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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).

2

Analysis of Hard Facing Material Designed for Application on the Forestry Tools

Ťavodová Miroslava, Hnilicová Michaela, Miturska Izabela

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 4

111--119

EN

The article deals with the assessment specific hard facing material with W2C high content – filled welding rod for manual flame hard facing RD 571. Is was applied in two layers on the samples (16MnCr5 steel) of the tool for crushing undesirable advance growths, frequently used in forestry technologies. The tools work in a heterogeneous environment. They are loaded by abrasive impression of wood mass, which are characterized by various hardness. The material loss on the functional parts is significant. The wear degradation of the tool and its subsequent early decommissioning represents economic losses for forest companies. The investigations conducted under laboratory conditions involved hardness measuring HV10 and HRC, wear resistance testing of materials by friction against loosely fixed abrasive parts, with assessment profile and depth of the mark as well as assessment of quality mixing of the layers, microstructure assessment by SEM with EDX analyses. By evaluating the laboratory tests, the conclusions were drawn to determine the suitability or the non-suitability of the selected hardfacing material in service. Whether the material increases the service life of the undesirable crusher tool, will by verified by performing field trials.

3

Revitalization of the damaged machine parts by hard facing as a way of saving funds

Lazic V., Arsic D., Nikolic R., Mutavzic M., Hadzima B.

Production Engineering Archives

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2016

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Vol. 12, No. 3

9--13

EN

The objective of the research, presented in this paper, was to demonstrate the superiority of the hard facing as the revitalization technology of various damaged machine parts. The analysis of the two different revitalization methods of the damaged machine parts is presented – the replacement of the damaged part by the new – spare part and reparation by hard facing. The comparison is done on the example of hard facing and replacing of damaged loader's teeth. The paper presents a method for calculating costs of the two revitalization technologies based on their profitability and their comparison. That method could be applied for similar calculations for any machine part, with smallest or no adjustments. The paper presents a verification of advantage of applying the hard facing as the machine parts reparatory technology with respect to the other revitalization technology. The savings realized by application of hard facing reparation of the loader's teeth reach 73.5 % for one set of teeth and 82.40per annum of the costs for purchasing the new spare parts. The analysis was conducted under an assumption that organization of the maintenance function is at the exceptionally high level so that the purchasing of the new part/repairing of the damaged one is always done in time. This idealized approach was adopted since in that way one obtains the least economic effects of the reparatory technology application with respect to replacing the part with the spare one. In any other case the economic effects would be significantly higher, namely even more positive in favor of the hard facing revitalization technology.

4

Comparative characteristics of gear teeth regenerated by hard facing

Marković S., Josifović D.

Tribologia

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2008

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nr 1

83-100

EN

Machinery parts regeneration is a procedure which is often applied in engineering practice with the aim to recover basie functional characteristies, and quite often to increase the duration of a machinery system working life. Hard facing, as a method of regeneration, is most commonly used in gears which are the vital parts of a machinery system. This paper contains analysis of the influence the type of hard facing has upon working characteristics of regenerated gears, made on the basis of ample experimental investigation. Cylindrical spur gears, both newly-made and regenerated, were subjected to investigation. Regeneration was carried out in two basically different manners: by hard facing with hard additional materials and hard facing with soft additional materials and subsequent cementation and quenching. What was considered in the first place were the results of investigation of regenerated gears in the process of destructive wear following the testing upon a test stand with closed circuit and variable load. The influence the type of hard facing has upon working characteristics of regenerated gears (their life-cycle above all) can be seen through the results of the carried out investigation.

PL

Regeneracja części maszyn ma na celu odtworzenie ich podstawowych cech użytkowych, a często także zwiększenie ich trwałości. W odniesieniu do kół zębatych często stosowanym sposobem regeneracji jest napawanie. Autorzy eksperymentalnie zbadali wpływ rodzaju zastosowanej techniki napawania na cechy użytkowe regenerowanych kół zębatych. Zbadano koła zębate walcowe o zębach prostych, nowe i regenerowane. Regeneracji dokonano dwoma sposobami: napawaniem z użyciem spoiwa twardego oraz miękkiego, z późniejszą obróbką cieplną. Szczególną uwagę zwrócono na wpływ zastosowanej techniki napawania na destrukcyjne zużycie przez pitting w badaniach na stanowisku przekładniowym, pracującym w układzie mocy krążącej pod zmiennym obciążeniem.

5

Selection of the optimum technology of the forging dies reparation from the aspect of tribological characteristics

Lazić V., Jovanović M., Adamović D., Ratković N.

Tribologia

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2005

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nr 2

11-30

EN

This paper presents a preceding procedure that should be conducted in order to successfully regenerate damaged forging dies by the hard facing process. After the tool damage types identification, as well as their causes, we have chosen the procedure and the parameters of hard facing that we further corrected by conducting the test hard facings on models. Thus, we were able to relate the output results with the repair technology, taking as a criterion the quality of the surface layers wear resistance, micro hardness, level of residual stresses and strains, etc. This enabled the selection of the optimum technology of hard facing for the adopted procedure and filler material, as well as the selected thermal-treating regime. Our tribological and other investigations have shown that the working life of the hard-faced tool can be longer than that of the new tool.

PL

W artykule przedstawiono procedurę, którą powinna poprzedzać regenerację uszkodzonych matryc kuźniczych metodą napawania. Po zidentyfikowaniu rodzajów zużycia matryc kuźniczych i jego przyczyn, autorzy wybrali procedurę i parametry napawania, a następni zweryfikowali je na próbkach modelowych. Badano wpływ technologii regeneracji na odporność na zużycie, mikrotwardość, poziom naprężeń szczątkowych, odkształceń itp. Pozwoliło to na wybór optymalnej technologii napawania oraz materiału elektrody, a także warunków obróbki cieplnej. Wykonane badania wykazały i potwierdziły, że trwałość narzędzi regenerowanych napawaniem może być wyższa niż narzędzi nowych.