Abrasive erosion

Standardized appHcations of different refractory types are Hsted ia an excellent series compiled by the ASTM (36). These surveys cover the principal iadustrial appHcations of refractories and furnish a description of furnace operations and destmctive influences such as slagging, erosion, abrasion, spalling, and load deformation. 

We can divide the surface contact properties of polymers into two categories those in which the surface remains intact when it comes into contact with another surface and the polymer surface s resistance to damage. Friction and cling fall into the first category. Surface damage can be caused by erosion, abrasion, or cavitation. 

Wear is the removal of surface material by one of three mechanisms erosion, abrasion, or cavitation. Erosion is the removal of a polymer s surface by abrasive materials carried in a fluid medium. We see this type of wear in plastic pipes used to transport waterborne slurries of minerals in mining operations and in vacuum transfer pipes used to convey powders in a stream of air. Abrasion is the result of two surfaces sliding against each other. We commonly observe abrasion of polymers in the fabrics of our clothes and upholstery. Cavitative wear is caused by voids in a liquid medium collapsing against a surface. It is essentially an impact process. Cavitation is a relatively uncommon cause of wear in polymers. Pump impellers are one of the few applications where polymers must resist this type of wear. 

Linings to protect floors, vessels and other equipment subjected to corrosion, erosion, abrasion and/or thermal attack from chemical environments. The most common substrates for CRM linings are carbon steel and concrete, but other structural materials such as wood and plastics may also be effectively protected. CRM linings can provide any one or all of the following protection modes ... 

The term tooth wear is commonly used to describe the loss of tooth hard tissue due to non-carious causes [1], This encompasses a variety of both chemical and mechanical causes of both intrinsic and extrinsic origin. The term tooth wear is preferred over some of the more precise definitions of individual hard tissue loss mechanisms, because it acknowledges the fact that wear is usually a multifactorial process one mechanism may dominate, but the overall wear is commonly due to the interaction between two or more wear mechanisms. In dentistry, the terms erosion, abrasion, attrition and abfraction are widely used to describe particular mechanisms of hard tissue loss. 

EROSION, ABRASIVE - Erosive wear caused by relative motion of solid particles which are present in fluids and are moving parallel to a solid surface. 

High temperature protection Wear-resistant coatings Antigaiiing coatings Erosion/abrasion resistance properties [20]... 

Such approach is proposed for study area of Berezniki (Permsky kray, Russia). On this territory are actively developing erosion, abrasion, slope and karst-suffusion processes and are widely developed weak soils (Fig. 1). 

Required modifications to existing thickeners, or filtering and dewatering plants as part of expansions of production and pumped flow rates Mitigation against erosion, abrasion, and corrosion... 

J. Sustersic, E. Mali and S. Urvancic, Erosion-abrasion resistance of steel fiber reinforced concrete , in V.M. Malhotra (ed.) Durability of Concrete Second International Conference, SP-126, American Concrete Institute, Farmington Hills, Ml, 1991, pp. 729-744. 

Erosion is the deterioration of a surface by the abrasive action of solid particles in a liquid or gas, gas bubbles in a liquid, liquid droplets in a gas or due to (local) high-flow velocities. This type of attack is often accompanied by corrosion (erosion-corrosion). The most significant effect of a joint action of erosion and corrosion is the constant removal of protective films from a metal s surface. This can also be caused by liquid movement at high velocities, and will be particularly prone to occur if the solution contains solid particles that have an abrasive action. 

J. Kac2marek, Principles of Machining hy Cutting, Abrasion and Erosion, Peter Peregrinus, Stevenage, U.K., 1976, pp. 487—513. 

Thermal spray processes can be used to give coatings of chromium carbide or nickel chromium for erosion resistance, copper nickel indium for fretting resistance, tungsten carbide cobalt for wear and abrasion resistance, and even aluminum siHcon polyester mixtures for abradabiHty. 

Erosion Corrosion. Erosion corrosion is the increase in the rate of metal deterioration from abrasive effects. It can be identified by grooves and rounded holes, which usually are smooth and have a directional pattern. Erosion corrosion is increased by high water velocities and suspended soHds. 

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. 

The abrasion resistance of cobalt-base alloys generally depends on the hardness of the carbide phases and/or the metal matrix. For the complex mechanisms of soHd-particle and slurry erosion, however, generalizations cannot be made, although for the soHd-particle erosion, ductihty may be a factor. For hquid-droplet or cavitation erosion the performance of a material is largely dependent on abiUty to absorb the shock (stress) waves without microscopic fracture occurring. In cobalt-base wear alloys, it has been found that carbide volume fraction, hence, bulk hardness, has Httie effect on resistance to Hquid-droplet and cavitation erosion (32). Much more important are the properties of the matrix. 

Erosion Erosion is the destruc tion of a metal by abrasion or attrition caused by the flow of hquid or gas (with or without suspended solids). The use of harder materials and changes in velocity or environment are methods employed to prevent erosion attack. 

Metal loss in these areas had produced a smooth surface, free of deposits and corrosion products. The rest of the internal surface was covered by a thin, uniform layer of soft, black corrosion product. The graphitically corroded surfaces of the pump casing provided soft, friable corrosion products that were relatively easily dislodged by the abrasive effects of high-velocity or turbulent water (erosion-corrosion). 

Abrasive pumps are made of hardened metal or even rubber-lined to handle abrasive particles in high quantities with minimal erosion. 

After a few revolutions, the rubber lip of the oil seal beeomes an abrasive lip, w hieh eats a groove into the stainless steel pump shaft. The rubbing aetion abrades the pump shaft, removing metal, and depleting the ehromium eontent of the stainless steel, wdiieh further aeeelerates its erosion. 

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