Wear Of Iron Research Articles

Erosive Wear of Cr30A High Chromium Cast Iron in a Simulated Circulating Pump Operation Condition with Slurry Related to Wet DesulfurationProcess in Thermal Power Plant

Erosive Wear of Cr30A High Chromium Cast Iron in a Simulated Circulating Pump Operation Condition with Slurry Related to Wet DesulfurationProcess in Thermal Power Plant

Effect of heat treatment on wear and corrosion behavior of high chromium white cast iron

AbstractThe abrasive wear and corrosion behavior of as-cast, heat-treated and tempered high chromium white cast iron was studied, and the results were evaluated by means of microstructure, hardness, surface roughness and corrosion resistance. The samples were subjected to wear on the ball-on-flat tribometer test machine under different loads. Corrosion tests were carried out using the potentiodynamic scanning (PDS) technique in both alkaline (3.5 % NaCl) and acidic (0.5 M H2SO4) media. According to the results obtained, the wear rate and hardness of the as-cast alloy were relatively low. After heat treatment higher wear resistance and hardness were achieved thanks to the thinned and elongated primary carbides, excessive amount of secondary carbides and the martensitic matrix. After the tempering process, the primary carbides were rounded and shortened, and all the carbides were homogeneously dispersed. This resulted in lower material hardness. Although the hardness of the tempered sample was lower than that of the heat-treated sample, the wear resistance was higher in virtue of the microstructure. The corrosion results showed that the differences between the corrosion resistance of as-cast, heat-treated and tempered samples are only due to microstructural transformation. The differences are related to the Cr/C ratio, primary carbide content and its form in the matrix, and residual stress. In addition, the study showed that secondary carbides play an influential role at the initialization of corrosion but that the primary carbide content in the alloy are dominant in the progression and orientation of the corrosion in the structure.

INVESTIGATION ON TRIBOLOGICAL BEHAVIOR OF DUCTILE CAST IRONS WITH NANOSIZED PARTICLES

The work in this study is focused on investigation of the tribological behavior of ductile cast iron with nanosized particles: titanium nitride TiN; titanium nitride 30% + titanium carbonitride 70% (30%TiN+70%TiCN). The ductile cast iron composition is: Fe-3,55C-2,67Si-0,31Mn-0,009S-0,027P-0,040Cu-0,025Cr-0,08Ni-0,06Mg wt%. Before the addition to the melt nanosized particles were coated with nickel by the electroless nickel deposition method EFFTOMNICKEL .The nickel coating on the nanosized particles ensures their wetting in the melt as well as their uniform distribution into the cast. The optical and quantity metallographic observations and wear test are performed to study the influence of the nanoparticle additives on the cast iron tribological properties. It is observed that the quantity proportion changes between pearlite, ferrite and graphite phase in the cast iron structure. The graphite shape is retained the same, but the nanosized additives decrease the average diameter of the graphite spheres Dmid and increase the quantity of the graphite phase in the structure of ductile cast irons. The cast iron wear resistance in the presence of nanosized additives of (TiN+TiCN) and TiN increases to 55–69% in comparison to wear resistance of the cast iron without nanoparticles.

The structure and properties formation in iron–carbon powder composite materials during infiltration

This paper describes some properties and structure formation features of the MMCs obtained by the infiltration of iron–carbon skeletons with tin bronze. It has been shown that the formation of the MMC structure depends on the composition and porosity of the iron skeleton. During the infiltration of a green skeleton, a redistribution of carbon and nickel occurs; outer layers have less carbon and more nickel; and carbon content is higher in the centre of the particles. With higher carbon content of the iron skeleton, the hardness and wear resistance properties of MMCs increase. The strength and wear resistance properties of the MMCs obtained by the infiltration of a green skeleton are higher compared to the sintered one regardless of the carbon content in the skeleton.

Effect of Low Oxygen Concentration on the Wear of Aluminum and Iron under Low Humidity Conditions

Effect of Low Oxygen Concentration on the Wear of Aluminum and Iron under Low Humidity Conditions

An experimental investigation on Compact Graphite Iron wear behavior at 32 °C and 200 °C

Abstract Compact Graphite Iron (CGI) is used at various applications at elevated temperatures. This material is recently using in automobile braking system and engine cylinders. In the present study, sliding wear test on Pin-on disc tribometer was conducted on CGI. The wear behavior was studied at room temperature (32 °C) and 200 °C test against rotating hardened steel metal disc as counter face. The influence of the temperatures on abrasive wear behavior of CGI was reported. The surface of CGI pins were examined using Scanning Electron Microscopy (SEM). It was found that the pins showed lower wear rates at 200 °C temperature compared to room temperature.

Abrasive Wear of Compacted Graphite Cast Iron with Added Tin

The abrasive wear behavior of traditional compacted graphite cast iron (CGI) and compacted graphite cast iron with 0.1% tin addition (CGI–Sn) is studied using a pin-on-disk tribometer. The microstructures of these two CGIs were observed by optical microscopy and scanning electron microscopy. The results show that Sn reduces the average size of vermicular graphite and promotes the generation of pearlite. Sn narrows the average lamellar spacing of pearlite. In the wear tests, CGI–Sn yields a decreased wear loss by 16.5% compared with CGI. Both CGI and CGI–Sn show typical abrasive worn morphology, while CGI presents a more severe wear condition in which large fragmentations can be seen. Under the current test condition, Sn is likely to improve the abrasive wear resistance of compacted graphite iron. Further studies of the specific working conditions are needed, such as testing against frictional material in braking systems, to check the validity of the findings.

Use of Directional Solidification for Improving Tubular Workpiece Quality of Different Cast Irons

A new efficient method of casting tubular billets by directional solidification without the use of a core is proposed making it possible to obtain a fine-grained dense structure of cast iron due to intensive onesided heat removal and excess supply to the solidification front of superheated liquid phase during the entire billet formation time in a metal water-cooled mold (crystallizer). It is shown that the method makes it possible to obtain a prescribed final cast iron structure by creating a certain cooling regime for castings outside the mold. In the positive effect of directional solidification of the melt inherited by iron a decisive role is played by the formation of a dense structure and a more dispersed carbide eutectic with a favorable carbide morphology, which determines the good cast iron wear resistance. The results of studies confirm that the new casting method provides production of workpieces with a prescribed phase composition and improved physical, mechanical, and operating properties. The effect is considered of various factors of the formation of workpieces from different types of cast iron: gray alloyed with lamellar graphite, high-strength and high-chromium, and also Niresist cast iron, on the structure, properties and service life of components for critical purposes of general, mining and oil refining engineering.

The Effects of Silicon on The Hardness and Wear of Ferritic Grey Cast Iron on Shoe Brake of Train

Grey cast iron has been used for a shoe brake of train due to the enough strength and the low cost. The shoe brake made of cast iron sometimes makes a problem in the operation of the train, because it make the wheel of the train is worn-out. The aim of this research is to find the data of cast iron in accordance with the wear rate and hardness properties by addition of various silicon contents. Cast iron returned (scrap) was melted by induction furnace and then poured into the sand mold of the shoe brake. The 75% ferro silicon was added to make the addition of the silicon content to the melted cast iron. Samples (specimen) of grey cast iron was made with five variation of silicon contents. The composition, hardness, and wear rate test was performed to the each sample. Maximum hardness and wear rate was happened at the cast iron of silicon content of 3.3% Si.

Graphene Coating via Chemical Vapor Deposition for Improving Friction and Wear of Gray Cast Iron at Interfaces.

This study reports the influence of CVD-graphene on the tribological performance of gray cast iron (GCI) from the internal combustion engine (ICE) cylinder liners by performing a ball-on-disk friction tests. The graphene-coated specimen exhibited a significant reduction (∼53%) of friction as compared to that of the uncoated specimen, whereas wear resistance increased by 2- and 5-fold regarding the wear of specimen and ball, respectively. Extremely low shear strength and highly lubricating nature of graphene contribute to the formation of a lubricative film between the sliding surfaces and decreases the interaction between surfaces in the dry environment. Under the applied load, a uniform film of iron oxides such as Fe2O3, Fe3O4, and FeOOH is found to be formed between the surfaces. It is proposed that the graphene encapsulation with the metal debris and oxides formed between the specimens increases the lubricity and decreases the shear force. The transformation of graphene/graphite into nanocrystalline graphites across the contact interfaces following the amorphization trajectory further increases the lubricity of the film that ultimately reduces friction and wear of the material.

Effect of Heat Treatment on the Hardness and Wear of Grinding Balls

The effect quenching and tempering by different regimes on Rockwell hardness and wear processes of grinding balls 50 and 70 mm in diameter made of two melts of chromium-molybdenum cast iron is studied. The heating temperature for quenching is 850, 950, and 1050°C; the tempering temperature is 250, 400, and 600°C. Iron is analyzed in an electron microscope. Diffraction patterns are obtained. A model of cast iron wear is suggested and compared to the Davis model and to experimental results. An optimum heat treatment regime is proposed.

Effects of laser surface texturing on the wear and failure mechanism of grey cast iron reciprocating against steel under starved lubrication conditions

The purpose of this work was to investigate the effects of different texture patterns and orientations on the wear and failure mechanisms of grey cast iron sliding against 42CrMo6 steel. Reciprocating tests were performed on 16 different micro-textures under starved lubrication conditions. The textures were designed using a design of experiments (DoE) approach and produced by a nanosecond-laser. Under starved lubrication conditions, the non-textured samples always failed catastrophically by scuffing, which is a sudden and catastrophic failure. However, textured samples showed two different wear and failure mechanisms. It is revealed that the sudden and catastrophic failure due to scuffing can be avoided by surface texturing. Choosing the right distance between the micro-textures can change the surface damage mode from scuffing to a more gradual oxidative wear mechanism. For the studied tribo-system, it was shown that if the distance of micro-textures in the direction of sliding (DMS) is less than 3 mm, samples will fail by an oxidation mechanism. For textured samples with DMS greater than 3.5mm, the failure mechanism is scuffing, the same as for the non-textured cast iron.

Influence of Multiple Bionic Unit Coupling on Sliding Wear of Laser-Processed Gray Cast Iron

In this study, in effort to improve the sliding wear resistance of gray cast iron under wet lubrication conditions, specimens with different bionic units were manufactured and modified according to bionic theory. Inspired by the structure and appearance of biological wear-resistant skin, two kinds of bionic units were processed by laser on the specimen surfaces. We investigated the wear resistance properties of the samples via indentation method and then observed the wear surface morphology of specimens and the stress distributions. The results indicated that coupling the bionic units enhanced the wear resistance of the cast iron considerably compared to the other samples. We also determined the mechanism of wear resistance improvement according to the results.

Anti-Wear Enhancement of Silicon-Grey Cast Iron for the Production of Grinding Plates: Effect of Snail Shell Powder as Carbide Forming Material

Grinding plates produced with silicon-grey cast iron wear out quickly. As a result of this molten grey iron is treated with ferrochrome to produce hard and wear resistant grinding plates. This makes the cost of the grinding plates very expensive for the rural community to purchase them for their domestic grinding operation. Because of this limitation this present research study looks at the effect of snail shell powder on the properties of grey cast iron with a view to using it as an alternative to conventional ferrochrome for the production of grinding plates. The grey cast iron scraps were melted in a crucible furnace. Ladle treatment of the molten metal was done by varying the percentage of snail shell powder from 0.1 to 0.5. The same process was repeated for ferrochrome to serve as a control. The molten metal was poured into a prepared sand mold. The microstructure, spectrometer analysis, hardness, wear and tensile properties were studied. The results show that the tensile strength increased with increasing snail shell powder up to a maximum value of 0.4 % and the hardness values increased linearly as the snail shell powder increased, while the wear rate decreased continuously with increasing composition of snail shell powder. The microstructure of all a samples showed the network of interdendritic cementite (white) surrounded by patches of pearlites. The practical test of the grinding plates was conducted and found that the developed grinding plates gave 96.7 % efficiency. The results obtained for the snail shell powder samples compare favorably with conventional ferrochrome. This work has established that snail shell powder can be used as an alternative to ferrochrome for the production of white cast iron for grinding plate’s application.

Effects of different bionic units coupling on the sliding wear of gray cast iron

To enhance the sliding wear resistance of gray cast iron under starved lubrication conditions, two kinds of bionic units were generated by using a pulsed Nd: YAG laser and a drill on the surface of the specimens. The microstructure and microhardness of the bionic strip unit were examined. Comparing the wear resistance of five groups of specimens (an untreated specimen; a specimen with a surface that was completely melted by the laser; a specimen containing only bionic pit unit; a specimen containing only bionic strip unit and a specimen coupling two kinds of bionic units), the results indicate that the wear resistance of the bionic unit coupling specimen is better than that of the others. The result of a stress analysis of the specimen surface shows that the bionic strip unit plays a supporting role and can reduce the stress concentration on the edge of the bionic pit unit. On the other hand, the bionic pit unit can supply lubricating oil to the wear gap, change the moving model of abrasive grains and improve the lubrication performance. The two kinds of units can protect and promote each other under starved lubrication conditions, improve the resistance to sliding wear.

Displaying structural property and inheritance of cast iron surfacing on steel base

Graphite inclusions heredity in deposited layer from remelted special cast iron billets was established. The possibility of controlling the structural state and the quality of the deposited layer due to technological parameters of welding and heat treatment of parts is shown. Ways of improving cast iron wear resistance durability are proposed.

Wear and Contact Temperature Evolution in Pin-on-Disc Tribotesting of Low-Metallic Friction Material Sliding Against Pearlitic Cast Iron

Pin-on-disc tribotesting is widely used to investigate the sliding behaviour of materials, including friction materials used in braking systems. The evaluation of the average contact temperature is paramount to understand the acting friction and wear mechanisms, and to determine the role of the materials. In the present work, the tribological behaviour of a commercial low-metallic friction material during dry sliding against a pearlitic cast iron has been investigated and the evolution of pin and disc temperature was recorded. The temperature distributions in the pin and the disc were modelled using a finite element analysis with three different approaches, i.e. considering a perfect contact, the separated bodies concept, and the presence of a third body between the sliding surfaces. The results were then discussed by considering the damaging phenomena occurring at the sliding contact. Wear was found to be nearly mild in nature in agreement with the contact temperatures that were determined to be lower than 100 °C. During sliding, a limited third body was formed, made of a partially covering friction layer on the pin surface, and a thin and irregular oxide layer on the cast iron wear track. The approach based on the perfect contact with thermal continuity at the interface was found to better fit the experimental temperature records and to be in substantial agreement with the observed wear phenomena occurring at the pin–disc interface.

Microstructures, Wear Behavior and Mechanical Properties of the TiC Ceramic Particulate Locally Reinforced Ni-Hard4 White Cast Iron Matrix

Titanium carbide ceramic particles could act as inoculants to generate fine microstructure and helps to increase the wear resistance for steel. In this article, the effect of titanium addition on the microstructure, wear and mechanical properties of Ni-Hard4 white cast iron was studied. The study was undertaken with five laboratory pieces of cast iron made with different titanium amounts. The microstructures were examined by optical microscopy, scanning electron microscopy equipped by EDS. The impact energy, hardness and wear resistance of the samples were determined. Thermodynamic calculation showed that solute titanium atoms can react with carbon and form TiC in modified samples. The results indicated that the morphology of chromium carbides can be improved by adding a suitable amount of titanium. This improvement was correlated with the emergence of TiC ceramic particles. These particles can act as the substrates for heterogeneous nucleation of primary chromium carbides, which result in significant refinement of the final average carbide diameter. In addition, the hardness and wear resistance were improved without significant variations in fracture toughness. The wear resistance was increased with titanium addition owing to change microstructure and the precipitation hardening of fine ceramic particles in the martensitic matrix.

Foreword for Special Issue on Wear of Cast Iron and Cast Steel

Foreword for Special Issue on Wear of Cast Iron and Cast Steel

Study on diagonal hammer of three kind metals composite casting with block protecting handle

Hammer crusher is widely used in cement, ceramic, mining and electricityother industries, hammer head is one of important parts in crusher, its abrasion performance directly affects the service life of hammer crusher and economic cost. According to bimetalcomposite hammer head is often appear “Hammer handle wear and tear”,“Composite difficult” and the set of casting alloy block hammer head set piece of “come off” phenomenon, which design a set piece type bimetal composite casting straight diagonal hammer, make full use of high chromium cast iron wear resistance and the toughness of low alloy steel. Design a protect block structure reasonably that solve the hammer when the actual production of composite interface is difficult to control and “the problem of hammer head wear” for use. Solve the problem of hammer head wear actively, achieve “energy saving, emission reduction and environmental protection”.