Cryogenic Rotary Ultrasonic Machining of Titanium Alloys (original) (raw)
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A CRITICAL REVIEW ON CRYOGENIC MACHINING OF TITANIUM ALLOY (TI-6AL-4V)
The alloys of Nickel, Cobal Titanium, Tungsten belongs to the group of super hard alloys, among them Titanium is one of the fastest growing materials used in aerospace applications. The prime rationale for designers to choose titanium in their designs is its relative low mass for a given strength level and its relative resistance to high temperature. Titanium has long been used in aircraft engine front sections and will continue to be used there for the foreseeable future. In fact, due to its properties, titanium alloys are becoming more prevalent than ever before in structural and landing gear components. One drawback of these alloys is their poor mach inability .Titanium alloy Ti-6Al-4V, a difficult-to-machine material having extremely short tool life. To overcome this problem, advanced techniques are being practiced in machining of titanium alloy, one such technique is cryogenic cooling. Nitrogen is more preferable in machining to dissipate heat generated because it is cost effective, safe, non flammable and environmental friendly gas, in addition to that it cannot contaminate work piece, no separate mechanism for disposal .A review is undertaken in this paper for the machining of titanium alloys in cryogenic conditions.
Investigation for ultrasonic machining of titanium and its alloys
Journal of Materials Processing Technology, 2007
This paper investigates the ultrasonic machining of tough materials like titanium and its alloys. Experimental investigations were conducted to understand machining characteristics of titanium and its alloys with high speed steel tool. The results of study highlighted that higher hardness of work piece is not the criteria for higher material removal rate in machining of titanium and its alloys. Also effect of power rating on work hardening of work piece and tool was highlighted.
Journal of Materials Processing Technology, 2011
Titanium alloys are widely used in applications that demand a good combination of high strength, good corrosion resistance and low mass. Beta-Titanium alloys offer the highest specific strength among titaniumbased materials. The mechanical properties lead to challenges in machining operations such as high process temperatures, high specific mechanical loads and rapidly increasing tool wear. The high chemical reactivity of titanium leads to rapidly developing flank and notch wear limiting cutting speeds and tool life. Applying industrial gases instead of conventional cooling and lubrication fluids promises increased productivity. In this work, the effectiveness of carbon dioxide snow (CO 2) as a coolant for turning Ti-10V-2Fe-3Al is analyzed. The carbon dioxide is provided in a pressurized gas bottle and is fed to the tool tip through holes in the tool holders clamping jaw. Compared to flood emulsion cooling the flank wear was uniform spreaded and tool life was increased by a factor of two even at higher cutting speeds. Tool-life-limiting notch wear and the burr formation at the workpiece have been suppressed.
Ultrasonically Assisted Machining of Titanium Alloys
Materials Forming, Machining and Tribology, 2014
In this chapter we discuss the nuances of a non-conventional machining technique known as ultrasonically assisted machining, which has been used to demonstrate tractable benefits in the machining of titanium alloys. We also demonstrate how further improvements may be achieved by combining this machining technique with the well known advantages of hot machining in metals and alloys.
The Influence of Cryogenic Coolants in Machining of Ti–6Al–4V
Journal of Manufacturing Science and Engineering, 2013
Machining of titanium alloy Ti–6Al–4V is a challenging task because of the greatly increased cutting temperature that results in short tool life. Numerous attempts have been made in the past by employing various cutting fluids for machining purpose, including liquid nitrogen (LN2) as the cryogenic coolant. This study deals with the influence of cryogenic coolants, especially LN2 and carbon dioxide (CO2), in machining of Ti–6Al–4V and its effects on cutting temperature, cutting forces, surface roughness, chip morphology, and tool wear. The results obtained in cryogenic machining are compared with that of dry and wet machining. Cutting temperature was reduced to an extent of 36% and 47% in cryogenic CO2 machining and cryogenic LN2 machining in comparison with wet machining. The application of CO2 produced reduced cutting forces up to 24% and improved surface finish up to 48% compared to cryogenic LN2 machining. It also produced better chip control and minimized tool wear than dry, wet...
An investigation into the machining characteristics of titanium using ultrasonic machining
International Journal of Machining and Machinability of Materials, 2008
This paper presents a review on the problems encountered in machining titanium and application of USM in machining titanium and its alloys. Experiments have been conducted to assess the effect of three factors-tool material, grit size of the abrasive slurry and power rating of ultrasonic machine on machining characteristics of titanium (ASTM Grade I) using full factorial approach for design and analysis of experiments. It has been concluded that all factors have significant effect on Material Removal Rate (MRR), Tool Wear Rate (TWR) and surface roughness of the machined surface. Two-way interactions having significant effect on MRR, TWR and surface roughness have also been identified using Minitab14 software. The levels for each factor that contribute the most to the variation in machining performance of USM of titanium have also been established. It has been concluded that titanium is fairly machinable with USM process. Moreover, the surface finish obtained is better than many of the other non-traditional processes.
Machining Science and Technology, 2019
Titanium, a difficult-to-cut material, consumes higher time and cost in removing material by machining to produce parts. Machining of Ti alloys has got serious attention owing to its reactive nature with tool materials at elevated temperature that aggravates tool wear. Reportedly, effective and efficient cooling and lubrication at the tool-work interface can ameliorate the machinability of Ti-alloys. In this perspective, this article interrogates the underlying mechanism of critical responses such as surface roughness, temperature, tool life and machining cost under dry, minimum quantity lubrication (MQL) and cryogenic liquid nitrogen (LN2) modes. The effect of cutting speeds and feed rates on such responses have been considered as a function of cooling strategy to standardize the cooling technique as the best alternative for machining. Cryogenic cooling seems to be preponderant regarding machining cost, temperature, surface roughness and tool life in hard turning of a-b titanium alloy. The feasibility of cryogenic cooling was investigated using the iso-response technique in comparison with dry and MQL-assisted hard turning. Experimental results revealed longer tool life and lower machining cost under cryogenic condition followed by MQL and dry machining. Moreover, cryogenic LN2 has been identified as an appropriate alternative to reduce the temperature and surface roughness. On contrary, dry turning evoked a high-temperature and rapid tool wear. In a nutshell, cryogenic assisted hard turning has acceded as a sustainable strategy from an environmental and economic perspective.
Experimental Investigations on Cryogenic Cooling in the Drilling of Titanium Alloy
In this study, a drilling experiment was conducted on titanium ASTM B265 Grade 2 material using PVD coated carbide inserts. Two types of coolants (Wet and LN 2 ) were used. The variables in the experiment were feed rate (f) and cutting speed (V c ). The depth of the drilling was constant. Cutting temperature (T), thrust force (F t ), surface roughness (R a ), and the hole quality (circularity, cylindricity, and perpendicularity) were analyzed. The tool wear and chip morphology were studied. The result of the experiment indicates that there is 6-59% reduction in cutting temperature when LN 2 is used, high thrust force values were recorded for LN 2 coolant condition, surface roughness (R a ) values were higher for LN 2 coolants. Hole quality is not favorable in LN 2 coolant supply.
Cryogenic Milling of Titanium Powder
Metals, 2018
Ti Grade 2 was prepared by cryogenic attritor milling in liquid nitrogen and liquid argon. Two types of milling balls were used-stainless steel balls and heavy tungsten carbide balls. The effect of processing parameters on particle size and morphology, contamination of powder and its microhardness was investigated. Milling in liquid nitrogen was not feasible due to excessive contamination by nitrogen. Minor reduction of particle size and significant alterations in particle morphology depended on type of milling balls and application of stearic acid as processing control agent. Heavily deformed ultra-fine grained (UFG) internal microstructure of powder particles was observed by the method of "transmission Kikuchi diffraction".