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Thin Films for Cutting Tools
Published in Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu, Thin Film Coatings, 2022
Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu
Cemented tungsten carbide coating can be deposited onto its substrate using both the CVD and PVD methods. It is employed mostly due to its high hardness characteristic on substrates such as steel and other ceramic cutting tools. It is usually used as the base coating layer in a hierarchical deposition. Cobalt is used as a binding agent in tungsten carbide coatings. Due to its high friction and poor thermal conductivity, it is layered with other materials which complement the friction and thermal properties. Multilayered WC coatings together with other materials coatings have higher efficiencies in increasing mechanical and tribological properties as compared to single-layer coatings [48]. Tungsten carbide thin films exhibit the following properties [49]: High melting point of 2870°CVery high modulus of elasticity 700 GN/m2Low coefficient of frictionHigh thermal and chemical stability (up to 4000°C)
The mechanical shaping of metal
Published in William Bolton, R.A. Higgins, Materials for Engineers and Technicians, 2020
One well-known use of powder metallurgy is in the manufacture of cemented carbides for use as tool materials. Here, tungsten powder is heated with carbon powder at about 1500°C to form tungsten carbide. This is ground in a ball mill, to produce particles of a very small size (about 20 μm) and the resultant tungsten carbide powder is mixed with cobalt powder, so that the particles of tungsten carbide become coated with powdered cobalt. The mixture is then compacted in hardened steel dies at pressure of about 300 MPa, causing cold-welding between the particles of cobalt. The compacts are then sintered at about 1500°C to cause recrystallisation and grain growth in the cobalt, resulting in a hard, continuous structure consisting of particles of very hard tungsten carbide in a matrix of hard, tough cobalt.
Chisels used in the experiments
Published in H.J.R. Deketh, Wear of Rock Cutting Tools, 2020
Materials used for rock cutting tools are mostly steel and tungsten carbide. The pick-points used for rock dredging are often made of steel, whereas the bits of rock cutting trenchers are made of steel with a tungsten carbide insert. Tungsten carbide is much harder than steel and has therefore a higher threshold to abrasive wear; minerals, of a Vickers hardness between 600 and 1200 Vickers, are abrasive to steel, used for rock cutting tools, but not to tungsten carbide. A disadvantage of tungsten carbide is its higher brittleness and its sensitivity to failure under impact loading conditions. Moreover, if rocks containing minerals harder than tungsten carbide are cut, abrasive wear takes place more severely than in case of steel cutting tools. The harder tungsten carbide suffers from more abrasive wear than steel because of a different failure mechanism; tungsten carbide fails by microcracking, whereas steel fails by microploughing and microcutting (chapter 3).
Effect of tool-electrode material in through-hole formation using ECDM process
Published in Materials and Manufacturing Processes, 2021
Julfekar Arab, Karan Pawar, Pradeep Dixit
To obtain the constant value of the working gap between tool and work material throughout the entire operation, Arab et al.,[23] recommended the use of a constant velocity feed mechanism to feed the tool electrode across the work material. Moreover, using a constant velocity feed mechanism avoids the tool bending issues, which normally occurs in low-strength tool materials having a smaller size, i.e., 100 µm. Therefore, the constant velocity feed mechanism is highly recommended in the ECDM process. Nonetheless, the use of tool electrodes with small dimensions exhibits high tool erosion, resulting in a larger working gap between tool and work material. Thus, there is a need to use such kind of tool material to provide low tool erosion at micron dimensions. Most of the ECDM related studies have used either iron-based materials, i.e., stainless steel, mild steel, high carbon steel (HCS), or Tungsten carbide as tool electrode.[1,24] Iron-based materials have lower cost and easier availability but have a lower melting point. On the other hand, tungsten carbide has a higher melting point but is expensive and brittle in nature.[25] Tool electrode material properties such as electrical conductivity, heat capacity, melting point, etc., directly affect the ECDM process behavior and the resultant geometric characteristics of the microholes and tool wear.[26,27]
Magnetorheological finishing of micro-punches for enhanced performance of micro-extrusion process
Published in Materials and Manufacturing Processes, 2019
Manpreet Singh, Anant Kumar Singh
The deformation of the billet or raw material takes place with the help of micro-extrusion punch. The micro-extrusion punches are hard and tough in nature. The micro-extrusion punches are made of tungsten carbide. The tungsten carbide has impressive mechanical properties such as high hardness value at higher working temperature, good toughness, and good wear resistance. Different diameter micro-extrusion punches are utilized for different applications. These punches are fulfilling the various industrial applications. The four punches are taken from the metal forming industry and utilized as a workpiece for experimentation. These punches have diameters of 3.5 mm, 2 mm, 1.5 mm, and 1.2 mm as shown in Fig. 3. The actual dimensions (diameter and length) and holding length of the micro-punches are shown in Fig. 3. There are various micro punching industrial applications like microfluidic device, micro-molds, micro-nozzles, micro-jet cooling devices and inkjet nozzles.[32] The 1.2 mm, 1.5 mm and 2 mm diameter micro-punches are used to manufacture the micro-nozzles in nozzle manufacturing industry. These micro-punches are collected from the industry. The 3.5 mm diameter micro-punch is used for manufacturing the micro-molds in the molds manufacturing industry.
Necessity and suitability of in-line inspection for corrosion resistant alloy (CRA) clad pipelines
Published in Ships and Offshore Structures, 2023
Ahmed Reda, Mohamed A. Shahin, Ibrahim A. Sultan, Chiemela Victor Amaechi, Kristoffer K. McKee
Table 2 lists the materials of the intelligent pigging tool that could have come into contact with the pipe cladding. Thermal spraying was used to apply tungsten carbide wear protection to the skids with a thickness of 0.3–0.4 mm. The tungsten carbide is known for its high brittleness and excellent wear resistance. When the front edge of the protection layer is chipped, it peeled off, whereas when the layer is removed (for whatever reason), the skids drive on the base material. To produce a swarf like the one shown above in Figures 1 and 2, a geometrically defined and hardened cutting edge is required, as well as constant cutting forces throughout the process (e.g. machining metal in a turning machine).