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Erosive wear

The heat generated by the abrasive wear is not as readily dissipated as with the erosive wear. [Pg.140]

Erosive wear can be considered to be an interfacial wear where the energy evolved in the wear is dissipated. The third component in the wear process removes some of the frictional heat generated when the wear particle strikes the surface of the sample. [Pg.140]

Erosion studies have shown that the softness and resilience of elastomers handle wear better in a number of cases than hard metals (Ephithite, 1985). In dry applications, the heat dissipation is poor and can result in rapid degradation of the elastomer. However, in slurry applications the lubrication of the water changes the friction resistance greatly. [Pg.140]

An elastomer with a low modulus will often have far better erosive wear than material with a higher modulus. An abrasive wear test (such as the DIN abrader) will show a poor result for a soft elastomer. This is also shown in field applications such as tire wear. When the application is changed from abrasive to erosive wear, the softer elastomer will wear very well. The reason for this is that the low modulus of the soft elastomer allows the stresses from each impact to be dissipated more readily than for hard polyurethanes. The soft material will stretch further and then snap back before damage is done. Any microcracks formed will have a slower growth rate and hence less erosion will occur. [Pg.141]

Studies of the properties of polyurethanes, both physical and physicochemical, showed only that resilience had some direct relationship to wear. A relationship of (1- resilience)1-4, where resilience is expressed as a fraction, has been shown (Hutchings, 1987). No other relationship has been found for other properties for erosive wear between 30° and 90° (Hutchings, 1987). External factors that affect the erosive wear of the elastomers include  [Pg.142]

In pneumatic conveying systems, bulk particulate materials are physically transported by air. Bends in pipelines, therefore, are particularly vulnerable to erosive wear, as are diverter valves and any other surface against which particles are likely to impact, including the pipeline itself to a limited extent. Where a pressure difference might exist on a plant, in the presence of abrasive particles, erosive wear will also occur, if there is a flow of air. A particular example here is with rotary air locks and screws used to feed materials into positive pressure pipelines. Even isolating valves will wear if they are not completely air-tight or fully shut. [Pg.193]

1 Impact angle and surface material The curve shown in Eigure 4.50 illustrates the variation of erosion with impact angle for two different surface materials. Both surface materials showed very significant differences in both erosive wear rate and the effect of impact angle. These materials do, in fact, exhibit characteristic types of behaviour that are now well recognised. The aluminium alloy is typical of ductile materials they suffer [Pg.193]

2 Velocity The model for the erosive wear of pipeline bends in terms of velocity is  [Pg.195]

This means that bends at the end of a single bore pipeline, with a 1 bar pressure drop, for example, will be more than five times that of bends at the start of the pipeline. This is another reason for using stepped pipelines to keep the velocity profile along the length of a pipeline as low as possible, consistent with always keeping above the minimum value for the given material and conveying conditions. [Pg.195]


The wedge restriction has no critical surface dimensions or sharp edges and tends to retain accuracy despite visible corrosive or erosive wear. It is commonly appHed to high viscosity Hquids, slurries, and hot multiphase mixtures. A similar device is also available using a cone, positioned so that its large diameter is upstream, mounted on the meter centerline. [Pg.61]

In addition to the reduction in performance, flow maldistribution may result in increased corrosion, erosion, wear, fouling, fatigue, and material failure, particularly for Hquid flows. This problem is even more pronounced for multiphase or phase change flows as compared to single-phase flows. Flow distribution problems exist for almost all types of exchangers and can have a significant impact on energy, environment, material, and cost in most industries. [Pg.496]

Wear owing to corrosion and/or erosion can be particularly dangerous. For example, as carbon steel corrodes, the reduced wall thickness can eventually lead to a stmctural failure. This problem can be compounded through erosive wear of the silo wall. [Pg.557]

Types of Wear. There are several distinct types of wear that can be divided into three main categories abrasive wear, sliding wear, and erosive wear. The type of wear encountered in a particular appHcation is an important factor influencing the selection of a wear-resistant material. [Pg.373]

Four distinct forms of erosive wear have been identified soHd-particle erosion, Hquid-droplet erosion, cavitation erosion, and slurry erosion. [Pg.374]

For erosive wear. Rockwell or Brinell hardness is likely to show an inverse relation with carbon and low alloy steels. If they contain over about 0.55 percent carbon, they can be hardened to a high level. However, at the same or even at lower hardness, certain martensitic cast irons (HC 250 and Ni-Hard) can out perform carbon and low alloy steel considerably. For simplification, each of these alloys can be considered a mixture of hard carbide and hardened steel. The usual hardness tests tend to reflect chiefly the steel portion, indicating perhaps from 500 to 650 BHN. Even the Rockwell diamond cone indenter is too large to measure the hardness of the carbides a sharp diamond point with a light load must be used. The Vickers diamond pyramid indenter provides this, giving values around 1,100 for the iron carbide in Ni-Hard and 1,700 for the chromium carbide in HC 250. (These numbers have the same mathematical basis as the more common Brinell hardness numbers.) The microscopically revealed differences in carbide hardness accounts for the superior erosion resistance of these cast irons versus the hardened steels. [Pg.270]

Corrosion may take various forms and may combine other forms of damage (erosion, wear, fatigue, etc.) to cause equipment failure. The forms of corrosion most encountered in drilling equipment are uniform corrosion and galvanic corrosion. [Pg.1268]

Leyland, A. and Matthews, A., Thick, Ti/TiN Multilayered Coatings for Abrasive and Erosive Wear Resistance, Surf. Coat. Technol., Wo. 70,1994, pp. 19-25. [Pg.165]

Abrasive wear is caused by sharp asperities cutting the plastic fatigue wear is caused by particles of plastic being detached as a result of dynamic stressing on a localised scale adhesive wear is the transfer of plastic to another surface as a result of adhesive forces between the two surfaces. There can also be corrosive wear due to the direct chemical attack on the surface and the term erosive wear is sometimes used for the action of particles in a liquid stream. [Pg.33]

Figure 8.12 illustrates a solid particle impinging on a surface. It has been found that the erosive wear rate depends upon the impingement angle, a, the particle velocity, vq, and the size and density of the particle, as well as the properties of the surface material. It has also been found that there is a difference in erosive wear properties of brittle and ductile materials. The maximum erosive wear of ductile materials occurs at a = 20°, whereas the maximum erosive wear for brittle materials occurs near a = 90°. Since the impingement angle is probably lower than 90° for these type of flow situations, we might consider only brittle materials, such as ceramics for this application. Let us examine brittle erosive wear in a little more detail first. [Pg.828]

The dependence of erosive wear rate, W, on particle velocity, vq, has been observed to follow the general form... [Pg.828]

Figure 8.12 Schematic illustration of erosive wear due to a particle impacting a solid surface. Reprinted, by permission, from G. Lewis, Selection of Engineering Materials, p. 171. Copyright 1990 by Prentice-Hill, Inc. Figure 8.12 Schematic illustration of erosive wear due to a particle impacting a solid surface. Reprinted, by permission, from G. Lewis, Selection of Engineering Materials, p. 171. Copyright 1990 by Prentice-Hill, Inc.
From the preceding descriptions of erosive wear, we see that fracture toughness and hardness are important parameters in the materials selection process. There is some... [Pg.829]

At this point, experiments must be performed. Experimental results for the erosive wear of the selected candidate ceramic materials in coal slurries are presented in Table 8.4. Notice that the wear rate has a very rough inverse correlation with which is consistent with some of the descriptions of erosive wear from the previous section. Any of these ceramic materials is suitable for the piping and pump components based solely on wear rate, with the lowest wear rate for SiC being the most attractive. Formability and economic criteria can be applied to assist in the final material selection. [Pg.831]

Each person should find the remaining parameters and physical property data for this material required to solve the three models [Eqs. (8.14), (8.19), and (8.20)] for the erosive wear of a coal slurry that is, each person will have three calculations to do and three erosion rates as a result. Assume that the test temperamre is 343°C, the slurry velocity is 100 m/s, and the angle of attack is 50°. [Pg.831]

Shetty, D. K., Erosive wear of advanced ceramics in coal-slurry streams. Corrosion, 38(9), 500-509 (1982). [Pg.848]

II.1 In Section 8.2, we saw how erosive wear can be different for brittle and ductile materials. In reality, most materials exhibit behavior that is a combination of... [Pg.849]

Use the data below for the erosive wear for alnmina particles impacting on a graphite-fiber-reinforced epoxy resin composite material to determine the four parameters Uf,Us,vi, and Vp in Eq. (P8.1). You may need to look up some additional data and make appropriate assumptions to solve this problem. You may also find a spreadsheet helpful for solving the fom equations with four unknowns. [Pg.850]

Wear by roll formation is where there is progressive tearing of a layer of rubber which forms a roll. The result is a characteristic abrasion pattern of ridges and grooves at right angles to the direction of movement. The term erosive wear can be applied to the action of particles conveyed in a liquid stream and there can also be corrosive wear due to direct chemical attack of the surface. [Pg.228]

D. Mills, J.S. Mason, Particle size effects in bend erosion, Wear 44 (1977) 311-328. [Pg.186]

Shipway, P.H. (1997), The effect of plume divergence on the spatial distribution and magnitude of wear in gas-blast erosion , Wear, 205, 169-77. [Pg.558]

Erosive wear is a three-bodied wear, which is found in pump and cyclone linings, impellers, and screens. The polyurethane is attacked by a solid object that is being transported by a third medium such as process water. The temperature and chemical composition of the process liquid also play an important part in the life of the component. [Pg.139]


See other pages where Erosive wear is mentioned: [Pg.321]    [Pg.163]    [Pg.162]    [Pg.71]    [Pg.259]    [Pg.596]    [Pg.828]    [Pg.828]    [Pg.829]    [Pg.829]    [Pg.831]    [Pg.850]    [Pg.163]    [Pg.761]    [Pg.80]    [Pg.122]    [Pg.123]    [Pg.558]    [Pg.247]    [Pg.139]    [Pg.140]    [Pg.141]    [Pg.141]   
See also in sourсe #XX -- [ Pg.140 , Pg.141 , Pg.142 ]

See also in sourсe #XX -- [ Pg.131 ]

See also in sourсe #XX -- [ Pg.193 ]

See also in sourсe #XX -- [ Pg.15 , Pg.137 ]




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Elastomer erosive wear

Erosion corrosion corrosive-erosive wear

Erosion, tooth wear

Erosive wear erosion rate

Erosive wear evaluations

Erosive wear impinging

Erosive wear mechanisms

Erosive wear particle shape

Erosive wear particle size

Erosive wear resistance

Erosive wear testers

Erosive wear, test methods

Hot erosion wear and carburization in petrochemical furnaces

Important features of elevated temperature erosive wear

Locations of Erosive Wear

Properties erosive wear

Properties erosive wear mechanisms

Temperature erosive wear

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