• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.327-328
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• 2008

• 소성∙가공
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• 제7권3호
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• pp.197-206
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• 1998

This paper presents the prediction of dynamic recrystallization behavior during hot forging of Inconel 718. Another experiment of pancake forging was also carried out to examine the recrystallization ration dynamically recrystallizaed grain size, and grain growth in the forging. In experiments cylindrical billets were forged by two operations with variations of forging temperature, reduction ration of deformation. and preheating process at each forging step. Also the finite element program, developed here for the prediction using the metallurgical models was used for the analysis of to Inconel 718 upsetting and the results were compared with experimental ones.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.285-291
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• 2004

LiCl-$Li_2O-O_2$ 용융염계에서 용융염 취급장치의 구조재료를 위한 평가의 일환으로 Inconel 718, X-750, Haynes 75, 263 합금의 부식거동을 분위기온도; $650^{\circ}C$, 부식시간: 24~168h, $Li_2O$농도; 3wt%, 혼합가스농도; Ar-10%$O_2$에서 조사하였다. LiCl-$Li_2O-O_2$ 용융염계에서 부식속도는 Haynes 263 ＜ Haynes 75 ＜ Inconel X-750 ＜ Inconel 718 순서로 나타났으며, Haynes 263 합금이 가장 우수한 내부식성을 나타내었다. Haynes 75의 부식생성물은 $Cr_2O_4$, $NiFe_2O_4$, $LiNiO_2$, $Li_2NiFe_2O_4$, Inconel 718의 부식생성물은 $Cr_2O_4$ 및 $NiFe_2O_4$ 이며 Haynes 263은 $Li(Ni,Co)O_2$, $NiCr_2O_4$ 및 $LiTiO_2$, Inconel X-750은 $Cr_2O_3$, $NiFe_2O_4$,$FeNi_3$, (Al,Nb,Ti)$O_2$의 부식생성물을 나타내었다. Haynes 263은 국부부식의 거동을 보이는 반면, Haynes 75, Inconel 718 및 Inconel X-750은 전면 부식 거동을 나타내었다.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.1049-1061
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• 2022

Neutron and gamma-ray shielding properties of Inconel 718 reinforced B₄C (0-25 wt%) were investigated using PSD software. Mean free path (MFP), linear and mass attenuation coefficients (LAC,MAC), tenth-value and half-value layers (TVL,HVL), effective atomic number (Z_eff), exposure buildup factors (EBF), and fast neutron removal cross-sections (FNRC) values were calculated for 0.015-15 MeV. It was found that MAC and LAC increased with the decrease in the content of B₄C compound by weight in Inconel 718. The EBFs were computed using G-P fitting method for 0.015-15 MeV up to the penetration depth of 40 mfp. HVL, TVL, and FNRC values were found to range between 0.018 cm and 3.6 cm, between 2.46 cm and 12.087 cm, and between 0.159 cm^-1 and 0.194 cm^-1, respectively. While Inconel 718 provides the maximum photon shielding property since it offered the highest values of MAC and Z_eff and the lowest value of HVL, Inconel 718 with B₄C(25 wt%) was observed to provide the best shielding material for neutron since it offered the highest FNRC value. The study is original in terms of several aspects; moreover, the results of the study may be used in nuclear technology, as well as other technologies including nano and space technologies.

• Corrosion Science and Technology
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• 제22권5호
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• pp.359-367
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• 2023

The localized corrosion resistance of the Ni-based Inconel 718 alloy after solution heat treatment was evaluated using electrochemical techniques in a solution of 25 wt% NaCl and 0.5 wt% acetic acid. Solution heat treatment at 1050 ℃ for 2.5 hours resulted in an increased average grain diameter. Both Ti carbides (10 ㎛ diameter) and Nb-Mo carbides (1 - 9 ㎛ diameter) were distributed throughout the material. Despite heat treatment, the shape and composition of these carbides remained consistent. An increase in solution temperature led to a decrease in pitting potential value. However, the pitting potential value of solution heat-treated Inconel 718 was consistently higher than that of as-received Inconel 718 at all tested temperatures. Localized corrosion initiation occurred at 0.4 V_SSE in a temperature environment of 80 ℃ for both as-received and solution heat-treated Inconel 718 alloys. X-ray photoelectron spectroscopic analysis indicated that the composition of the passive film formed on specimen surfaces remained largely unchanged after solution heat treatment, with O1s, Cr2p_3/2, Fe2p_3/2, and Ni2p_3/2 present. The difference in localized corrosion resistance between as-received and solution heat-treated Inconel 718 alloys was attributable to microstructural changes induced by the heat treatment process.

• 한국정밀공학회지
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• 제34권3호
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• pp.161-166
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• 2017

Inconel 718, a typical ultraheat-resistant alloy, is recognized as a useful component in aircraft parts owing to its high-temperature strength and good chemical stability. Although many studies have been conducted to determine the proper drill shape to overcome the poor machinability when drilling into Inconel 718, most have involved a cutting process program known as AdvantEdge, as an experimental approach requires much time and money. In this study, our purpose is to optimize the drill shape for efficient drilling by conducting a trust force and temperature analysis using AdvantEdge. In order to achieve this purpose, the reliability of the results of the analysis was verified and by applying design of experiment an analysis of the geometric parameters of the drill shape considering the thrust force and temperature was conducted.

• 한국기계가공학회지
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• 제18권8호
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• pp.51-59
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• 2019

Flow forming is an eco-friendly and high-efficiency plastic deformation process with fewer chips during a process which is specifically used to manufacture seamless tubular products like tire wheels, rocket motor cases etc. On the development of mortar barrel using Inconel718 tube, some flow formed products had dimensional errors on their thickness. In this study, our purpose is to optimize the process conditions with the smallest dimensional error. In order to find an optimum process condition, 2D axisymmetric FEM simulation analyses with Taguchi method were conducted. Geometric variables (attack angle, flatting angle, roller nose radius) and operating parameters (depth of forming, feed rate) are considered as control factors. Forward flow forming with single roller was first analyzed to determine the effective factors using AFDEX software and attack angle of the roller was identified as the most influential factor. Also, the nose radius of the rollers was confirmed as a significant factor in multi-rollers flow forming system. The effect of rollers offset values are also studied and finally, we proposed optimal conditions to improve the accuracy of flow forming process with Inconel718 tube for mortar barrel manufacturing.

• 한국기계가공학회지
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• 제21권8호
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• pp.1-8
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• 2022

Inconel 718 is nickel-based and is increasingly being used as a key component in the nuclear, aerospace, and chemical industries which require high fatigue strength and oxidation, because of its excellent corrosion resistance, heat resistance, and wear resistance. It is a heat-resistant alloy which has excellent mechanical properties; however, material deformation, cracking, and shaking occur because of the high cutting temperature accumulated on the cutting surface during cutting processing, and heat accumulated at the insert boundary. Owing to these characteristics, various studies have been conducted, such as developing a tool exclusively for non-deletion, analyzing tool wear, and developing a tool cooling system. However, the optimization of the cutting process is still insufficient. In this study, the optimal process conditions were derived experimentally by cutting conditions according to the insert type during the cutting of Inconel 718.

• 한국생산제조학회지
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• 제21권6호
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• pp.982-987
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• 2012

Inconel 718 alloy has been widely used in the aerospace, heavy industry and electronic industry. However, the machinability of this alloy is very poor, which is attributed to their inherent high strength that is maintained at elevated temperatures. The tool life is dominant problem in machining difficult-to-cut materials, so it is necessary to select the efficient cutting conditions for the improvement of tool life. In this study, the cutting force, tool wear and surface roughness are investigated in end milling machining under various cutting conditions. By this experiment, the efficient machining condition of this alloy is suggested to adopt in various industries.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1996년도 재료학회 춘계학술발표회
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• pp.92-92
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• 1996