High-Speed Machining of Malleable Cast Iron by Various Cutting Tools Coated by Physical Vapor Deposition

The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron. However, the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched. In this paper, turning tests were conducted on cemented carbide tools with different coatings (a thick TiN/TiAlN coating, a thin TiN/TiAlN coating, and a nanocomposite (nc) TiAlSiN coating). All coatings were applied by physical vapor deposition. In a comparative study of chip morphology, cutting force, cutting temperature, specific cutting energy, tool wear, and surface roughness, this study analyzed the cutting characteristics of the tools coated with various materials, and established the relationship between the cutting parameters and machining objectives. The results showed that in malleable cast iron machining, the coating material significantly affects the cutting performance of the tool. Among the three tools, the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force, the lowest cutting temperature, least tool wear, longest tool life, and best surface quality. Moreover, in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions, the wear mechanism of the coated tools was found to depend on the cast iron being machined. Therefore, the performance requirements of a tool depend on multiple factors, and selecting an appropriately coated tool for a particular cast iron material is essential.

Advances in Carbidic Austempered Ductile Iron (CADI) – a wear resistant material

Background: Ductile irons provide a more viable alternative for malleable cast iron in areas that do not demand extreme wear resistance. Austempering of ductile irons was a well researched area in the last two decades. Attempts to further improve the wear resistance led to the development of Carbidic austempered ductile iron (CADI), wherein the carbides contribute to wear resistance. Combination of ausferritic matrix, graphite nodules, and carbides (eutectic and alloy) symbolizes the microstructure of CADI. Methods: Two principal approaches adopted by the researchers to change the microstructure are (i) addition of carbide forming elements (ii) heat treatment (s). Results: Both the above methods result in the refinement of graphite nodules, carbide precipitations, along with fine ausferrite. Conclusion: Improvement in hardness, toughness and wear resistance was observed largely as a consequence of fine carbide precipitations and formation of martensite.

Using Computer Microscopy Methods to Control the Microstructure of Malleable Cast Iron Product with Spherical Graphite

The method of identification of objects on images of the microstructure of cast iron with spherical graphite of the correct shape with uniform distribution is presented. Morphological analysis techniques were used to identify shrinkage pores and graphite inclusions in microstructure images. Geometric features of the shape of graphite inclusions were used as methods for identifying graphite, in particular, particle size analysis, which is widely used to identify various objects in computer microscopy. The computer analysis of the image was performed with the program ImageJ. To determine the pores against the background of graphite inclusions, two characteristics were used - the shape and size of the objects themselves. The pores, presented on the image, differ from graphite inclusions by a complex, fractal border and comparatively large areas. For the visualization of the research results, the combination of the graphite part with the calculation and analytical part was used. Such presentation of the results is the most significant and allows to perform the most correct evaluation of the graphitized cast iron microstructure in accordance with GOST 3443-87.

Static and Dynamic Analysis of Selective Leverage System Gear Train

Nowadays, the mechanical advantage is strongly emphasized in a mechanical system. Therefore, the most modern gearboxes are used to increase the torque without also increasing their output speed while reducing it. In this study, Selective Leverage System (SLS) gear train is generated in Solidworks 2016 and together with dynamic motion study and static simulation analysis. Dynamic motion analysis is performed to provide output speed of SLS gear train. It can be concluded that the gear system runs with unchanged speed (RPM) for input and output which is approximately the same with theoretical value in Selective Leverage System patent. The maximum output torque is evaluated by using theoretical calculation. At every 90° rotation, maximum value of output torque is produced. The results are validated and compared to the analytical value of patent. For static simulation analysis, the stress distribution of T-shaped lever of Selective Leverage System gear train is identified by using composite material compared to the existing gear materials. The static simulation analysis between Aluminium Alloy, S45C Steel, Malleable Cast Iron and Glass Filled Polyamide are compared and composite materials are capable to be used as a material of gear train components instead of current material, S45C Steel for better result.

Tellurium Effect on ASTM A 220 Graphite Malleable Cast Iron

The result of investigation of tellurium malleable cast iron are presented in the paper. Various small quantity of tellurium are added in the ladle before pouring molten metal. The main aim of investigation was determination of the influence composition of tellurium on graphite microstructure and mechanical properties. In addition, the final mechanical property of composition determined by hardness measurements. The favourable influence of the addition of tellurium into malleable cast iron molten metal on the tested properties after annealing as well as an percentation of graphite structure from 2% up to 6.5% and increase hardness from 38 HRc up to 43 HRc

Sorting nipple castings from malleable cast iron from the result of measuring their residual magnetization

The physical principles of magnetic control of the structure of malleable cast iron compact castings are summarized. It reports on the technical features and mode of operation of the automated instrument used for control. The features of formation of remanent magnetization of unhealed castings of nipples from malleable cast iron with bleached surface layer, features of the influence of changes in the layer thickness on the result of magnetization of the castings are established. A criterion for sorting castings with thickness of the bleached layer was developed based on the result of measuring its residual magnetization a given. Recommendations on its use when adjusting the rejection limit for automated magnetic sorting of castings by structure at the Minsk plant of heating equipment are given.

Experimental Study on Effect of Laser Hardening Parameters on Carbon Steel, Non-Malleable Cast iron and X20Cr13 Materials

Laser hardening is a surface heat treatment process used to enhance tribological and mechanical properties of metals which also leads to increase in service life of the components. Material removal, wear and tear, load concentration occurs mostly at rotating and reciprocating parts. Hence it is sufficient to enhance the hardness of a component at functional areas rather than the entire component. Laser hardening process is designed to change the microstructure of metals through controlled heating and cooling to get a modified surface. The constraints of traditional surface heat treatment process such as inability to treat specific area, distortion, poor degree of controllability, requirement of a quenching medium, long cycle time can be overcome by using Laser surface heat treatment and in addition to that it can be automated. With its benefits Laser surface hardening turns out to be a cost effective and energy saving process. The presented work is an investigation of the laser surface hardening via experimental results making use of a 6 axis robotic arm and a 10KW high power diode laser system as heat source with a wavelength of 980nm on leading automotive parts such as retainer, hub, and turbine blade whose materials being non-malleable cast iron, carbon steel, X20Cr13 respectively. Process parameters such as laser power from power source, scan speed were varied to understand the influence on resulting heat treated surface and efforts were made to optimize the process parameters to attain maximum hardness for the component to enhance its working life.