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Downhole Hammer Drilling
Published in C.P. Chugh, Ken Steele, V.M. Sharma, Design Criteria for Drill Rigs: Equipment and Drilling Techniques, 2020
C.P. Chugh, Ken Steele, V.M. Sharma
Tungsten carbide is an alloy of tungsten powders together with a cobalt medium which is fused together under extreme temperature and pressure to form a material of uniform through hardness and abrasion resistance. The characteristics of the material can be regulated to provide specific and consistent qualities by specifying the mesh sizes of the carbide, density of the mix and additional alloying mediums used with the cobalt in the production. Manufacturing should employ the hot isostatic pressing or “hipped” carbide process to ensure a consistent quality in the material best suited to those conditions found in the drilling operation. Cemented carbide always suffers some adverse effect on its mechanical properties due to residual porosity during the manufacturing process. Hot isostatic pressing helps in overcoming this difficulty. The process involves reheating the material after initial infiltration and recompacting to some 2000 bars in an argon-enriched atmosphere. The result is a product with a far greater wear resistance and a transverse rupture strength.
Diffusion Bonding
Published in Yoseph Bar-Cohen, Advances in Manufacturing and Processing of Materials and Structures, 2018
WC-base cemented carbide is widely used in cutting tools for its high wear resistance. Bonding of WC-Co composites to various metals such as steel (Guo et al., 2016; Lemus-Ruiz et al., 2007) and titanium alloys (Barrena et al., 2008) is of particular importance, but the joint reliability is impeded by the high thermal stresses caused by the mismatch in CTE between the composites and metals. Ni foil is commonly used as an interlayer in the bonding of WC-Co to steels, due to its good diffusivity and solid solubility with both components of the brazement, and the thickness of Ni interlayer was found to greatly influence the bonding strength (Guo et al., 2016; Lemus-Ruiz et al., 2007). To further reduce residual stresses, an additional layer of Cu can be electroplated between the Ni interlayer and the steel (Barrena et al., 2010).
Ceramics and Composites
Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022
A cermet is simply a mixture of ceramics and metals, a special case of composite materials. The intent is to combine the high strength of ceramics with the high fracture toughness of metals. A good example is WC-Co. Adding 5%–10% cobalt (a tough metal) to tungsten carbide (a strong and wear-resistant ceramic) results in a tough material with excellent wear resistance under high stress. This material is known as cemented carbide and is used in cutting tools.
Surface Roughness Influence on Tribological Behavior of HiPIMS DLC Coatings
Published in Tribology Transactions, 2023
Sharjeel Ahmed Khan, João Oliveira, Fabio Ferreira, Nazanin Emami, Amilcar Ramalho
Cemented carbide (WC-Co) is a widely used material for various tool applications in machining, forming, drilling, and mining operation due to its excellent mechanical and wear resistance characteristics (17). WC-Co tools are generally coated with different coatings systems like carbides, nitrides, and oxides of transition metals, for example, TiN, TiAlN, CrAlN, WC, CrC, and Al2O3; and often with diamond-based coatings to further improve the wear resistance and increase the lifetime of the tool (18). As large majority of WC-Co tools are coated in industries before employing them in their final application. Generally, the coating deposition was performed on surfaces with poor quality due to the high cost associated with the surface polishing stage and the strenous process of grinding hard WC-Co. The poor surface quality could result in reduced adhesion of the coatings and adversely affect the tribological properties. Therefore, a certain degree of surface preparation could be vital to reduce the high points of asperities in cutting tools in order to avoid elevated contact pressure causing flaking, chipping, and premature failure of the coatings.
Vat photopolymerization-based 3D printing of complex-shaped and high-performance Al2O3 ceramic tool with chip-breaking grooves: Cutting performance and wear mechanism
Published in Journal of Asian Ceramic Societies, 2023
Haidong Wu, Wei Liu, Yuerui Xu, Lifu Lin, Yehua Li, Shanghua Wu
Figure 3 shows the wear morphology of the rake and flank face of the different cutting tools when the cutting speed was 100 m/min. Crescent wear occurred in the rake face of all tools, as shown in Figure 3(a, d, g, j, m). The flank face of YCB and YWCB exhibited adhesive wear and cracks, with larger cracks in YWCB, as shown in Figure 3(b, e). This is attributed to the cemented carbide, which is not resistant to high temperatures, thereby easily causing cracks when subjected to thermal shock or local temperature rise. Compared to YCB, the chip removal of YWCB was lower, and the tool tip temperature and local temperature difference were higher, resulting in more obvious cracks. For the ceramic tools, the flank wear mainly includes abrasive wear, adhesion wear, and micro chipping, as shown in Figure 3(h, k, n), which are related to the properties of alumina ceramics. Owing to the high hardness, good wear resistance, and low toughness of alumina ceramics, chipping can be easily produced with a large cutting force, which reduces the cutting life.
Recovery of Cobalt from Secondary Resources: A Comprehensive Review
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Michael Chandra, Dawei Yu, Qinghua Tian, Xueyi Guo
In the case of superalloys, even though it is one of the largest cobalt secondary resources, the difficulties of superalloy recycling due to their complex composition has led to slow development in cobalt recycling. It can be seen from the low amount of research conducted related to the recycling of superalloys in the past few years. Nowadays, superalloy scrap is usually remelted as an additional feed in the new superalloy making process, recovering only the base metal such as nickel, iron, and cobalt. A hydrometallurgical or pyro-hydrometallurgical process can be a great option if all the components need to be recovered. The cemented carbide recycling process, on the other hand, has been matured enough with the application of pyrometallurgical and hydrometallurgical processes. Further improvement could be directed toward a greener process like molten salt electrolysis and a more efficient process.