Impact Abrasion Research Articles

Economic Adaptation Strategies of Coastal Communities Affected by Environmental Degradation (Study Case: Sayung Sub-district, Demak)

Sayung sub-district experienced the most severe abrasion impact in some villages. Abrasion not only drowns Rejosari and Tambaksari dukuh, but also shifts the pattern of life or social culture of coastal communities who choose no longer rely on the fishery sector ponds. The research used descriptive qualitative method that is research type which use description of field condition in writing. The type of questionnaire used is a questionnaire with open-closed questions (open-closed questions). The result is that 74% of Bedono local people feel that the environmental condition has worsened since the increasing of abrasion. The income level of Bedono local people as much as 60% of its citizens experienced a decrease in income level due to abrasion. Although, with the worse conditions caused by severe abrasion that damage the environment, local people of Sayung sub-district have economic adaptation strategies to improve their financial aspect based on tourism development. On the other hand, the potential of Sayung Beach and surrounding areas to become Community Based Tourism is considered very unique.

Long-term durability tests of andesite aggregates from Hungary

The Micro-Deval test method is used for testing of aggregate durability. The present paper focuses on two Hungarian andesites obtained from the quarries of Recsk (Matra Mountains, Hungary) and of Nogradkovesd (Cserhat Mountains, Hungary). The aim of this study is to find a simple test method based on the original Micro-Deval test method to assess the long-term durability of aggregates. An additional part of the research was to develop suitable mathematical models that can describe the behavior of the andesite aggregates under continuous abrasive impact. The relevant standard (EN 1097-1:2012) recommends 12,000 rotations to determine the Micro-Deval coefficient required for classification of the aggregates. Within the framework of this research, a modified Micro-Deval test was applied: the number of rotations was increased in several steps and the degree of abrasion was measured afterwards. Regression analyses were used to outline mathematical forms which characterize the dependence between the number of rotations and the degree of abrasion. According to the results, the long-term Micro-Deval tests significantly modify the assessed durability and thus provide information on the long-term abrasive impact. The degree of change depends on the studied material: the ratio of the long-term Micro-Deval coefficients of the two studied andesite types is larger than 3. The regression analyses of the measured Micro-Deval coefficients revealed that quadratic curves are suitable to describe these tendencies for both andesite aggregates.

Wear Behaviour of Iron Matrix Composite Reinforced by ZTA Particles in Impact Abrasion

Zirconia toughened alumina (ZTA) particles reinforced high chromium cast iron composites (ZTA/Iron composites) were prepared by a two-step processing method, i.e. mixing particles by the molten metal and cohering by high pressure, which based on the squeeze casting process. The impact wear resistance under different impact energies were investigated using dynamically loaded abrasive wear tester at room temperature. For comparison, the wear tests of high chromium cast iron were also carried out under the same conditions. Worn surfaces of the samples were observed under scanning electron microscopy equipped with an energy dispersive detector. The results showed that the composites have better impact wear resistance than that of high Cr cast iron regardless of impact energy level, and the wear resistance of the two materials all decrease with the increase of the impact energy. The main wear mechanisms of the high Cr cast iron were micro-cutting and fatigue peeling, while the wear of composites occurred through micro-cutting of the matrix (lower impact energy) and breaking and shedding of the reinforced particles (higher impact energy).

Prediction of Abrasive Erosion Impact Wear of Composite Hardfacings

In this paper an attempt is made to use in wear prediction besides the wear from plastic and brittle components also fatigue fracture component. As example, WC-Co hardmetal reinforced composite hardfacing wear at abrasive impact erosion wear conditions was calculated at low and high impact energy, accountig microcutting with surface fatigue for the wear of matrix and brittle fracture, surface fatigue and plastic deformation for the wear of reinforcement. Calculated wear rates are compared with data obtained from experimental tests. The obtained results show that the used surface fatigue wear model is not applicable in the current case; the recommendations for the further improvement of the model are issued.

Wear of cemented tungsten carbide percussive drill–bit inserts: Laboratory and field study

Design of the drill–bit and selection of the Cemented Tungsten Carbide (CC) grade for drill–bit inserts are crucial for efficient percussive drilling. This study presents the results of an experimental campaign executed with the aim to identify the distinctive wear mechanisms and behaviour of different CC grades. Three laboratory and one full–scale drilling tests were performed using nine CC grades with different binder contents, binder chemical compositions, mean tungsten carbide (WC) grain sizes, and grain size distributions. Wear traces found on the drill–bit inserts after the full–scale drilling test show noticeable differences depending on their position on the drill–bit. Tensile forces present on the leading edge of the inserts due to the sliding contact with rock are suspected to play a significant role. Laboratory tests performed include: (i) single impact tests using a modified Split Hopkinson Pressure Bar (SHPB) apparatus, (ii) Abrasion Value (AV) rotating disk tests, and (iii) impact abrasion (LCPC) tests. Volume loss and shape change were used as macroscopic measures of wear. Greater volume losses were found for the grades with nickel–based binders compared to those with pure cobalt binder. The use of a narrower WC grain size distribution leads to lesser volume loss in drilling and AV tests. Surface analysis of the damaged microstructure was performed using scanning electron microscope. Distinct meso–scale (few dozens of WC grain sizes) patterns of damaged microstructure zones surrounded by the intact surface were found on the surfaces of specimens after single impact test. The pattern indicates the potential influence of a non–uniform contact due to the rock roughness and internal rock heterogeneities, which is supported by the study of the rock crater roughness. Size of such zones could be seen as a certain length–scale, which determines the insert–rock contact behaviour. A specific “peeling” mechanism of material removal was observed in the full–scale drilling test, where portion of the CC microstructure fused with the rock tribofilm gets removed when that tribofilm peels off.

Wear resistance and mechanisms of composite hardfacings at abrasive impact erosion wear

Tungsten carbide based hardmetal containing sprayed and melted composite hardfacings are prospective for protection against abrasive wear. For selection of abrasive wear resistant hardfacings under intensive impact wear conditions, both mechanical properties (hardness, fracture toughness, etc.) and abrasive wear conditions (type of abrasive, impact velocity, etc.) should be considered.This study focuses on the wear (wear rate and mechanisms) of thick metal-matrix composite hardfacings with hardmetal (WC-Co) reinforcement produced by powder metallurgy technology. The influence of the hardmetal reinforcement type on the wear resistance at different abrasive impact erosion wear (AIEW) conditions was studied. An optimal reinforcement for various wear conditions is described. Based on wear mechanism studies, a mathematical model for wear prediction was drafted.

Photodegradation of UHMWPE Filled with Iron Ore Fine

Ultra high molecular weight polyethylene (UHMWPE) is one of the most important engineering materials owing to outstanding properties like impact strength and abrasion resistance. However, the relatively low Young´s modulus restricts some application and the use of fillers may be a suitable way to overcome this. The fillers can influence the photo stabilization of the compound, as it occurs to other polymers. Neat UHMWPE and its composites with 1 and 10% of iron ore fine were exposed to ultraviolet radiation for up to 33 days and then tested for mechanical properties. The stress-strain behaviour changed with degradation, with an evident necking and strain hardening region that was not observed before exposure, due to a reduction in entanglements density. From the tensile results, the filler may have a protection action against UV, particularly when a loading of 10% was present. Complementary analyses were performed, including X-ray diffraction, DSC and SEM.

Self‐formed waterfall plunge pools in homogeneous rock

AbstractWaterfalls are ubiquitous, and their upstream propagation can set the pace of landscape evolution, yet no experimental studies have examined waterfall plunge pool erosion in homogeneous rock. We performed laboratory experiments, using synthetic foam as a bedrock simulant, to produce self‐formed waterfall plunge pools via particle impact abrasion. Plunge pool vertical incision exceeded lateral erosion by approximately tenfold until pools deepened to the point that the supplied sediment could not be evacuated and deposition armored the pool bedrock floor. Lateral erosion of plunge pool sidewalls continued after sediment deposition, but primarily at the downstream pool wall, which might lead to undermining of the plunge pool lip, sediment evacuation, and continued vertical pool floor incision in natural streams. Undercutting of the upstream pool wall was absent, and our results suggest that vertical drilling of successive plunge pools is a more efficient waterfall retreat mechanism than the classic model of headwall undercutting and collapse in homogeneous rock.

Relationships Between Structural, Functional, and X-Ray Microcomputed Tomography Parameters of Pervious Concrete for Pavement Applications

Several countries have begun using pervious concrete (PC) pavements to reduce the adverse effects of impermeable surfaces resulting from high-impact development. Pore parameters and their relationship to other PC properties are not yet fully understood; however, this information is essential for rational designs of PC pavements. This study investigated the strength, functional, and permeability properties of 18 PC mixtures and used X-ray computed microtomography methods to determine the three-dimensional pore parameters and their relationships, which were thought to affect PC properties. The major findings of this study included the observation that the failure mode in compression was of the shear brittle type, in which the failure plane was inclined at 45° to the ground, and impact abrasion resistance was higher for larger-sized aggregates and was chiefly attributable to the individual aggregate particles debonding. Permeability was more sensitive at low hydrostatic pressure than at higher pressures. The sphericity and compactness of pores had positive correlations with each other, unlike the relationship between surface area and sphericity. The tortuosity calculated for six of the PC mixtures was less than one; this finding was attributed mainly to the single-sized pore structure. Tortuosity increased with an increase in porosity and permeability and decreased with increasing surface area and pore radius. This research should move the current understanding of PC pore structure one step forward and, therefore, will be helpful in modeling PC in a rational manner.

Tribological performances of ZrC-Ni and TiC-Ni cermet reinforced PTA hardfacings at elevated temperatures

The aim of this study was to characterise TiC-Ni and ZrC-Ni cermet reinforced NiCrBSi hardfacings in a 40:60vol.% ratio respectively and to investigate their respective wear behaviour at temperatures up to 700°C. Coatings were produced using plasma transferred arc welding; optimised methods and parameters were meant to ensure a uniform distribution of the cermet across the metal matrix composite. High-temperature testing included macro hot-hardness, cyclic impact abrasion, and cyclic abrasion, all featuring temperatures between room temperature and 700°C. During cyclic abrasion, both TiC-Ni and ZrC-Ni reinforced hardfacing show decreasing wear rate with increasing temperatures. During impact abrasion testing, it was shown that TiC-Ni and ZrC-Ni reinforced hardfacings possess superior wear properties in comparison to conventional WC reinforced ones. The role of TiO2 oxide, and in the case of ZrC-Ni, the role of a complex mixed carbide phase, M23C6, played an important role in stabilising the kinetics of oxidative wear at temperatures beyond 500°C.

Effect of nitrogen alloying on the microstructure and abrasive impact wear resistance of Fe-Cr-C-Ti-Nb hardfacing alloy

Abstract The effect of nitrogen additive on the microstructure and abrasive impact wear resistance of high chromium Fe-Cr-C-Ti-Nb hardfacing alloy, which developed by an open arc welding technique was investigated in this work. The phase structure and microstructures of the hardfacing alloys were studied by means of optical microscopy (OM), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectrometry (EDS) and transmission electron microscope (TEM). Moreover, the hardness of carbides in the hardfacing alloy was measured by nanoindentation test, and abrasive impact wear resistance was determined. Besides, the influence of variables on the wear behavior was investigated. The results show that, the high chromium Fe-Cr-C-Ti-Nb hardfacing alloys with different nitrogen additive mainly consist of primary (Cr, Fe)7C3 carbides, eutectic matrix and (Ti, Nb)(C, N) precipitates. With increase of nitrogen content in high chromium Fe-Cr-C-Ti-Nb hardfacing alloy, the primary carbides can be refined obviously. Meanwhile, the hardness of (Cr, Fe)7C3 is increased slightly from 18.7 GPa to 21.3 GPa, and that of (Ti, Nb)(C, N) is from 27.0 GPa to 27.6 GPa. Moreover, the volume loss of hardfacing alloys is decreased from 72 mm3 to 39 mm3. During abrasive impact wear test, the large primary carbides in the hardfacing alloy without nitrogen additive are fractured and spalled from the matrix, its abrasive impact wear resistance is low. While, the refined (Cr, Fe)7C3 carbides in the hardfacing alloy with nitrogen additive can be bended during the wear test, which increase its abrasive impact wear resistance. The lattice disregistry between (Ti, Nb)(C, N) and (Cr, Fe)7C3 is 6.15%, which indicates that (Ti, Nb)(C, N) can serve as heterogeneous nucleation sites for the primary (Cr, Fe)7C3 carbides. So that, the large primary (Cr, Fe)7C3 are refined and the abrasive impact wear resistance is improved. In addition, it is found that the volume loss of HC2N is increased with the increase of hardness, size, velocity and impact angle of the abrasive particles.

A versatile route to polymer-reinforced, broadband antireflective and superhydrophobic thin films without high-temperature treatment

Broadband high transmittance, good mechanical robustness as well as simple and low temperature fabrication are three important aspects that dictate the practical applications of superhydrophobic thin films, especially on organic substrates. However, it has proved difficult to meet these challenges. In the present work, superhydrophobic thin films were prepared by first dip-coating solid silica nanoparticles, then spray-coating hollow silica nanoparticles, followed by spray-coating mesoporous silica nanosheets & poly(vinyl alcohol) (PVA), and eventually chemical vapor deposition of 1H,1H,2H,2H-perflurooctyltriethoxysilane (POTS) at 90°C. The optimized thin film has a maximum transmittance of 96.0% in the wavelength range of 300–2500nm and a WCA of 164° and a RA of 1°. The thin film also shows good mechanical robustness toward water droplet impact test, sand impact abrasion test and tape adhesion tests, which results from PVA as a binder, the formation of covalent bond between the hydroxyl group of PVA and the ethoxy group of POTS and the chemical inertness of CC, CF bonds of POTS molecules. To our best knowledge, it is the first example where antireflective and superhydrophobic thin films of excellent mechanical robustness were realized at low temperature on organic substrates (PMMA, PC). The current work would provide a promising route to meet the challenges in practical applications simultaneously posed by the requirements of broadband antireflection, good mechanical robustness as well as simple and low temperature fabrication of superhydrophobic thin films.

Wear Behavior and Hardening Mechanism of Novel Lightweight Fe–25.1Mn–6.6Al–1.3C Steel Under Impact Abrasion Conditions

The aim of the present work was to reveal the wear behavior and hardening mechanism of novel lightweight Fe–25.1Mn–6.6Al–1.3C cast steel under abrasive impact wear with different heat treatments. The impact wear tests were carried out by using MLD-10 abrasive wear testing tester under the same impact wear condition. For this purpose, the cast steel upon quenching (Q) and quenching (1050 °C) + aging (Q–A) at 550 °C for a different time from 1 to 4 h was chosen to conduct impact abrasive wear tests. It was shown that the best wear resistance of Fe–25.1Mn–6.6Al–1.3C steel under Q–A (2 h) process was about 2.29 times higher than that of under Q process, which results from the fact that the fine nano-size second-phase (Fe, Mn)3A1C κ-carbides tend to precipitate coherently within the austenite matrix under the additional aging treatment. In consequence, the fine nano-size κ-carbides improved both the initial hardness and wear resistance of the substrate. However, when the specimen was treated at 550 °C for longer aging time (4 h), coarse κ-carbides would precipitate around the grain boundaries, which made the material extremely brittle and decreased the wear resistance. The surface hardening showed Lomer–Cottrell locks, high density of dislocation tangles and dislocation walls; neither martensite nor mechanical twins were observed under the low impact energy condition for both heat treatment processes.

Segment wear characteristics of diamond frame saw when cutting different granite types

An experimental study was carried out to determine the influence of rock properties on segment wear during the cutting of granite using an innovative diamond frame saw prototype. Wear is the main cost of frame saws with diamond-impregnated segments. Ten different granite types with a large market demand were cut by a stone-processing company. The diamond segment topography was studied. The microscopic appearance and a statistical analytical method were used to study the wear characteristics. The main diamond particle abrasion types are whole and micro-fractured crystals. No polished diamond particles resulted from using the frame saw prototype cutting stone. The frame saw cuts only in a half-cycle within a reciprocating stroke. The principal wear mechanisms of the diamond particles and the matrix are impact abrasion and flushing abrasive erosion, respectively. The statistical analysis indicated that uniaxial compressive strength, bending strength and quartz content were the first three rock properties that affected segment wear. The developed mathematical model can predict segment wear for manufacturers and users.

Surface failure behavior of 70Mn martensite steel under abrasive impact wear

The aims of this paper are to reveal the surface failure behavior of 70Mn martensite steel under abrasive impact wear by impart wear tests. The wear tests were performed with the MLD-10 abrasive wear testing machine, using SiO2 abrasive with three different impact loads for 30000 cycles. Worn surfaces and white-etching layers (WEL) were analyzed by scanning electron microscopy, x-ray diffraction and transmission electron microscopy, and the abrasive impact wear mechanism was analyzed. Strain-hardening effects beneath the contact surfaces were researched by Micro-hardness profiles. Results indicated that the main formation mechanism of white-etching layers (WEL) in test steel were the formation of twin martensite and accumulation of dislocations attributing to plastic deformation during impact wear tests. The thickness and hardness of WEL were both increased with test load, which led to an increased brittleness of WEL. Under the effects of impact load, the micro-cracks initiated at subsurface and extended to surface, eventually led to delamination and fracture. Therefore, the delamination and fracture resulting from plastic deformation fatigue were the primary surface failure mechanism of the steel at abrasive impact wear.

A novel magnetic field-assisted polishing method using magnetic compound slurry and its performance in mirror surface finishing of miniature V-grooves

A novel magnetic field-assisted polishing technique was proposed for finishing 3D structured surface using a magnetic compound (MC) slurry. The MC slurry was prepared by blending carbonyl-iron-particles, abrasive grains and α-cellulose into a magnetic fluid which contains nano-scale magnetite particles. An experimental setup was constructed firstly by installing an oscillation worktable and a unit onto a polishing machine. Then, experimental investigations were conducted on oxygen-free copper workpiece with parallel distributed linear V-grooves to clarify the influence of the polishing time and abrasive impact angle on the grooves surface qualities. It was found that (1) the groove form accuracy, i.e. the form retention rate η varied with the polishing locations. Although the form retention rate η deteriorated during the polishing process, the final η was greater than 99.4%; (2) the effective impact angle θm affected the material removal and form accuracy seriously. An increase of the absolute value θm resulted with an increase of material removal rate and a decrease of the form accuracy; (3) the work-surface roughness decreased more than 6 times compared with the original surface after MC slurry polishing. These results confirmed the performance of the proposed new magnetic field-assisted polishing method in the finishing of 3D-structured surface.

レーザピーニングにおけるアブレージョンによる衝撃力と気泡の崩壊衝撃力の比較

レーザピーニングにおけるアブレージョンによる衝撃力と気泡の崩壊衝撃力の比較

Influence of Wear Performance of PTA Processed High Speed Steel Hardfacing by Solidification Kinetics

Fe-based hardfacings with high vanadium content become more important for industrial applications because of low production and material costs, combined with high abrasion resistance. The aim of this work is to gain a deeper fundamental understanding of heat management impact of a Fe-based hardfacing alloy on resulting wear properties related to real field conditions. In this work a FeVCrC alloy was deposited by plasma transferred arc welding technology varying solidification kinetics due to active heat management. In-situ thermal couple measurements during processing were performed to determine t8/5 cooling-off time relevant for precipitation formation. Microstructural investigation was done by microscopy (e.g. OM, SEM), X-ray diffraction as well as macroscopic hardness, respectively. Wear performance was characterized by using the ASTM G65 dry-sand rubber-wheel procedure A for 3-body abrasion under low-stress. In addition 2-body impact/abrasion behavior was evaluated utilizing continuous impact abrasion test (CIAT). For quantitative wear description 3D microscopy and mass loss determination were done after the test. Additional SEM investigations on the worn surface and on the tribologically stressed near-surface region were applied to deepen the fundamental wear understanding.Results showed that the t8/5 cooling-off time is strongly influenced by solidification conditions due to thermal substrate properties. Nevertheless t8/5 cooling-off time is not necessarily correlated to wear behavior. Significant variations of micro-and macro structural parameters were obtained for dilution with substrate, precipitation content and distribution, whereas macro hardness was obtained on a relatively constant level. Two-body impact/abrasion wear behavior showed plastically deformed zones where the fine precipitations act in a ductile way. Under 3-body abrasion conditions precipitations of hard phases play a dominant role for providing high wear resistance related to microstructural features like amount, distribution and size of precipitations. It can be claimed that no direct correlation of 2-body and 3-body wear rates with deposition hardness of hardfacing has been observed.

Effect of Substrate Heat Treatment on Wear Behavior of Fe- and Ni-Based Hardfacings

In different fields of high abrasive processes, e.g. in agriculture and mining industry, components made of tempering steel are additionally protected with a wear resistant alloy on high loaded sections. An industrial standard process flow includes heat treatment of components after hardfacing process. However, the exact effect of heat treatment procedure on wear performance of hardfacings is still mostly unknown.The main aim of this study was to determine the influence of substrate heat treatment on iron and nickel based hardfacings under two and three-body conditions. Commonly used wear resistant tempered steel was used as substrate material. Heat treatment investigations were performed on two Fe-based tool steel alloys (M2 and FeVCrC) and a Ni-based alloy reinforced with WC/W2C (Ni-FTC) deposited by plasma transferred arc technology (PTA), respectively. After hardfacing a heat treatment optimized for tempered steel substrate was performed on hardfaced samples.Microstructure investigations were done by optical microscopy, scanning electron microscopy and hardness measurements. Additionally wear behavior was estimated by dry-sand rubber-wheel test (three-body abrasion) and continuous impact abrasion test (two-body abrasion).Results showed significant influence of heat treatment, due to microstructural changes, on wear performance under 3-body conditions of Fe-based tool steels. This effect was not as pronounced in Ni-based alloy than in types of tool steel. Interestingly, in both M2 tool steel and Ni-based systems heat treatment led to decrease 2-body wear resistance. However, heat treated V-rich tool steel type showed good wear performance in continuous impact abrasion test. Composed wear map, based on this study, shows critical changes in general wear performance for investigated hardfacings.

Experimental Investigation and Determination of Abrasive Granularity Change Impact to Technology Head Vibration Generating during AWJ Technology Steel Cutting

The paper describes abrasive kind and granularity change impact to technology head vibration generating during cutting of seven selected investigated kinds of steel by means of AWJ technology. The investigation of abrasive granularity impact is carried out for three speeds of the technology head shift. A set of 3D comparative graphs of vibration parameter relations for seven analyzed kinds of steel from graphical records of vibration acceleration amplitude to frequency relation was created. On the base of the comparative graphs a discussion about results is generated and conclusions are defined. The work presents a thematically integrated part of a dissertation results and completes a group of recent knowledge focused on production systems working state diagnostics with the water jet technology.