Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.
In stone shaping
Ancient artists, working in stone, used abrasion to create sculptures. The artist selected dense stones like carbonite and emery and rubbed them consistently against comparatively softer stones like limestone and granite. The artist used different sizes and shapes of abrasives, or turned them in various ways as they rubbed, to create effects on the softer stone's surface. Water was continuously poured over the surface to carry away particles. Abrasive technique in stone shaping was a long, tedious process that, with patience, resulted in eternal works of art in stone.
The resistance of materials and structures to abrasion can be measured by a variety of test methods. These often use a specified abrasive or other controlled means of abrasion. Under the conditions of the test, the results can be reported or can be compared items subjected to similar tests.
Such standardized measurements can produce two quantities: abrasion rate and normalized abrasion rate (also called abrasion resistance index). The former is the amount of mass lost per 1000 cycles of abrasion. The latter is the ratio of former with the known abrasion rate for some specific reference material.
One type of instrument used to get the abrasion rate and normalized abrasion rate is the abrasion scrub tester, which is made up of a mechanical arm, liquid pump, and programmable electronics. The machine draws the mechanical arm with attached brush (or sandpaper, sponge, etc.) over the surface of the material that is being tested. The operator sets a pre-programmed number of passes for a repeatable and controlled result. The liquid pump can provide detergent or other liquids to the mechanical arm during testing to simulate washing and other normal uses.
The use of proper lubricants can help control abrasion in some instances. Some items can be covered with an abrasion-resistant material. Controlling the cause of abrasion is sometimes an option.
ASTM B611 Test Method for Abrasive Wear Resistance of Cemented Carbides
ASTM C131 Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
ASTM C448 Standard Test Methods for Abrasion Resistance of Porcelain Enamels
ASTM C535 Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
ASTM C944 Standard Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method
ASTM C1027 Standard Test Method for Determining Visible Abrasion Resistance of Glazed Ceramic Tile
ASTM C1353 Standard Test Method for Abrasion Resistance of Dimension Stone Subjected to Foot Traffic Using a Rotary Platform, Double-Head Abraser
ASTM D968 Standard Test Methods for Abrasion Resistance of Organic Coatings by Falling Abrasive
ASTM D1630 Standard Test Method for Rubber Property — Abrasion Resistance (Footwear Abrader)
ASTM D 2228 Standard Test Method for Rubber Property - Relative Abrasion Resistance by the Pico Abrader Method
ASTM D3389 Standard Test Method for Coated Fabrics Abrasion Resistance (Rotary Platform Abrader)
ASTM D4060 Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser
ASTM D4158 Standard Guide for Abrasion Resistance of Textile Fabrics],
ASTM D4966 Standard Test Method for Abrasion Resistance of Textile Fabrics
ASTM D5181 Standard Test Method for Abrasion Resistance of Printed Matter by the GA-CAT Comprehensive Abrasion Tester
ASTM D5264 Standard Practice for Abrasion Resistance of Printed Materials by the Sutherland Rub Tester
ASTM D5963 Standard Test Method for Rubber Property—Abrasion Resistance (Rotary Drum Abrader)
ASTM D6279 Standard Test Method for Rub Abrasion Mar Resistance of High Gloss Coatings
ASTM D7428 Standard Test Method for Resistance of Fine Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus
ASTM F1486 Standard Practice for Determination of Abrasion and Smudge Resistance of Images Produced from Office Products
ASTM G56 Standard Test Method for Abrasiveness of Ink-Impregnated Fabric Printer Ribbons and Other Web Materials
ASTM G65 Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus
ASTM G75 Standard Test Method for Determination of Slurry Abrasivity (Miller Number) and Slurry Abrasion Response of Materials (SAR Number)
ASTM G81 Standard Test Method for Jaw Crusher Gouging Abrasion Test
ASTM G105 Standard Test Method for Conducting Wet Sand/Rubber Wheel Abrasion Tests
ASTM G132 Standard Test Method for Pin Abrasion Testing
ASTM G171 Standard Test Method for Scratch Hardness of Materials Using a Diamond Stylus
ASTM G174 Standard Test Method for Measuring Abrasion Resistance of Materials by Abrasive Loop Contact
DIN 53516 Testing of Rubber and Elastomers; Determination of Abrasion Resistance
ISO 4649 Rubber, vulcanized or thermoplastic -- Determination of abrasion resistance using a rotating cylindrical drum device
ISO 9352 Plastics -- Determination of resistance to wear by abrasive wheels
ISO 28080 Hardmetals -- Abrasion tests for hardmetals
ISO 23794 Rubber, vulcanized or thermoplastic -- Abrasion testing -- Guidance
ISO 21988:2006 Abrasion-resistant cast irons. Classification
ISO 28080:2011 Hardmetals. Abrasion tests for hardmetals
ISO 16282:2008 Methods of test for dense shaped refractory products. Determination of resistance to abrasion at ambient temperature
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, the process can also involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut, grind and polish other softer materials are known as abrasives.
Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Some common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, lapping, and sanding (see abrasive machining). (For simplicity, "mineral" in this article will be used loosely to refer to both minerals and mineral-like substances whether man-made or not.)
Files are not abrasives; they remove material not by scratching or rubbing, but by the cutting action of sharp teeth which have been cut into the surface of the file, very much like those of a saw. However, diamond files are a form of coated abrasive (as they are metal rods coated with diamond powder).
Abrasive blasting, more commonly known as sandblasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurised fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material (often called the media). The first abrasive blasting process was patented by Benjamin Chew Tilghman on 18 October 1870.There are several variants of the process, using various media; some are highly abrasive, whereas others are milder. The most abrasive are shot blasting (with metal shot) and sandblasting (with sand). Moderately abrasive variants include glass bead blasting (with glass beads) and plastic media blasting (PMB) with ground-up plastic stock or walnut shells and corncobs. Some of these substances can cause anaphylactic shock to both operators and passers by. A mild version is sodablasting (with baking soda). In addition, there are alternatives that are barely abrasive or nonabrasive, such as ice blasting and dry-ice blasting.
This is an alphabetical list of articles pertaining specifically to electrical and electronics engineering. For a thematic list, please see List of electrical engineering topics. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.
Tunnel rock recycling is a method to process rock debris from tunneling into other usable needs. The most common is for concrete aggregates or as subbase for roadbuilding. Crushers and screeners normally used in quarries are placed at the tunnel site for the one purpose which is to crush and screen the rock debris. Swiss engineers/entrepreneurs have the most comprehensive experience in this field. The largest tunnel rock recycling facility ever to be created was for the construction of the Gotthard Base Tunnel which took 17 years, finishing in 2016.
In an average tunnel project the excavated rock is mostly regarded as waste. In most cases it is given away or used in a landfill. Starting up a facility for recycling the rock debris is hugely expensive. Though for a large project, as for example a double barrel tunnel longer than 20 km it is feasible. The Gotthard Base Tunnel was a 57 km long tunnel.
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in machine elements, together with other processes such as fatigue and creep, causes functional surfaces to degrade, eventually leading to material failure or loss of functionality. Thus, wear has large economic relevance as first outlined in the Jost Report.Wear of metals occurs by plastic displacement of surface and near-surface material and by detachment of particles that form wear debris. The particle size may vary from millimeters to nanometers. This process may occur by contact with other metals, nonmetallic solids, flowing liquids, solid particles or liquid droplets entrained in flowing gasses.The wear rate is affected by factors such as type of loading (e.g., impact, static, dynamic), type of motion (e.g., sliding, rolling), and temperature. Depending on the tribosystem, different wear types and wear mechanisms can be observed.
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