摘要 :
In the mining and related industries, the abrasion and impact phenomena operate among the chain of ore processing. While abrasion-corrosion and/or erosion-corrosion phenomena in ore processing are relatively well understood, the c...
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In the mining and related industries, the abrasion and impact phenomena operate among the chain of ore processing. While abrasion-corrosion and/or erosion-corrosion phenomena in ore processing are relatively well understood, the concurrent operation of abrasion and impact wear is not well comprehended. The distinctive mechanisms and features of abrasion-impact wear and the synergy, if one exists, between impact and abrasion have not been either explored or discussed systematically in the literature. Furthermore, their economic impact on mining cannot be underestimated especially as past research focused mainly on improving the hardness even at the expense of toughness. Understanding the complex relation between abrasion and impact can efficiently mitigate countless wear problems in mining. The purpose of this paper is to discuss critically the topic, stimulating new questions, and propose some general ideas that might be used as basic guidelines.
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Tempering is an essential part in the fabrication of ultra-high strength steels and it is also widely applied in the processing of wear-resistant steels. In this paper, the effects of different tempering temperatures on the impact...
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Tempering is an essential part in the fabrication of ultra-high strength steels and it is also widely applied in the processing of wear-resistant steels. In this paper, the effects of different tempering temperatures on the impact-abrasive and abrasive wear properties of martensitic ultra-high strength steels were studied. A novel press-hardening steel with carbon content of 0.4 wt% was received in hot-rolled condition and further austenitized, water-quenched and tempered for 2 h at different temperatures (150-400 ℃). Tensile strength values up to 2200MPa and hardness exceeding 650HV were measured. Wear testing was done with impact-abrasive impeller-tumbler and abrasive dry-pot application-oriented test methods simulating mining and mineral handling environments. A laboratory rolled 600HB steel and a commercial 500HB grade wear-resistant steel were included for comparison. The wear surfaces and cross-sections of the samples were thoroughly characterized. Both testing methods produced highly deformed surface layers and strong work-hardening. Wear performance was mainly controlled by the initial hardness of the steels, but differences were found in the highly work-hardened surfaces of the steels.
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A technique is developed for evaluating the impact-abrasive resistance of cast specimens, which allows simulating the conditions of impact and abrasive wear when changing the following factors: impact energy, abrasive impact angle...
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A technique is developed for evaluating the impact-abrasive resistance of cast specimens, which allows simulating the conditions of impact and abrasive wear when changing the following factors: impact energy, abrasive impact angle, abrasive type, and its consumption and grain size. The complex experiment results for five carbide-promoting elements effect on abrasive (AR), impact and abrasive (IAR), and antifriction (AFR) steel resistance in the cast and hardened states are presented. The possibility of using the new technique for evaluating wear resistance and optimizing the composition of steel operating under impact-abrasive effects is shown.
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In many fields of industry, erosion is the dominant wear mechanism that reduces the lifetime of costly machine parts such as crushers, hammer bars, or cutting edges. Particles of specific mechanical and geometrical properties hit ...
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In many fields of industry, erosion is the dominant wear mechanism that reduces the lifetime of costly machine parts such as crushers, hammer bars, or cutting edges. Particles of specific mechanical and geometrical properties hit the surface with a certain energy and, under different angles of impact, cause abrasion and surface fatigue, or, in the case of high single particle impact energy, immediate damage by exceeding the rupture strength. Different types of wearfacing alloy layers applied through welding are used to protect exposed surfaces. The structure of state-of-the-art welding alloys is always based on multi-phase systems containing effective hard phases based mainly on borides and carbides of W, Cr, Nb, and others. Within this work the so-called continuous impact abrasion test was established to compare different wearfacing alloys as described above and to develop a relation between parameters of the tribological system and properties of multi-phase materials. In the first step, morphology, energy, and size of the abrasive particles were varied and applied onto two different Fe-based wearfacing alloys. Observations on the phenomena of wear on the test samples accompanied by a quantitative evaluation of volumetric wear loss finally resulted in defining a model that enables a prognosis oriented consideration of wear. It was found within this study that wear phenomena in the microstructure have to be clearly differentiated according to the total energy applied and the impact energy of a single particle.
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摘要 :
In many fields of industry, erosion is the dominant wear mechanism that reduces the lifetime of costly machine parts such as crushers, hammer bars, or cutting edges. Particles of specific mechanical and geometrical properties hit ...
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In many fields of industry, erosion is the dominant wear mechanism that reduces the lifetime of costly machine parts such as crushers, hammer bars, or cutting edges. Particles of specific mechanical and geometrical properties hit the surface with a certain energy and, under different angles of impact, cause abrasion and surface fatigue, or, in the case of high single particle impact energy, immediate damage by exceeding the rupture strength. Different types of wearfacing alloy layers applied through welding are used to protect exposed surfaces. The structure of state-of-the-art welding alloys is always based on multi-phase systems containing effective hard phases based mainly on borides and carbides of W, Cr, Nb, and others. Within this work the so-called continuous impact abrasion test was established to compare different wearfacing alloys as described above and to develop a relation between parameters of the tribological system and properties of multi-phase materials. In the first step, morphology, energy, and size of the abrasive particles were varied and applied onto two different Fe-based wearfacing alloys. Observations on the phenomena of wear on the test samples accompanied by a quantitative evaluation of volumetric wear loss finally resulted in defining a model that enables a prognosis oriented consideration of wear. It was found within this study that wear phenomena in the microstructure have to be clearly differentiated according to the total energy applied and the impact energy of a single particle.
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In order to more accurately simulate wear behavior that occurs in the field (i.e., impact coupled with abrasion), an impeller-in-drum wear test has been developed. The apparatus is similar to the one first developed by Bond; howev...
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In order to more accurately simulate wear behavior that occurs in the field (i.e., impact coupled with abrasion), an impeller-in-drum wear test has been developed. The apparatus is similar to the one first developed by Bond; however, in the apparatus used at the Albany Research Center, three paddles instead of just one are situated in the drum which can be impacted and abraded during the course of the wear test. In using three paddles, a standard can be run at the same time as the specimens of interest. Two test procedures have been developed which provide information on the relative resistance of a material to the combined action of impact and abrasion. In the first procedure, the wear samples are run for 1 h on each side of the specimen paddle. This average value of the two tests gives an upper average limit to the impact-abrasive wear of the material, but has the advantages of being easy to run and relatively quick. The second procedure attempts to determine the steady-state wear behavior by running sequential wear tests on one surface of the specimen paddle. In this procedure, anywhere from three to five 1-h tests are run on one surface of the paddle. The cumulative mass or volume loss is plotted as a function of time and the slope of the linear portion of the curve provides the value for the steady-state wear rate. In addition to describing the experimental procedure, wear mechanisms will be discussed and the changes that occur in the microstructure as a result of the wear tests will also be described. The way various alloys behave in pure abrasion and in impact-abrasion will be discussed, highlighting the change in a material's wear behavior with a change in wear mode.
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Two new low alloyed steels were developed with different fracture toughness values but at similar level of hardness with same composition and microstructural phase. The steels were subjected to impact-abrasion wear test. This work...
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Two new low alloyed steels were developed with different fracture toughness values but at similar level of hardness with same composition and microstructural phase. The steels were subjected to impact-abrasion wear test. This work examines specifically the additional role of toughness during impact-abrasion wear, using a newly developed high toughness steel. Microstructural characterisation of the damaged samples revealed that better toughness helps resist both impact and abrasion damage.
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Many abrasion resistant steels rely on a martensitic microstructure to ensure hardness, which in general correlates with better wear performance. However, in practice the steel may be subjected to a complex combination of conditio...
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Many abrasion resistant steels rely on a martensitic microstructure to ensure hardness, which in general correlates with better wear performance. However, in practice the steel may be subjected to a complex combination of conditions where hardness alone may not be sufficient to ensure tribological performance. This review is a critical assessment of the mechanical and metallurgical parameters that control wear resistance of steel in impact-abrasion conditions, although relevant work dealing with abrasion has also been included. It is found, for example, that fracture toughness and work-hardening behaviour have a role in enhancing the wear resistance of hard steels.
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A concept for creating sparingly alloyed wear-resistant steels by solid-solution and grain-boundary hardening is developed and implemented. The efficiency of combined hardening of steel with silicon and carbides, borocarbides, and...
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A concept for creating sparingly alloyed wear-resistant steels by solid-solution and grain-boundary hardening is developed and implemented. The efficiency of combined hardening of steel with silicon and carbides, borocarbides, and carbonitrides is demonstrated.
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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 e...
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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.
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