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1

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

Szala Mirosław, Hejwowski Tadeusz

Tribologia

|

2022

|

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).

2

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

Szala Mirosław

Tribologia

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2021

|

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.

3

Erozja kawitacyjna pomp : zapobieganie i ograniczanie jej skutków

Karaśkiewicz Krzysztof

Przemysł Chemiczny

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2021

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T. 100, nr 5

452--456

PL

Typowy zapas NPSHA względem NPSH3 nie zawsze zapewnia bezkawitacyjną pracę pomp wirowych, co jest związane z dużą wartością proporcji NPSHi/NPSH3. Omówiono stosowane w przemyśle nowoczesne materiały odlewnicze oraz powłoki ceramiczne i elastomerowe o wysokiej odporności na erozję kawitacyjną.

EN

Typical NPSHA margin not always ensures non-cavitation operation of centrifugal pumps, which is related to the large ratio NPSHi/NPSH3. The article discusses the materials for cavitation erosion resistance. Modern casting materials used in industry as well as ceramic and elastomeric coatings with high resistance to cavitation erosion are presented.

4

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

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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.

5

Factors Influencing Cavitation Erosion of NiCrSiB Hardfacings Deposited by Oxy-Acetylene Powder Welding on Grey Cast Iron

Szala Mirosław, Walczak Mariusz, Hejwowski Tadeusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 4

376--386

EN

The work presents the results of a study on cavitation erosion (CE) resistance of two NiCrSiB self-fluxing powders deposited by oxy-acetylene powder welding on cast iron substrate grade EN-GJL-200. The mean hardness of deposits A-NiCrSiB, C-NiCrSiB is equal to 908 HV, 399 HV and exceeds those of EN-GJL-200 and X5CrNi18-10 reference specimens 197 HV and 209 HV, respectively. To study CE, the vibratory apparatus has been used and tests were conducted according to the ASTM G32 standard. Cavitation eroded surfaces were examined using a profilometer, optical and scanning electron microscopy. The research indicated that the CE resistance, expressed by the cumulative mass loss decreased in the following order C-NiCrSiB > A-NiCrSiB > X5CrNi18-10 > EN-GJL-200. Therefore, hardfacings were characterised by lower cumulative mass loss, in turn, higher CE resistance than the reference sample and therefore they may be applied as layers to increase resistance to cavitation of cast iron machine components. Results indicate that in the case of multiphase materials, hardness cannot be the main indicator for CE damage prediction while it strongly depends on the initial material microstructure. To qualitatively estimate the cavitation erosion damage (CEd) of NiCrSiB self-fluxing alloys at a specific test time, the following factors should be considered: material microstructure, physical and mechanical properties as well as surface morphology and material loss both estimated at specific exposure time. A general formula for the CEd prediction of NiCrSiB deposits was proposed.

6

O kawitacji w pompach wirowych raz jeszcze

Jędral Waldemar

Energetyka Cieplna i Zawodowa

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2020

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Nr 5

34--41

PL

W artykule [1] przedstawiono pięć przykładów realnych problemów eksploatacyjnych spowodowanych kawitacją w pompach do ścieków, różnej konstrukcji i wielkości. Podano też ogólne zależności dotyczące różnie definiowanych nadwyżek antykawitacyjnych i relacji między nimi oraz przedstawiono podstawowe charakterystyki kawitacyjne pompy wirowej. Ze względu na wciąż aktualny problem skutków pracy różnych pomp wirowych w obszarze kawitacji oraz na istotne wątpliwości dotyczące nadwyżek antykawitacyjnych, powrócono do tematu, podając równocześnie nowe informacje dotyczące m.in. pomp zasilających.

7

Phenomenological technique for prediction of cavitation erosion performance

Gireń B. G., Welzant A., Baran P.

Archives of Materials Science and Engineering

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2020

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Vol. 104, nr 2

69--85

EN

Purpose: Major aim of the work was to formulate 2-parameters models of the cavitation erosion process and to bring about the particular methods for prediction of its performance with due calculation formulas. Design/methodology/approach: Phenomenological model of the erosion supplemented with functional relationships between calculation parameters and the strength parameters stand for the foundations of the method. Having assumed the probabilistic nature of the process and fatigue regime of the material destruction, the volume loss in time has been determined as proportional to the integral of the appropriate probability function. Correlations between parameters have been derived by adjusting the computed erosion curves to the experimental ones for the vast diversity of the cases. Findings: Two different formulas for the volume loss of the material in time under cavitation loading have been derived. Research limitations/implications: Results obtained from both the International Cavitation Erosion Test program as well as the own experiments carried out at the rotating disk set-up supplied necessary experimental data. Preliminary verification of the method soundness was completed. Assumption on the independence of the calculation parameters on the loading conditions have been taken. The approach is valid provided the defined relationships are also independent on the type and amplitude of the loading. Practical implications: Achieving the objectives is expected to result in developing a technique for assessment of the material damage under cavitation loadings. Numerical implementation of the model completed with the derived functional relationships stand for a tool, enabling a prospective user to predict the material performance under defined cavitation loading. Originality/value: New formulas for calculating the efficiency of cavitation erosion, inferred from the models of high physical clarity are the original contribution to the methodology and techniques concerned.

8

Cavitation erosion and sliding wear of MCrAlY and NiCrMo coatings deposited by HVOF thermal spraying

Szala M., Walczak M., Łatka L., Gancarczyk K., Özkan D.

Advances in Materials Science

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2020

|

Vol. 20, nr 2(64)

26--38

EN

The investigation into wear resistance is an up-to-date problem from the point of view of both scientific and engineering practice. In this study, HVOF coatings such as MCrAlY (CoNiCrAlY and NiCoCrAlY) and NiCrMo were deposited on AISI 310 (X15CrNi25-20) stainless steel substrates. The microstructural properties and surface morphology of the as-sprayed coatings were examined. Cavitation erosion tests were conducted using the vibratory method in accordance with the ASTM G32 standard. Sliding wear was examined with the use of a ball-on-disc tribometer, and friction coefficients were measured. The sliding and cavitation wear mechanisms were identified with the SEM-EDS method. In comparison to the NiCrMo coating, the MCrAlY coatings have lower wear resistance. The cavitation erosion resistance of the as-sprayed M(Co,Ni)CrAlY coatings is almost two times lower than that of the as-sprayed NiCrMoFeCo deposit. Moreover, the sliding wear resistance increases with increasing the nickel content as follows: CoNiCrAlY < NiCoCrAlY < NiCrMoFeCo. The mean friction coefficient of CoNiCrAlY coating equals of 0.873, which almost 50% exceed those reported for coating NiCrMoFeCo of 0.573. The as-sprayed NiCrMoFeCo coating presents superior sliding wear and cavitation erosion resistance to the as-sprayed MCrAlY (CoNiCrAlY and NiCoCrAlY) coatings.

9

Cavitation erosion resistance influence of material properties

Zakrzewska D. E., Krella A. K.

Advances in Materials Science

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2019

|

Vol. 19, nr 4(62)

18--34

EN

The cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components, there are many methods to increase cavitation erosion resistance. The paper discusses the correlations between structural and mechanical properties and the resistance to cavitation erosion (CER) of pure materials, their alloys and coatings. Methods to increase CER have also been described - using heat / thermo-chemical treatment and application of coatings by various methods.

10

Cavitation erosion and sliding wear resistance of HVOF coatings

Szala M., Walczak M.

Welding Technology Review

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2018

|

R. 90, nr 10

31--36

EN

The aim of the work was to investigate the resistance to cavitation erosion and sliding wear of as-sprayed HVOF coatings. M(Ni,Co)CrAlY and Cr3C2-NiCr based coatings were deposited using HVOF method onto stainless steel substrate grade AISI 304. As-sprayed coatings’ surface morphology was examined by SEM-EDS and profilometer methods. Cavitation erosion tests were conducted in distilled water with the use of vibratory rig and stationary specimen method. Cavitation erosion curves were plotted as well as cavitational wear mechanism was observed with the use of SEM microscope. Sliding wear tests were performed using the ball-on-disc tribotester with counter-specimen (ball) made of steel 100Cr6. Wear rates and coefficient of friction were computed. Normalized wear resistance with reference to stainless steel reference sample AISI 304 was calculated. In addition, comparable analysis of wear resistance results was conducted. M(Ni,Co)CrAlY coating presented the highest cavitation erosion resistance, therefore Cr3C2-NiCr coating represented the highest sliding wear resistance of all tested materials.

PL

Celem pracy było zbadanie odporności na zużycie kawitacyjne i ścierne powłok natryskiwanych metodą HVOF. Powłoki typu M(Ni,Co)CrAIY oraz Cr3CrNiCr wytworzono na podłożu ze stali odpornej na korozję gatunku AISI 304. Morfologię powłok w stanie po natryskiwaniu scharakteryzowano metodą SEM-EDS (skaningowy mikroskop elektronowy) oraz profilometrycznie. Badania kawitacyjne prowadzono w wodzie destylowanej na stanowisku wibracyjnym ze stacjonarną próbką. Wyznaczono krzywe erozyjne badanych materiałów, powierzchnię zużycia poddano obserwacjom mikroskopowym SEM. Badania odporności na zużycie ścierne przeprowadzono metodą ball-on-disc stosując przeciwpróbkę 100Cr6, wyznaczono współczynniki zużycia i tarcia. Obliczono znormalizowaną odporność na zużycie w odniesieniu do próbki referencyjnej wykonanej ze stali odporniej na korozję AISI 304 oraz dokonano analizy porównawczej odporności na zużycie. Powłoka M(Ni,Co)CrAIY charakteryzowała się najwyższą odpornością na erozję kawitacją natomiast powłoka Cr3CrNiCr wykazała najwyższą odporność na zużycie ścierne.

11

Erozja w dyfuzorze elektrofiltru z dolnym dopływem spalin

Malcher T.

Przemysł Chemiczny

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2018

|

T. 97, nr 9

1499-1501

PL

Dyfuzor elektrofiltru w postaci geometrii 3D poddano symulacji numerycznej, której celem było wykrycie rejonów narażonych na erozję. Erozja taka często towarzyszy przepływowi spalin zawierających duże ilości cząstek stałych, pochodzących ze spalania w kotłach elektrociepłowni. Efekt obliczeń przedstawiono w formie graficznej.

EN

Simulation of the erosion allowed for detection of areas particularly exposed to damage. The results of the calculations were presented graphically.

12

Identification of cavitation wear areas on inner lining of tubes with variable radius using computer modeling of fluid flow

Rybacki P., Grześ Z.

Journal of Research and Applications in Agricultural Engineering

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2018

|

Vol. 63, nr 1

92--103

EN

The paper presents applicability of the computer system to model and simulate fluid and gas flow to assess surface cavitation wear. Abstract tube models with a decreasing inside diameter were developed and fluid flow with varying flow velocities was simulated. This facilitated identification of areas particularly at risk of cavitation wear. Results of simulation analyses were verified by comparing them with actual empirical results concerning cavitation erosion of tubing materials.

PL

W pracy przedstawiono możliwości wykorzystania systemów komputerowego modelowania oraz symulowania przepływu cieczy i gazów do oceny stopnia zużycia kawitacyjnego powierzchni. Opracowano abstrakcyjne modele przewodów o zmniejszającej się średnicy wewnętrznej oraz symulowano przepływ cieczy z różnymi prędkościami. Pozwoliło to wyznaczenie obszarów szczególnie narażonych na erozję kawitacyjną. Dokonano weryfikacji wyników analizy symulacyjnej porównując je z rzeczywistymi wynikami badań erozji kawitacyjnej materiałów do budowy przewodów.

13

Cavitation erosion – phenomenon and test rigs

Krella A. K., Zakrzewska D. E.

Advances in Materials Science

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2018

|

Vol. 18, nr 2(56)

15--26

EN

The cavitation and cavitation erosion phenomenon have been shortly presented. The main four types of test rigs to investigate the cavitation erosion resistance have been shown. Each type of test design is described and an example of a design is shown. A special attention has been payed to the designs described in the International ASTM Standards: a vibratory design and a cavitating jet cell. There was shown that the design of a test device and the test conditions affect the resistance to cavitation erosion of a material.

14

Numerical analysis of the cavitation effect occurring on the surface of steel constructional elements

Linek T., Tański T., Borek W.

Archives of Materials Science and Engineering

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2017

|

Vol. 85, nr 1

24--34

EN

Purpose: The aim of the work is to present the results of own investigations concerning the geometric optimisation of constructional elements working in the environment of cavitation wear together with a computer numerical analysis. The engineering material used for constructional elements working in the environment of cavitation wear is steel, commonly used for pressure devices working at elevated temperatures, P265GH, acc. to PN-EN 10028:2010. Design/methodology/approach: SOLID EDGE ST 7 software, for synchronous designing, was used for the parametrisation of the shape, distribution, configuration and size of openings in constructional elements. Five models, with a different spacing and number of openings, were proposed for the optimisation of internal geometry of the cavitation generator and for the investigations; the models were then subjected to a numerical analysis using specialised software, ANSYS FLUENT v.16, employed for modelling the effects associated with fluid mechanics (Computational Fluid Dynamics - CFD). The data was implemented for this purpose in the software used, such as: density, yield point, tensile strength, heat conductivity coefficient for steel P265GH, material surface roughness, medium (water) flow rate, constant pressure loss of medium, pressure of steam saturation in a medium; and such data was called boundary conditions. Findings: The authors’ principal accomplishment is the optimisation of the shape, the selection of the most appropriate geometry of a constructional element generating the maximum number of cavity implosions in the environment of a flowing medium (water), with the use of computer tools dedicated to engineering design: a 3D and numerical computer analysis of fluid mechanics, CFD. Moreover, an attempt was made in this work to develop a methodology for characterisation of the phenomena accompanying the environment of cavitation wear. Practical implications: A possibility of examining the phenomena and a process of wear of a constructional element made of P265GH grade steel for pressure devices working at elevated temperatures. The demonstration and presentation of potential places, areas and sizes of erosion existing on constructional elements working in the environment of cavitation wear.

15

Cavitation Erosion of Nodular Cast Iron - Microstructural Effects

Orłowicz A. W., Mróz M., Tupaj M., Trytek A., Jacek M., Radoń M.

Archives of Foundry Engineering

|

2017

|

Vol. 17, iss. 4

119--122

EN

The paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features to be damaged are graphite precipitates. The ferritic matrix of the alloy turned out to be definitely less resistant to cavitation erosion compared to the pearlitic matrix component.

16

Cavitation erosion degradation of Belzona® coatings

Bolewski Ł., Szkodo M., Kmieć M.

Advances in Materials Science

|

2017

|

Vol. 17, nr 1(51)

22--33

EN

In hydrocarbon and maritime industry there is a constant need of materials and coatings withstanding severe conditions. One of adverse phenomena present there is cavitation erosion. The paper presents evaluation of cavitation resistance of three different steel coatings. Belzona 2141 (ACR-Fluid Elastormer), 1321 (Ceramic S-Steal) and 5831 (ST-Barrier) were deployed on P110 steel and subjected to ultrasound cavitation in distilled water and drilling mud environment. According to mass loss measurements Belzona 2141 shows superior performance comparing to two other coatings and bare p110 steel surface. This is due to its high elasticity comparing to steel.

17

Cavitation wear of pump impellers

Szala M., Łukasik D.

Journal of Technology and Exploitation in Mechanical Engineering

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2016

|

Vol. 2, nr 1

40--44

EN

Cavitation is a common phenomenon in pump systems, negatively influencing their operating parameters and components such as impellers and, thus, causing considerable financial losses. This paper explains the problem of cavitation and cavitation erosion. The causes of cavitation in pump systems are analyzed. A selection of centrifugal pump impellers damaged by cavitation erosion are presented and examined. The authors also discuss ways of preventing cavitation and cavitation erosion in pump systems. Finally, relevant conclusions are drawn.

PL

Kawitacja w układach pompowych jest zjawiskiem powszechnym, oddziaływującym negatywnie na parametry pracy oraz podzespoły pomp np. wirniki, przyczyniając się do dużych strat finansowych. W pracy wyjaśniono pojęcie kawitacji i erozji kawitacyjnej. Przedstawiono przyczyny występowania kawitacji w układach pompowych. Scharakteryzowano przykłady uszkodzonych w wyniku działania erozji kawitacyjnej wirników pomp wirowych. Omówiono sposoby zapobiegania kawitacji i erozji kawitacyjnej w układach pompowych, oraz sformułowano adekwatne wnioski.

18

Cavitation erosion of P110 steel in different drilling muds

Kmieć M., Karpiński B., Szkodo M.

Advances in Materials Science

|

2016

|

Vol. 16, nr 2(48)

57--67

EN

The P110 steel specimens were subjected to ultrasonic cavitation erosion in different compositions of drilling muds and surfactant additive. The test procedure was based on ASTM-G-32 standard recommendations. API 5CT-P110 steel is used for pipes in oil and gas industry. The harsh environment and high velocity of flows poses corrosive and erosive threat on materials used there. The composition of drilling fluid influences its rheological properties and thus intensity of cavitation erosion. The erosion curves based on weight loss were measured.

19

Zwiększanie odporności kawitacyjnej stopów metali przez napawanie powłok

Szala M., Hejwowski T.

Przegląd Spawalnictwa

|

2015

|

R. 87, nr 9

56--60

PL

W pracy przedstawiono wyniki pomiarów odporności na zużycie kawitacyjne powłok NiCrBSi oraz powłoki stellitowej. Powłoki na osnowie niklu wykonano metodą napawania płomieniowo-proszkowego, na osnowie kobaltu metodą TIG. Badania kawitacyjne wykonano na stanowisku wibracyjnym zgodnie z normą ASTM G-32. Na podstawie badań makroskopowych oraz przy użyciu mikroskopii elektronowej dokonano identyfikacji mechanizmu zużywania powłok. Określono cechy i właściwości wytworzonych powłok sprzyjające ich odporności kawitacyjnej. Powłoki na osnowie niklu wykazują wysoką odporność kawitacyjną i mogą być stosowane w celu zwiększania odporności elementów maszyn przepływowych.

EN

In the work results of cavitation erosion test of NiCrBSi and stellite coatings were presented. Nickel based coatings were pad welded with the oxy-acetylene powder torch, cobalt based with TIG method. Cavitation tests were conducted on vibratory test rig according do ASTM G-32 standard. The cavitation erosion mechanism was examined by using macroscopic and SEM microscopy observation. The influence of the microstructure features and properties of produced coatings on cavitation erosion resistance was investigated. Presented coatings can be applied to increase erosion resistance of fluid machine elements.

20

Odporność kawitacyjna powłok na osnowie niklu napawanych metodą płomieniowo-proszkową

Szala M., Hejwowski T.

Przegląd Spawalnictwa

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2015

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R. 87, nr 10

36--41

PL

W pracy przedstawiono wyniki pomiarów odporności na zużycie kawitacyjne powłok na osnowie Ni. Powłoki wykonano metodą napawania płomieniowo-proszkowego. Badania kawitacyjne wykonano na stanowisku wibracyjnym zgodnie z normą ASTM G-32. Określono wpływ mikrostruktury, twardości i mikrotwardości wytworzonych warstw na ich odporność kawitacyjną. Przy użyciu mikroskopii elektronowej dokonano identyfikacji mechanizmu zużywania powłok. Obserwacji dokonano w oznaczonych obszarach na powierzchni powłok w wybranych czasach ekspozycji. Powłoki objęte badaniami mogą być rozważane do regeneracji elementów maszyn i urządzeń podlegających zużyciu kawitacyjnemu.

EN

In the work results of cavitation erosion test of nickel based coatings were presented. Coatings were pad welded with the oxy-acetylene powder torch. Cavitation tests were conducted on vibratory test rig according do ASTM G-32 standard. The influence of microstructure, hardness and microhardness on cavitation erosion resistance was investigated. The cavitation erosion mechanism was examined by using SEM microscopy. Observations were conducted in specified areas of coatings in defined times of exposition. Presented coatings could be considered to repair cavitation worn machines elements and appliance.