Erosion corrosion corrosive-erosive wear

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. 

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. 

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. 

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. 

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. 

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

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. 

Testing. The measurement of corrosion, wear, and corrosion-wear interactions as well as erosion-corrosion interactions is a multistep process. Each component of the interaction must be measured separately. The results may then be combined to identify the synergistic effects and create a complete picture of the damage process. Measurement of the interaction between corrosion and wear modes or damage is more difficult. The standard (ASTM, G119)4 applies to systems in liquid solutions or slurries and some aspects of it can be adapted to dry corrosion and wear interactions as well. (Tylczak and Adler)5... 

SLURRY EROSION - Material removal due to the combined action of corrosion and wear. 

V. J. Sethi and I. G. Wright, Proceedings of the Conference on Corrosion-Erosion-Wear of Materials at High Temperatures, ed. A. V. Levy, Houstan, TX, NACE, 1991, p. 18-1. 

Equation (7.8) is also of interest when erosion is combined with corrosion. It can be used in modified form for limited ranges of the involved parameters. The limitation is particularly caused by the fact that the velocity exponent for erosion corrosion is much less than that for pure erosion (neon 5 1.5, usually Ucorr < 1.0) [7.37]. In addition, erosion corrosion increases less than proportionally with particle concentration. Together these relationships mean that for combined erosion and corrosion (corrosive-erosive wear) W oc c v, where x < 1 and 1 < y < 3, and both X and y depend on the relative contribution of erosion and corrosion (they increase with increasing erosivity and decreasing corrosivity). 

Combination of abrasion and corrosion is also called corrosive-abrasive wear. Particle abrasion with low pressure between the particles and the material surface is closely related to particle erosion at low impact angles. Corrosive-abrasive wear has... 

Erosion corrosimi occurs under the conditions of corrosion and wear by flowing water, the collision of sands, etc. The simultaneous application of both factors accelerates the corrosion and failure significantly also in this case. 

The simultaneous action of erosive wear and corrosion is called erosion corrosion. Erosion corrosion is often encountered in pumps and pipes exposed to turbulent flow in the presence of suspended particles. It also occurs in other situations, for example in incinerators due to ash particles that are entrained by the exhaust gas. The damage caused by the combined effect of the impingement of a liquid and of corrosion is sometimes referred to as impingement corrosion or impingement attack. 

Erosion corrosion is the combined action of erosive wear by impacting solids or liquids and of corrosion. In practice, the term erosion corrosion is often used broadly... 

Wear- and Erosion-Resistant Applications Zirconia s exceptional resistance to erosive wear and corrosion has led to its application in pump component parts subjected to high stress, such as shafts, coupHngs, or thrust parts. These types of pump are currently utilized as high-performance sludge and process pumps for... 

The selection of the materials used in the incineration systems shall give due consideration to the components that are subject to substantial mechanical and thermal loads, erosion, corrosion and wear. The following aspects should be considered ... 

Fifi, 1 5 Slurry erosion wear modes, (a) Abrasion-corrosion, (b) Scouring wear, with wear areas equal (left) and unequal (center and right), (c) Crushing and grinding, (d) High-velocity erosion, (e) Low-velocity erosion, (f) Saltation erosion, (g) Cavitation... 

D. Martinez, R. Gonzalez, K. Montemayor, A. Juarez-Hernandez, G. Fajardo, M.A.L. Hernandez-Rodriguez 2009. Amine type inhibitor effect on corrosion-erosion wear in oil gas pipes. Wear 161 (1-4), 255-258. 

---