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Building Materials
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
Abrasives are those materials used in operations such as grinding, polishing, lapping, honing, pressure blasting, or other similar process. Abrasives come in different particle or grit sizes depending on how much material needs to be removed. Abrasives can either be bonded or coated. The abrasives on sandpaper are coated on paper that can be held by the hand. The person can control the smoothing strength of the sandpaper by adjusting the pressure and speed of the hand movement.
Grinding Operations and Machines
Published in Zainul Huda, Machining Processes and Machines, 2020
Grit Number. Grit number is the inverse of grain size of an abrasive. Coarse grains are specified by grit numbers in the range of 10–60. On the other hand, very fine grains are specified by grit numbers ranging from 320 to 600. The abrasives with high grit numbers (fine grain size) are recommended for excellent surface finish and for cutting hard materials. On the other hand, abrasives with low grit numbers (coarse grain size) are suitable for achieving high MRR and for cutting softer materials.
Nontraditional Manufacturing Processes
Published in Leo Alting, Geoffrey Boothroyd, Manufacturing Engineering Processes, 2020
Leo Alting, Geoffrey Boothroyd
Abrasives Slurries of synthetic abrasive powders in a liquid, usually water, are generally used in ultrasonic machining. The criteria for selection of an abrasive for a particular application include hardness,usable life, cost, and particle size. Diamond is by far the fastest abrasive, but is not practical because of its cost. Boron carbide is economical and yields good machining rates. It is therefore one of the most commonly used abrasives for USM, but silicon carbide and aluminum oxide are also widely used.
TIG torch surfacing of metallic materials – a critical review
Published in Transactions of the IMF, 2019
M. Azwan, M. A. Maleque, M. M. Rahman
Thermal spraying is a method whereby the coating material is heated and deposited as individual particles onto the substrate. The sprayed reinforcing particles impinge onto the substrate surface, solidify and build up into laminar structure forming the new coating layer.21,22,29 For this method, the strength of the bond, crucially, relies on the cleanliness and roughness of the substrate, hence, the surface preparation is very important in any thermal spraying coating technique. The substrate is usually grit blasted prior to the coating technique to provide a mechanical key for the coating material to form an adhesive bond. Grit blasting is a surface treatment process where abrasive material is accelerated through a blasting nozzle via a high-velocity jet of air.30 Several examples of abrasive materials used are steel shot, steel grit, glass bead, crushed glass, aluminium oxide, silicon carbide, plastic, walnut shell, corn cob, baking soda, ceramic grit and copper slag.30 However, this means that grit blasting demands more labour and its associated cost. Moreover, the manual valuations by only visual inspection of the surface finish in the grit blasting process often result in inconsistent and poor surface finish.29
Cement-casing shear bond strength: a review of the affecting variables and various enhancement techniques
Published in Petroleum Science and Technology, 2023
Sivakumar Pandian, Gaurav Hazarika, Udita Deota, Divya Shah, Rakesh Kumar Vij
Abrasive particles are reinforcement materials added to the resin-coating to increase the shear-bond strength between casing and cement by increasing the casing surface roughness. They have excellent corrosion resistance to extreme environments and a low friction coefficient also adds value to the process (Lin et al. 2019). Natural abrasives include sand grains, natural quartz, emery, corundum, garnet, etc. whereas synthetic abrasives include aluminum oxide, silicon carbide, etc. However, a commonly used abrasive for oil well cementing is natural sand because of its feasible economics and availability.
Empirical approach to develop a multilayer icebonded abrasive polishing tool for ultrafine finishing of Ti-6Al-4V alloy
Published in Materials and Manufacturing Processes, 2018
Recent attempts were made to study the feasibility of a two-layered IBAP tool, with each layer having different sizes of abrasives and concentrations, for polishing of the Ti-6Al-4V alloy and alumina ceramics in a single polishing step. Such a tool has produced a fine finish and quality on the titanium alloy surface in a short time [19, 20]. Similarly, a multilayered ice fixed abrasive polishing tool was employed to polish a single-crystal germanium wafer surface in a single step [21]. As the purpose of a multilayer IBAP tool is to accomplish multistage polishing, i.e., rough, fine and ultrafine polishing, in one setup, it is important to develop the tool by selecting the number of layers, the type of abrasive, its size and concentration in each layer and the thickness of each layer. In essence, the type of abrasive, its size and concentration can influence the performance of the polishing process such as material removal rate, finish and quality of the polished specimen [22232425]. Different types of abrasives such as diamond, boron carbide, silicon carbide and aluminum oxide are the most widely used abrasive materials with the diamond having the highest hardness and aluminum oxide having the least hardness. Therefore, it suggests that the choice of abrasive material depends on the hardness of the work material [22]. Furthermore, the choice of abrasives also depends on the initial roughness on the work surface. For polishing of rough surfaces, it is preferable to choose coarse abrasives that are harder than the work material. Apart from this, the concentration of abrasives can also influence the material removal rate and the finish achieved over the polished surface [24, 25]. However, there was no systematic effort for the selection of the number of layers, thickness of each layer, and the type, size and concentration of abrasives in each layer of a multilayered IBAP tool.