Effects of annular-cooler surface-roughness on wind resistance and thermal environment in a high-speed geotechnical centrifuge chamber

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.

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Characteristic properties of AlTiN and TiN coated HSS materials

Industrial Lubrication and Tribology ◽

10.1108/ilt-10-2012-0097 ◽

2015 ◽

Vol 67 (2) ◽

pp. 172-180 ◽

Cited By ~ 3

Author(s):

Mumin Sahin ◽

Cenk Misirli ◽

Dervis Özkan

Keyword(s):

Surface Roughness ◽

Tensile Strength ◽

High Speed ◽

Cutting Tools ◽

High Speed Steel ◽

Wear Properties ◽

Content Type ◽

X Ray ◽

Number Of Cycles ◽

Future Work

Purpose – The purpose of this paper is to examine mechanical and metallurgical properties of AlTiN- and TiN-coates high-speed steel (HSS) materials in detail. Design/methodology/approach – In this study, HSS steel parts have been processed through machining and have been coated with AlTiN and TiN on physical vapour deposition workbench at approximately 6,500°C for 4 hours. Tensile strength, fatigue strength, hardness tests for AlTiN- and TiN-coated HSS samples have been performed; moreover, energy dispersive X-ray spectroscopy and X-ray diffraction analysis and microstructure analysis have been made by scanning electron microscopy. The obtained results have been compared with uncoated HSS components. Findings – It was found that tensile strength of TiAlN- and TiN-coated HSS parts is higher than that of uncoated HSS parts. Highest tensile strength has been obtained from TiN-coated HSS parts. Number of cycles for failure of TiAlN- and TiN-coated HSS parts is higher than that for HSS parts. Particularly TiN-coated HSS parts have the most valuable fatigue results. However, surface roughness of fatigue samples may cause notch effect. For this reason, surface roughness of coated HSS parts is compared with that of uncoated ones. While the average surface roughness (Ra) of the uncoated samples was in the range of 0.40 μm, that of the AlTiN- and TiN-coated samples was in the range of 0.60 and 0.80 μm, respectively. Research limitations/implications – It would be interesting to search different coatings for cutting tools. It could be the good idea for future work to concentrate on wear properties of tool materials. Practical implications – The detailed mechanical and metallurgical results can be used to assess the AlTiN and TiN coating applications in HSS materials. Originality/value – This paper provides information on mechanical and metallurgical behaviour of AlTiN- and TiN-coated HSS materials and offers practical help for researchers and scientists working in the coating area.

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Aerodynamic Losses in Turbines with and without Film Cooling, as Influenced by Mainstream Turbulence, Surface Roughness, Airfoil Shape, and Mach Number

International Journal of Rotating Machinery ◽

10.1155/2012/957421 ◽

2012 ◽

Vol 2012 ◽

pp. 1-28 ◽

Cited By ~ 4

Author(s):

Phil Ligrani

Keyword(s):

Surface Roughness ◽

Mach Number ◽

Film Cooling ◽

Total Pressure ◽

High Speed ◽

Density Ratio ◽

Aerodynamic Loss ◽

Pressure Losses ◽

Loss Coefficients ◽

Exit Mach Number

The influences of a variety of different physical phenomena are described as they affect the aerodynamic performance of turbine airfoils in compressible, high-speed flows with either subsonic or transonic Mach number distributions. The presented experimental and numerically predicted results are from a series of investigations which have taken place over the past 32 years. Considered are (i) symmetric airfoils with no film cooling, (ii) symmetric airfoils with film cooling, (iii) cambered vanes with no film cooling, and (iv) cambered vanes with film cooling. When no film cooling is employed on the symmetric airfoils and cambered vanes, experimentally measured and numerically predicted variations of freestream turbulence intensity, surface roughness, exit Mach number, and airfoil camber are considered as they influence local and integrated total pressure losses, deficits of local kinetic energy, Mach number deficits, area-averaged loss coefficients, mass-averaged total pressure loss coefficients, omega loss coefficients, second law loss parameters, and distributions of integrated aerodynamic loss. Similar quantities are measured, and similar parameters are considered when film-cooling is employed on airfoil suction surfaces, along with film cooling density ratio, blowing ratio, Mach number ratio, hole orientation, hole shape, and number of rows of holes.

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A Comprehensive Study on Surface Roughness in Machining of AISI D2 Hardened Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.576.60 ◽

2012 ◽

Vol 576 ◽

pp. 60-63 ◽

Cited By ~ 7

Author(s):

N.A.H. Jasni ◽

Mohd Amri Lajis

Keyword(s):

Surface Roughness ◽

High Speed ◽

End Milling ◽

Cutting Speed ◽

Hardened Steel ◽

Depth Of Cut ◽

Feed Speed ◽

Radial Depth ◽

Aisi D2 ◽

Coated Carbide

Hard milling of hardened steel has wide application in mould and die industries. However, milling induced surface finish has received little attention. An experimental investigation is conducted to comprehensively characterize the surface roughness of AISI D2 hardened steel (58-62 HRC) in end milling operation using TiAlN/AlCrN multilayer coated carbide. Surface roughness (Ra) was examined at different cutting speed (v) and radial depth of cut (dr) while the measurement was taken in feed speed, Vf and cutting speed, Vc directions. The experimental results show that the milled surface is anisotropic in nature. Surface roughness values in feed speed direction do not appear to correspond to any definite pattern in relation to cutting speed, while it increases with radial depth-of-cut within the range 0.13-0.24 µm. In cutting speed direction, surface roughness value decreases in the high speed range, while it increases in the high radial depth of cut. Radial depth of cut is the most influencing parameter in surface roughness followed by cutting speed.

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Wind Resistance in High-Speed Train Service

Scientific American ◽

10.1038/scientificamerican10311903-302a ◽

1903 ◽

Vol 89 (18) ◽

pp. 302-302

Keyword(s):

High Speed ◽

High Speed Train ◽

Wind Resistance

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Theoretical Surface Roughness Model in High Speed Face Milling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.3331 ◽

2014 ◽

Vol 989-994 ◽

pp. 3331-3334

Author(s):

Tao Zhang ◽

Guo He Li ◽

L. Han

Keyword(s):

Surface Roughness ◽

Surface Integrity ◽

High Speed ◽

Cutting Parameters ◽

Angular Speed ◽

Face Milling ◽

Advanced Manufacturing ◽

Roughness Model ◽

Machined Parts ◽

Important Object

High speed milling is a newly developed advanced manufacturing technology. Surface integrity is an important object of machined parts. Surface roughness is mostly used to evaluate to the surface integrity. A theoretical surface roughness model for high face milling was established. The influence of cutting parameters on the surface roughness is analyzed. The surface roughness decreases when the cutter radius increases, total number of tooth and rotation angular speed, while it increases with the feeding velocity. The high speed face milling can get a smooth surface and it can replace the grinding with higher efficiency.

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Machining quality of high speed helical milling of carbon fiber reinforced plastics

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406221996736 ◽

2021 ◽

pp. 095440622199673

Author(s):

Adel Abidi ◽

Sahbi Ben Salem ◽

Mohamed Athmane Yallese

Keyword(s):

Surface Roughness ◽

Carbon Fiber ◽

High Speed ◽

Hole Diameter ◽

Feed Speed ◽

Carbon Fiber Reinforced Plastics ◽

Reinforced Plastics ◽

Machining Quality ◽

Fiber Reinforced Plastics

Among advanced cutting methods, High Speed Milling (HSM) is often recommended to improve the productivity and to reduce the costs of machining parts. As every cutting process, HSM is characterized by some defects like surface roughness and delamination are the main defects generated in composite materials. The aim of this experimental work is the studying of the machining quality of woven Carbon fiber reinforced plastics (CFRP) using the HSM technology. Experiments were done using different machining parameters combinations to make opened holes in CFRP laminates. This study investigated the effect of cutting speed, orbital feed speed, hole diameter on the delamination defect and surface roughness responses generated in the drilled holes. The design of experimental tests was generated using the approach of Central Composite Design (CCD). The characterization of these responses was treated with the Analysis of variance (ANOVA) and Response surface methodology (RSM). Results showed that the surface roughness is highly affected by the orbital feed speed (F) with contribution of 22.45%. The delamination factor at entry and exit of holes is strongly influenced by the hole diameter D (25.97% and 57.43%) respectively. The developed model equations gave a good correlation between the empirical and predicted results. The optimization of the milling parameters was treated using desirability function to minimize the surface roughness (Ra) and the delamination factor simultaneously.

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