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1

Enhancing Electrical Discharge Machining Performance by Mixing Nano Chromium Trioxide Powder with Soybean Dielectric to Machine Inconel 718 Alloy

Ghulam Dunya Adnan, Ibrahim Abbas Fadhi

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

129--142

EN

Inconel 718 super alloy is suitable for components exposed to high temperatures and demanding high strength; it is one of the hardest alloys to machine by conventional processes due to its properties. Nano Powder mixed electrical discharge machining is one of the most sophisticated processes to produce precise three dimensional complicated forms of hard metals through a thermo-physical process, so it is suitable for machining Inconel 718. This study reports an experimental investigation to improve the machining performance of Inconel 718 super alloy by adding nano chromium oxide powder particles to biodegradable and renewable soybean oil, which is used as a dielectric fluid to preserve the environment, with a magnetic field to assist in improving the process performance. The effects of machining parameters, namely peak current, pulse on time, powder concentration, and magnetic field on the responses in terms of white layer thickness, heat affected zone, surface roughness, material removal rate, and surface crack density were investigated. The observed results manifested that the addition of nano chromium oxide particles to dielectric fluid enhances the process performance. The white layer thickness and heat affected zone improved by 43.93% and 48.82%, respectively. The enhancements in measured surface roughness and material removal rate were 51.76% and 20.62%, respectively. Micrographs of scanning electron microscope verifies that the number of cracks on the machined surface with 4 g/l of nano (Cr2O3) powder addition was reduced by half, and surface crack density improved by 10.31%, in comparison to machining without powder addition. It is observed that the current had the largest effect on the responses, followed by powder concentration, pulse on time, and magnetic field.

2

Effect of surface integrity on fatigue life of 7075‑T6 aluminum alloy by combination of fine turning with hydrostatic deep rolling

Zhou Yongxin, Chu Xingrong, Zang Shunlai, Sun Jiao, Yang Lei, Gao Jun

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e41, 2023

EN

In this study, the 7075-T6 aluminum alloy sample was firstly prepared by fine turning(FT) process, and then the surface treatments were subjected to hydrostatic deep rolling(HDR), including constant pressure deep rolling(CPDR) and increasing pressure deep rolling(IPDR). Subsequently, the influence of surface integrity on the fatigue life of the 7075-T6 aluminum alloy is investigated by the combination of FT with HDR. The results show that the fatigue life of IPDR and CPDR samples is increased significantly by 148% and 450% compared to the FT sample in the tensile-compression fatigue test. The improved fatigue life of IPDR and CPDR samples is a result of reduced significantly surface roughness and the increase of surface compressive residual stress, surface micro-hardness and the depth of plastic deformation layer. In addition, the deeper plastic deformation layer is the main reason for the higher fatigue life of the CPDR sample than the IPDR sample.

3

Evaluation of dimensional accuracy and surface integrity of cylindrical array microelectrodes and cylindrical array microholes machined by EDM

Sun Yao, Gong Yadong, Wen Xuelong, Xin Bo, Yin Guoqiang, Meng Fantao, Tang Benjia

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e46, 2022

EN

In this study, the loss self-finishing method based on EDM reverse copy principle was proposed aiming to enhance the prepared efficiency of cylindrical array microholes. First, the effects of geometric parameters of microelectrodes on the diameter consistent error, inlet and outlet deviation, section profile, surface roughness parameters and the heat affected zone thickness were quantitatively investigated. The forming accuracy of cylindrical array microelectrodes obtained by self-finishing and multi-finishing methods were contrastively analyzed. Furthermore, 8 × 8 cylindrical array microelectrodes with diameter of about 185.18 μm and length of 2168.79 μm were fabricated by the loss self-finishing method for the first time. Besides, the size accuracy, surface morphology and surface roughness parameters of cylindrical array microholes machined using array microelectrodes prepared by loss self-finishing method were evaluated. Experimental results disclosed that the average consistent errors of inlet and outlet diameter for cylindrical array microholes, respectively, were 1.495 μm and 3.13 μm, indicating that the cylindrical array microelectrodes obtained by loss self-finishing method are capable to manufacture cylindrical array microholes with good surface quality and high dimensional accuracy.

4

Characterization of residual stresses induced into bearing rings by means of soft turning using different turning parameters

Zaghal Jawad, Mertinger Valeria, Filep Adam, Varga Gyula, Benke Marton

Journal of Machine Engineering

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2021

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Vol. 21, No. 4

49--56

EN

Residual stresses are those stresses which remain in solid materials after removing the external load. Residual stresses which are induced by machining processes play important role in determining the service life of the machined components, depending on its magnitude, sign, and direction. This research provides a comprehensive correlation between three turning parameters and the resulting residual stresses formed on the surface of the outer ring of tapered roller needle bearing, made of 100CrMnSi6-4 type steel. The examined parameters were cutting speed, feed and tool nose radius. Radial and axial residual stresses on the surface were measured using sample cutting-free X-ray diffraction method. It is shown that the effect of one processing parameter can even be opposing depending on the other parameters. Thus, the effects of turning parameters on residual stresses must be examined in a comprehensive manner.

5

Surface properties enhancement of Inconel 718 alloy by ultrasonic roller burnishing coupled with heat treatment

Shen Xuehui, Gong Xianhong, Wang Baolin, He Jianqun, Xu Chonghai, Su Guosheng

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

618--634

EN

Ultrasonic burnishing (UB), in which a ball tip is usually utilized, has been proved to be an effective method for metal surface strengthening. In this study, a roller tip was employed in the ultrasonic burnishing of Inconel 718 alloy (ultrasonic roller burnishing, URB). Meanwhile, a new surface modification technique, i.e., a combination of URB and heat treatment (URB/HT), was advanced to achieve better surface finishing. The surface integrities together with the mechanical behaviors of various samples treated by URB or URB/HT were experimentally examined and compared. Meanwhile, the transient stress distribution of the being treated materials with two treatments was comparatively analyzed by the FEA method. As result, compared with URB, the URB/HT-treated sample had better surface morphology, lower surface roughness, higher micro-hardness, and more well-distributed compressive residual stress. Furthermore, URB/HT-treated samples presented higher yield strength and lower wear rate in comparison with the URB-treated ones. The reduction of deformation resistance and easy flow of the near-surface material during URB/HT treatment mostly contributed to the excellent surface finishing.

6

New approach towards the machining process after laser cladding

Shen Xuehui, Su Hao, Wang Jiatian, Zhang Changsheng, Xu Chonghai, Bai Xiaolan

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

136--152

EN

As a chip-free and high-efficiency three-dimensional forming technology, laser cladding has been successfully applied in the green manufacturing and remanufacturing of some high-end engineering parts/components. However, in most cases, cladding coatings need to be machined due to the poor surface finishing by sole laser cladding technique. The study aims to explore an effective way to replace the current machining process after laser cladding, which is supposed to be incapable of satisfying the various technical requirements of some high-demand engineering parts/components. With this purpose, three new surface strengthening processes, i.e. ultrasonic roller burnishing at ambient temperature (URB), ultrasonic roller burnishing at warm temperature (UWB), and UWB coupled with continuous heat treatment (UWB/HT), were proposed and comparatively explored. The contact stresses between the contact pairs in URB were calculated and analyzed in theory. A set of ultrasonic roller burnishing equipment was self-manufactured to perform the experiment. Comparing with the conventional process, the three new processes were evaluated mainly from aspects of surface finishing, the adhesion behavior and corrosion resistance of the finished surface. Summarily, ultrasonic warm burnishing coupled with continuous heat treatment (UWB/HT) is considered to have the greatest potential to achieve the effective machining after laser cladding with excellent surface finishing over the other two strategies, which is expected to further advance the application of laser cladding technique particularly in the fabrication of some high-demand products serving in harsh conditions.

7

Influence of ultrasonic vibration-assisted cutting on ploughing effect in cutting Ti6Al4V

Chen Feiyang, Wang Dazhong, Wu Shujing

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

55--73

EN

In this study, the finite element method (FEM) is used to study the ploughing effect of ultrasonic vibration-assisted cutting Ti6Al4V. Due to the existence of the cutting edge radius of the tool, there will be a ploughing area in the cutting of Ti6Al4V. The ploughing area is an area where the stress state is very complex in the cutting process. The ploughing force and temperature of the ploughing area are important factors that affect the machined surface quality and tool wear. The main research of this paper includes the establishment of ploughing force, temperature and dynamic friction coefficient model of the ploughing area, and the correctness of the analysis model is verified by using the finite element method. Then, by changing the cutting conditions, the influence of changing the cutting parameters on the ploughing effect is discussed. The results show that the analysis model can be used to monitor the ploughing force and ploughing area temperature, and ultrasonic vibration-assisted cutting can significantly reduce the ploughing force and ploughing area temperature, reducing tool wear and plastic deformation of the machined surface.

8

Surface integrity enhancement of austenitic stainless steel treated by ultrasonic burnishing with two burnishing tips

Shi Ya-Long, Shen Xue-Hui, Xu Guo-Feng, Xu Chong-Hai, Wang Bao-Lin, Su Guo-Sheng

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

224--240

EN

A set of ultrasonic burnishing equipment with two different burnishing tips was designed and manufactured, with which a series of experiments were performed to explore the effects of process parameters and burnishing tips on the surface integrity of austenitic stainless steel material being treated by ultrasonic burnishing (UB). Based on the experiment data, the two surface treatments, i.e. UB with ball tip and UB with roller tip, were comparatively assessed together with the other two surface machining methods of fine turning and grinding. As a further study, a microscopic FE model was built to investigate the three-dimensional transient stress and strain field inside the being treated material. It was found that parameter combination is determinative to surface finishing in UB process, and static pressure and burnishing pass are supposed to be the two most significant parameters for surface integrity of the treated sample. On the whole, roller tip is more preferable to achieve good surface enhancement than ball tip. The superposition of ultrasonic vibration leads to the dynamic change of the stress and strain field in UB, resulting in the oscillating propagation of stress wave inside the material, which gives explanation for the good performance of UB than that of conventional burnishing without ultrasonic.

9

On wire spark erosion machining induced surface integrity of Ni55.8Ti shape memory alloys

Sharma Neeraj, Gupta Kapil, Davim Joao Paulo

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

680--693

EN

Ni55.8Ti shape memory alloys (SMAs) find applications in different fields of medical and engineering. In every field, surface integrity greatly affects the functional performance of shape memory alloy parts. In the present work, wire spark erosion machining of Ni55.8Ti shape memory alloys has been conducted and surface integrity parameters of the machined specimens have been evaluated. Experiments are designed using Taguchi L16 robust design of experiment technique. Effect of important process parameters, i.e. voltage, pulse-on time and pulse-off time on maximum surface roughness has been studied. Deterioration in surface integrity at various combinations of pulse-on and pulse-of time which produced high discharge energy has been observed. Scanned electron microscopic investigation, energy dispersive spectroscopy and XRD analyses, roughness measurement, and micro-hardness testing results are presented, analyzed and discussed. Optimization of process parameters resulted in surface integrity enhancement with low roughness (Rt – 7.78 mm and Ra – 1.45 mm) and very thin recast layer (4–6 mm) along with minimum subsurface defects.

10

The influence of the tool surface texture on friction and the surface layers properties of formed component

Šugárová Jana, Šugár Peter, Frnčík Martin, Necpal Martin, Moravčíková Jana, Kusý Martin

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 1

181--193

EN

The morphological texturing of forming tool surfaces has a high potential to reduce friction and tool wear and also has an impact on the surface layers properties of formed material. In order to understand the effect of different types of tool textures, produced by nanosecond fibre laser, on the tribological conditions at the interface tool-formed material and on the integrity of formed part surface layers, the series of experimental investigations have been carried out. The coefficient of friction for different texture parameters (individual feature shape, including the depth profile of the cavities and orientation of the features relative to the material flow) was evaluated via a Ring Test and the surface layers integrity of the formed material (surface roughness and subsurface micro hardness) was also experimentally analysed. The results showed a positive effect of surface texturing on the friction coefficients and the strain hardening of test samples material. Application of surface texture consisting of dimple-like depressions arranged in radial layout contributed to the most significant friction reduction of about 40%. On the other hand, this surface texture contributed to the increase of surface roughness parameters, Ra parameter increased from 0.49 μm to 2.19 μm and the Rz parameter increased from 0.99 μm to 16.79 μm.

11

Surface microhardening studies on steels after high feed milling

Petrů Jana, Zlámal Tomáš, Špalek František, Čep Robert

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 2

222--230

EN

The paper deals with the impact of high-speed machining production methods on the integrity of component surfaces. One has to point out that cutting conditions during machining have a significant impact on the final properties of surface and subsurface layers of the workpiece. The conclusion summarizes and analyzes the achieved results of experimental activities on stainless austenitic steel 1.4301, hardened tool steel 1.2343 and high-speed steel 1. 3344 (ASP 2023). The results of the work experimental parts demonstrate the influence of cutting parameters on selected surface integrity ones, specifically strengthening the surface and subsurface layers. The performed experiments show that microhardness of a surface layer of the machined material can be influenced by suitable cutting conditions and other cutting process parameters.

12

Technological parameters of belt grinding process of hard steel

Hamdi A., Aliouane T., Bouzid D.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

843--853

EN

A mechanical workpiece in the field of the automobile industry (crankshaft, camshaft, valves, gear, synchronizer gearbox ... etc) is good quality, if it fulfills the function for which, it is destined. To ensure the required function of these workpieces, they are necessary for the purpose of machining a high precision superfinishing process. There are several methods of superfinishing in this area, for example: honing, polishing, belt grinding ... etc. The belt grinding is a mechanical manufacturing process by removing of material involving a tool called abrasive belt. It is complementary to the hard turning and recent compared to other process principle and objective. To date the cutting mechanism and its exact effect on the surface integrity remains unclear. This study allows optimizing the technological parameters, such as time of belt grinding, size of the abrasive grains, the rotation speed and lubrication, and seeing the influence of these parameters on the surface state of the hard steel.

13

EDM of aluminum alloy 6061 using graphite electrode using paraffin oil and distilled water as dielectric medium

Imran M., Rahmanshah S. M., Mehmood S., Arshad R.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 3

72--79

EN

EDM machining of Al 6061 was performed under varying conditions of pulse current and pulse duration. Graphite was used as an electrode material with distilled water and paraffin oil as two different dielectric mediums. The aim is to characterize the surface integrity produced as a result of EDM machining under both varying electrical and non-electrical parameters as it is important in determining the service life of EDM machined components. The vertical, horizontal and corner surfaces are studied independently for each single set of conditions. The average white layer thickness (AWLT) and surface roughness was found to be dependent on pulse current values and pulse duration. The dielectric medium also has an influence on the thickness and nature of white layer. It was found that the thickness and nature of the white layer formed from distilled water is different from that of paraffin oil. New methods of AWLT and surface roughness measurement through an optical microscope are described. The surface roughness method developed was calibrated against an identical surface roughness tester. Finally, material removal rate, tool wear rate, the presence of micro cracks, voids and globules were compared for different conditions and conclusions were drawn according to the actual physical conditions during machining.

14

Surface integrity of hard turned parts modified by ball burnishing

Grzesik W., Żak K., Prażmowski M.

Journal of Machine Engineering

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2012

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Vol. 12, No. 1

18--27

EN

The purpose of this research is to test the applicability of ball burnishing for improving surface integrity produced in hard machining on parts made of high-strength, low alloy 41Cr4 steel with hardness of about 57 HRC. Machined surfaces were characterized using 2D and 3D scanning techniques. Moreover, the distribution of microhardness beneath the surface was determined and the microstucture of the sublayer was examined using SEM/EDS technique. This investigation confirms that ball burnishing allows producing surfaces with acceptable surface roughness and better service properties. The main conclusion is that this sequential technology can partly eliminate grinding operations when hard machining is not enough to produce the desired surface integrity.

15

Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718

Bhopale N N, Pawade R S

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

616--622

EN

The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting parameters. It is observed that at large cutting speed as well as feeds, thicker work piece with larger work piece inclination shows higher micro hardness as compared to the other machining conditions.

16

Effects of cryogenic cooling on surface layer characteristics produced by hard turning

Grzesik W., Żak K., Prażmowski M., Storch B., Pałka T.

Archives of Materials Science and Engineering

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2012

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Vol. 54, nr 1

6-12

EN

Purpose: The purpose of this research is to test the applicability of cryogenic hard machining for improving surface integrity produced in turning operations on parts made of high-strength, low alloy 41Cr4 steel with hardness of 57š2 HRC. The aim of the research is to quantify the surface roughness and the mechanical properties of the sublayer produced under practical working conditions. Design/methodology/approach: The objectives were achieved by the characterization of machined surfaces using 2D and 3D scanning techniques. The surface profile and surface topographies were characterized and compared for optimal machining conditions. Moreover, microhardness beneath the surface was measured using a hardness tester with a Berkovich indenter. The microstucture of the sublayer was examined using SEM/EDS technique. Findings: This investigation confirms that hard machining allows producing surfaces with acceptable surface roughness and, in some cases, with attractive service properties. The main conclusion is that cryogenic hard cutting operations can partly eliminate grinding operations in cases when white layer is not produced. Research limitations/implications: The basic limitations concern the measurement of residual stresses and microstructural alterations including phase analysis. Another important problem is to optimize the surface integrity including surface roughness and sublayer properties. Practical implications: One practical outcome is selecting the machining conditions which guarantee the demanded surface finish together with bearing properties. Moreover, they should be selected in terms of desired microhardness distribution. Originality/value: Original value of the paper is the presentation of the effects of cryogenic pre-cooling of the workpiece in hard turning operations. Experiments were performed under the conditions combining low surface roughness with attractive service properties. This knowledge can support the design of technological processes of hard steel parts.

17

Functional properties of hardened steel parts generated by turning and ball burnishing operations

Grzesik W.

Advances in Manufacturing Science and Technology

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2012

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Vol. 36, nr 4

5-17

EN

This paper presents the experimental results of the role of ball burnishing in improving of the surface integrity produced in finish hard machining of hardened 41Cr4 steel. The characterization of the surface integrity includes two standardized sets of 2D and 3D roughness parameters, the distributions of microhardness, residual stresses and the microstucture of the sublayer which was examined using SEM/EDS technique. The functional properties of the surface layer were predicted and discussed. This study reveals that ball burnishing performed on hard turned surfaces improves not only surface roughness but also results in better service properties compared with those generated by CBN hard turning.

PL

W artykule przedstawiono analizę wyników doświadczalnych dotyczących roli nagniatania tocznego kulką ceramiczną w polepszeniu właściwości warstwy wierzchniej wytworzonej podczas wykończeniowego toczenia utwardzonej stali 41Cr4. Charakteryzacja wytworzonej warstwy wierzchniej obejmuje określenie dwóch zbiorów znormalizowanych parametrów chropowatości powierzchni, rozkład wartości twardości naprężeń własnych oraz badania mikrostruktury metodami mikroskopii elektronowej EM/BSE/EDX. Analiza wyników badań pozwala stwierdzić, że nagniatanie kulką po toczeniu na twardo poprawia nie tylko chropowatość powierzchni, ale również polepsza właściwości eksploatacyjne w porównaniu z efektami toczenia narzędziami z CBN.

18

Characteristics of surface integrity generated by oblique machining of steel parts

Grzesik W.

Advances in Manufacturing Science and Technology

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2012

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Vol. 36, nr 3

5-18

EN

In this study the surface integrity produced by oblique turning of a C45 carbon steel was quantified by means of 2D and 3D surface roughness parameters, strain-hardening effects and associated residual stresses. Surfaces were produced by a special straight-edged cutting tool with large inclination angle of 55 degrees equipped with carbide cutting tool inserts. It was documented that oblique machining performed with relatively higher feed rate allows to obtain lower surface roughness and, in general, better bearing characteristics. Moreover, compressive stresses with the maximum value located close to the machined surface and with parabolic profile can be induced into the surface layer. The magnitude of stresses depends on the strain-hardening rate of the surface layer.

PL

W pracy scharakteryzowano stan technologicznej warstwy wierzchniej wytworzonej w ukośnym toczeniu stali C45. Stosowano kryteria parametrów chropowatości powierzchni 2D i 3D, efektu umocnienia odkształceniowego i naprężeń własnych. Powierzchnie kształtowano specjalnym narzędziem z węglików spiekanych, w którym prostoliniowa krawędź skrawająca ma duży kąt pochylenia 55 stopni. Analiza wyników badań pozwala stwierdzić, że ukośne skrawanie prowadzone z dużą wartością posuwu pozwala uzyskać powierzchnię o mniejszej chropowatości i lepszej nośności. Dodatkowo w warstwie wierzchniej są wytworzone ściskające naprężenia własne o maksymalnej wartości w pobliżu powierzchni i profilu parabolicznym. Wartość maksymalna naprężeń ściskających zależy od stopnia umocnienia odkształceniowego materiału warstwy wierzchniej.

19

Surface integrity functional analysis in hard turning AISI 8620 case hardened steel through 3D topographical measurement

Farias A., Delijaicov S., Batalha G.

Archives of Materials Science and Engineering

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2010

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Vol. 46, nr 1

47-52

EN

Purpose: This work aims investigate the resulting machined surface condition from hard turning process of mechanical components manufactured from case hardened steel. Design/methodology/approach: The surface was examined by parameters obtained from the three-dimensional surface topography obtained with an interferometric laser instrument. Findings: The selected roughness parameters analysis intends to have a functional characterization such as bearing capacity, fluid and lubricants retention ability and contact wear resistance. Research limitations/implications: The obtained results were validated against similar ones, showing that the employed measuring techniques and analyses were correctly conducted. Practical implications: The functional bearing area curve analysis parameters indicates that the resulting surface has a good area contact, good bearing capacity and reasonable ability to fluid retention as the reduced valley depth parameter Svk not produced higher values for all conditions tested. Originality/value: The obtained results in the surface roughness measurement shows consistency with other authors results, and it shows that the technique of hardened material turning is capable of producing surfaces with functionality and quality.