Surface Finish when Threading Titanium-Based Alloy under Dry Machining

Abstract

This paper discusses the quality of surface finish when threading titanium-based alloy under dry condition. The quality of surface finish was studied at various cutting parameters and at the two extreme stages of the machining process, i.e. at the beginning and end of the process. The objective is to evaluate the effect of a worn-out tool on the quality of surface finish. PVD-coated carbide tools were used in this study. Experiments were conducted at two cutting speeds, 35 and 55 m/min, two depths of cut, 0.2 and 0.25 mm, and a constant pitch of 2.0 mm. The tool wear and the quality of surface finish were inspected visually by microscope. The tool's flank wear was measured gradually and machining was stopped when the flank wear reached the rejection criterion of0.3 mm. The microstructure beneath the machined surface was also evaluated. It was found that, at the beginning of machining, there was only a feed mark on the surface finish. When the machining was prolonged until the tools reached the rejection criterion, a bad surface finish was produced. Metal debris, surface cavities and a boundary crack were observed. Results show that machining with a worn-out tool can cause microstructure alteration beneath the machined surface. The selection of cutting parameters and monitoring of tool wear are crucial in order to obtain a good surface finish. Characterization of the surface finish with respect to the threading process under a dry condition would ultimately help in the development of suitable parameters for machining titanium-based alloys.

Thermal shock resistance of yttrium aluminium oxide Y3Al5O12 thermal barrier coating for titanium alloy

“…The use of light engines results in lower fuel consumption and less gas emission [1]. Titanium alloys and titanium aluminide are used as high temperature structural materials in aerospace and automotive applications due to their high strength-to-weight ratio, their low density and high corrosion resistance [2][3][4][5][6]. However, the susceptibility of titanium alloys to oxidation at high temperatures results eventually in degradation of the alloys mechanical performance and limit their operating temperature to around 600 o C. Therefore, several methods have been used to increase the operating temperatures of titanium alloys and protect them from oxidation,these methods are based either on bulk modification using alloying elements or using surface modification methods as coating.The former method may negatively affect the mechanical properties of the alloys, whereas the later method can also be used without affecting the mechanical properties of Ti alloys, such coatings include glass coatings and thermal barrier coatings (TBCs) [7,8].…”

Empirical modelling of machining parameters for turning operations using multiobjective Taguchi method

“…Thus, it is of utmost important to identify the optimal parameter settings to increase tool life, improve surface accuracy, and reduce cutting force and chip thickness in turning operations. Cutting speed, feed rate, depth of cut, tool-workpiece material, tool geometry, and coolant conditions are the turning parameters that highly affect the performance [5][6][7][8]. Turning produces three cutting force components: the main cutting force i.e.…”

Porous titanium alloy/hydroxyapatite composite using powder compaction route

“…Many biomaterials such as Co-Cr alloy, stainless steel, and titanium alloy are available. Titanium alloy is one of the potential candidates usually chosen by researchers because it is characterised by excellent corrosion resistance, bioinertness, and high strength-to-weight ratio [8][9][10][11]. Another important property of titanium alloy is that it has a lower Young's modulus than other biomaterials (110 GPa) [12].…”