An Experimental Investigation of Hot Machining with Induction to Improve Ti-5553 Machinability

Abstract

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract. The manufacturing of aeronautic parts with high mechanical properties requires the use of high performance materials. That's why; new materials are used for landing gears such as the titanium alloy Ti-5553. The machining of this material leads to high cutting forces and temperatures, and poor machinability which requires the use of low cutting conditions. In order to increase the productivity rate, one solution could be to raise the workpiece initial temperature. Assisted hot machining consists in heating the workpiece material before the material removal takes place, in order to weaken the material mechanical properties, and thus reducing at least the cutting forces. First, a bibliography review has been done in order to determine all heating instruments used and the thermal alleviation that exists on conventional materials. An induction assisted hot machining was chosen and a system capable to maintain a constant temperature into the workpiece during machining (turning) was designed. Trails permit to identify the variation of cutting forces according to the initial temperature of the workpiece, with fixed cutting conditions according to the TMP (Tool-Material-Pair) methodology at ambient temperature. Tool life and deterioration mode are identified notably. The results analysis shows a low reduction of specific cutting forces for a temperature area compatible with industrial process. The reduction is more important at elevated temperature. However, it has consequences on quality of the workpiece surface and tool wear.

An investigation of cutting forces and cutting temperatures during laser-assisted machining of the Ti–6Cr–5Mo–5V–4Al beta titanium alloy

“…Boyer and Briggs [15] have presented a review on the history of the applications of beta titanium alloys in the aerospace industry for the past half century and the recent development of beta alloys such as Ti-15V-3Cr-3Al-2Sn and Ti-1023 as possible substitutes for various aircraft parts providing both improved performance and economic advantages. It has been reported by Baili et al [2] that Messier-Dowty uses the Ti-5553 beta titanium alloy for landing gear applications. However, work carried out on the machining of Ti-1023 with cryogenic coolant using carbon dioxide snow has shown that the machinability of this alloy cannot be improved further beyond a cutting speed of 100 m/min, due to the development of rapid tool wear, causing catastrophic tool failure [16].…”

“…These properties lead to the accumulation of high amounts of heat and mechanical stress around the cutting tool edge at high cutting speeds, subsequently increasing the cutting temperature and cutting force which leads to rapid cutting tool failure [2]. Hence, low cutting speeds and long production cycle times are common when machining aerospace materials.…”

Cutting Force Model for Thermal-Assisted Machining of Tool Steel Based on the Taguchi Method

“…From this, the optimum values in conventional machining of SKD11 were obtained as A3B1C1 with a cutting speed of 280 m/min, feed rate of 230 mm/min, and cutting depth of 0.5 mm, as shown in Figure 6. The mathematical model of cutting force depends on technological parameters (Vc, f, t) in the milling of SKD11 steel at room temperature, and is described by Equation (2).…”

“…Thermal-assisted machining (TAM) is one of the new technology solutions for the continuous development of advanced materials that have high hardness, less resistance to wear and thermal conductivity. It supports the cutting process, improves the machinability of material, increases machining productivity, improves surface quality, and reduces product cost [1,2]. With TAM, metals are softened and hardness decreases [3].…”

“…It made the decreasing stress on the tool, increasing tool life and reducing chatter in the cutting process. Baili et al [2] studied thermal-assisted turning by induction heating to improve the machinability of Ti-5553. The research results also showed that the cutting forces reduced 34.4% when the blank's temperature was 750 • C. However, the material structure could not be changed.…”