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1

Surface Characteristics and Wear Resistance of 316L Stainless Steel after Different Shot Peening Parameters

Walczak Mariusz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 3

124--132

EN

The study was conducted to evaluate the effect of ZrO2-based ceramic beads shot peening on the performance properties of AISI 316L austenitic steel. The results obtained in the roughness and microhardness measurements, the state of the surface layer, and the tribological properties (ball-on-disc) of the specimens after the peening process were compared to the results obtained for the reference specimen. The tests were carried out with varying parameters of pressure (0.3 MPa, 0.4MPa) and time (30s, 60s). The lowest values of COF (µ=0.576) and wear factor (K=3.95*10-4 mm3N-1m-1) were observed for the surface peened using parameters: 0.4 MPa and 60s. By increasing the time twice, a much lower wear factor can be achieved unlike when increasing the shot peening by 0.1 MPa. Observations of wear traces indicate that abrasive wear is predominant and the transfer of specimen material by countersample is also observed.

2

Abrasive Wear Mechanisms of S235JR, S355J2, C45, AISI 304, and Hardox 500 Steels Tested Using Garnet, Corundum and Carborundum Abrasives

Szala Mirosław, Szafran Michał, Matijošius Jonas, Drozd Kazimierz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 2

147--160

EN

Wear resistance is one of the main indicators of the reliability of machine parts. The selection of wear-resistant material should consider the operational environment and specific types of abrasive material. The steel abrasive wear resistance depends not only on its hardness and microstructure but also on the abrasive material's properties, such as hardness and particle morphology. This work aimed to determine abrasion wear mechanisms of a set of steels, i.e., S235, S355, C45, AISI 304 and Hardox 500, abraded by different types of grit i.e. garnet, corundum and carborundum. The abrasion tests were conducted using T-07 tribometer (rubber wheel method). Wear traces were examined with a scanning electron microscope (SEM), and a contact profilometer. SEM analysis revealed that apart from Hardox 500, ploughing and microfatigue were the dominant wear mechanisms. Microcutting was the main wear mechanism for Hardox 500 tested with carborundum (SiC). The highest mass loss was usually obtained for carborundum. The lowest wear resistance in garnet and carborundum was obtained for the S235JR and S235J2 steels and Hardox 500 tested with corundum. The effect of steel microstructure on the wear mechanism has been confirmed. AISI 304 austenitic steel abraded by carborundum grit, presented outstanding roughness parameters: Ra, Rz, RSm, Rk, Rvk and Rpk than other steels tested with carborundum. Steel hardness affects the morphology of the wear trace reducing the Ra and Rz roughness parameters. The effect of abrasive hardness and grain morphology on abraded surfaces has been stated. Contrary to fine grains of the hardest carborundum, coarse garnet grains caused high roughness parameters (Rk, Rpk and Rvk) determined in wear trace.

3

Concept for a Research Methodology of Surface Topography – Testing and Analysis of Tribological Wear Traces

Niemczewska-Wójcik Magdalena

Tribologia

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2022

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nr 4

31--38

EN

The methodology of surface topography research plays a key role in identifying and describing the wear mechanism, including the tribological wear traces. In the published literature, wear traces are most often described based on the surface morphology created in the operation process (microscopic image – optical microscope OM, scanning electron microscope SEM, atomic force microscope AFM); less frequently used are 2D profile description (contact or non-contact profilometer) or 3D topography (profilometer, confocal microscope, interference microscope, focus variation microscope). Each method of testing the worn surface has its own characteristics and purposefulness of use. The combination of different methods enables a comprehensive assessment of the surface topography created in the operation process and the characterisation of tribological wear traces.This work presents the main issues in the range of research methodology of the surface topography created in the operation process (operated/worn surface topography) – the purpose of research, research programme, research methods and tools, analysis of research results (quantitative – parametric and qualitative – non parametric). The research methodology of the surface topography and tribological wear traces is presented on selected examples. The method of conducting a comprehensive analysis, including all elements – surface morphology, 2D profile analysis and 3D topographic analysis – is discussed.

PL

Metodyka badań topografii powierzchni odgrywa kluczową rolę w identyfikowaniu i opisie mechanizmów zużycia, w tym śladów zużycia tribologicznego. W publikowanych pracach najczęściej identyfikacja śladów zużycia przeprowadzana jest na podstawie morfologii powierzchni eksploatowanej (obraz mikroskopowy – mikroskop optyczny OM, skaningowy mikroskop elektronowy SEM, mikroskop sił atomowych AFM), rzadziej stosowane są opisy profilu 2D (profilometr stykowy lub bezstykowy) czy topografii 3D (mikroskop konfokalny, mikroskop interferencyjny, mikroskop różnicowania ogniskowego). Każda z metod badań powierzchni eksploatowanej ma swoją charakterystykę oraz celowość zastosowania. Połączenie różnych metod umożliwia kompleksową ocenę powierzchni eksploatowanej oraz charakterystykę śladów zużycia tribologicznego. W niniejszym opracowaniu przedstawiono główne zagadnienia w zakresie metodyki badań powierzchni eksploatowanej – cel badań, program badań, metody i narzędzia badawcze, analiza wyników badań (ilościowa – parametryczna oraz jakościowa – nieparametryczna). Metodykę badań powierzchni eksploatowanej i śladów zużycia tribologicznego zaprezentowano na wybranych przykładach. Omówiono sposób przeprowadzenia kompleksowej analizy, obejmującej wszystkie elementy – morfologię powierzchni, analizę profilową 2D oraz analizę topograficzną 3D.

4

Cavitation Erosion Resistance of High-Alloyed Fe-Based Weld Hardfacings Deposited Via SMAW method

Szala Mirosław, Hejwowski Tadeusz

Tribologia

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2022

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nr 4

85--94

EN

In order to investigate the cavitation erosion (CE) resistance of high-alloyed ferrous hardfacings, the three different deposits were pad welded by the shielded metal arc welding (SMAW) method. Consumable electrodes differed in the content of carbide-forming elements, and pad welds were deposited onto the S235JR structural. The CE tests, conducted according to ASTM G32 standard, indicated that hardfacings reveal lower mass loss than the reference stainless steel AISI 304 (X5CrNi18-10). The hardfacings show increasing resistance to CE in the following order: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. The reference steel revealed more than twenty times higher material loss in the CE test than Cr-C-Mo-V-W hardfacing, which had outstanding hardness (825HV0.3). The profilometric measurements and scanning electron microscopy investigations showed large changes in valley and peak sizes of the roughness profiles for materials which displayed high erosion rates. The erosion mechanism of the coatings can be classified as brittle-ductile and relies on cracking, chunk removal of material, pits and craters formation, and deformation of fractured material tips and edges. Hardfacing materials failed primarily due to brittle fractures with different severities. Specimen surface degradation follows the changes in Ra, Rz, Rv, and Rp roughness parameters and well-corresponds to the proposed roughness rate (RR) parameter.

PL

W celu zbadania odporności na erozję kawitacyjną (EK) wysokostopowych napoin na osnowie żelaza napawano trzema materiałami metodą SMAW. Elektrody otulone różniły się zawartością pierwiastków węglikotwórczych. Napoiny wykonano na stali konstrukcyjnej S235JR. Testy EK, przeprowadzone zgodnie z normą ASTM G32, wykazały niższy ubytek masy napoin w porównaniu do referencyjnej stali odpornej na korozję AISI 304 (X5CrNi18-10). Napoiny wykazują rosnącą odporność na EK w następującej kolejności: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. Referencyjna próbka stalowa wykazała w teście EK ponad dwudziestokrotnie większy ubytek materiału niż napoina Cr-C-Mo-V-W, która miała wyjątkowo wysoką twardość (825HV0.3). Pomiary profilometryczne i badania przeprowadzone przy użyciu skaningowego mikroskopu elektronowego wykazały duże zmiany wielkości dolin i szczytów profilu chropowatości dla materiałów wykazujących wysoką szybkość erozji. Mechanizm EK powłok można sklasyfikować jako krucho-plastyczny i opiera się na pękaniu, usuwaniu kawałków materiału, tworzeniu wgłębień i kraterów oraz deformacji pękniętych fragmentów kraterów oraz deformacji wyodrębnionych szczytów i krawędzi materiału. Napawany materiał podlega niszczeniu przez jego pękanie w różnym nasileniu. Degradacja powierzchni próbek pogłębia się wraz ze zmianą parametrów chropowatości Ra, Rz, Rv i Rp i dobrze koresponduje z proponowanym parametrem RR (zmiana chropowatości pow. degradowanej).

5

Tribological Studies on AlCrFeCuCoNi High Entropy Alloy Surface Coated on Ti-6Al-4V Using Plasma Transferred Arc Technique

Prabu G., Duraiselvam Muthukannan

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

409--420

EN

AlCrFeCuCoNi high entropy particles were alloyed on Ti-6Al-4V surface using Plasma transferred arc (PTA) process. PTA alloyed surfaces were investigated for their phase formation, microhardness improvement and wear behaviour. The various wear mechanism and their corresponding surface roughness were studied. The results revealed that the dual phase of BCC and FCC microstructure along with some intermetallic compounds were grown in the alloyed region through the PTA technique and good metallurgical bonding of the alloyed region with the base material were achieved. The PTA alloyed region exhibited a hardness of 718 HV0.2 which is 2.2 times higher than the hardness of base material. The PTA alloyed samples showed higher wear resistance due to the solid solution strengthening as the HEA has high entropy of mixing that leads to the reduction of free energy of the alloyed region. It exhibited better interconnection of the coated material and superior metallurgical bonding to the base material. Frictional heat produced during the wear test has promoted the formation of FeO, Cr2O3, CuO, NiO and Al2O3 oxide film on the PTA alloyed sample. These oxide films act as a barrier between two mating surfaces and improve the tribo performance of the PTA alloyed sample.

6

Destruction mechanisms of Cu-ETP copper guides for sectional insulators of railway traction

Konieczny Jarosław

Zeszyty Naukowe. Transport / Politechnika Śląska

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2021

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z. 113

101--113

EN

This article presents the results of a research on the operational damage to sectional insulator guides made of hard electrolytic copper Cu-ETP (Electrolytic Tough Pitch Copper). The guides were used on various rail routes, in real conditions, on which the trains ran at maximum speeds between 40 and 120 km/h for periods of 6 or 12 months. The microstructure of the surface, the working layer of the guide, which contacts the graphite plate of the current collector and the cross-section of the guide in the place where it was damaged was examined using the Olympus light microscope. The analysis of the chemical composition in the EDS micro-regions was performed using the Zeiss Supra 53 scanning electron microscope (SEM), while the qualitative X-ray phase analysis was performed with the use of the Panalytical X'Pert diffractometer. Scratches and deformations of the surface layer characteristic of the phenomenon of friction caused by the current collector were observed in the microstructure of the damaged parts of the guides of section insulators. The effect of a very intense oxidation process was also observed, as well as the effects of an electric arc, which according to the author, is the factor that has the most destructive effect on the condition of the guides.

7

Cavitation erosion phenomenological model of MCrAlY and NiCrMoNbTa metallic coatings deposited via the HVOF method

Szala Mirosław

Tribologia

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2021

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nr 4

45--55

EN

The work describes the phenomenological model of cavitation erosion (CE) elaborated for MCrAlY (where M = Co, Ni or Co/Ni) and NiCrMoNbTa. Coatings were deposited via the HVOF method from CoNiCrAlY, NiCoCrAlY and NiCrMoNbTa feedstock powders. CE tests, conducted according to ASTM G32 standard, indicate that MCrAlYs have a 50% higher maximum erosion rate and twice lower CE resistance than the NiCrMoNbTa coating. CE kinetics of coatings were comparatively studied, combining the mass loss, erosion rate, roughness changes of the eroded surface with microstructure, and mechanical properties of the coatings. Results of SEM analysis of damaged coatings allow identifying the mechanism of CE. In the case of both types of coatings, the erosive damage is initiated at the removal of loose splats, cracking at the border splats and peeling off the coating material, and surface pitting. However, NiCrMoNbTa, due to higher ductility and microstructure homogeneity, presents lesser surface pitting contrary to the MCrAlYs, which have multiphase microstructure higher hardness and consequently was prone to cracking, resulting in the formation of craters and higher surface roughening. The CE mechanism of MCrAlYs was dominated by the brittle mode, while the NiCrMoNbTa coating has mainly a ductile damage behaviour.

PL

W pracy opisano fenomenologiczny model erozji kawitacyjnej (EK) opracowany dla powłok MCrAlY (gdzie M = Co, Ni lub Co/Ni) i NiCrMoNbTa. Powłoki wytworzono metodą HVOF z komercyjnych proszków CoNiCrAlY, NiCoCrAlY i NiCrMoNbTa. Testy erozji kawitacyjnej, przeprowadzone zgodnie z normą ASTM G32, wskazują, że MCrAlY mają o 50% wyższą prędkość erozji i dwukrotnie niższą odporność EK niż powłoka NiCrMoNbTa. Kinetyka erozji kawitacyjnej powłok została poddana analizie porównawczej syntetyzującej utratę masy, szybkość erozji, zmiany chropowatości erodowanej powierzchni z mikrostrukturą oraz właściwościami mechanicznymi badanych powłok. Wyniki analizy SEM uszkodzonych powłok umożliwiły zidentyfikowanie mechanizmu EK. Uszkodzenie erozyjne powłok inicjowane jest w wyniku usuwaniu słabo umocowany cząstek materiału, pękaniu na granicach lameli następnie usuwaniu materiału i tworzeniu wżerów. Jednak NiCrMoNbTa ze względu na wyższą ciągliwość i jednorodność mikrostruktury wykazuje mniejsze wżery powierzchniowe w przeciwieństwie do MCrAlYs, które cechują się wielofazową mikrostruktura o wyższej twardości i w konsekwencji są podatne na pękanie, co powoduje powstawanie dużych wżerów i wyższe chropowacenie powierzchni. Mechanizm erozji kawitacyjnej powłok MCrAlY jest zdominowana przez kruche pękanie, natomiast w przypadku powłoki NiCrMoNbTa dominuje plastyczne odkształcenie.

8

Microstructure, tribological performances, and wear mechanisms of laser-cladded TiC-reinforced NiMo coatings under grease-lubrication condition

Weixin Zhu, Dejun Kong

Materials Science Poland

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2021

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Vol. 39, No. 3

395--409

EN

NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings were prepared on GCr15 steel by laser cladding (LC). The microstructure and the phases of the obtained coatings were analyzed using ultra-depth-of-field microscopy (UDFM) and X-ray diffraction (XRD), respectively. A ball-on-disk wear test was used to analyze the friction-wear performance of the substrate and the NiMo-TiC coatings under grease-lubrication condition. The results show that the grain shape of NiMo-TiC coatings is dendritic. The wear resistance of NiMo-TiC coatings is improved by the addition of TiC, and the depths of the worn tracks on the substrate and on the NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings are 4.183 μm, 2.164 μm, 1.882 μm, and 1.246 μm, respectively, and the corresponding wear rates are 72.25 μm3/s/N, 32.00 μm3/s/N, 18.10 μm3/s/N, and 7.99 μm3/s/N, respectively; this shows that the NiMo-25%TiC coating has the highest wear resistance among the three kinds of coatings. The wear mechanism of NiMo-TiC coatings is abrasive wear, and the addition of TiC plays a role in resisting wear during the friction process.

9

Cavitation erosion of electrostatic spray polyester coatings with different surface finish

Szala Mirosław, Świetlicki Aleksander, Sofińska-Chmiel Weronika

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

|

Vol. 69, nr 4

art. no. e137519

EN

Polyester coatings are among the most commonly used types of powder paints and present a wide range of applications. Apart from its decorative values, polyester coating successfully prevents the substrate from environmental deterioration. This work investigates the cavitation erosion (CE) resistance of three commercial polyester coatings electrostatic spray onto AW-6060 aluminium alloy substrate. Effect of coatings repainting (single- and double-layer deposits) and effect of surface finish (matt, silk gloss and structural) on resistance to cavitation were comparatively studied. The following research methods were used: CE testing using ASTM G32 procedure, 3D profilometry evaluation, light optical microscopy, scanning electron microscopy (SEM), optical profilometry and FTIR spectroscopy. Electrostatic spray coatings present higher CE resistance than aluminium alloy. The matt finish double-layer (M2) and single-layer silk gloss finish (S1) are the most resistant to CE. The structural paint showed the lowest resistance to cavitation wear which derives from the rougher surface finish. The CE mechanism of polyester coatings relies on the material brittle-ductile behaviour, cracks formation, lateral net-cracking growth and removal of chunk coating material and craters’ growth. Repainting does not harm the properties of the coatings. Therefore, it can be utilised to regenerate or smother the polyester coating finish along with improvement of their CE resistance.

10

Influence of heat treatment on the mechanical and tribological properties of Incoloy 800H Superallo

Palanisamy A., Jeyaprakash N., Sivabharathi V., Sivasankaran S.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

171--185

EN

The selection and use of high strength alloys with high wear resistance (at room and high temperature) are mandatory in aerospace, nuclear, automotive, petroleum, space, furnace, and chemical industries in which Incoloy 800H superalloy is the right choice. However, this alloy is under the class of ‘difficult to cut material’ caused by their significant properties. In the present work, the heat treatment on Incoloy 800H superalloy was carried out at 1075 °C for 60 min and then the samples were cooled in the air (air cooling, AC) and furnace (furnace cooling, FC) to modify the microstructure. The mechanical and tribological behavior were examined on the heat-treated samples at room temperature to eliminate the effect of dynamic strain aging (DSA) which usually occurs at elevated temperatures in superalloys. Hardness measurement and compression tests were carried out to examine the variation of strength. Further, the dry sliding wear tests at room temperature were performed to analyze wear resistance of heat-treated specimens and compared with the as-received (AR) sample. Besides, the wear mechanism and surface roughness of worn-out specimens were analyzed. The result indicates that the air-cooled (AC) sample possessed high hardness, high compression strength, and more resistance to wear as compared to AR and FC samples. The identified wear mechanisms in AR and FC samples were abrasive, deep grooves, plastic deformation while the AC specimen exhibits mild grooves and lesser debris particles. Fractography analysis was also performed to find the nature or mode of fractures on the samples. ANOVA result indicates that the sample hardness after heat treatment has the most influencing parameter followed by the applied load on the wear rate and the coefficient of friction (CoF). The measured average roughness of the AC specimen has shown lesser value than the AR and FC specimens due to refined grain structure.

11

Impact of Tool Magnetization on Changes in the Surface Layer of Forging Tools

Zwierzchowski M.

Archives of Metallurgy and Materials

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2019

|

Vol. 64, iss. 1

317--324

EN

The paper presents a description of the phenomena occurring on the surface of the forging dies. A detailed analysis was made of 24 pre-forging dies due to the most intensive wear in this operation. To compare the results, new tools were also analysed. The research described in the study showed that the most dangerous factor for the hot forging process analysed is thermal-mechanical fatigue, which causes small cracks, which in turn quickly leads to the formation of a crack network on the entire contact surface of the tool with forged material. The second phenomenon is the tempering of the surface of the material for a long-term temperature effect. The presence of hard iron oxides in the form of scale from forging material is the accompanying phenomenon that intensifies the processes of tool wear. The paper presents the results of the analysis of the presence of residual magnetic field for forging tools and the results of laboratory tests of wear processes of tool steels for hot work in the presence of a magnetic field and in the presence of scale.

12

Adhesion of PVD and CVD hard coatings as an essential parameter that determines the durability of coated tools

Pancielejko M.

Archives of Materials Science and Engineering

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2019

|

Vol. 96, nr 1

5--21

EN

Purpose: The work is connected with the current trend related to the modification of tool surfaces with PVD and CVD methods through the deposition of coatings to increase their durability. The research results of coated tools tests that are carried out in industrial conditions are presented in details. Design/methodology/approach: Structure, chemical and phase composition investigations related to the mechanical and tribological properties of coatings produced on tool substrates and analysis of the results are included. Investigations of the properties of deposited coatings on the following tool materials were made: high speed steels, hot work tool steel, sintered carbides and SiAlON tool ceramics. Findings: Interpretation of production tests results of coated tools and an analysis of the wear mechanisms of tool blades in relation to the properties of coatings and their adhesion, in particular characterized in the scratch test, were described. Research limitations/implications: Adhesion scratch test cannot be the only and final method of such evaluation. For example a direct comparison of the results of the scratch tests of coatings is possible when adhesion is being examined of different coatings yet on the same type of the substrate. Practical implications: Based on the adhesion test results using the scratch test, the suitability of the coatings produced on the cutting tools can be quickly assessed. Originality/value: It was sought those parameters which characterize the properties of coatings, ones which would permit to effectively/practically assess the performance of tools with coatings produced, with an exclusion or limitation of long-term and expensive durability tests of tools that are carried out in industrial conditions.

13

Fretting-Wear Mechanism of Textured Surfaces

Pashechko Mykhaylo, Marchuk Volodymyr, Kindrachuk Myroslav, Tisov Oleksandr, Kornienko Anatolii, Dukhota Oleksandr

Advances in Science and Technology. Research Journal

|

2019

|

Vol. 13, no 3

186--191

EN

The wear mechanism of textured dimpled in conditions of lubricated fretting-wear is established, which, in contrast to others, takes into account possibility of removing deterioration products out of tribo-contact areas into dimples, preventing their action as abrasive material. Selection of optimal structural parameters of selectively dimpled areas allows to reduce duration of tribological couple running-in time. Depending on texture type, friction coefficient was reduced from 0.27 (for untreated furface) to 0.18, and wear loss – from 7.8 ×10–3g to 3.3 ×10–3g.

14

Wear Mechanism of Spheroidal Cast Iron Piston Ring-Aluminum Matrix Composite Cylinder Liner Contact

Bąkowski H.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 1

481--490

EN

The paper presents the results of research on the impact of stereological characteristics of microstructure of graphite in nodular GJS-400 cast iron and Al2 O3 fibers in the composite AC-47000 + 10% Al2 O3 F on the mechanism of wear in a cast iron piston ring – composite cylinder liner contact in a combustion engine. To elucidate the mechanisms of wear in the tested contact was used Finite Element Method (FEM). On the basis of quantitative metallographic examination of test materials were determined stereological parameters of their structures. It was necessary for the implementation of the 3D model that reflects the actual structure with particular focus on the different phases in order to determine the distribution of stresses and strains. The determination Strains of the local stresses value of allowed the prediction of wear initiating places. Formation of stereological parameters of cast iron in the technological process allows a prediction of values and distributions of the stresses/strains and thus reduce wear and extend durability of the analyzed contact.

15

Research on tool wear based on multi-scale simulation in high speed cutting Inconel 718

Fan Y. H., Wang T., Hao Z. P., Lan H., Cui R. R.

Archives of Civil and Mechanical Engineering

|

2018

|

Vol. 18, no. 3

928--940

EN

Nickel-based superalloy Inconel718 has excellent properties such as good fatigue resistance, creep resistance, oxidation resistance and corrosion resistance. It has been widely used in aerospace industry. However, nickel-based superalloy is a kind of typical difficult-to process-material. The alloying elements which enhanced material exist in the form of high hardness compound (TiC, NbC and other interphase hard point). These high hardness compounds led to complicate cutting deformation, high cutting temperature, large cutting force and severe tool wear. According to the characteristics in cutting Inconel718 and the microstructure of cemented carbide tool, the wear properties and mechanism of carbide tool in cutting Inconel718 process are revealed by multi-scale analysis method. The main wear forms that wear debris peeled from the tool substrate are given and the evolution mechanism of tool wear caused by the crack in the cutting process is deeply studied.

16

Wybrane aspekty zużycia narzędzi kuźniczych

Zwierzchowski M.

Rudy i Metale Nieżelazne Recykling

|

2017

|

R. 62, nr 12

58--61

PL

W artykule przedstawiono rezultaty badań wpływu oddziaływania podwyższonych temperatur na właściwości warstwy wierzchniej stali narzędziowych do pracy na gorąco. Przedstawiono również wyniki badań oraz obserwacji oddziaływania (obecności) zgorzeliny z materiału odkuwki na stale narzędziowe do pracy na gorąco. Analizę oparto na wynikach badań przeprowadzonych w przemyśle oraz wynikach testów wykonanych w laboratorium badawczym. Szczegółowe badania dotyczyły: analiz termowizyjnych zjawisk podczas kucia na gorąco odkuwek stalowych, badania mikroskopowe, badania zużycia ściernego w obecności ścierniwa (zgorzeliny z odkuwki stalowej), badania mikrotwardości dla różnych parametrów badań laboratoryjnych oraz narzędzi z procesów kucia odkuwek stalowych.

EN

This article presents the results of studies on the effects of elevated temperatures on the properties of the surface layer of hot tool steels. The results of investigations and observations of the impact (presence) of the scale from the forging material on the tool steels for hot work were also presented. The analysis is based on the results of research conducted in the industry and the results of tests performed in the research laboratory. Detailed investigations concerned thermal analysis of steel forging, microscopic examination, abrasive wear in the presence of abrasive (steel forgings), microhardness tests for various laboratory tests and tools for forging of steel forgings.

17

Factors Affecting the Wear Resistance of Forging Tools

Zwierzchowski M.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1567--1576

EN

The durability of forging tools is a function of many variables: tool heat treatment, surface quality, temperature, pressure, number of forgings, diffusion layers (nitriding) and many others. The objective of study was to analyze and compare the working conditions of forging tools. For the analysis of selected flat surfaces of tools. Analyzed forging dies subjected to normal use. Presented results of laboratory tests . The effect of temperature and time on the properties of the surface layer of forging tools. The results were compared with the literature data. This article shows the results of microhardness tests for forging dies which have forged the corresponding number of forgings. The results of laboratory studies on microhardness of hot working steel 1.2344 in the furnace at various temperatures and time are also presented. The working conditions of the forging tools are very complex. The most often described in the literature are: thermal fatigue, abrasive wear, mechanical fatigue and cracks. The article discusses the effects of increased temperature on the surface properties of forging tools. Forging dies were made of hot work tool steel 1.2344. FEM modeling of changes in the surface layer should take into account changes in tool hardness as a function of time (number of forgings).

18

New observations on wear mechanism of self-reinforced SiAlON ceramic tool in milling of Inconel 718

Hao Z. P., Fan Y. H., Lin J. Q., Ji F. F., Liu X.

Archives of Civil and Mechanical Engineering

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2017

|

Vol. 17, no. 3

467--474

EN

Self-reinforced SiAlON ceramic tool materials, due to its unique properties such as high wear resistance, high hardness and low affinity with metal, is widely used in machining nickel-based alloy. The self-reinforced SiAlON ceramic tool was used in the experimental process of high speed milling nickel-based alloy Inconel718. The results obtained through observing the tool wear morphology and further analysis showed that when cutting speed vc = 50–200 m/min, abrasive wear and lamellar spalling was the main cause of tool wear. When cutting speed vc = 350, 500 m/min, the bond strength between β-SiAlON whisker and SiAlON matrix reduced, and then the tool material fell off, which led to the formation of hole and groove. When the hole and groove mark connected, the crack nucleation formed. The crack propagation resulted in fracture eventually. At last, according to the tool wear mechanism, tool wear model was established and the optimal cutting temperature range, which can lead to minimum tool wear in milling Inconel718 using self-reinforced SiAlON ceramic tool, was obtained.

19

Contribution of titanium, chromium and carbon buffer interlayers to bio-tribological properties of multilayer composites

Major Ł., Janusz M., Lackner J. M., Major B.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 3

1391--1398

EN

Research studies on bio-tribological protective coatings of titanium, chromium and carbon based have been performed. Thin films were fabricated by hybrid PLD technique (PLD supported by magnetron sputtering). Coatings consisted of two parts; the inner part (first from the substrate) in each case was formed by titanium or chromium/titanium nitride or chromium nitride (Ti/TiN or Cr/Cr2N). The outer part was formed by pure DLC or multilayer DLC'Ti or Cr. No delamination was found at the interface. Titanium or chromium metallic layer was deposited as a first layer directly on the metallic substrate to avoid delamination. All individual layers were built of columnar nano- crystallites. Mechanisms of the mechanical wear of analyzed systems were presented, focusing on the cracking propagation in ball-on-disc tests using an 1 N and 5 N applied loads for 5 000 cycles. Complex microstmcture analysis of presented nano-multilayer coatings, before and after mechanical tests, were performed by means of transmission electron microscopy (TEM). The highest stress concentration during mechanical uploading was moved through the multilayer coating by breaking only one layer at the time. The microstructure characterization revealed that cracking propagating in the outer part of the coating was stopped at the interface. In the case of the inner part of the coating Ti/TiN; Cr/Cr2N, ceramic layers showed brittle cracking, while metallic (Ti or Cr) ones deformed plastically. Fabricated coatings were subjected under the analysis in the biomechanical system optimized to test for the direct contact with a human whole blood. The study considered physiological conditions mainly related to the temperature and humidity and the frequency of cyclic deformation of the artificial vessel into which the tested sample was introduced.

20

Obecność fazy ciekłej w obszarze kontaktu narzędzia z odkuwką ze stopu tytanu jako źródło katastrofalnego mechanizmu zużycia

Frocisz Ł., Krawczyk J., Tokarski T., Cios G., Paćko M.

Tribologia

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2015

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nr 4

57--65

PL

Celem niniejszej pracy było określenie mechanizmu zużywania się materiału matrycy, jak i odkuwki tytanowej podczas procesu kucia matrycowego. Materiałem do badań była stal narzędziowa 55NiCrMoV7 z warstwą napawaną o pod-wyższonej zawartości Cr i Mo oraz odkuwka ze stopu Ti6Al4V. W wyniku kucia w temperaturze 940ºC na powierzchni obu materiałów pojawiły się wyraźne wy-żłobienia. Analiza metalograficzna pozwoliła stwierdzić, iż na powierzchni materiałów występują porowate struktury tlenkowe. Analiza chemiczna z tych obsza-rów wykazała obecność w produktach zużycia występujących na materiale matrycy – zwiększonej zawartości tytanu i aluminium. Wzajemne mieszanie materiału odkuwki i matrycy skutkowało powstaniem na powierzchni materiału niskotopliwej eutektyki. Zwiększenie temperatury na powierzchni styku najprawdopodob-niej związane było z efektem egzotermicznym od odkształcenia, jak i tarciem występującym podczas procesu kucia. Zwiększony udział fazy α na powierzchni odkuwki skutkował powstawaniem w obszarach przypowierzchniowych siatki pęknięć. Pęknięcia te powodowały dodatkową intensyfikację procesu zużycia.

EN

The wear mechanisms of titanium alloy forging and tool steel used for die forging are presented. Materials for the investigations were 55NiCrMoV7 tool steel and Ti6Al4V titanium alloy. The die forging process was performed at 940ºC on backward hammer BECHE. On the surface of the die and forging, a groove net was observed after the process. Metallographic analysis indicated the presence of oxidation products on the surfaces of the tested materials. A net of micro-cracks and an increase in the α phase volume fraction was observed in the subsurface area of the titanium alloy. Chemical microanalysis from the die surface area and on the cross section revealed the presence of titanium and aluminium in the wear products. Mutual mixing of materials resulted in the formation of low-temperature eutectics on the surfaces. The exothermic effect of titanium alloy plastic deformation and the friction resulted in a temperature increase. The liquid phase cased gridding of materials surfaces. The higher volume fraction of the α phase and presence of cracks in the subsurface area of titanium alloy also probably intensify wear.