• Title/Summary/Keyword: Inconel

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Welding of Inconel Tube with Pulsed Nd:YAG Laser (펄스형 Nd:YAG 레이저 빔에 의한 Inconel Tube의 용접)

  • Kim, J.D.;Chang, W.;Chung, J.M.;Kim, C.J.
    • Journal of Welding and Joining
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    • v.17 no.1
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    • pp.82-87
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    • 1999
  • The basic remote sleeve repair-welding technology by the pulsed Nd:YAG laser for increasing the lifetime of the steam generator tube in a nuclear power plant has been developed. The relationship between the connection width and welding parameters have been investigated for the fundamental research to apply the sleeve-repair-welding technique to the nuclear industry. The Inconel 600 tube and Inconel 690 sleeve used for high temperature and high pressure service were welded as round lap welding by Nd:YAG laser. It was observed that the tensile shear strength, 340MPa of the welded specimen is equivalent to about 60% of that of the base metal (Inconel 600), 550MPa. The difference between the hardness of the base metal and that of the laser welds was about 10%. Ductile fracture was partly occurred in the weld but the cracking has not been observed. In spite of absence of the crack, the strength of welds was not sufficient in terms of the tensile shear strength.

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Dynamic Material Characteristics of Superalloy INCONEL 718 with the Variation of Strain Rates (변형률속도 변화에 따른 INCONEL 718 초내열합금의 동적 물성특성)

  • Song J. H.;Huh H.
    • Transactions of Materials Processing
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    • v.14 no.6 s.78
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    • pp.559-564
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    • 2005
  • INCONEL 718, nickel based superalloy, has good formability, high strength, excellent corrosion resistance and mechanical properties at high temperature. Owing to theses attractive properties, it is utilized in applications such as combustion system, turbine engines and nuclear reactors. In such applications, components are typically required to be tolerant of high stress impact loading. This may cause material degradation and lead to catastrophic failure during service operation. Accurate understanding of material's mechanical properties with various strain rates is required in order to guarantee the reliability of structural parts made of INCONEL 718. This paper is concerned with the dynamic material properties of the INCONEL 718 at various strain rates. The dynamic response of the INCONEL 718 at the intermediate strain rate is obtained from the high speed tensile test and at the high strain rate is from the split Hopkinson pressure bar test. The effect of the strain rate on dynamic flow stress, work hardening characteristics, strain rate sensitivity and elongation to the failure is evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 5000/sec are interpolated in order to construct the Johnson-Cook model as the constitutive relation that should be applied to simulate and design the structural parts made of rNCONEL 718.

Electrochemical Corrosion Damage Characteristics of Austenite Stainless Steel and Nickel Alloy with Various Seawater Concentrations (오스테나이트계 스테인리스강과 니켈합금의 해수 농도 변화에 따른 전기화학적 부식 손상 특성)

  • Heo, Ho-Seong;Kim, Seong-Jong
    • Corrosion Science and Technology
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    • v.20 no.5
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    • pp.281-288
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    • 2021
  • Due to advancement of the industry, operation of a device in a harsh environment is increasing. Especially, the marine environment contains Cl- ions which causes localized corrosion such as pitting and crevice corrosion of stainless steel and various metals. In this study, electrochemical corrosion behaviors of austenitic stainless steel (STS 316L) and nickel alloy (Inconel 600) with different seawater concentrations (fresh water, seawater, mixed water) were investigated. The STS 316L and Inconel 600 were etched in 10% oxalic acid and composed of an austenitic phase. Results of Tafel analysis in seawater showed that STS 316L and Inconel 600 presented the highest corrosion current densities of 7.75 × 10-4 mA/cm2 and 1.11 × 10-4 mA/cm2 and the most negative pitting potentials of 0.94 V and 1.06 V, respectively. The maximum damage depths and surface damage ratio by pitting corrosion increased with chloride concentration. The STS 316L had higher PREN than Inconel 600. However, the surface damage and weight loss of Inconel 600 were superior to STS 316L. It was difficult to compare the pitting resistance of STS 316L based on Fe and Inconel 600 based on Ni with PREN simply.

A Study on Reusable Metal Component as Burnable Absorber Through Monte Carlo Depletion Analysis

  • Muth, Boravy;Alrawash, Saed;Park, Chang Je;Kim, Jong Sung
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.4
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    • pp.481-496
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    • 2020
  • After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.

Thermal Distortion Analysis by Inconel Over-Lay At Circular Moonpool Structures

  • Ha, Yunsok
    • International Journal of Ocean System Engineering
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    • v.3 no.2
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    • pp.95-101
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    • 2013
  • This study is mainly interested in roundness of a circular moonpool structure in FPSO. Because this structure needs abrasion-resistance on inner wall, we should do buttering widely and deeply by using Inconel. But a general buttering can cause a severe distortion at structures. If someone can analyze the roundness by thermal distortion under Inconel over-lay, an erection policy can be established. In this study, shrinkage methodology by designed stress-strain curve was used and the result allowed deciding an appropriate block size.

Microstructure and Properties of TiC-Inconel 718 Metal Matrix Composites Fabricated by Liquid Pressing Infiltration Process (용융가압함침 공정으로 제조된 고체적률 TiC-Inconel 718 금속복합재료의 미세조직 및 특성)

  • Cho, Seungchan;Lee, Yeong-Hwan;Ko, Seongmin;Park, Hyeonjae;Lee, Donghyun;Shin, Sangmin;Jo, Ilguk;Lee, Sang-Bok;Lee, Sang-Kwan
    • Composites Research
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    • v.32 no.3
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    • pp.158-162
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    • 2019
  • Titanium carbide (TiC) reinforced Inconel 718 matrix composites were successfully fabricated by a novel liquid pressing infiltration process. Microstructure and mechanical properties of the fabricated 55 vol% TiC-Inconel 718 composite are analyzed. The composite exhibits superior mechanical properties, such as hardness and compressive strength as compared with Inconel 718. It is believed that Mo and Nb, which are alloying elements in the matrix, diffuse and solidify into the TiC reinforcement, resulting in generation of core-rim structure with excellent interfacial properties.

Effect of Solution Annealing Heat Treatment on the Localized Corrosion Resistance of Inconel 718 (Inconel 718의 국부 부식 저항성에 미치는 용체화 열처리의 영향)

  • Yoonhwa Lee;Jun-Seob Lee;Soon Il Kwon;Jungho Shin;Je-hyun Lee
    • Corrosion Science and Technology
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    • v.22 no.5
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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 VSSE 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, Cr2p3/2, Fe2p3/2, and Ni2p3/2 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.