Papers by Keyword: Inconel 718

Abstract: Inconel 718 alloy is a typical difficult-to-cut material and widely used in the aerospace industry. Finite element simulation is an efficient method to investigate the cutting process, whereby a work material constitutive model plays an important role. In this paper, finite element simulation of the cutting process for Inconel 718 alloy using a new material constitutive model for high strain rates is presented. The effect of tool cutting edge radius on the cutting forces and temperature is then investigated with a view to facilitate cutting tool design. It is found that as the cutting edge radius increases, the characteristics of tool-work friction and the material removal mechanisms change, resulting in variation in cutting forces and temperature. It is shown that a smaller cutting edge radius is preferred to reduce the cutting forces and cutting temperature.

Abstract: A Si₃N₄ ceramic tool material with high mechanical properties was fabricated by hot-pressing sintering process. The high speed machining of Inconel 718 tests were carried out with round ceramic inserts. The failure surface and microstructure were analyzed by scanning electron microscopy (SEM) to reveal the ceramic tool failure mechanisms. The results showed that the main failure mechanisms of the Si₃N₄ ceramic tool were flaking, micro-chipping, abrasive wear and adhesive wear in the turning process. On the other hand, chipping, flaking and adhesive wear were the main failure reasons in the milling process. Meanwhile, some small flaking along the cutting edge and step-shaped flaking on the rake face closed to the cutting edge were found on the failure surfaces, which was a typical self-sharpening failure characteristic of the ceramic tool in the high-speed cutting process. This tool failure evolution characteristic of the ceramic tool can be attributed to its higher flexural strength and fracture toughness, which was beneficial to improve the tool life and was constrained by cutting conditions.

Abstract: In the present work, a finite element modeling of hot turning has been carried out for predicting computationally the state variables like temperature distribution on chip surface and cutting forces in hot machining of Inconel 718. The hot turning operation has been carried out with L₉ orthogonal design of experiment (DOE) with varying cutting speed, feed rate, heating temperature and constant depth of cut to analyze the responses. The model predicts the temperature distribution, cutting forces with and without heating. DEFORM 2D is applied for modeling hot turning simulation as similar as possible to the experimental result. Flow stress and input parameters should be modeled according to the actual machining conditions. The predicting results i.e. cutting forces and temperature distribution were partially validated with the experimental data.

Abstract: This article deals with the machining of Inconel 718 alloy. In the research, several carbide milling tools with different carbide grades and coatings were used. The main aim is compare all cutting tools in terms of their cutting tool life during machining super alloy Inconel 718. This material is used for highly stressed components in the nuclear industry, such as combustion turbine. Due to its rapid hardening and high heat generation, it is very problematic to machining. The right choice of appropriate carbide grade is necessary to achieve high-quality cutting wedge, which is important for good adhesion of the coating. The results of this work will be used for further research and development of cutting tools for machining Inconel 718.

Abstract: Recently, high-combustion-efficiency jet engines have become essential in the aircraft industry. High burning temperatures are necessary to maximize the combustion efficiency of jet engines. Inconel 718, which has excellent mechanical and chemical properties, has been selected for use in many jet engine parts. However, it is difficult to cut because of its low thermal conductivity. Consequently, wet cutting is typically used to reduce the heat generated in cutting Inconel 718. In this study, we conducted experiments to examine the relationships between the cutting characteristics and tool fracture in wet cutting.

Abstract: Nickel-based superalloys such as Inconel 718 are known as one of the most difficult-to-cut materials due to their mechanical and chemical properties and the tool life is extremely short. Recently, Cubic-Boron-Nitride (CBN) has received a considerable attention as a material for cutting tools and has been considered to be a major candidate for high performance cutting of Inconel 718. However, the detailed wear behavior of CBN tools in cutting of Inconel 718 is not sufficiently understood yet, and the performances of CBN tools are still insufficient in practical use. To overcome this problem, we first conducted orthogonal cutting experiments on Inconel 718 at low (20 m/min) and high (100 m/min) cutting speeds employing CBN cutting tools to clarify the detailed wear mechanisms. Moreover, relationship between surface microstructures of the cutting tool and wear resistance was investigated. As a result, it was found that a rake face with micro grooves significantly suppressed the crater wear at low cutting speed, although polished surface rake face reduced the initial crater wear by approximately 40 % compared to the non-polished tool in high speed cutting of Inconel 718.

Abstract: Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at v_c 105 m/min, f 0.3 mm/rev and a_p 1 mm where the regular insert had a catastrophic failure at v_c 90 m/min, f 0.1 mm/rev and a_p 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

Abstract: Al6061 has immense use in manufacture of several internal combustion engine parts as well. However the internal parts of an IC engine manufactured using Al6061 are susceptible to corrosion. Water may condense on the cylinder walls or move across the piston rings owing to blow-by and thus be admitted into the crankcase. This usually occurs in cold environment or short duration drive since pertaining to these conditions the engine may still be not hot enough to get rid of this water by evaporation. Upon amalgamation of this condensed water with the sulphur present in considerable quantities especially in low-grade fuels, sulphuric acid is formed thereby leading to a localized corrosion enhancing corrosive environment. In this work, TiO₂ and Inconel 718 are plasma sprayed on Al6061 specimen and their ability to protect against corrosion is studied and observed that the corrosion resistance of specimen coated with TiO₂ has improved by a considerable margin.

Abstract: Surface coating is sharing the responsibility between coating and substrate, which enhances the surface properties such as strength, hot hardness and toughness, wear resistance, antifriction and chemical inertness. The present work is focused on wear behavior of Mild Steel substrate material deposited with Titanium dioxide-30 wt % of Inconel718 incorporating plasma spray process. These composite coatings were subjected to slurry erosion wear test by simulating the corrosive-erosive atmosphere by mixing of silica sand and 3.5 percent of NaCl in distilled water. Under identical conditions, coated mild steels gave better wear resistance compared to uncoated sample.

Abstract: Inconel 718, a Nickel based superalloy is widely used for aerospace applications mainly due to its high temperature resistance and high strength to weight ratio. Its poor machinability is a limiting factor in commercial, cost intensive applications. This paper investigates the machinability of Inconel 718 in high speed drilling. The impact of the material on thrust forces, torque and chip microstructure have been measured at four different cutting speeds – 19, 27,43 and 67 m/min. The high tensile strength coupled with low thermal conductivity compounds the machining process. The thrust forces decrease with cutting speed, but the torque fluctuates at intermediate cutting speeds. Chip formation is continuous across cutting speeds, with thin cross sections and evidence of saw tooth edges. Inconel work hardens more than titanium alloys and shows good ductile to brittle transition at low temperatures creating chips of lesser length as observed using scanning electron microscopy.