Abrasive wear

ABSTRACT Filler material choice for repair welding of stop valve spindle of thermal power plant by-pass pipeline was presented in this paper. Repair welding of the stop valve spindle was necessary because of plant operating problems due to very frequent localized damage appearance in the form of erosive wear on it. For this purpose it was necessary to choice appropriate filler material with high wear resistance characteristic. Experimental investigation and testing (hardness measurement, chemical composition analysis and microstructural investigation) of prepared specimens after welding simulation with different kind of filler material was performed. On the basis of obtained results it was recommended procedure for application of the filler material with generally preferable characteristic.

The main cause of damage to oil and gas equipment is wear. This paper proves that
the principal wear mechanism is abrasive and shock-abrasive wear; and analyzes
materials test methods and techniques for wear rate identification. The author considers
standardized and non-standardized methods and establishes that despite a large
number of materials test methods, we don’t have a unique one for adequate assessment
of wear resistance in metals. It is concluded that selection of test methods depends on
working conditions of the equipment and use of different types of wear to assess
resistance of metals.

Abrasive wear is an important component in failure analyses in mining equipment. This work relates to a wear test for mill components after the occurrence of a failure in an iron ore pelletizing plant at Vale’s Tubarao Complex, Vitoria, Brazil. The equipment involved is a ball mill, which is used to grind the pellet feed into extremely fine powder for use in pelletizing process. Metallurgical components of this mill, such as screws, shell and mill head, are analyzed in a milling system simulation using iron ore slurry in order to correlate the components loss weight with running time. The analysis results and the tribology involved in this iron ore grinding process are presented in this paper. Finally, the value of the inspection process is evidenced as a key factor at the prevention of failures, at the prediction of the life cycle of the mill's components and at the reliability of the production assets.
Keywords: :Abrasive Wear; Iron Ore; Pelletizing; Grinding.

An analytical ploughing model is used to compute the forces on a rigid, elliptical, i.e. ellipsoid and elliptic-paraboloid shaped, asperity sliding through a rigid-plastic substrate as a function of its axes size, ellipticity ratio and sliding orientation. The normal force due to the plastic deformation of the substrate and the tangential force due to the shearing of the asperity-substrate interface are calculated from the surface normal vector and the tangent vector along the direction of plastic flow. The elemental forces are integrated over the boundaries of the asperity-substrate contact to obtain the individual force components. In this way, an analytical model to study the effect of asperity geometry on ploughing forces has been developed and compared with the available theories .

... A nickel based matrix reinforced with WC/W 2 C carbides is deposited by a CO 2 laser on low carbon steel substrates. Different coatings are made with three different particle sizes of the carbides and volume fractions ranging from 0 up to 50%. ...

Abrasive wear is one of the most common types of wear, which makes abrasive wear resistance very important in many industries. The hardfacing is considered as useful and economical way to improve the performance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron-based and one WC-based), which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried-out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

The damage caused by the combination of corrosion and wear processes on the materials that machine elements are produced causes huge losses in several industries such as mineral processing, chemical, petrochemical and power generation. Some devices that operate in harsh environments, such as centrifugal pumps for transportation of caustic liquor used in the industries of production of aluminum, undergo a rapid deterioration of their materials by the coexistence of corrosion and erosion at temperatures around 75°C. The aim of this work is to study new ways for the corrosive-erosive problems confronted by the aluminum and nickel
industries. Several coating materials in powder or wire form applied by GMA welding and HVOF thermal spray techniques are compared in erosion and erosion-corrosion tests.
Corrosion tests were performed for comparison. A solution of 1M NaOH was used as corrosive medium to get the polarization curves The temperature of the electrolyte was 25°C.
For pure erosion test, the slurry erosive agent was 4 liters of water and an erosive particle concentration of 400 g/l. Particles of ferric oxide, HRC = 40-50 and average diameter of 600
um, were used as erosive agent. The impact angle of 90° was tested, with impact velocity of the abrasive particles of 31 m / s. Tests were performed for each condition at a time of 2 hours
at intervals of 20 minutes. The results show that the best performance was that of the mixed stainless steel and Cobalt alloys welded coating even though the general resistance to erosive corrosive wear significantly favors cermets in relation to the other welded deposits.

This study aims to determine the influence of metallic aggregate content, cement content and different loads applied on the abrasive wear of concrete by using artificial neural networks (ANN) and general linear model (GLM) approaches. For this purpose, experimental studies are made and suitable models based on experimental results are developed to estimate the abrasive wear of concrete. In these models, 60 data set was used. For training set, 48 data (80%) were randomly selected and the residual data (12 data, 20%) were selected as test set. Root mean square error (RMSE) and determination coefficient (R2) statistics are used as evaluation criteria of the ANN and GLM models and the experimental results are compared with these models. The comparison results indicate that the ANN models are superior to the GLM models in modeling of the influence metallic aggregate content, cement content and different loads applied on the abrasive wear of concrete.► Hematite addition has increased abrasive wear of concrete. ► Developed models are reliable and accurate, and result in good agreement with experimental data. ► Parameters affecting wear of concrete have observed as hematite, cement and load.

Abrasive wear resistance is very important in many applications and in most cases it is directly correlated with hardness of materials. Possible solutions for overcoming poor abrasive wear resistance of light metals, like Al-alloys, is using of coatings. In this paper the investigated results of the two types of ferrous-based coatings were presented and compared with gray cast iron, known as a material with good abrasive wear resistance. Process used for coating deposition on an Al-Si alloy substrate was Atmospheric Plasma Spraying (APS). Scratch tests with diamond indenter were used to simulate abrasive wear process. The indenter velocity of 10 mm/min was used over a wear tracks of 10 mm, with different normal loads applied. Both, coefficient of friction and wear rate of the samples were investigated and analysed in correlation with its mechanical properties.