Wear-resistant Cast Research Articles

Influence of the chemical composition on the structure formation and properties of temperature- and wear-resistant cast iron

229 The most important trend in metallurgy and machine building is the introduction of materials with improved operational properties, so that components are able to withstand high-temperature oxidation (up to 1100 ° C) and intense abrasive and impact-abrasive wear. The material used to manufacture gratings and sintering cars at sinter plants must be characterized by high strength, thermal stability, and wear resistance. These requirements are best met by wear-resistant chromium-bearing cast iron, which is studied in the present work.

Effect of Microstructure on Impact Fatigue Resistance and Impact Wear Resistance of Medium Cr-Si Cast Iron

Abstract A great amount of iron grinding balls in tube mills have been consumed. Under this impact abrasive wear working condition, the failure of wear resistant alloying white irons grinding balls is mainly caused by fatigue spalling. The impact wear resistance of martensitic high chromium cast iron (Cr of 15%) is not high sometimes, but its cost is not low. Thus, medium Cr-Si wear resistant cast iron is recommended. The influence of the iron on impact fatigue resistance and impact wear resistance is pronounced. Ball-on-ball impact fatigue test and high stress impact wear test of the grinding balls have been carried out. The results show that the impact fatigue resistance (IFR) and impact wear resistance (IWR) of medium Cr-Si cast iron are superior to those of martensitic high chromium cast iron (Cr of 15%). The main reasons are that (1) the stress in medium Cr-Si cast iron is released in the as-cast state; (2) the matrix is fine pearlite with better toughness and plasticity; (3) the pearlite is more stable compared with a retained austenite under repeated impact load and less phase transformation can take place; (4) high silicon content improves the morphology of eutectic carbide; (5) there is no secondary carbide which results in less crack sources. All these factors are beneficial to improvement of impact fatigue spalling resistance. The eutectic carbide M7C3 is the main constituent to resist wear.

Alloy fluxes for surfacing

Submerged arc surfacing is the most productive fusion process for surface refining. The chosen alloyed agglomerated fluxes can efficiently affect surfacing quality and productivity. They enable single-layer surfacing of selected wear-resistant and corrosion-resistant cast irons on unalloyed structural steels. With alloyed agglomerated fluxes, it is recommended to surface with a low welding current and high welding voltage. The low welding current will produce minimum melting of the substrate and minimum burnout of alloying elements. The high welding voltage, however, will produce more intense melting of the welding flux, which will increase welding efficiency and alloying of the surfacing deposit by means of the welding flux. Such setting of the welding parameters is characteristic of welding with a multiple-wire electrode.

A Newly-developed High Wear Resistant Cast Hot-forging Die Steel

The alloying design of the cast hot-forging die steels was analyzed. The key property and parameters for the alloying design were selected. The cast hot-forging die steel with high wear resistance was developed through optimizing the parameters. The wear resistance of the newly-developed cast die steel was evaluated in comparison with commercial H13 steels and 3Cr2W8V steel. The wear mechanism is also discussed. The newly-developed cast die steel takes VC as predominant carbide with solid solution strengthening of Cr and Mo. The cast die steel was found to have significantly lower wear rate than normal H13 steel and 3Cr2W8V steel, and almost the same wear rate as high-purified H13 steel. The high wear resistance of the new-developed cast die steel could be attributed to the reasonable alloying design and no sensitivity to detrimental function of S and P. Under the elevated-temperature air at 400°C, the wear for the cast die steels and commercial hot-forging die steels is a typical oxidation wear.

Effect of Hot Deformation on Formation and Growth of Thermal Fatigue Crack in Chromium Wear Resistant Cast Iron

The formation and growth of thermal fatigue crack in chromium wear resistant cast iron was investigated, and the effect of hot deformation on the crack was analyzed by means of optical microscope and scanning electron microscope and high frequency induction thermal fatigue tester. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, hot deformation can improve the eutectic carbide’s morphology and distribution, inhibit the generation and propagation of thermal fatigue cracks. In the experiment, the propagation rate of thermal fatigue crack reduces with the quantity of hot deformation increasing, which was analyzed in the point view of the activation energy of crack propagation.

Impact angle of maximum erosion rate of wear resistant spheroidal graphite cast iron eroded by SiO2 and AI2O3 particles

The influence of matrix structure, erodent and impact angle on the wear resistance of pearlitic and bainitic spheroidal graphite cast irons was studied using impact tests with SiO2 and AI2O3 particles. Erosion with AI2O3 particles produced significantly larger materials removal rates for both irons. The bainitic ADI was more wear resistant than the pearlitic PDI specimens at impact angles > 30°. The type of erodent did not affect the impact angle of maximum erosion rate for ADI, but for the PDI specimens this angle was higher with AI2O3 particles than with SiO2. Examination of the wear surface by SEM provided evidence of many brittle cracks on PDI specimens following impact with A12O3; this correlates with the higher impact angle of maximum wear for this material-erodent combination. The higher fracture toughness of the AI2O3 particles also played a role in the erosion wear behaviour observed for both PDI and ADI. IJCMR/435

Ecodesign for wear resistant ductile cast iron with medium manganese content

Based on the reuse and recycling of manganese resource from disposed high manganese steel scraps, the wear resistant ductile cast iron of low carbon and medium manganese content was designed for grinding balls. High manganese steel scraps were used as the main charge in the melting process to replace a large fraction of pig iron, and the ferromanganese alloy was saved. The processing technology, the wear properties and the environmental impacts of the new material were studied by comparing with the traditional material KmTQMn6. The results of the experiments show that the new material has better abrasive wear resistance and lower environmental impacts. Therefore, it can be developed to a type of environmentally conscious wear resistant cast iron.

Wear-resistant castings out of complexly doped carbon-iron alloys

Wear-resistant castings out of complexly doped carbon-iron alloys

Structural Factors of Elevation of Wear-Resistance of White Chromium Cast Iron

The use of white wear-resistant cast iron instead of steel 110G13L for the production of rapidly wearing parts of crushing and milling equipment increases their service life [1]. The choice of rational alloying of cast iron can be based on correct understanding of the qualitative proportion of excess phases, their morphology, and the nature of alloying of the metallic matrix, which should provide maximum wear resistance in abrasion. It is known that cast iron of the type of ICh250Kh16 alloyed with molybdenum has the highest wear resistance if the matrix has a structure of martensite with a certain amount of metastable retained austenite [2]. The presence of even a low amount of nonmartensitic products of the decomposition of austenite, i.e., pearlite or troostite, in the structure of the matrix decreases markedly the wear resistance of cast iron. There is an opinion that the contribution of retained austenite to the wear resistance is determined by its stability. The occurrence of the martensitic transformation in metastable austenite promotes an increase in the wear-resistance of cast iron. In the presence of stable retained austenite the initial hardness of cast iron decreases as well as its wear resistance [2]. The aim of the present work2 consisted in determining the role of the phase composition of the matrix and the stability of retained austenite in providing the wear resistance of sparingly alloyed wear-resistant chromium cast irons upon abrasive wear and developing optimum regimes for their heat treatment.

Investigation and development of the GrT-4000/71 soil pump

1. Theoretical investigations and bench tests on a pump model made it possible to obtain the setting geometry that ensures extremely good power characteristics for pumps having large setting flow areas. 2. It is recommended to use wear-resistant white chromium-manganese cast iron for components in the setting of the GrT-4000/71 soil pump, which is intended for the transfer of sandy-gravelly soils with a lump size no greater than 60 mm. 3. Use of a dual-cup rubber shaft seal is recommended to improve the operational reliability of the pump. 4. To extend the longevity and improve the reliability of the drive of the soil pump, it is proposed to use a bearing with a set of spring that lower the axial forces on the bearing.

Pyrometallurgical Separation of Boron from Iron in Ludwigite Ore.

Laboratory scale experiments and industrial scale tests have been performed in order to develop a new pyrometallurgical process for the separation of boron from iron in ludwigite ore. The results indicate that boron can be effectively separated from iron in ludwigite ore meantime two products can be got. The boron-containing pig iron can be a good substitute for the expensive boron alloys to produce B-series wear resistant cast while the boron-rich slag can be used to extract borax or boric acid.

The use of a continuous-wave CO2 laser for hardening of wear-resistant high-chromium cast iron

The use of a continuous-wave CO2 laser for hardening of wear-resistant high-chromium cast iron

Influence of alloying elements on the structure and wear resistance of chilled cast iron

To work out the optimal chemical composition of wear-resistant cast iron with a pearlitic metallic matrix that is able to restore the relief of a rough surface, we investigated the properties of cast iron with different composition by the method of single factor experiment.

The effects of RE on Toughness of 30CrMnSi wear-resistant cast steel

The effects of RE (La and Ce) on toughness of 30CrMnSi wear-resistance cast steel have been investigated by means of analysing microstructures and mearsering the properties of the steel with and without RE. The results show that RE can refine the as-cast microstructures, hinder or eliminate needle and network ferrite, increase the dislocation density and the quantity of dislocated martensite, and improve the shape and distribution of inclusions. Therefore the mechanical properties of the steel can be greatly enhanced, especially the toughness of the steel.

Wear-resistant Stable-mottled Cast Iron used in Conditions involving Thermal Cycling

Alloying cast iron with copper promotes graphitisation during solidification, but prevents graphitisation during the eutectoid transformation. Copper shares these unique properties with nickel and ...

Effect of alloying elements on the structure and properties of cast low-alloy steel for wear-resistant castings

Effect of alloying elements on the structure and properties of cast low-alloy steel for wear-resistant castings

Processes occurring during the tempering of wear-resistant cast irons

1. Carbon exerts a greater influence than manganese on the temper resistance of cast irons with 30% Cr. 2. The critical tempering temperature of wear-resistant cast irons depends on the carbon content and is independent of the manganese content. 3. According to diagrams that we have constructued, it is possible to determine the hardness of cast iron as a function of its carbon and manganese content and the tempering temperature; this makes it possible to assign heat-treatment regimes on a rational basis.

Structure and properties of wear-resistant white cast irons

1. The favorable combined effect of vanadium and chromium on the wear resistance of white cast iron is manifested when their contents are 2...6 and 0...12%, respectively. In this case, the optimal vanadium content in cast iron operating under complex conditions of shock and bending loads can be determined from the equation % V=3+1/3 (% Cr) for a chromium content of not more than 12%. 2. The increase in the wear resistance of white cast irons when alloyed with vanadium is governed by the following factors: its modifying effect and the effect of structure inversion; a reduction in the amount of ledeburitic segments; and, the high hardness of the vanadium carbide particles with their optimal morphology. 3. The wear resistance of chromium-vanadium cast irons of the optimal composition (2.8...3.2% C; 0.4...0.8% Si; 0.8...1.5% Mn; 6...9% Cr; 4...6% V) with a hardness of HRC 63...66 is 8...10 times higher than that of steel ShKh15 with a hardness of HRC 61...62.

Effect of laser and heat treatment on the structure and properties of high-chromium cast iron

The authors investigate the effect of continuous radiation of a CO/sub 2/ laser in combination with standard heat treatment on the structure, phase composition, and properties of the wear-resistant high chromium cast iron IChKh16NMFTL. To compare the results of the effect of laser and heat treatment, the authors subjected specimens after quenching at 900/sup 0/C in oil together with laser treatment also to additional heta treatment: normalization, normalization with subsequent tempering at 250/sup 0/C 3 h, tempering along at 250 and 550/sup 0/C 3 h. Metallographic analysis was carried out with microscopes ''EPITYP-2'' and NUM-1, x-ray diffraction analysis on an installation URS-50IM in chromium K /SUB alpha/ radiation. It was established that in laser treatment with preliminary heating, the temperature at which cracks begin to appear depends on the direction in which the beam moves over the surface of the specimens. Thus, as a result of the investigations, it was established that hardening of wear-resistant cast iron IChKh16NMFTL is attained by the precipitation of disperse carbides (Cr, Fe)/sub 7/C/sub 3/ from the martensitic matrix.

Optimizing the compositions of wear-resistant chromium cast irons

1. The computational-experimental method makes it possible to optimize the composition of chromium cast irons for components operating under conditions of impact-abrasive wear. 2. Using "composition-property" diagrams, it is possible to select the optimum ratio of carbon, chromium, and manganese in wear-resistant cast irons, and also to predict the properties of chromium-manganese cast irons with various alloying-element contents.