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1

Post-processing in multi-material 3D printing

Brancewicz-Steinmetz E., Sawicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 117, nr 1

5--14

EN

Purpose: This study aims to investigate the adhesion of combining two materials with different properties (PLA-TPU and TPU-PLA) printed in FFF (fused filament fabrication) with post-processing treatments. Design/methodology/approach: The scope of the study includes making variants of samples and subjecting them to three different post-printing treatments. After processes, shear tests were conducted to determine the adhesion. Findings: The post-printing treatment results in a stronger inter-material bond and increased adhesion strength; the best average shear strength results were achieved for annealing without acetone and for PLA/TPU samples for treatment in cold acetone vapour. Research limitations/implications: In the study, adhesion was considered in the circular pattern of surface development. Practical implications: Reinforcement of the biopolymer broadens the possibilities of using polylactide. Examples of applications include personalised printing items, where the elastomer will strengthen the polylactide. Originality/value: These studies aim to promote the use and expand the possibilities of using PLA biopolymer. The strength properties of printouts from different materials are often insufficient, hence the proposal to use post-printing processing.

2

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.

3

Impact of single-piece flow thermo-chemical treatment process conditions on hole quenching deformation

Stachurski Wojciech, Sawicki J., Zgórniak P., Wołowiec-Korecka E.

Archives of Materials Science and Engineering

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2023

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Vol. 121, nr 1

18--24

EN

Purpose: Pulsed low-pressure carburizing (LPC) and omnidirectional high-pressure gas quenching (HPGQ) are innovative methods for quenching the surface layer. The thermo-chemical treatment carried out by this method reduces quenching geometric deformations, with detailed numerical values not available in the literature due to the short existence of this method. Design/methodology/approach: Sixteen toothed elements of EN 20MnCr5 steel were subjected to pulsed low-pressure carburising with omnidirectional jet quenching in 4 groups, varying the process temperature (920°C, 960°C) and in two groups performing a tempering treatment. The elements were tested before machining by measuring their internal hole diameters, radial runout, roundness and cylindricity. These values were tested again after treatment. The direction of change and the statistical significance of the effect of treatment and its parameters, temperature and tempering were analysed. Findings: Thermo-chemical treatment significantly affects geometric changes in diameters, roundness, cylindricity and radial runout compared to elements without heat treatment due to physical transformations occurring during this treatment (p<0.05). Changing the process temperature in the value range of 920°C-960°C affects the hole diameter (makes it smaller) (p<0.05), but does not affect radial runout, cylindricity and roundness. The observed dimensional changes in diameters have numerically small values (<0.005 mm). The tempering treatment can affect the values of average diameters. Its effect on roundness, cylindricity and radial runout was not observed. Research limitations/implications: In the temperature range studied, the method of pulsed low-pressure carburising + omnidirectional high-pressure gas quenching makes it possible to raise the temperature of the process and shorten its duration without significant geometric changes in the treated elements. Practical implications: The method of pulsed low-pressure carburising and omnidirectional high-pressure gas quenching (HPGQ) ensures the maintenance of reproducible quenching deformations at a level significantly lower than conventional processing methods. Originality/value: The method of pulsed low-pressure carburising together with omnidirectional high-pressure gas quenching (HPGQ) is a method that has been used briefly in the industry, and there are few reports on it to date.

4

Effect of grinding conditions of gears made of 20MnCr5 steel after single-piece flow heat treatment on the condition of the surface layer of the tooth working surface

Stachurski W., Janica J., Januszewicz B., Pawłowski W., Sawicki J.

Archives of Materials Science and Engineering

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2023

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Vol. 120, nr 2

60--69

EN

Purpose: The paper investigated the effect of selected processing conditions during gear grinding on the value and distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment (TCT) conducted by a continuous single-piece flow method. Design/methodology/approach: The gears were carburised with LPC at 920°C, then quenched in a 4D Quenching chamber at 7 bar and tempered at 190ºC for 3 hours. In the next step, the working surfaces of the gear teeth were ground by supplying grinding fluid (GF) to the grinding zone using the WET method and the MQL method with a minimum amount. Measurements were made on the distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment and after the grinding process. Findings: The results of the study showed the influence of workpiece speed vw and the method of delivery to the grinding zone GF on selected parameters describing the condition of the technological surface layer of the teeth of gears made of 20MnCr5 steel. The grinding process with a white aluminium oxide grinding wheel causes deterioration in the material's residual stress state. For each of the three analysed workpiece speeds vw, smaller changes in microhardness with respect to the microhardness of the material before grinding occur in the surface layer of samples ground with GF fed with the MQL method. Similarly, residual stress values are in the area of favourable compressive stresses. Research limitations/implications: Environmental considerations and the need to comply with increasingly stringent environmental protection and worker safety regulations are pushing researchers and entrepreneurs to completely eliminate or reduce the consumption of grinding fluids in the grinding process. Based on the research and analysis carried out in this study, it was concluded that applying minimum GF by the MQL method could be an alternative to the conventional WET method.Practical implications: 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. This includes the manufacture of gears, a basic component used in gear transmissions in the automotive industry, for example. The research has established that it is possible to use the MQL method, which reduces the amount of GF used when grinding the working surfaces of gear teeth, as an alternative to the conventional WET method. Originality/value: The conducted research was the first to determine the most favourable conditions, in terms of the obtained residual stresses and microhardness, for grinding the working surface of gear teeth using the MQL method.

5

Study of the adhesion between TPU and PLA in multi-material 3D printing

Brancewicz-Steinmetz E., Valverde Vergara R., Buzalski V. H., Sawicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2022

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Vol. 115, nr 2

49--56

EN

Purpose: In the Fused Filament Fabrication (FFF/FDM) technology, the multi-material manufacturing additive method is achieved by a single nozzle or multiple nozzles working simultaneously with different materials. However, the adhesion between different materials at the boundary interface in FDM multi-material printing is a limiting factor. These studies are concerned with improving and study the adhesion between two polymers. Design/methodology/approach: Due to the numerous applications and possibilities of 3D printed objects, combining different materials has become a subject of interest. PLA is an alternative to the use of petrochemical-based polymers. Thermoplastic Polyurethane is a flexible material that can achieve different characteristics when combined with a rigid filament, such as PLA. To improve the adhesion between PLA and TPU in multi-material FFF/FDM, we propose the comparison of different processes: post-processing with acetone immersion, surface activation during printing with Acetone, surface activation during printing with tetrahydrofuran, post-processing annealing, and connection of printed parts with tetrahydrofuran. Findings: Modifying the 3D printing process improved the quality of the adhesive bond between the two different polymers. Activation of the surface with THF is the treatment method recommended by the authors due to the low impact on the deformation/degradation of the object. Research limitations/implications: In the study, adhesion was considered in relation to the circular pattern of surface development. Further analysis should include other surface development patterns and changes in printing parameters, e.g. process temperatures and layer application speed. Practical implications: 3D printing with multi-materials, such as PLA biopolymer and thermoplastic polyurethane, allows for the creation of flexible connections. The strengthening of the biopolymer broadens the possibilities of using polylactide. Examples of applications include: automotive (elements, where flexible TPU absorbs vibrations and protects PLA from cracking), medicine (prostheses with flexible elements ensuring mobility in the joints). Originality/value: Multi-material printing is a new trend in 3D printing research, and this research is aimed at promoting the use and expanding the possibilities of using PLA biopolymer.

6

The influence of workpiece speed on microhardness and residual stresses in vacuum-carburised 20MnCr5 steel using the single-piece flow method

Sawicki J., Januszewicz B., Sikora M., Witkowski B.

Archives of Materials Science and Engineering

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2022

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Vol. 115, nr 2

66--75

EN

Purpose: To determine the impact of selected conditions of abrasive treatment on the value and distribution of microhardness and residual stresses in layers carburised by a continuous single-piece flow method. Design/methodology/approach: Reference pieces were low pressure carburised at 920°C and then heat-treated in a 4D Quench heat treatment chamber at a pressure of 7 bar and tempered at 190ºC for 3 hours. In the next stage, samples were ground at various vw piece speeds, introducing grinding fluid into the cutting zone using the WET spraying method or using the MQL method at a minimum flow rate. The distribution of microhardness and residual stresses generated in the technological outer layer of the pieces following heat and chemical treatment and the grinding process was measured. Findings: Results of the tests indicated that the vw piece speed and method used to supply cooling and lubricating fluid to the grinding zone had an impact on selected parameters of the technological outer layer of flat samples made of 20MnCr5 steel. The process of grinding using an electrocorundum grinding wheel results in a deterioration of residual stresses in the material. For each of the three analysed vw piece speeds, reduced changes in material microhardness prior to cutting occur in the outer layer of samples ground using GF supplied at a minimum flow rate using the MQL method. Research limitations/implications: Environmental considerations and having to conform to increasingly stringent regulations related to environmental protection and employee safety motivate researchers and businesses to entirely eliminate or reduce the use of grinding fluids in the grinding process and, therefore, to optimise grinding technology. Practical implications: Modern manufacturing industry requires the grinding process, which follows heat and chemical treatment, to be performed with the highest possible efficiency. However, retaining high parameters of the technological outer layer in comparison to the sample material following vacuum carburisation (before grinding) is extremely difficult. An optimised configuration of parameters of the grinding process and method of supplying grinding fluids enables meeting the current and future high expectations of the industry in this regard. Originality/value: The tests have enabled us to determine the impact of the applied vw workpiece speed and method of supplying grinding fluid on microhardness and residual stresses. Generally speaking, grinding with an electrocorundum grinding wheel results in a deterioration of residual stresses. For both methods of supplying GF (WET and MQL), the distribution of microhardness in the material of the samples ground with the highest workpiece speed (18.0 m/min) indicated no significant differences with regard to the distribution of microhardness in the material of the samples following heat and chemical treatment.

7

An analysis of crystallographic texture and residual stresses of aluminium alloy RSA-501 after selected processes of twist extrusion (TE)

Byczkowska P., Sawicki J., Adamczyk-Cieślak B., Januszewicz B.

Archives of Materials Science and Engineering

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2022

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Vol. 118, nr 1

5--28

EN

Purpose: This study presents the residual stress analysis for the twist extrusion (TE) process after the experiment and numerical simulation and the analysis of the crystallographic texture changes and changes in hardness before and after the TE process for an RSA-501 aluminium alloy (Al; Mg5%; Mn1.5%; Sc0.8%; Zr0.4%). Design/methodology/approach: Crystallographic textures were obtained with the PANAlytical Empyrean X-ray diffractometer. The stresses were measured by applying the X-ray method with the use of using the PROTO iXRD diffractometer. Findings: The use of severe plastic deformation processes in the mass of the material leads to a significant change difference in the stress distribution in the workpiece and a change in texture compared to the reference material. The stress distribution in the sample cross-section and stress values varied and depended on the stage of the twisting process to which the surface was subjected. The highest stress (about 600 MPa) appears at the peaks of the front surface when exiting the twist area die TE. Higher stress values at the edges of the specimen are caused by friction (deformation) of the material against the die surface. The TE process strengthened – the highest crystallographic texture background level was 49%. Practical implications: The conducted tests and the obtained results allow the determination of the process parameters and critical areas of the sample by carrying out a numerical simulation. Originality/value: Microhardness increases due to the TE process and the largest values were observed at the edges. This phenomenon is confirmed by the numerical simulation results presented in this paper.

8

Numerical analysis of mechanical properties of 3D printed aluminium components with variable core infill values

Baras P., Sawicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 103, nr 1

16--24

EN

Purpose: The purpose of this paper is to present numerical modelling results for 3D-printed aluminium components with different variable core infill values. Information published in this paper will guide engineers when designing the components with core infill regions. Design/methodology/approach: During this study 3 different core types (Gyroid, Schwarz P and Schwarz D) and different combinations of their parameters were examined numerically, using FEM by means of the software ANSYS Workbench 2019 R2. Influence of core type as well as its parameters on 3D printed components strength was studied. The “best” core type with the “best” combination of parameters was chosen. Findings: Results obtained from the numerical static compression tests distinctly showed that component strength is highly influenced by the type infill choice selected. Specifically, infill parameters and the coefficient (force reaction/volumetric percentage solid material) were investigated. Resulting total reaction force and percentage of solid material in the component were compared to the fully solid reference model. Research limitations/implications: Based on the Finite Element Analysis carried out in this work, it was found that results highlighted the optimal infill condition defined as the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength. The best results were obtained by Schwarz D core type samples. Practical implications: In the case of the aviation or automotive industry, very high strength of manufactured elements along with a simultaneous reduction of their wight is extremely important. As the viability of additively manufactured parts continues to increase, traditionally manufactured components are continually being replaced with 3D-printed components. The parts produced by additive manufacturing do not have the solid core, they are rather filled with specific geometrical patterns. The reason of such operation is to save the material and, in this way, also weight. Originality/value: The conducted numerical analysis allowed to determine the most favourable parameters for optimal core infill configurations for aluminium 3D printed parts, taking into account the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength.

9

Thermogravimetric analysis of modified cellulose mixtures in air

Zawieja Z., Sawicki J.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

153--157

EN

The paper includes the TG-DTG thermogravimetric air-testing of a cellulose mixture modified with the additives of expanded vermiculite or expanded perlite. A thermal degradation test was carried out at 1000°C with a simultaneous qualitative analysis of the emitted gases. During the thermal degradation process, the thermal effects were also measured. The research results indicate that expanded vermiculite or expanded perlite do not emit toxic gases during thermal degradation. The cellulose mixture modification, with the additives of expanded vermiculite or perlite, does not result in the creation of new gaseous compounds in the process of thermal degradation. As investigated below, the mixtures tested in this article find application in gating systems for supplying liquid metal in no-bake moulds. Such cellulose-based material solutions shall allow the foundry industry to introduce less gas vaporising technologies within the entire casting production process.

10

Pierwsi polscy badacze elektryczności: Daniel Gralath i Józef Rogaliński

Sawicki J.

Maszyny Elektryczne : zeszyty problemowe

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2018

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Nr 4 (120)

85--90

PL

Przedstawiono sylwetki i prace naukowe dwóch polskich autorów publikacji o elektryczności w XVIII wieku. Daniel Gralath opublikował w Gdańsku w latach 1745–1756 trzyczęściową historię europejskich badań zjawisk elektrycznych. Była to pierwsza tego rodzaju publikacja na świecie. Był wynalazcą baterii butelek elektrycznych, czyli połączonych równolegle kondensatorów. Przeprowadzał eksperymenty z rozładowaniem kondensatora przez łańcuch połączonych dłońmi osób. Józef Rogaliński wykładał fizykę w kolegium jezuickim w Poznaniu. W 1766 roku opublikował prawdopodobnie pierwszą pracę napisaną w języku polskim o zjawiskach elektrycznych. Wprowadzał oryginalne polskie słownictwo do opisu eksperymentów elektrycznych. Przypomniane w artykule prace naukowe Gralatha i Rogalińskiego są wcześniejsze od prac Hermana Osińskiego uważanego za pierwszego polskiego elektryka.

EN

In the article profiles and scientific publications of two eighteenth century Polish authors writing about electricity are presented. Daniel Gralath published in Gdańsk, in years 1745–1756, history of European researches about electrical phenomenon in three volumes, which was the very first published text on that subject. He was also the first who came with idea of connecting electric jars in parallel, creating in this way socalled battery of capacitors, and used them in experiments of discharging capacitor through the chain of people connected with their hands. Józef Rogaliński was lecturing physics in Jesuit school in Poznań. In 1766 he published probably the first text about electric occurrence written in Polish, in which he was using Polish lexis of his own idea to describe electrical experiments. Mentioned in article thesis of Gralath and Rogaliński are older than those written by Herman Osiński, who is thought to be the first Polish electrician.

11

Bond between single artificial teeth and the base plate in removable denture metal framework

Taczała J., Sawicki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 90, nr 1

11--21

EN

Purpose: The purpose of this paper is to analyse attempts at improving the bond between acrylic artificial teeth and the denture base plate - considered in the context of single incisors in framework denture. Design/methodology/approach: It is a review article focusing on the analysis of state of the art in the field of the bond between the polymerised acrylic (teeth) and the polymerising acrylic resin during the production of denture (denture plate). Previous works regard the issue of individual incisor teeth (both upper and lower) breaking off from the metal partial denture. Findings: The bond between artificial acrylic teeth and the acrylic denture plate of the prosthesis was discussed. Ways of improving this bond were also presented. Although researchers and companies offer many methods for improving this bond, none of them refer directly to the issue discussed in this article. In conclusion- the hitherto scientific achievements work well in the case of acrylic prostheses without a metal frame, which constitutes an obstacle for achieving the effect required. In this work, it is suggested that further research would not only develop and provide more detail on the issue of the bond between artificial teeth and the denture plate, but also solve the problem appearing in cases of metal partial denture. Originality/value: This article shows a significant problem that hasn’t been discussed in detail in the past.

12

Granice wynagrodzenia ryczałtowego w umowie o roboty budowlane

Sawicki J., Sawik W.

Inżynier Budownictwa

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2018

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nr 7-8

24--26

13

Design and manufacture of customized medical implants

Elgalal M., Komorowski P., Makowski K., Styczyński A., Ulański P., Kubiak T., Sawicki J., Domżalski M., Walkowiak B.

Engineering of Biomaterials

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2018

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Vol. 21, no. 148

36

14

Misfit landforms imposed by ill-conditioned inverse parametric problems

Łoś M., Smołka M., Schaefer R., Sawicki J.

Computer Science

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2018

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Vol. 19 (2)

157--178

EN

In this paper, we put forward a new topological taxonomy that allows us to distinguish and separate multiple solutions to ill-conditioned parametric inverse problems appearing in engineering, geophysics, medicine, etc. This taxonomy distinguishes the areas of insensitivity to parameters called the landforms of the misfit landscape, be it around minima (lowlands), maxima (uplands), or stationary points (shelves). We have proven their important separability and completeness conditions. In particular, lowlands, uplands, and shelves are pairwise disjoint, and there are no other subsets of the positive measure in the admissible domain on which the misfit function takes a constant value. The topological taxonomy is related to the second, “local” one, which characterizes the types of ill-conditioning of the particular solutions. We hope that the proposed results will be helpful for a better and more precise formulation of ill-conditioned inverse problems and for selecting and profiling complex optimization strategies used in solving these problems.

15

The Effect of Non-Metallic Inclusions Formed as a Result of Deoxidation on the Fatigue Strength of 15CrNi6 and 16MnCr5 Steel

Lipa S., Sawicki J., Dybowski K., Pietrasik R., Januszewicz B.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1345--1350

EN

This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.

16

Numerical Analysis of Twist Extrusion Pressing of Al-Mg-Mn-Sc-Zr Scalmalloy

Sawicki J., Świniarski J., Stegliński M., Byczkowska P.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1385--1392

EN

Twist extrusion is a processing method involving the extrusion of a sample with a prismatic cross-section using a tool composed of four prismatic parts bisected by a screw component. A beneficial change in mechanical durability is one of the main factors enabling the use of highly durable Al-Mg-Mn-Sc-Zr alloys to construct functional components of non-stationary robots. As part of the present research, ANSYS® software was used to simulate a twist extrusion process. An analysis of a sample entering and passing through the entire twisting area was performed, up to the point of full twisting of the base of the sample. The stress conditions in the sample were analysed as it passed through the twisting area. The highest stress values (reaching up to 600 MPa) were detected at the tips of the sample face as the sample exited the twisting area. The lowest stress values, at around 170 MPa, were detected at the side edges of the sample.

17

Influence of Single-Stage and Duplex Shot Peening on Surface Roughness and Residual Stresses in Al Mg5 Mn1 Sc0,8 Zr0,4 Alloy

Byczkowska P., Sawicki J., Januszewicz B., Stegliński M.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

505--511

EN

Conventional shot peening (SP) is cheap surface treatment widely used to enhance fatigue life of mechanical components [3,4]. Basically, it is shooting small particles (shots) on the surface of the sample. However, the process itself is so complex that a lot of companies are not able to optimally employ it due to the amount of parameters that must be controlled all at the same time. The duplex process consists in two stages of shot-peening treatment. The first one consist of shot-peening with spherical cast steel shots or cut wire shots. During the second stage the samples processed in stage one were subject to shot-peening with glass beads. In this work, RSA-501 aluminium alloy was shot peened using shots of different material and diameter and tested using a measurement of residual stresses and surface roughness. Tests and studies conducted so far on RSA-501 aluminium alloy demonstrate that bombardment by a treatment medium in the form of glass beads or shots of various shapes and diameters induces permanent plastic deformation of the surface layer. The roughness achieved after the shot-peening process was determined for each treatment medium. The largest value of Ra parameter was achieved for cut wire shots and this result is consistent with the above-mentioned theoretical knowledge. This medium is the most aggressive one to the surface being treated primarily due to the sharp edges of shots. The duplex process was successful in obtaining higher values of compressive stresses in surface layer than values achievable in conventional single-stage shot peening process.

18

Fatigue Life Predicting for Nitrided Steel - Finite Element Analysis

Sawicki J., Siedlaczek P., Staszczyk A.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

921--927

EN

Thermo-chemical treatments are known to increase the fatigue life of industrial parts. Due to the imprecise consideration of residual stresses in predicting the durability of components subjected to cyclic loading and their effect on the fatigue life, the authors developed a numerical model combining the influence of residual stresses with stresses caused by bending. The authors performed the numerical simulation with the use of Finite Element Method to analyse material behaviour during cyclic loading. The residual stress state developed during nitriding was introduced onto cross-section of the numerical specimen. The goal of this work was better understanding of the real conditions of the nitride steel fatigue processes and improving the knowledge about numerical predicting of the fatigue life for parts with residual stresses. The results of simulation were compared with plane bending fatigue tests. The presented method indicates the possibility of increasing the accuracy of the fatigue analysis of elements after surface treatment, increasing its certainty and the ability to perform better optimization of service life.

19

The impact of nozzle configuration on the heat transfer coefficient

Krupanek K., Staszczyk A., Sawicki J., Byczkowska P.

Archives of Materials Science and Engineering

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2018

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Vol. 90, nr 1

16--24

EN

Purpose: The purpose of this paper is to elaborate guidelines regarding geometric configurations of a nozzle manifold that have an impact on the effectiveness of the quenching process and occurrence of quenching distortions. Design/methodology/approach: Within the framework of this study there an optimisation of nozzle manifold geometry was carried out with the help of numerical simulations created using Ansys CFX software. In the first stage, a simplification of the nozzle-sample system reduced to a two-dimensional simulation was employed to determine the most optimal location of the coolant stream. In the second stage, several arrangements of nozzle manifolds were tested in a three-dimensional simulation. The parameters that were taken into account included the rate of sample cooling, the uniformity of cooling with a sample volume and heat coefficient takeover read from its surface. Findings: The different active/inactive nozzle arrangements within the manifold and the impact of the specific arrangements on the uniformity of heat transfer from the sample surface were compared. Research limitations/implications: The simulations carried out within the framework of this study are one of the elaboration stages of a new flow heat treatment technology. Practical implications: The application of an efficient cooling chamber in flow treatment makes it possible to limit quenching distortions to a minimum. An optimal adjustment of cooling parameters and cooling nozzle configuration to the shape of the element in order to make the cooling uniform translate directly into a reduction in distortions. Avoiding the necessity to reduce distortions after quenching means there is a significant reduction in detail production costs (grinding). Originality/value: The concept of single-piece flow in the heat treatment for the mass industry is developing rapidly and constitutes a fully automated element of a manufacturing line, adjusted for the purposes of being included in the production process automatic control system. It also makes it possible to conduct comprehensive and integration quality supervision and management at the level of an individual element, which is not possible in the case of batch heat treatment, which is a gap in the production process.

20

Mathematical model for determining the expenditure of cooling and lubricating fluid reaching directly the grinding zone

Stachurski W., Sawicki J., Krupanek K., Midera S.

Archives of Materials Science and Engineering

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2018

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Vol. 94, nr 1

27--34

EN

Purpose: The purpose of this article is to discuss the method of determining the mathematical model used for calculating the amount of emulsion reaching directly the grinding zone during the hob sharpening process. Design/methodology/approach: The mathematical model, in the form of a multiple regression function, was determined based on the acceptance and rejection method. The data for the calculations was obtained by conducting numerical simulations of fluid flow in the Ansys CFX software. Findings: A mathematical model enables calculating the amount of efficient expenditure of emulsion reaching directly the zone of contact between the grinding wheel and workpiece (hob cutter rake face) at various nozzle angle settings and different nominal expenditures of emulsion. The verification of the mathematical relationship confirmed its accuracy. Research limitations/implications: Further research should focus on the other types of grinding process and other types of cooling and lubricating fluids. Practical implications: The mathematical model enables a selection and application in the workshop and industrial practice of various variants of emulsion supply during the grinding of hob cutter rake face. Analysis of the multiple regression equation created on the basis of the acceptance and rejection method also allows predicting changes in the analyzed numerical model. Originality/value: The literature review has shown that no research of this type has been conducted with regard to analyses and optimisation of the grinding process during hob cutter sharpening. The results of this research are a novelty on a worldwide scale.