, w którym momencie produkcji powstają krytyczne naprężenia będące przyczyną przedwczesnego pękania w czasie pracy turbiny. Poprawa technologii produkcji eliminująca niekorzystny rozkład naprężeń pozwoliła na uzyskanie oczekiwanego czasu pracy turbiny bez awarii.

EN

The paper presents the methodology of diagnostics of the causes of cracking of a gas turbine detail in the place of a welded joint of two heat-resistant alloys. The stress distribution in the area of the welded joint was made after the element was made, which allowed to determine the cause of the cracking. Attempts at annealing and vibration stressing did not bring the expected results. In the further part of the work, measurements of the stresses of the elements connected by welding were carried out at subsequent stages of its production, which allowed to determine at which point in production critical stresses arise, which cause premature fracture during the operation of the turbine. The improvement of the production technology eliminating the unfavourable stress distribution allowed to obtain the expected working time of the turbine without failure.

6

Study on the influence of sheet straightening process on residual stress distribution, mechanical properties and structure of deep-drawing steel sheets

Radwański Krzysztof, Adamiec Andrzej, Kuziak Roman, Zaława Dariusz, Sozańska-Jędrasik Liwia

Journal of Metallic Materials

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2021

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Vol. 73, no. 4

3--10

EN

The article describes the impact of the stretch levelling process of DC03 and DC04 steel sheets on their quality in terms of further application for products formed in technologies used in the automotive industry. The straightening process was carried out in a demonstration line developed as part of a project carried out by DAR STAL Dariusz Zaława together with the Łukasiewicz Research Network - Institute for Ferrous Metallurgy. The study examined the influence of stretch levelling on waviness and the state of internal stresses of the sheets. It was found that the use of stretch levelling with a controlled elongation value results in obtaining a favourable and stable state of stress in the sheets. No significant influence of the straightening process on the structure and mechanical properties of the sheets was found.

PL

W ramach artykułu opisano wpływ procesu prostowania naciągowego blach ze stali DC03 i DC04 na ich jakość pod kątem dalszego przeznaczenia na wyroby kształtowane w technologiach stosowanych w przemyśle motoryzacyjnym. Proces prostowania prowadzono w linii demonstracyjnej opracowanej w ramach projektu realizowanego przez firmę DAR STAL Dariusz Zaława wspólnie z Sieć Badawcza Łukasiewicz - Instytutem Metalurgii Żelaza. W ramach pracy badano wpływ prostowania naciągowego na falistość i stan naprężeń własnych blach. Stwierdzono, że zastosowanie prostowania naciągowego, z kontrolowaną wartością wydłużenia, powoduje uzyskanie korzystnego i stabilnego stanu naprężenia w blachach. Nie stwierdzono znaczącego wpływu procesu prostowania na strukturę oraz właściwości mechaniczne blach.

7

Wpływ zmian kalibrowania walców na stan naprężeń własnych w szynie kolejowej – symulacje numeryczne

Żak Sylwester, Woźniak Dariusz, Pidvysots’kyy Valeriy, Cieślik Łukasz

Hutnik, Wiadomości Hutnicze

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2021

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Vol. 88, nr 1

3--10

PL

W artykule przedstawiono wyniki pierwszego i drugiego etapu prac nad wpływem zmian kalibrowania walców na stan naprężeń własnych w szynach kolejowych. Etapy te stanowią kontynuację prac prowadzonych w ramach projektu dofinansowanego przez Narodowe Centrum Badań i Rozwoju. Badania obejmowały symulacje numeryczne procesu walcowania z wykorzystaniem nowego kalibrowania walców oraz prostowania przy użyciu rolek kształtowych prostownic pionowej i poziomej, wyznaczenie map rozkładu naprężeń w szynie po chłodzeniu i prostowaniu. Przedstawiono również wyniki pomiarów naprężeń własnych w szynach po eksperymentach w warunkach przemysłowych. Badania przemysłowe przeprowadzono na szynach o długości 120 metrów typu 60E1 w gatunku stali R260. Uzyskano znaczące zmniejszenie naprężeń własnych rozciągających w środku osi stopki szyny w stosunku do poziomu określonego w normie EN13674-1.

EN

The article presents the results of the first and second stage of work on the impact of changes in roll pass design on the state of residual stresses in rail rails. These stages are a continuation of the work carried out under the project co-financed by the National Centre for Research and Development. The research included numerical simulations of the rolling process using a new roll pass design and straightening operation using shaped rollers of vertical and horizontal straighteners, determination of maps of stress distribution in the rail after cooling and straightening. Measurements of residual stresses in rails after experiments in industrial conditions were also presented. The industrial tests were carried out on 120 meters long rails 60E1 type rails in the R260 steel grade. A significant reduction in tensile stress in the centre of the rail foot axis was obtained in relation to the level specified in the EN13674-1 standard.

8

Wpływ zmian kalibrowania walców na stan naprężeń własnych w szynie kolejowej – eksperymenty przemysłowe

Żak Sylwester, Woźniak Dariusz, Cieślik Łukasz

Hutnik, Wiadomości Hutnicze

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2021

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Vol. 88, nr 2

13--20

PL

W artykule przedstawiono wyniki pierwszego i drugiego etapu prac nad wpływem zmian kalibrowania walców na stan naprężeń własnych w szynach kolejowych. Etapy te stanowią kontynuację prac prowadzonych w ramach projektu dofinansowanego przez Narodowe Centrum Badań i Rozwoju. Badania obejmowały symulacje numeryczne procesu walcowania z wykorzystaniem nowego kalibrowania walców oraz prostowania przy użyciu rolek kształtowych prostownic pionowej i poziomej, wyznaczenie map rozkładu naprężeń w szynie po chłodzeniu i prostowaniu. Przedstawiono również pomiary naprężeń własnych w szynach po eksperymentach w warunkach przemysłowych. Badania przemysłowe przeprowadzono na szynach o długości 120 metrów typu 60E1 w gatunku stali R260. Uzyskano znaczące zmniejszenie naprężeń własnych rozciągających w środku osi stopki szyny w stosunku do poziomu określonego w normie EN13674-1.

EN

The article presents the results of the first and second stage of work on the impact of changes in roli pass design on the state of residual tresses in rail rails. These stages are a continuation of the work carried out under the project co-financed by the National Centre for Research and Development. The research included numerical simulations of the rolling process using a new roli pass design and straightening operation using shaped rollers of vertical and horizontal straighteners, determination of maps of stress distribution in the rail after cooling and straightening. Measurements of residual stresses in rails after experiments in industrial conditions were also presented. The industrial tests were carried out on 120 rneters long rails 60E1 type rails in the R260 steel grade. A significant reduction in tensile stress in the centre of the railfoot axis was obtained in relation to the level specified in the EN13674-1 standard.

9

Technological Forecasting of Deformations in Flat Parts

Ivanova Tatiana N., Biały Witold, Fries Jiri, Nordin Victor

Multidisciplinary Aspects of Production Engineering

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2020

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Vol. 3, Iss. 1

1--12

EN

The deformation of a part occurring in the process of grinding directly influences its exploitation and quality parameters. The instability of shape and size, which occurs due to an imbalance of residual stress, can be the one of the major causes of deformation of a part. The decrease in stress slows down the deformation process. Considering the regularities of heat source intensity dependence on the grinding modes, it can be asserted that with increasing grinding depth and grinding wheel hardness, the value increases and it decreases with a growth in a speed of the part and the use of cooling. The higher the heat removal is and the better lubricant properties of the liquid are, the more significant the decrease in is. Changing these values allows regulation of the residual stresses. As a result of the research on determination of deformations, it is recommended to reduce thermal deformations by considering the geometric size of a plate to be machined, linear expansion coefficient of plate material and an allowance for nonflatness from thermal deformations. The value of nonflatness from thermal deformations is directly proportional to linear expansion coefficient of plate material and its square overall dimensions. At the same time, the value of nonflatness is inversely proportional to the plate thickness.

10

Wpływ kształtu powierzchni roboczej rolek prostujących prostownic pionowej i poziomej na stan naprężeń własnych w szynie kolejowej - etap drugi badań

Żak Sylwester, Woźniak Dariusz, Pidvysots’kyy Valeriy, Urbanik Tomasz

Journal of Metallic Materials

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2020

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Vol. 72, no. 1

48--58

PL

W artykule przedstawiono wyniki drugiego etapu prac nad wpływem kształtu rolek prostownic na stan naprężeń własnych w szynach prowadzonych w ramach projektu dofinansowanego przez Narodowe Centrum Badań i Rozwoju. Badania obejmowały symulacje numeryczne procesu prostowania szyn z zastosowaniem nowego kalibrowania rolek prostownicy pionowej oraz poziomej, wyznaczenie map rozkładu naprężeń w szynie po prostowaniu w kolejnych rolkach obu prostownic, a także pomiary naprężeń własnych w szynach po operacji prostowania w warunkach przemysłowych. Badania wykonano na szynach typu 60E1 w gatunku R260. Uzyskano zmniejszenie naprężeń własnych rozciągających w środku osi symetrii stopki szyny, aż do średnich wartości 32 MPa tj. o ponad czterokrotnie mniej w stosunku do poziomu osiąganego przy użyciu tradycyjnej technologii.

EN

The paper presents the results of the second stage of work on the influence of the shape of straightening rollers on the state of residual stresses in rails, conducted as part of a project co-financed by the National Centre for Research and Development. The tests included numerical simulations of the rail straightening process using a new roll pass design of vertical and horizontal straightener rollers, determination of stress distribution maps in the rail after straightening in successive rollers of both straightening machines, as well as measurement of residual stresses in the rails after straightening operation in industrial conditions. The tests were carried out on R260 grade 60E1 rails. The reduction of tensile residual stresses in the centre of symmetry axis of the rail foot was obtained up to an average level of 32 MPa, i.e. by more than four times less in relation to the level achieved using traditional technology.

11

Wpływ kształtu powierzchni roboczej rolek prostujących prostownic pionowej i poziomej na stan naprężeń własnych w szynie kolejowej – trzeci etap badań

Żak Sylwester, Woźniak Dariusz, Pidvysots’kyy Valeriy, Dzierżawczyk Tomasz

Hutnik, Wiadomości Hutnicze

|

2020

|

Vol. 87, nr 9

225--232

PL

W artykule przedstawiono wyniki trzeciego etapu prac nad wpływem nowego kalibrowania rolek prostownic na stan naprężeń własnych w szynach kolejowych prowadzonych w ramach projektu dofinansowanego przez Narodowe Centrum Badań i Rozwoju. Badania obejmowały symulacje numeryczne procesu prostowania szyn z zastosowaniem innowacyjnego kształtu rolek prostownicy pionowej oraz poziomej, wyznaczenie map rozkładu naprężeń w szynie po prostowaniu w kolejnych rolkach obu prostownic, a także pomiary naprężeń własnych w szynach po operacji prostowania w warunkach przemysłowych. Badania przeprowadzono na szynach o długości 120 metrów typu 60E1 w gatunku stali R260. Uzyskano znaczące zmniejszenie naprężeń własnych rozciągających w środku osi symetrii stopki szyny oraz w główce szyny w stosunku do poziomu określonego w normie EN 13674-1.

EN

In this paper the results of the third stage of works on the influence of the shape of straightening rollers on the state of residual stresses in railway rails conducted as part of a project co-financed by the National Centre for Research and Development are presented. The performed tests included numerical simulations of the straightening process of rails using a new roll pass design of vertical and horizontal straightener rollers, determination of stress distribution maps in the rail after straightening in successive rollers of both straightening machines, as well as measurements of residual stresses in rails after straightening operation in industrial conditions. The tests were carried out on 120 meters long rails type 60E1 in the R260 steel grade. Obtained the significant reduction of tensile residual stresses in the centre of symmetry axis of the rail foot as well as of the rail head in relation to the level specified in the standard EN 13674-1.

12

Hot isostatic pressing influence on the mechanical properties of selectively laser-melted 316L steel

Kluczyński J., Śnieżek L., Grzelak K., Oziębło A., Perkowski K., Torzewski J., Szachogłuchowicz I., Gocman K., Wachowski M., Kania B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

|

Vol. 68, nr 6

1413--1424

EN

Industries that rely on additive manufacturing of metallic parts, especially biomedical companies, require material science-based knowledge of how process parameters and methods affect the properties of manufactured elements, but such phenomena are incompletely understood. In this study, we investigated the influence of selective laser melting (SLM) process parameters and additional heat treatment on mechanical properties. The research included structural analysis of residual stress, microstructure, and scleronomic hardness in low-depth measurements. Tensile tests with specimen deformation analysis using digital image correlation (DIC) were performed as well. Experiment results showed it was possible to observe the porosity growth mechanism and its influence on the material strength. Specimens manufactured with 20% lower energy density had almost half the elongation, which was directly connected with the porosity growth during energy density reduction. Hot isostatic pressing (HIP) treatment allowed for a significant reduction of porosity and helped achieve properties similar to specimens manufactured using different levels of energy density.

13

Guidelines to select suitable parameters for contour method stress measurements

Naveed N.

Archives of Mechanics

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2020

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Vol. 72, nr 1

39--58

EN

The contour method is one of the promising techniques for the measurement of residual stresses in engineering components. In this method, the cut surfaces deform, owing to the relaxation of residual stresses. The deformations of the two cut surfaces are then measured and used to back calculate the 2-dimensional map of original residual stresses normal to the plane of the cut. Thus, it involves four main steps; specimen cutting, surface contour measurement, data analysis and finite element simulation. These steps should perform in a manner that they do not change the underlying features of surface deformation especially where the residual stress distribution varies over short distances. Therefore, to carefully implement these steps, it is important to select appropriate parameters such as surface deformation measurement spacing, data smoothing parameters (‘knot spacing’ for example cubic spline smoothing) and finite element mesh size. This research covers an investigation of these important parameters. A simple approach for choosing initial parameters is developed based on an idealised cosine displacement function (giving a self-equilibrated one-dimensional residual stress profile). In this research, guidelines are proposed to help the measurer to select the most suitable choice of these parameters based on the estimated wavelength of the residual stress field.

14

Effects of CO2 and Nd:YAG laser remelting of the Ti6Al4V alloy on the surface quality and residual stresses

Jażdżewska M.

Advances in Materials Science

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2020

|

Vol. 20, nr 1(63)

82--90

EN

The titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level of residual stresses in the Ti6Al4V alloy, which determine the initiation and propagation of cracking. Two lasers were used, the CO2 and Nd:YAG lasers. The specimens were remelted in liquid nitrogen, water or calm air at different pre-heating temperature. The different laser power and scan rates were applied. The increase in energy density increased the number of cracks, the change of an environment and pre-heating affected alo the surface cracking. The cracks observed after remelting with Nd:YAG laser were longer than those observed after treatment with CO2 laser. The compressive stresses after the CO2 laser treatment, and tensile stresses after treatment with the Nd:YAG laser, were found. The appearance of cracks was attributed to an excessive energy density. The different distribution of heat energy inside and around the laser tracks was discussed as the origin of presence either tensile or compressive stresses in the alloy treated with different lasers.

15

Magneto - sprężystość w stalach krzemowych diagnostyka struktury i defektu - eksperyment

Żurek Zbigniew Hilary, Chmiela Bartosz, Idziak Paweł, Kowalski Krzysztof, Wolnik Piotr

Maszyny Elektryczne : zeszyty problemowe

|

2019

|

Nr 1 (121)

97--104

PL

Blachy krzemowe o zastosowaniach elektrotechnicznych są produkowane ze względu na przeznaczenie. W obwodach magnetycznych transformatorów struktura blach jest projektowana ze względu na zgodność kierunku magnesowania z kierunkiem wektora indukcji. Są to blachy o strukturze zorientowanej (GO - e.g. anisotropic transformer sheets). W napędach przetwarzających energię pola magnetycznego na ruch obrotowy stosujemy blachy o strukturze niezorientowanej (NGO - e.g. isotropic or generator sheets). Defekty struktury będące wynikiem cięcia lub wycinania (dowolnymi technikami mają wpływ na deformację kierunku magnesowania bez względu na stosowane techniki cięcia. W procesie tym uczestniczą zjawiska magnetosprężyste i odwrotne, znane jako efekty Vilariego i Joule’a. W artykule opisano kierunkowe zmiany magnesowania na dwóch modelach testowych przygotowanych z blachy krzemowej M130 w obszarze materiałowym, elektrotechnicznym i mechanicznym, a także w obszarze badań nieniszczących NDT (Non-destructive testing) i SHM (Structural health monitoring) monitorowanie stanu strukturalnego SHM, a także monitorowanie stanu w procesie eksploatacji (ang. Condition Monitoring - CM).

EN

Silicone sheets for electrical purposes are made for their intended purpose. In transformer magnetic circuits, the sheet structure is designed due to the compatibility of the direction of magnetization with the direction of the induction vector. These are oriented metal sheets (for example, anisotropic transformer sheets). In drives that convert the energy of a magnetic field into rotational motion, we use plates with a non-oriented structure (NGOs — for example, isotropic or generator sheets). Design defects resulting from cutting or cutting (using any methods that affect the deformation of the magnetization direction, regardless of the cutting methods used.) This process includes magneto-elastic and backward effects, known as the Vilary and Joule effects. tests prepared from silicon steel sheet M130 in the material, electrical and mechanical fields, as well as NDT (non-destructive testing) and SHM (Structural health monitoring), monitoring the state of structures SHM, and monitoring the state (Condition Monitoring - CM).

16

Measurement of residual stresses of locomotive wheel treads during the manufacturing technological cycle

Muravev Vitaly V., Muraveva Olga V., Volkova Ludmila V., Sága Milan, Ságová Zuzana

Management Systems in Production Engineering

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2019

|

nr 4 (27)

236--241

EN

The production of two-wheeled rolling stock represents, at first glance, a simple assembly process that significantly affects the overall functionality and safety of the vehicle. This is due to residual stresses that arise after assembly by pressing the wheel on the axle. The state of stress after assembly remains in the design has a decisive influence on the load-bearing capacity of the two-wheel drive, its lifespan but also the transfer of the pulling force in the case of locomotives. Therefore, it is very important to find suitable methods for determining residual stresses. Numerical and experimental approaches are already in place to gain information on the state of stress after compression, or during a real operation. The developed techniques and tools for estimation of residual stresses in locomotive wheel treads based on the acoustoelasticity effect using electromagnetic acoustic transformation are described in the paper. The original results of residual stress measurement in the treads during a technological cycle of locomotive wheel pair manufacturing are presented.

17

Experimental and numerical parametric study of resistance spot welding process of AISI 1008 steel sheets

Khabaz-Aghdam Ata, Rahmani Azhdar, Fadaei Abbas

Journal of Theoretical and Applied Mechanics

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2019

|

Vol. 57 nr 4

807--820

EN

In the present research, a parametric study in Resistance Spot Welding (RSW) of thin AISI 1008 steel sheets is investigated via FEM. All the time steps through the RSW process, including squeeze time, welding time, holding time and cooling time are taken into account. First, the effects of various parameters such as electrical current, welding time and electrode tip diameter are investigated in the nugget geometry. Then, a time history stress diagram and residual stresses are obtained in RSW weldment. FEM results are validated very well by some experiments which were performed in two parts of nugget geometry and residual stresses.

18

Pomiary naprężeń własnych tytanu Ti6Al4V po procesach kulowania na potrzeby inżynierii biomedycznej

Bańczerowski Jakub, Mońka Grzegorz, Skalski Konstanty

Inżynieria Powierzchni

|

2019

|

nr 4

10--17

PL

W pracy przedstawiono wyniki pomiarów naprężeń własnych odpowiednio przygotowanych próbek tytanu Grade 5 (Ti6Al4V). Próbki były uprzednio kulowane śrutem stalowym o średnicach 0,6 mm, i 1,2 mm i twardości 640 HV. Przeprowadzono pomiary naprężeń własnych metodą Waismana-Philipsa polegającą na pomiarze strzałki ugięcia próbki w próbie trawienia stopu tytanu Ti6Al4V w roztworze kwasu fluorowodorowego (HF) i siarkowego (H2SO4). Badanie przeprowadzono na stanowisku zaprojektowanym i wykonanym wcześniej w Instytucie Mechaniki Precyzyjnej (IMP). W celu oceny wpływu parametrów procesu kulowania na próbki wykonano pomiary chropowatości ich powierzchni przed trawieniem. Wyznaczenie wartości i rozkładów naprężeń własnych sprowadza się, jak nadmieniono, do określenia zmian krzywizny w funkcji zmian grubości badanej próbki, a następnie wykonaniu niezbędnych obliczeń. Wyniki pomiaru przemieszczeń w funkcji czasu oraz grubości próbek uzyskane po trawieniu posłużyły do wyznaczenia wartości naprężeń własnych w funkcji odległości od powierzchni próbki. Obliczenia wykonano przy pomocy programu NWW 11.

EN

The paper presents results of measurements of residual stresses of the properly prepared Grade 5 titanium (Ti6Al4V) samples. The samples previously underwent the process of shot-peening with steel shots with 0.6 mm, and 1.2 mm in diameter and 640 HV hardness. Measurements of residual stresses were carried out using the Waismman-Philips method consisting in measuring the sample deflection arrow in the etching test of Ti6Al4V titanium alloy in the solution of hydrofluoric acid (HF) and sulfuric acid (H2SO4). Tests were carried out on the stand designed and constructed earlier at the Institute of Precision Mechanics (IMP). In order to assess the impact of the shot-peening process parameters on the samples, roughness measurements of the surface before etching were carried out. Determining the values and distributions of the residual stresses is reduced, as mentioned, to determining the changes in curvature as a function of changes in the thickness of the sample tested, and then conducting the necessary calculations. The results of the measurement of displacements as a function of time and thickness of the samples obtained after etching were used to determine the value of residual stresses as a function of distance from the sample surface. Calculations were conducted with using the NWW.11 program.

19

Wpływ kształtu powierzchni roboczej rolek prostujących prostownicy pionowej na poziom naprężeń własnych w szynie kolejowej

Żak Sylwester, Woźniak Dariusz, Pidvysotskyy Valeriy, Radosz Mariusz

Hutnik, Wiadomości Hutnicze

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2019

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Vol. 86, nr 10

319--323

PL

W artykule przedstawiono wyniki pierwszego etapu prac nad wpływem kształtu rolek prostownic na stan naprężeń własnych w szynach prowadzonych w ramach projektu dofinansowanego przez Narodowe Centrum Badań i Rozwoju. Wykonane badania obejmowały symulacje numeryczne procesu prostowania szyn z zastosowaniem nowego kalibrowania rolek prostownicy pionowej, wyznaczenie map rozkładu naprężeń w szynie po prostowaniu w kolejnych rolkach, pomiary naprężeń własnych w szynach po operacji prostowania w warunkach przemysłowych. Badania przeprowadzono na szynach typu 60E1 w gatunku R260. Uzyskano zmniejszenie naprężeń własnych rozciągających w środku osi symetrii stopki szyny o ponad 52% w stosunku do poziomu osiąganego.

EN

In this paper the results of the first stage of works on the influence of the shape of straightener rollers on the state of residual stresses in rails conducted as part of a project co-financed by the National Center for Research and Development are presented. The performed tests included numerical simulations of the straightening process of rails using a new roll pass design of vertical straightener rollers, determination of stress distribution maps in the rail after straightening in successive rolls, measurements of residual stresses in rails after straightening operation in industrial conditions. The tests were carried out on 60E1 rails in the R260 grade. The reduction of tensile residual stresses in the center of symmetry axis of the rail foot was obtained by over 52% in relation to the level achieved during straightening with the use of traditional rollers.

20

Estimation of residual stresses for multi-layer circumferential welds of oil and gas pipelines

Kychma Andrii, Predko Rostyslav

Diagnostyka

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2019

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Vol. 20, No. 4

11--18

EN

The article presents results of investigation of residual stresses for multi-layer circumferential welds of oil and gas pipelines. The research was carried out on a designed and manufactured testing equipment for the experimental determination of the stress state parameters in the zone of multi-layer welded joints of pipe segments with the external diameter of 1020 mm and the wall thicknesses of 9.5 mm, of 14 mm, and of 22 mm which were made of carbon steels of different quality (13G1S, 13G1SU, 17G1S and 17G1SU). Determination of residual stresses in the zone of multi-layered circumferential welds of pipe segments was carried out by means of the method by the electronic speckle-interferometry and by the method of magnetoelasticity. On the basic of analysis of the obtained graphic dependences, the recommendations for engineering practice are suggested.