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Sample records for alloy-600 inconel

  1. Effect of hydrogen in Inconel Alloy 600 on corrosion in high temperature oxygenated water

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    Hou, J. [Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, 6-6-01, Aramaki Aoba, Aoba-ku, Sendai 980-8579 (Japan); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang 110016 (China); Peng, Q.J. [Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, 6-6-01, Aramaki Aoba, Aoba-ku, Sendai 980-8579 (Japan)], E-mail: qpeng@rift.mech.tohoku.ac.jp; Sakaguchi, K.; Takeda, Y.; Kuniya, J.; Shoji, T. [Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University, 6-6-01, Aramaki Aoba, Aoba-ku, Sendai 980-8579 (Japan)

    2010-03-15

    Corrosion test on hydrogen charged and uncharged coupons of Inconel Alloy 600 in high temperature oxygenated water showed more weight loss of charged coupon. Observation of the oxide film by transmission electron microscopy (TEM) showed a defective, thicker oxide layer on charged coupon. Analyses of the oxide film by TEM-energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy indicated enrichment of Ni but depletion of Cr in the oxide film on charged coupon. The changes in corrosion behavior and microstructure of the oxide film were most likely due to the hydrogen enhanced preferential dissolution of Cr cations in the water.

  2. Relationship between ferromagnetic properties and grain size of Inconel alloy 600

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    Kikuchi, H., E-mail: hkiku@iwate-u.ac.jp; Takahashi, H.; Yanagiwara, H.; Murakami, T.

    2015-05-01

    Inconel alloy 600 is widely used in steam generator tubings where sensitization due to chromium depletion occurs at grain boundaries and the sensitization induces tubing failures. Though the alloy usually exhibits paramagnetic properties, it shows ferromagnetic properties along grain boundaries when chromium depletion occurs. This means that magnetic nondestructive evaluation of sensitization is possible. Therefore, as a fundamental study to develop magnetic nondestructive evaluation technique for sensitization, the relationship between ferromagnetic properties and grain size in Inconel 600 was investigated using isothermal heat treatment. The grain was controlled using solution annealing, and then, specimens were heat treated at 873, 923, and 973 K within 400 h. The saturation magnetization increases as heat treatment time increases and eventually peaks. The peak time depends on the heat treatment temperature. The coercivity increases during the initial heat treatment stage, and decreases as the duration of heat treatment increases. The maximum saturation magnetization decreases as the grain diameter increases and is inversely proportional to the grain diameter squared, which is consistent with the fact that the ferromagnetic phase only formed along grain boundaries. - Highlights: • Relationship between ferromagnetism and grain size in Inconel 600 was clarified. • The saturation magnetization increases and eventually peaks during heat treatment. • The coercivity increases during the initial heat treatment stage, and then decreases. • The saturation magnetization is inversely proportional to the grain diameter squared. • The magnetic property changes are explained by the Cr depletion at grain boundaries.

  3. Stress corrosion cracking of alloy 600 using the constant strain rate test

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    Bulischeck, T. S.; van Rooyen, D.

    1980-01-01

    The most recent corrosion problems experienced in nuclear steam generators tubed with Inconel alloy 600 is a phenomenon labeled ''denting''. Denting has been found in various degrees of severity in many operating pressurized water reactors. Laboratory investigations have shown that Inconel 600 exhibits intergranular SCC when subjected to high stresses and exposed to deoxygenated water at elevated temperatures. A research project was initiated at Brookhaven National Laboratory in an attempt to improve the qualitative and quantitative understanding of factors influencing SCC in high temperature service-related environments. An effort is also being made to develop an accelerated test method which could be used to predict the service life of tubes which have been deformed or are actively denting. Several heats of commercial Inconel 600 tubing were procured for testing in deaerated pure and primary water at temperatures from 290 to 365/sup 0/C. U-bend type specimens were used to determine crack initiation times which may be expected for tubes where denting has occurred but is arrested and provide baseline data for judging the accelerating effects of the slow strain rate method. Constant extension rate tests were employed to determine the crack velocities experienced in the crack propagation stage and predict failure times of tubes which are actively denting. 8 refs., 17 figs., 5 tabs.

  4. Integrated Guidelines for Management of Alloy 600 Locations

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    Na, Kyung-Hwan; Chung, Hansub; Yang, Jun-Seog; Lee, Kyoung-Soo [KHNP-Central Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The locations experiencing PWSCC include steam generator tubes, pressurizer instrumental nozzles, control rod driving mechanism(CRDM) penetration nozzles, reactor outlet nozzles, and bottom mounted instrumental(BMI) nozzles. Korea Hydro and Nuclear Power Co.(KHNP) has developed integrated guidelines for management of alloy 600 locations and the guidelines are under review by the regulator. The guidelines consist of alloy 600 location database, inspection program, maintenance/preventive maintenance method, and finally water chemistry management for PWSCC mitigation. In this paper, the detailed contents are presented. The integrated guidelines collected all relevant information on the management of alloy 600 locations. This information may be useful for establishing the most effective preventive maintenance strategies by prioritization in addition to maintenance strategies. Table II summarize maintenance strategies for alloy 600 locations.

  5. Dissolution of Oxide Layer on Alloy 600 by HYBRID Solution

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    Won, H. J.; Lee, W. S.; Kim, S. B.; Park, S. Y.; Choi, W. K.; Moon, J. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The simulated oxide layer formed on Alloy 600 surface was efficiently dissolved by the successive applications of NP and HYBRID. The total concentration of HYBRID used for the dissolution of simulated oxide layer is below 0.2 wt%. From the test results, we can also infer that HYBRID does not cause any corrosion problem to Alloy 600. The simultaneous destruction of hydrazine and nitrate ion will greatly reduce the generation of the secondary waste. A feasibility study on the reduction of the generation of the secondary waste is performed.

  6. Performance of NiB inhibitor for PbSCC of alloy 600 in Pb-contaminated water and caustic solutions

    Science.gov (United States)

    Kim, Joung Soo; Yi, Yong-Sun; Kwon, Oh Chul; Kim, Mi-Ae; Kim, Hong Pyo

    2008-06-01

    Nickel-based iron-chromium alloys are used as steam generator (SG) tubing materials in nuclear power plants (NPPs) but experience intergranular stress corrosion cracking (IGSCC) and lead stress corrosion cracking (PbSCC) due to the harsh operating conditions of NPPs. In order to improve the integrity of SGs, many studies have sought suitable inhibitors for IGSCC, while those for PbSCC have been sought to a limited extent. In this study, the performance of nickel boride (NiB) as an inhibitor for PbSCC was evaluated. Nickel boride has been shown to be a good inhibitor for IGSCC of Alloy (or Inconel) 600 in a caustic aqueous solution containing no lead (Pb). No significant SCC was observed to occur in Alloy 600 tested in pure water under the slow strain rate test (SSRT) condition in this study. A mixed mode of IGSCC and TGSCC, however, occurred relatively easily in Alloy 600 tested in pure water containing lead oxide (PbO) at 315 °C. The susceptibility of Alloy 600 to SCC decreased with the addition of NiB, implying that NiB can be used as an inhibitor for PbSCC in Pb-contaminated water.

  7. EFFECTS OF LASER SHOCK PEENING ON SCC BEHAVIOR OF ALLOY 600

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    Abhishek Telang; Amrinder Gill; S.R.Mannava; Vijay K. Vasudevan; Dong Qian; Sebastien P. Teysseyre

    2013-08-01

    In this study, the effects of laser shock peening (LSP) on stress corrosion cracking (SCC) behavior of Alloy 600 in tetrathionate solution were investigated. The degree of sensitization was quantified using double loop electrochemical potentiokinetic reactivation (DLEPR) tests. The sensitized Alloy 600 was demonstrated to be susceptible to intergranular SCC in tetrathionate solution. Following LSP, residual stresses and the amount of plastic strain introduced in Alloy 600 were characterized. The effects of LSP on SCC susceptibility of Alloy 600 in tetrathionate solution were evaluated by slow strain rate tests and constant load tests. Results indicate a significant increase in resistance to crack initiation and decreased susceptibility to SCC after LSP.

  8. PWSCC growth assessment model considering stress triaxiality factor for primary alloy 600 components

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    Kim, Jong Sung [Dept. of Nuclear Engineering, Sejong University, Seoul (Korea, Republic of); Kim, Ji Soo; Jeon, Jun Young; Kim, Yun Jae [Dept. of of Mechanical Engineering, Korea University, Seoul (Korea, Republic of)

    2016-08-15

    We propose a primary water stress corrosion cracking (PWSCC) initiation model of Alloy 600 that considers the stress triaxiality factor to apply to finite element analysis. We investigated the correlation between stress triaxiality effects and PWSCC growth behavior in cold-worked Alloy 600 stream generator tubes, and identified an additional stress triaxiality factor that can be added to Garud's PWSCC initiation model. By applying the proposed PWSCC initiation model considering the stress triaxiality factor, PWSCC growth simulations based on the macroscopic phenomenological damage mechanics approach were carried out on the PWSCC growth tests of various cold-worked Alloy 600 steam generator tubes and compact tension specimens. As a result, PWSCC growth behavior results from the finite element prediction are in good agreement with the experimental results.

  9. PWSCC Growth Assessment Model Considering Stress Triaxiality Factor for Primary Alloy 600 Components

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    Jong-Sung Kim

    2016-08-01

    Full Text Available We propose a primary water stress corrosion cracking (PWSCC initiation model of Alloy 600 that considers the stress triaxiality factor to apply to finite element analysis. We investigated the correlation between stress triaxiality effects and PWSCC growth behavior in cold-worked Alloy 600 stream generator tubes, and identified an additional stress triaxiality factor that can be added to Garud's PWSCC initiation model. By applying the proposed PWSCC initiation model considering the stress triaxiality factor, PWSCC growth simulations based on the macroscopic phenomenological damage mechanics approach were carried out on the PWSCC growth tests of various cold-worked Alloy 600 steam generator tubes and compact tension specimens. As a result, PWSCC growth behavior results from the finite element prediction are in good agreement with the experimental results.

  10. Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

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    Berge, Ph. [Electricite de France, 92 - Paris la Defense (France); Noel, D.; Gras, J.M.; Prieux, B. [Electricite de France, 77 - Moret-sur-Loing (France). Direction des Etudes et Recherches

    1997-10-01

    The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author) 21 refs.

  11. Computational simulation of cold work effect on PWSCC growth in Alloy 600TT steam generator

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    Jeon, Jun-Young; Kim, Yun-Jae [Korea University, Seoul (Korea, Republic of); Kim, Jong-Sung [Sunchon National University, Suncheon (Korea, Republic of)

    2016-02-15

    The paper presents verification results for the validity of a numerical method considering the effect of cold work on Primary water stress corrosion cracking (PWSCC) growth rate in the Alloy 600TT steam generator tubes with a part-through single axial PWSCC. PWSCC growth simulations using Finite element (FE) analysis were performed with considering various cold work levels of the material. From the FE analysis results, the cold work effect was investigated from the variations of the PWSCC growth rate vs. Stress intensity factor (SIF) for the various cold work degrees and initial SIF values. Investigated results were compared with experimental test data available. It was identified that the numerical method could adequately assess the cold work effect on PWSCC growth in the Alloy 600TT tubes. In the simulation, it was found that the cold work could strongly influence the PWSCC growth rate even in a low degree of cold work, less than 2%.

  12. Fracture toughness of Alloy 600 and EN82H weld in air and water

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    Mills, W.J.; Brown, C.M.

    1999-06-01

    The fracture toughness of Alloy 600 and its weld, EN82H, was characterized in 54 C to 338 C air and hydrogenated water. Elastic-plastic J{sub IC} testing was performed due to the inherent high toughness of these materials. Alloy 600 exhibited excellent fracture toughness under all test conditions. While EN82H welds displayed excellent toughness in air and high temperature water, a dramatic toughness degradation occurred in water at temperatures below 149 C. Comparison of the cracking response in low temperature water with that for hydrogen-precharged specimens tested in air demonstrated that the loss in toughness is due to a hydrogen-induced intergranular cracking mechanism. At loading rates about approx. 1000 MPa {radical}m/h, the toughness in low temperature water is improved because there is insufficient time for hydrogen to embrittle grain boundaries. Electron fractographic examinations were performed to correlate macroscopic properties with key microstructural features and operative fracture mechanisms.

  13. Accelerated Stress Corrosion Crack Initiation of Alloys 600 and 690 in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Was, Gary S.

    2017-01-01

    The objective of this study is to determine whether stress corrosion crack initiation of Alloys 600 and 690 occurs by the same mechanism in subcritical and supercritical water. Tensile bars of Alloys 690 and 600 were strained in constant extension rate tensile experiments in hydrogenated subcritical and supercritical water from 593 K to 723 K (320 °C to 450 °C), and the crack initiation behavior was characterized by high-resolution electron microscopy. Intergranular cracking was observed across the entire temperature range, and the morphology, structure, composition, and temperature dependence of initiated cracks in Alloy 690 were consistent between hydrogenated subcritical and supercritical water. Crack initiation of Alloy 600 followed an Arrhenius relationship and did not exhibit a discontinuity or change in slope after crossing the critical temperature. The measured activation energy was 121 ± 13 kJ/mol. Stress corrosion crack initiation in Alloy 690 was fit with a single activation energy of 92 ± 12 kJ/mol across the entire temperature range. Cracks were observed to propagate along grain boundaries adjacent to chromium-depleted metal, with Cr2O3 observed ahead of crack tips. All measures of the SCC behavior indicate that the mechanism for stress corrosion crack initiation of Alloy 600 and Alloy 690 is consistent between hydrogenated subcritical and supercritical water.

  14. Accelerated Stress Corrosion Crack Initiation of Alloys 600 and 690 in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Was, Gary S.

    2017-04-01

    The objective of this study is to determine whether stress corrosion crack initiation of Alloys 600 and 690 occurs by the same mechanism in subcritical and supercritical water. Tensile bars of Alloys 690 and 600 were strained in constant extension rate tensile experiments in hydrogenated subcritical and supercritical water from 593 K to 723 K (320 °C to 450 °C), and the crack initiation behavior was characterized by high-resolution electron microscopy. Intergranular cracking was observed across the entire temperature range, and the morphology, structure, composition, and temperature dependence of initiated cracks in Alloy 690 were consistent between hydrogenated subcritical and supercritical water. Crack initiation of Alloy 600 followed an Arrhenius relationship and did not exhibit a discontinuity or change in slope after crossing the critical temperature. The measured activation energy was 121 ± 13 kJ/mol. Stress corrosion crack initiation in Alloy 690 was fit with a single activation energy of 92 ± 12 kJ/mol across the entire temperature range. Cracks were observed to propagate along grain boundaries adjacent to chromium-depleted metal, with Cr2O3 observed ahead of crack tips. All measures of the SCC behavior indicate that the mechanism for stress corrosion crack initiation of Alloy 600 and Alloy 690 is consistent between hydrogenated subcritical and supercritical water.

  15. Accelerated IGA/SCC testing of Alloy 600 in contaminated PWR environments

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    Miglin, B.P.; Sarver, J.M. [Babcock & Wilcox R& D Division, Alliance, OH (United States); Aoki, K. [NFI, Osaka (Japan); Koch, D.W. [Babcock & Wilcox Nuclear Services, Lynchburg, VA (United States); Takamatsu, H. [Kansai Electric, Osaka (Japan)

    1992-12-31

    An accelerated corrosion test (360{degrees}C for 2000 hrs) was performed on C-ring specimens machined from one heat of Alloy 600 tubing in the mill-annealed condition. The specimens were exposed to secondary-side pressurized-water-reactor (PWR) solutions contaminated with lead, sulfur, silicon, and a combination of these contaminants. Where possible, MULTEQ calculations were performed to determine the chemical concentrations so that a constant elevated-temperature pH of 4.5 was achieved. This test was designed to examine the ability of these contaminants to cause intergranular attack and/or stress corrosion in stressed Alloy 600 tubing. The results from this test demonstrated that under the test conditions used, lead-contaminated PWR secondary water induces and propagates intergranular attack (IGA) and stress corrosion cracking (SCC) in Alloy 600. Attack was intergranular; the degree of attack did not vary in the liquid or vapor portions of the test environments. Although attack was more severe at higher stresses, significant attack was observed in samples stressed to the typical operating stress. Solutions of only sulfur and only silicon displayed no initiation or propagation of either IGA or SCC. However, the solution containing all three contaminants caused attack with identical morphology to that observed in the lead-contaminated solution.

  16. Oxidation of Alloy 600 and Alloy 690: Experimentally Accelerated Study in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Cao, Guoping; Was, Gary S.

    2017-02-01

    The objective of this study is to determine whether the oxidation of Alloys 600 and 690 in supercritical water occurs by the same mechanism in subcritical water. Coupons of Alloys 690 and 600 were exposed to hydrogenated subcritical and supercritical water from 633 K to 673 K (360 °C to 400 °C) and the oxidation behavior was observed. By all measures of oxide character and behavior, the oxidation process is the same above and below the supercritical line. Similar oxide morphologies, structures, and chemistries were observed for each alloy across the critical point, indicating that the oxidation mechanism is the same in both subcritical and supercritical water. Oxidation results in a multi-layer oxide structure composed of particles of NiO and NiFe2O4 formed by precipitation on the outer surface and a chromium-rich inner oxide layer formed by diffusion of oxygen to the metal-oxide interface. The inner oxide on Alloy 600 is less chromium rich than that observed on Alloy 690 and is accompanied by preferential oxidation of grain boundaries. The inner oxide on Alloy 690 initially forms by internal oxidation before a protective layer of chromium-rich MO is formed with Cr2O3 at the metal-oxide interface. Grain boundaries in Alloy 690 act as fast diffusion paths for chromium that forms a protective Cr2O3 layer at the surface, preventing grain boundary oxidation from occurring.

  17. Crack growth of throughwall flaw in Alloy 600 tube during leak testing

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    Bahn, Chi Bum, E-mail: bahn@pusan.ac.kr [Pusan National University, 2 Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Majumdar, Saurin [Argonne National Laboratory, Lemont, IL 60439 (United States)

    2015-04-01

    Graphical abstract: - Highlights: • A series of leak testing was conducted at a constant pressure and room temperature. • The time-dependent increase in the leak rate was observed. • The fractography revealed slip offsets and crystallographic facets. • Time-dependent plasticity at the crack tip caused the slip offsets. • Fatigue by jet/structure interaction caused the crystallographic facets. - Abstract: We examined the issue of whether crack growth in a full thickness material can occur in a leaking crack. A series of leak tests was conducted at a room temperature and constant pressure (17.3 MPa) with Alloy 600 tube specimens containing a tight rectangular throughwall axial fatigue crack. To exclude a potential pulsation effect by a high pressure pump, the test water was pressurized by using high pressure nitrogen gas. Fractography showed that crack growth in the full thickness material can occur in the leaking crack by two mechanisms: time-dependent plasticity at the crack tip and fatigue induced by jet/structure interaction. The threshold leak rate at which the jet/structure interaction was triggered was between 1.3 and 3.3 L/min for the specific heat of the Alloy 600 tube tested.

  18. Oxidation of Alloy 600 and Alloy 690: Experimentally Accelerated Study in Hydrogenated Supercritical Water

    Science.gov (United States)

    Moss, Tyler; Cao, Guoping; Was, Gary S.

    2017-04-01

    The objective of this study is to determine whether the oxidation of Alloys 600 and 690 in supercritical water occurs by the same mechanism in subcritical water. Coupons of Alloys 690 and 600 were exposed to hydrogenated subcritical and supercritical water from 633 K to 673 K (360 °C to 400 °C) and the oxidation behavior was observed. By all measures of oxide character and behavior, the oxidation process is the same above and below the supercritical line. Similar oxide morphologies, structures, and chemistries were observed for each alloy across the critical point, indicating that the oxidation mechanism is the same in both subcritical and supercritical water. Oxidation results in a multi-layer oxide structure composed of particles of NiO and NiFe2O4 formed by precipitation on the outer surface and a chromium-rich inner oxide layer formed by diffusion of oxygen to the metal-oxide interface. The inner oxide on Alloy 600 is less chromium rich than that observed on Alloy 690 and is accompanied by preferential oxidation of grain boundaries. The inner oxide on Alloy 690 initially forms by internal oxidation before a protective layer of chromium-rich MO is formed with Cr2O3 at the metal-oxide interface. Grain boundaries in Alloy 690 act as fast diffusion paths for chromium that forms a protective Cr2O3 layer at the surface, preventing grain boundary oxidation from occurring.

  19. Stress corrosion cracking behavior of Alloy 600 in high temperature water

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    Webb, G.L.; Burke, M.G.

    1995-07-01

    SCC susceptibility of Alloy 600 in deaerated water at 360 C (statically loaded U-bend specimens) is dependent on microstructure and whether the material was cold-worked and annealed (CWA) or hot-worked and annealed (HWA). All cracking was intergranular, and materials lacking grain boundary carbides were most susceptible to SCC initiation. CWA tubing materials are more susceptible to SCC initiation than HWA ring-rolled forging materials with similar microstructures (optical metallography). In CWA tubing materials, one crack dominated and grew to a visible size. HWA materials with a low hot-working finishing temperature (<925 C) and final anneals at 1010-1065 C developed both large cracks (similar to those in CWA materials) and small intergranular microcracks detectable only by destructive metallography. HWA materials with a high hot-working finishing temperature (>980 C) and a high-temperature final anneal (>1040 C), with grain boundaries that are fully decorated, developed only microcracks in all specimens. These materials did not develop large, visually detectable cracks, even after more than 300 weeks exposure. A low-temperature thermal treatment (610 C for 7h), which reduces or eliminates SCC in Alloy 600, did not eliminate microcrack formation in high temperature processed HWA materials. Conventional metallographic and analytical electron microscopy (AEM) were done on selected materials to identify the factors responsible for the observed differences in cracking behavior. Major difference between high-temperature HWA and low-temperature HWA and CWA materials was that the high temperature processing and final annealing produced predominantly ``semi-continuous`` dendritic M{sub 7}C{sub 3} carbides along grain boundaries with a minimal amount of intragranular carbides. Lower temperature processing produced intragranular M7C3 carbides, with less intergranular carbides.

  20. Surface Oxidation Phenomena of Ni-Based Alloy 600 in PWR Primary Water Conditions

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    Lim, Yun Soo; Hwang, Seong Sik; Kim, Sung Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    There is, nevertheless, growing evidence in support for the internal oxidation model by Scot, in which grain boundary oxidation is responsible for embrittlement and cracking. Grain boundaries can act as an enhanced diffusion path for oxidation, and grain boundary oxidation can be regarded as a precursor for crack initiation. Oxidation of the grain boundary in almost all nickel-based alloys exposed to primary water is known to be detrimental for grin boundary cohesion. Panter et al. showed that the crack initiation time is strongly reduced when the specimens are pre-exposed in a simulated PWR environment in the absence of applied stress. The changes of the grain boundary structure and chemistry owing to oxygen penetration can increase the sensitivity to PWSCC under a load since grain boundary oxidization significantly weakens the grain boundary strength. Most of the important experimental results obtained are believed to correlate with the oxidation penetration into the material. A spinel structure was detected by XRD in the oxide layers. Several different types of oxide scales were found by SEM examination on the corroded surface of Alloy 600 after an immersion test in the primary water environments. Surface grain boundaries were oxidized by oxygen penetration into the matrix through grain boundaries. Grain boundary oxidization is thought to be the main reason for intergranular cracking in this alloy in a primary water environment of a PWR.

  1. Electrochemical properties and stress corrosion cracking of alloys 600, 690, and 800 in solutions containing boric acid and chloride

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    Bae, J. H.; Won, C. H. [Chungnam Nation Univ., Taejon (Korea, Republic of); Lee, E. H.; Kim, H. P.; Kim, W. C. [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    Electrochemical characteristics and stress corrosion cracking(SCC)of Alloy 600, Alloy 690 and Alloy 800 have been studied in boric acid solution with chloride. Electrochemical characteristics were measured in mixed solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C. SCC resistance was predicted with Parameter(P{sub SCC}) including current density ratio obtained at two different scan rates. P{sub SCC} increased with a following sequence: Alloy 600MA, 600TT, 690TT and Alloy 800. SCC test was carried out with C-ring specimens and reverse U-bend(RUB) specimens at 320 .deg. C and 350 .deg. C. Test solutions were mixture of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C and mixture of 27% H{sub 3}BO{sub 3} and 2g/l Cl{sup -} at 350 .deg. C. C-ring specimens test in the solution of 3% H{sub 3}BO{sub 3} and 0.2g/l Cl{sup -} at 320 .deg. C for 2400hrs did not show SCC. RUB specimen of Alloy600MA and 600TT showed SCC after 1920 hours exposure to the solution of 27% H{sub 3}BO{sub 3} and 0.2g/l Clat 350 .deg. C.

  2. Lead-induced SCC of alloy 600 in plausible steam generator crevice environments

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    Wright, M.D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Manolescu, A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Mirzai, M. [Ontario Hydro, Toronto, Ontario (Canada)

    1998-07-01

    Laboratory stress corrosion cracking (SCC) test environments developed to simulate representative BNGS-A steam generator (SG) crevice chemistries have been used to determine the susceptibility of Alloy 600 to lead-induced SCC under plausible SG conditions. Test environments were based on plant SG hideout return data and analysis of removed tubes and deposits. Deviations from the normal near neutral crevice pH environment were considered to simulate possible faulted excursion crevice chemistry and to bound the postulated crevice pH range of 3-9 (at temperature). The effect of lead contamination up to 1000 ppm, but with an emphasis on the 100 to 500 ppm range, was determined. SCC susceptibility was investigated using constant extension rate tensile (CERT) tests and encapsulated C-ring tests. CERT tests were performed at 305 degrees C on tubing representative of BNGS-A SG U-bends. The C-ring test method allowed a wider test matrix covering three temperatures (280, 304 and 315 degrees C), three strain levels (0.2%, 2% and 4%) and tubing representative of U-bends plus tubing given a simulated stress relief to represent material at the tubesheet. The results of this test program confirmed that in the absence of lead contamination, cracking does not occur in these concentrated, 3.3 to 8.9 pH range, crevice environments. Also, it appears that the concentrated crevice environments suppress lead-induced cracking relative to that seen in all-volatile-treatment (AVT) water. For the (static) C-ring tests, lead-induced SCC was only produced in the near-neutral crevice environment and was more severe at 500 ppm than 100 ppm PbO. This trend was also observed in CERT tests but some cracking/grain boundary attack occurred in acidic (pH 3.3) and alkaline (pH 8.9) environments. The C-ring tests indicated that a certain amount of resistance to cracking was imparted by simulated stress relief of the tubing. This heat treatment, confirmed to have resulted in sensitization, promoted

  3. Lead-induced stress-corrosion cracking of alloy 600 in plausible steam generator crevice environments

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    Wright, M.D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Manolescu, A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Mirzai, M. [Ontario Hydro, Toronto, Ontario (Canada)

    1999-03-01

    Laboratory stress-corrosion cracking (SCC) test environments were developed to simulate crevice chemistries representative of Bruce Nuclear Generating Station A (BNPD A) steam generators (SGs); these test environments were used to determine the susceptibility of Alloy 600 to lead-induced SCC under plausible SG conditions. Test environments were based on plant SG hideout return data and analysis of removed tubes and deposits. Deviations from the normal near-neutral crevice pH environment were considered to simulate possible faulted excursion crevice chemistry and to bound the postulated crevice pH range of 3 to 9 (at temperature). The effect of lead contamination up to 1000 ppm, but with an emphasis on the 100- to 500-ppm range, was determined. SCC susceptibility was investigated using constant extension rate tensile (CERT) tests and encapsulated C-ring tests. CERT tests were performed at 305 degrees C on tubing representative of BNPD A SG U-bends. The C-ring test method allowed a wider test matrix, covering 3 temperatures (280 degrees C, 304 degrees C and 315 degrees C), 3 strain levels (0.2%, 2% and 4%), and tubing representative of U-bends plus tubing given a simulated stress relief to represent material at the tube sheet. The results of this test program confirmed that in the absence of lead contamination, cracking does not occur in these concentrated, 3.3 to 8.9 pH range, crevice environments. Also, it appears that the concentrated crevice environments suppress lead-induced cracking relative to that seen in all-volatile-treatment (AVT) water. For the (static) C-ring tests, lead-induced SCC was only produced in the near-neutral crevice environment and was more severe at 500 ppm than at 100 ppm PbO. This trend was also observed in CERT tests, but some cracking-grain boundary attack occurred in acidic (pH 3.3) and alkaline (pH 8.9) environments. The C-ring tests indicated that a certain amount of resistance to cracking was imparted by simulated stress relief of

  4. Effects of ethanolamine, pH change, and increased hydrazine levels on deposit-covered alloy 600 and brass corrosion

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    Barkatt, A.; Labuda, E.; Wilder, D.M. [Catholic Univ. of America, Washington, DC (United States). Dept. of Chemistry; Smialowska, S.; Rebak, R.B. [Ohio State Univ., Columbus, OH (United States). Fontana Corrosion Center; Cherepakhov, G. [Consolidated Edison Co. of New York, Inc., New York, NY (United States); Burns, R.J. [Consolidated Edison Co. of New York, Inc., Buchanan, NY (United States)

    1997-09-01

    Chemical dissolution tests and electrochemical tests were carried out on alloy 600 (UNS N06600) specimens covered with synthetic deposit simulating the tube deposits in the steam generators at Indian Point 2 Station in Buchanan, New York. The tests showed that the introduction of ethanolamine (ETA) and a moderate increase in pH gave rise to lower corrosion rates, but enhancement of hydrazine levels caused them to rise. In the case of brass, both types of tests showed that raising the pH caused the corrosion rates to increase, but the introduction of ETA led to a mild decrease in these rates.

  5. Microfissuring of Inconel 718

    Science.gov (United States)

    Nunes, A. C., Jr.

    1983-01-01

    A tentative mathematical computer model of the microfissuring process during electron beam welding of Inconel 718 has been constructed. Predictions of the model are compatible with microfissuring tests on eight 0.25-in. thick test plates. The model takes into account weld power and speed, weld loss (efficiency), parameters and material characteristics. Besides the usual material characteristics (thermal and strength properties), a temperature and grain size dependent critical fracture strain is required by the model. The model is based upon fundamental physical theory (i.e., it is not a mere data interpolation system), and can be extended to other metals by suitable parameter changes.

  6. Effect of water chemistry on environmentally assisted cracking of alloy 600 in simulated primary side PWR environments

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, M. [Studsvik Nuvlear (Sweden); Lidar, P. [GSE Power Systems (Sweden); Engstroem, J. [Ringhals NPP (Sweden); Gott, K. [SKI Sweden (Sweden)

    2002-07-01

    Environmental aspects of crack growth due to intergranular stress corrosion cracking (IGSCC) of Alloy 600 in simulated primary side PWR environments have been studied. The purpose of the study was to quantify the effects of the water chemistry (Li, B and H{sub 2} concentrations, and the pH-value by adding KOH) on the crack growth rate, da/dt. 12.5 mm thick compact tension (CT) specimens were used for testing at a constant maximum stress intensity factor in the range of 26-32 MPa{open_square}m. The crack growth was continuously monitored using a direct current potential drop system. Intergranular crack growth due to IGSCC was dominant in the specimens, although there were also small fractions of transgranular cracking. Multivariate analysis was used on the results from the present work together with results from previous tests on the same material. Temperature and the stress intensity were also included as factors in the analysis. A partial least squares regression was developed and interaction effects between the factors were found to affect the crack growth rate. The Partial Least Square regression predicts the observed crack growth rates reasonably well. (authors)

  7. Cryogenic fatigue data developed for Inconel 718

    Science.gov (United States)

    Schmidt, E. H.

    1967-01-01

    Data were obtained on the cryogenic fatigue properties of Inconel 718 bar using axial loading and rotating beam fatigue tests. Results also disclosed the fatigue properties of Inconel 718 sheet materials.

  8. PWSCC susceptibility evaluation of mill annealed Alloy 600 SG tubings using mock-up specimens in lithium enhanced 360 C water

    Energy Technology Data Exchange (ETDEWEB)

    Tsuruta, T.; Okamoto, S.; Kitera, T. [Mitsubishi Heavy Industries, Ltd., Takasago (Japan); Takamatsu, H.; Matsunaga, T. [Kansai Electric Power Co., Inc., Osaka (Japan)

    1995-12-31

    Intergranular stress corrosion cracking (IGSCC) behavior of Alloy 600 steam generator (SG) tubing in pressurized water reactor (PWR) primary water environments, or so called PWSCC, has been investigated since the first report by Coriou in 1959. The acceleration of PWSCC by elevating the test temperature up to 365 C, was first reported in 1980 by Bulischeck et al.. Since then, many results of PWSCC phenomena have been reported. It is important for preventive maintenance planning, to predict the life expectation at the operating temperature for a specific structural design. PWSCC susceptibility of mill annealed alloy 600 (MA 600) SG tubing was investigated using mock-up specimens, such as tube sheet expansion specimens and dent shape deformed specimens in lithium enhanced 360 C water (500ppm as B, 20ppm as Li, 45ccH{sub 2}/kgH{sub 2}O). Uniaxial constant load (UCL) tests were carried out for MA 600, thermally treated (TT) Alloy 600, and TT 690 to evaluate the effect of stress, and to evaluate the acceleration factor of the environment compared with the results in normal 360 C reactor coolant system (RCS) water (500ppm as B, 2ppm as Li, 30ccH{sub 2}/kgH{sub 2}O).

  9. The role of Hydrogen and Creep in Intergranular Stress Corrosion Cracking of Alloy 600 and Alloy 690 in PWR Primary Water Environments ? a Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Hua, F H

    2004-07-12

    Intergranular attack (IGA) and intergranular stress corrosion cracking (IGSCC) of Alloy 600 in PWR steam generator environment has been extensively studied for over 30 years without rendering a clear understanding of the essential mechanisms. The lack of understanding of the IGSCC mechanism is due to a complex interaction of numerous variables such as microstructure, thermomechanical processing, strain rate, water chemistry and electrochemical potential. Hydrogen plays an important role in all these variables. The complexity, however, significantly hinders a clearer and more fundamental understanding of the mechanism of hydrogen in enhancing intergranular cracking via whatever mechanism. In this work, an attempt is made to review the role of hydrogen based on the current understanding of grain boundary structure and chemistry and intergranular fracture of nickel alloys, effect of hydrogen on electrochemical behavior of Alloy 600 and Alloy 690 (e.g. the passive film stability, polarization behavior and open-circuit potential) and effect of hydrogen on PWSCC behavior of Alloy 600 and Alloy 690. Mechanistic studies on the PWSCC are briefly reviewed. It is concluded that further studies on the role of hydrogen on intergranular cracking in both inert and primary side environments are needed. These studies should focus on the correlation of the results obtained at different laboratories by different methods on materials with different metallurgical and chemical parameters.

  10. The role of time-dependent deformation in intergranular crack initiation of alloy 600 steam generator tubing material

    Energy Technology Data Exchange (ETDEWEB)

    Was, G.S.; Lian, K.

    1998-03-01

    Intergranular stress corrosion cracking (IGSCC) of two commercial alloy 600 conditions (600LT, 600HT) and controlled- purity Ni-18Cr-9Fe alloys (CDMA, CDTT) were investigated using constant extension rate tensile (CERT) tests in primary water (0.01M LiOH+0.01M H{sub 3}BO{sub 3}) with 1 bar hydrogen overpressure at 360{degrees}C and 320{degrees}C. Heat treatments produced two types of microstructures in both commercial and controlled-purity alloys: one dominated by grain boundary carbides (600HT and CDTT) and one dominated by intragranular carbides (600LT and CDMA). CERT tests were conducted over a range of strain rates and at two temperatures with interruptions at specific strains to determine the crack depth distributions. Results show that in all samples, IGSCC was the dominant failure mode. For both the commercial alloy and the controlled-purity alloys, the microstructure with grain boundary carbides showed delayed crack initiation and shallower crack depths than did the intragranular carbide microstructure under all experimental conditions. This data indicates that a grain boundary carbide microstructure is more resistant to IGSCC than an intragranular carbide microstructure. Observations support both the film rupture/slip dissolution mechanism and enhanced localized plasticity. The advantage of these results over previous studies is that the different carbide distributions were obtained in the same commercial alloy using different heat treatments, and in the other case, in nearly identical controlled-purity alloys. Therefore, observations of the effects of carbide distribution on IGSCC can more confidently be attributed to the carbide distribution alone rather than other potentially significant differences in microstructure or composition.

  11. Strength of Rewelded Inconel 718

    Science.gov (United States)

    Bayless, E.; Lovoy, C. V.; Mcllwain, M. C.; Munafo, P.

    1982-01-01

    Inconel 718, nickel-based alloy used extensively for high-temperature structural service, welded repeatedly without detriment to its strength. According to NASA report, tests show 12 repairs on same weld joint do not adversely affect ultimate tensile strenth, yield strength, fatigue strength, metallurgical grain structures, or ability of weld joint to respond to post weld heat treatments.

  12. Effects of ETA, pH change, and increased hydrazine levels on deposit-covered Alloy 600 and brass corrosion at Indian Point 2

    Energy Technology Data Exchange (ETDEWEB)

    Barkatt, A.; Labuda, E.; Wilder, D.M. [Catholic Univ. of America, Washington, DC (United States); Smialowska, S.; Rebak, R.B. [Ohio State Univ., Columbus, OH (United States). Fontana Corrosion Center; Cherepakhov, G. [Consolidated Edison Co. of New York, Inc., NY (United States); Burns, R.J. [Consolidated Edison Co. of New York, Inc., Buchanan, NY (United States)

    1997-12-01

    Chemical dissolution tests and electrochemical tests were carried out on Alloy 600 specimens covered with synthetic deposit simulating the tube deposits in the steam generators at Indian Point 2. The tests showed that the introduction of ETA and a moderate increase in pH gave rise to lower corrosion rates, but enhancement of hydrazine levels caused them to rise. In the case of brass, both types of tests showed that raising the pH caused the corrosion rates to increase, but the introduction of ETA led to mild decrease in these rates.

  13. Hydrogen diffusion and distribution in alloy 600 and related effects on the plasticity; Diffusion et distribution de l`hydrogene dans l`alliage 600, effet sur la plasticite

    Energy Technology Data Exchange (ETDEWEB)

    Lecoester, F.; Brass, A.M.; Chene, J. [Laboratoire de metalurgie structurale, URA CNRS No. 1107, Bat. 413, Universit Paris-Sud, 91405 Orsay (France); Noel, D. [Electricite de France (EDF), 77 - Ecuelles (France)

    1997-12-31

    Hydrogen can play a part in several mechanisms proposed for explaining the stress corrosion cracking of nickel based alloy 600, used in steam generators of pressurized water nuclear reactors. This study presents data on diffusion and hydrogen trapping in alloy 600 as well as the embrittlement which results from it. Distribution data were obtained by deuterium analysis of samples cathodically charged with heavy water. Secondary ion mass spectrometry, liquid scintillation counting and tritium autoradiography have been used for analysis. Data on hydrogen embrittlement were obtained by imposed tensile tests on samples with or without cathodic charging. Different microstructures were studied. The results show that alloy 600 embrittlement greatly depend on the structure and increases with the degree of intergranular precipitation. An effect of hydrogen on the plasticity of the alloy was noted. (author). 9 refs.

  14. Stress corrosion mechanisms of alloy-600 polycrystals and monocrystals in primary water: effect of hydrogen; Mecanismes de corrosion sous contrainte de l'alliage 600 polycristallin et monocristallin en milieu primaire: role de l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Foct, F

    1999-01-08

    The aim of this study is to identify the mechanisms involved in Alloy 600 primary water stress corrosion cracking. Therefore, this work is mainly focussed on the two following points. The first one is to understand the influence of hydrogen on SCC of industrial Alloy 600 and the second one is to study the crack initiation and propagation on polycrystals and single crystals. A cathodic potential applied during slow strain rate tests does not affect crack initiation but increases the slow crack growth rate by a factor 2 to 5. Cathodic polarisation, cold work and 25 cm{sup 3} STP/kg hydrogen content increase the slow CGR so that the K{sub ISCC} (and therefore fast CGR) is reached. The influence of hydrogenated primary water has been studied for the first time on Alloy 600 single crystals. Cracks cannot initiate on tensile specimens but they can propagate on pre-cracked specimens. Transgranular cracks present a precise crystallographic aspect which is similar to that of 316 alloy in MgCl{sub 2} solutions. Moreover, the following results improve the description of the cracking conditions. Firstly, the higher the hydrogen partial pressure, the lower the Alloy 600 passivation current transients. Since this result is not correlated with the effect of hydrogen on SCC, cracking is not caused by a direct effect of dissolved hydrogen on dissolution. Secondly, hydrogen embrittlement of Alloy 600 disappears at temperatures above 200 deg.C. Thirdly, grain boundary sliding (GBS) does not directly act on SCC but shows the mechanical weakness of grain boundaries. Regarding the proposed models for Alloy 600 SCC, it is possible to draw the following conclusions. Internal oxidation or absorbed hydrogen effects are the most probable mechanisms for initiation. Dissolution, internal oxidation and global hydrogen embrittlement models cannot explain crack propagation. On the other hand, the Corrosion Enhanced Plasticity Model gives a good description of the SCC propagation. (author)

  15. Beryllium coating on Inconel tiles

    Energy Technology Data Exchange (ETDEWEB)

    Bailescu, V.; Burcea, G.; Lungu, C.P.; Mustata, I.; Lungu, A.M. [Association EURATOM-MEC Romania, National Institute of Laser, Plasma and Radiation Physics, Bucharest (Romania); Rubel, M. [Alfven Laboratory, Royal Institute of Technology, Stockholm (Sweden); Coad, J.P. [Culham Science Centre, EURATOM-UKAEA Fusion Association, Abingdon, OX, Oxon (United Kingdom); Matthews, G.; Pedrick, L.; Handley, R. [UKAEA Fusion, Association Euratom-UKAEA, Culham Science and Engineering Centre, OX 3DB ABINGDON, Oxon (United Kingdom)

    2007-07-01

    Full text of publication follows: The Joint European Torus (JET) is a large experimental nuclear fusion device. Its aim is to confine and study the behaviour of plasma in conditions and dimensions approaching those required for a fusion reactor. The plasma is created in the toroidal shaped vacuum vessel of the machine in which it is confined by magnetic fields. In preparation for ITER a new ITER-like Wall (ILW) will be installed on Joint European Torus (JET), a wall not having any carbon facing the plasma [1]. In places Inconel tiles are to be installed, these tiles shall be coated with Beryllium. MEdC represented by the National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest and in direct cooperation with Nuclear Fuel Plant Pitesti started to coat Inconel tiles with 8 {mu}m of Beryllium in accordance with the requirements of technical specification and fit for installation in the JET machine. This contribution provides an overview of the principles of manufacturing processes using thermal evaporation method in vacuum and the properties of the prepared coatings. The optimization of the manufacturing process (layer thickness, structure and purity) has been carried out on Inconel substrates (polished and sand blasted) The results of the optimization process and analysis (SEM, TEM, XRD, Auger, RBS, AFM) of the coatings will be presented. Reference [1] Takeshi Hirai, H. Maier, M. Rubel, Ph. Mertens, R. Neu, O. Neubauer, E. Gauthier, J. Likonen, C. Lungu, G. Maddaluno, G. F. Matthews, R. Mitteau, G. Piazza, V. Philipps, B. Riccardi, C. Ruset, I. Uytdenhouwen, R and D on full tungsten divertor and beryllium wall for JET TIER-like Wall Project, 24. Symposium on Fusion Technology - 11-15 September 2006 -Warsaw, Poland. (authors)

  16. An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments. Technical Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Lumsden, Jesse

    1999-01-01

    OAK-B135 An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments. Technical Progress Report. This program focuses on understanding the mechanisms causing corrosion damage to steam generator tubes in a pressurized water reactor (PWR) and the effects of the proposed remedial measures. The crevice formed by the tube/tube support plate (T/TSP) intersection in a PWR steam generator is a concentration site for nonvolatile impurities (referred to as hideout) in the steam generator water. The restricted mass transport in the small crevice volume prevents the species, which concentrate during the generation of steam, from quickly dispersing into the bulk water. The concentrated solutions in crevices have been a contributing cause of several forms of corrosion of steam generator tubes including intergranular attack/stress corrosion cracking (IGA/SCC), pitting, and wastage.

  17. Crack growth rates and metallographic examinations of Alloy 600 and Alloy 82/182 from field components and laboratory materials tested in PWR environments.

    Energy Technology Data Exchange (ETDEWEB)

    Alexandreanu, B.; Chopra, O. K.; Shack, W. J.

    2008-05-05

    In light water reactors, components made of nickel-base alloys are susceptible to environmentally assisted cracking. This report summarizes the crack growth rate results and related metallography for field and laboratory-procured Alloy 600 and its weld alloys tested in pressurized water reactor (PWR) environments. The report also presents crack growth rate (CGR) results for a shielded-metal-arc weld of Alloy 182 in a simulated PWR environment as a function of temperature between 290 C and 350 C. These data were used to determine the activation energy for crack growth in Alloy 182 welds. The tests were performed by measuring the changes in the stress corrosion CGR as the temperatures were varied during the test. The difference in electrochemical potential between the specimen and the Ni/NiO line was maintained constant at each temperature by adjusting the hydrogen overpressure on the water supply tank. The CGR data as a function of temperature yielded activation energies of 252 kJ/mol for a double-J weld and 189 kJ/mol for a deep-groove weld. These values are in good agreement with the data reported in the literature. The data reported here and those in the literature suggest that the average activation energy for Alloy 182 welds is on the order of 220-230 kJ/mol, higher than the 130 kJ/mol commonly used for Alloy 600. The consequences of using a larger value of activation energy for SCC CGR data analysis are discussed.

  18. Machinability studies on INCONEL 718

    Science.gov (United States)

    Xavior, M. Anthony; Patil, Mahesh; Maiti, Abheek; Raj, Mrinal; Lohia, Nitesh

    2016-09-01

    The main objective of proposed work is to determine the influence of controllable parameters on machining characteristics of Inconel-718 and to achieve the optimum parameters for sustainable and efficient turning. Understanding the consequences of advanced tool materials together with higher cutting speeds on the formation of residual stresses and therefore the underlying mechanisms of small structural alteration within the subterranean layer thereby becomes terribly crucial for predicting product quality and more optimizing the machining conditions. Controllable cutting parameters such as cutting velocity, feed rate and depth of cut were selected at different level for experimentations in accordance with the Taguchi L9 array method using Minimum Quantity Lubrication (MQL) cutting condition and three different tools namely PVD TiAlN carbide, Cubic boron nitride and ceramic. Extensive study is done on the resulting surface roughness, surface subsurface hardness, tool wear and chip morphology. The results obtained from each of the tool were thoroughly analyzed and finally the optimized parameters are obtained for efficient machining of Inconel 718.

  19. Materials data handbook, Inconel alloy 718

    Science.gov (United States)

    Sessler, J.; Weiss, V.

    1967-01-01

    Materials data handbook on Inconel alloy 718 includes data on the properties of the alloy at cryogenic, ambient, and elevated temperatures and other pertinent engineering information required for the design and fabrication of components and equipment utilizing this alloy.

  20. Total hemispherical emissivity of Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Benjamin P.; Nelson, Shawn E.; Walton, Kyle L.; Ghosh, Tushar K.; Tompson, Robert V.; Loyalka, Sudarshan K., E-mail: LoyalkaS@missouri.edu

    2015-06-15

    Highlights: • We have measured the total hemispherical emissivity for Inconel 718 from about 600–1250 K. • Oxidation in air at 1073 K resulted in an increase in emissivity. • Sandblasting of Inconel 718 was also observed to increase the emissivity. • Coating of graphite powder onto the ‘as-received’ Inconel 718 showed no increase in the emissivity. • Coating of graphite powder onto the 220 grit sandblasted Inconel 718 did show an increase in emissivity. - Abstract: Total hemispherical emissivity for Inconel 718 was measured in anticipation of its application in Very High Temperature Gas Reactors (VHTRs). A majority of current emissivity data for Inconel 718 is in the form of spectral measurements. The data presented here were obtained with an experimental apparatus based on the standard ASTM C835-06 for total hemispherical emittance. Measurements of Inconel 718 were made for four different surface types including: (i) ‘as-received’ from the manufacturer, (ii) oxidized in air and humidified helium, (iii) sandblasted with aluminum oxide powder, and (iv) with a thin coating of nuclear grade graphite powder (grade NGB-18). The emissivity for the ‘as-received’ sample ranged from 0.21 to 0.28 in the temperature interval from 760 K to 1275 K. Oxidation in air at 1073 K resulted in an increase in emissivity into the range from 0.2 at 650 K to 0.52 at 1200 K. There was no dependence on the oxidation times studied here. Oxidation with humidified helium at 1073 K produced less of an increase in emissivity than the oxidation in air but there was an increase up to the range from 0.2 at 600 K to 0.35 at 1200 K. Sandblasting of Inconel 718 was also observed to increase the emissivity up to the range from 0.43 at 780 K to 0.53 at 1270 K when 60 grit sized powder was used and up to the range from 0.45 at 683 K to 0.57 at 1267 K when 120 and 220 grit sized powders were used. Coating of graphite powder onto the ‘as-received’ Inconel 718 showed no increase

  1. Microstructure and mechanical property change of dissimilar metal welds Alloy 600 - Alloy 182 - A508 Gr. 3 according to thermal aging effect at 400 .deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Ham, Jun Hyuk; Choi, Kyoung Joon; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-10-15

    To prevent such critical matters above mentioned, investigation about degradation mechanism of materials by thermal aging should be conducted. However, there are no sufficient studies on this field. Therefore, the final goal of this study is to investigate microstructure along the DMW undergone thermal aging process. Firstly, in order to get a reference data for further comparison analysis which is expected to show degradation mechanism of the weld joint, un-heated weld joint was investigated with several instruments, Vickers hardness tester, scanning electron microscope (SEM), and an energy-dispersive X-ray spectrometer (EDS). Detail instrumental analysis in Alloy 600 - Alloy 182 - A508 Gr. 3 DMW joint were performed in order to investigate microstructure and mechanical properties of material. Following conclusions can be drawn from this study. Alloy 182 has austenitic dendrite structure which is formed by heat flow during welding process. Type-II boundaries were observed at the interface between Alloy 182 and A508 Gr. 3. Chemical composition shows rapid transition at the interface which makes 3000 µm of chromium dilution zone. Microstructure of A508 Gr. 3 was investigated from the interface between Alloy 182 to base metal.

  2. Fatigue strain-life behavior of carbon and low-alloy steels, austenitic stainless steels, and Alloy 600 in LWR environments

    Energy Technology Data Exchange (ETDEWEB)

    Keisler, J.; Chopra, O.K.; Shack, W.J. [Argonne National Lab., IL (United States)

    1995-08-01

    The existing fatigue strain vs. life (S-N) data, foreign and domestic, for carbon and low-alloy steels, austenitic stainless steels, and Alloy 600 used in the construction of nuclear power plant components have been compiled and categorized according to material, loading, and environmental conditions. Statistical models have been developed for estimating the effects of the various service conditions on the fatigue life of these materials. The results of a rigorous statistical analysis have been used to estimate the probability of initiating a fatigue crack. Data in the literature were reviewed to evaluate the effects of size, geometry, and surface finish of a component on its fatigue life. The fatigue S-N curves for components have been determined by adjusting the probability distribution curves for smooth test specimens for the effect of mean stress and applying design margins to account for the uncertainties due to component size/geometry and surface finish. The significance of the effect of environment on the current Code design curve and on the proposed interim design curves published in NUREG/CR-5999 is discussed. Estimations of the probability of fatigue cracking in sample components from BWRs and PWRs are presented.

  3. A Study on Ultrasonic Elliptical Vibration Cutting of Inconel 718

    OpenAIRE

    Zhao Haidong; Zou Ping; Ma Wenbin; Zhou Zhongming

    2016-01-01

    Inconel 718 is a kind of nickel-based alloys that are widely used in the aerospace and nuclear industry owing to their high temperature mechanical properties. Cutting of Inconel 718 in conventional cutting (CC) is a big challenge in modern industry. Few researches have been studied on cutting of Inconel 718 using single point diamond tool applying the UEVC method. This paper shows an experimental study on UEVC of Inconel 718 by using polycrystalline diamond (PCD) coated tools. Firstly, cuttin...

  4. Detection of Cracks in Aluminum Structure Beneath Inconel Repair Bushings

    Science.gov (United States)

    2008-04-01

    conductivity (i.e. Inconel 718 ) – Primary challenge then becomes detecting the weak eddy current field in the structure beyond the bushing wall...was able to be selected with inspectability as a goal. – Inconel 718 • low permeability (~μ0) • low conductivity (< 2% IACS) • Combined with...Detection of Cracks in Aluminum Structure beneath Inconel Repair Bushings Mr. Kenneth J. LaCivita (USAF) AFRL/RXSA Air Force Research Laboratory

  5. Study of alloy 600`S stress corrosion cracking mechanisms in high temperature water; Etude des mecanismes de corrosion sous contrainte de l`alliage 600 dans l`eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rios, R.

    1994-06-01

    In order to better understand the mechanisms involved in Alloy 600`s stress corrosion cracking in PWR environment, laboratory tests were performed. The influence of parameters pertinent to the mechanisms was studies : hydrogen and oxygen overpressures, local chemical composition, microstructure. The results show that neither hydrogen nor dissolution/oxidation, despite their respective roles in the process, are sufficient to account for experimental facts. SEM observation of micro-cleavage facets on specimens` fracture surfaces leads to pay attention to a new mechanism of corrosion/plasticity interactions. (author). 113 refs., 73 figs., 15 tabs., 4 annexes.

  6. Residual stresses in Inconel 718 engine disks

    Directory of Open Access Journals (Sweden)

    Dahan Yoann

    2014-01-01

    Full Text Available Aubert&Duval has developed a methodology to establish a residual stress model for Inconel 718 engine discs. To validate the thermal, mechanical and metallurgical parts of the model, trials on lab specimens with specific geometry were carried out. These trials allow a better understanding of the residual stress distribution and evolution during different processes (quenching, ageing, machining. A comparison between experimental and numerical results reveals the residual stresses model accuracy. Aubert&Duval has also developed a mechanical properties prediction model. Coupled with the residual stress prediction model, Aubert&Duval can now propose improvements to the process of manufacturing in Inconel 718 engine disks. This model enables Aubert&Duval customers and subcontractors to anticipate distortions issues during machining. It could also be usedt to optimise the engine disk life.

  7. Bending of pipes with inconel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Nachpitz, Leonardo; Menezes, Carlos Eduardo B.; Vieira, Carlos R. Tavares [Primus Processamento de Tubos S.A. (PROTUBO), Macae, RJ (Brazil)

    2009-07-01

    The high-frequency induction bending process, using API pipes coated with Inconel 625 reconciled to a mechanical transformation for a higher degree of resistance, was developed through a careful specification and control of the manufacturing parameters and inherent heat treatments. The effects of this technology were investigated by a qualification process consisting of a sequence of tests and acceptance criteria typically required by the offshore industry, and through the obtained results was proved the effectiveness of this entire manufacturing process, without causing interference in the properties and the quality of the inconel cladding, adding a gain of resistance to the base material, guaranteed by the requirements of the API 5L Standard. (author)

  8. Aspects of precipitation in alloy Inconel 718

    OpenAIRE

    Azadian, Saied

    2004-01-01

    A study was made of the microstructure of the Ni-base alloy Inconel 718 with emphasis on the precipitation and stability of intermetallic phases as affected by heat treatments. In addition the effect of the precipitation on selected mechanical properties namely hardness, creep notch sensitivity and hot ductlity were investigated. The materials studied were a spray-formed version and three wrought versions of the alloy. The spray-formed version of the alloy was of interest since it exhibited a...

  9. Economical Inconel 718%经济型Inconel 718合金

    Institute of Scientific and Technical Information of China (English)

    狄志高; 黄漫

    2012-01-01

    为了降低Inconel 718合金的生产成本,设计了常规方案和经济方案两种试验方案:常规方案用纯金属冶炼718合金,经济方案用铌铁合金替代金属铌、用铬铁合金替代金属铬冶炼718合金.运用两种方案在真空感应炉内分别冶炼了一炉718合金并浇铸成锭,将两支铸锭按照相同的工艺参数进行扩散退火、轧制成材及热处理,随后取样进行力学性能及金相组织分析.试验结果表明,用两种方案冶炼的718合金均能满足国内优质Inconel718合金的技术标准,且用铌铁合金替代金属铌、用铬铁合金替代金属铬冶炼的Inconel 718合金可降低18%的原料成本.%In order to decrease the production costs of Inconel 718 alloy, two kinds of test programs were designed including conventional program and economical program. The conventional program was designed to smelt Inconel 718 alloy with elemental metal. The economical program was designed to smelt Inconel 718 alloy with Nb-Fe and Cr-Fe instead of metal Nb and Cr. Two heats of 718 alloy were smelted separately by two kinds of test programs in vacuum induction furnace, molten alloy were casted to two ingots. Under the same processing parameter, two ingots were carried out diffusion annealing, roll forming and heat treatment. Specimens were taken to analyze the mechanical properties and metallurgical structure. The testing results show Inconel 718 alloy by both kinds of test programs can reach domestic technical standard of superior alloy. Compared with conventional program, economical program of using Nb-Fe and Cr-Fe instead of metal Nb and Cr can decrease 18% costs of the raw material.

  10. Bending of pipes with inconel cladding; Curvamento de tubos revestidos com inconel

    Energy Technology Data Exchange (ETDEWEB)

    Nachpitz, Leonardo; Menezes, Carlos Eduardo B.; Vieira, Carlos R. Tavares [PROTUBO, Macae, RJ (Brazil)

    2008-07-01

    The pipes used in offshore equipment, such as wet Christmas trees, sub sea manifolds and rigid platform risers, as well as some pipes for refineries and ships, must have mechanical resistance to high pressure and also be resistant to corrosion from acids. Some special materials, such as stainless steel, duplex and super duplex steel are used to resolve this problem, but the cost is very high. Besides the problem of cost, these materials have other drawbacks, such as the difficulty of welding them, a technology mastered in few countries. As a better alternative, the use has been increasing of carbon steel and API pipes coated internally with inconel by welding deposition. This groundbreaking technology, of proven efficiency, has a far superior cost-benefit relation. Carbon steel and API pipes, besides having better mechanical resistance to high pressure and corrosion resistance, can be fabricated with technology mastered worldwide. Nickel alloys, such as inconel, are highly resistant to corrosion and temperature, and in these aspects are better than stainless steels. The pipes for transportation equipment and for refining hydrocarbons, as mentioned above, require various turns and special geometries, which generally are solved by the use of bends and spools made by high-frequency induction. This technology, already well established for various carbon and stainless steels, was developed to work with pipes coated internally with inconel (inconel cladding). Therefore, our work describes the process of fabricating bends from API steel pipes with inconel cladding, demonstrating the efficacy of this technology along with its quality gains and cost reduction. (author)

  11. Thermo-Physical Properties of Selected Inconel

    Directory of Open Access Journals (Sweden)

    Krajewski P.K.

    2014-10-01

    Full Text Available The paper brings results of examinations of main thermo-physical properties of selected Inconel alloys, i.e. their heat diffusivity, thermal conductivity and heat capacity, measured in wide temperature range of 20 – 900 oC. Themathematical relationships of the above properties vs. temperature were obtained for the IN 100 and IN 713C alloys. These data can be used when modelling the IN alloys solidification processes aimed at obtaining required structure and properties as well as when designing optimal work temperature parameters.

  12. Influence of gaseous hydrogen on Inconel 718

    Science.gov (United States)

    Walter, R. J.; Chandler, W. T.

    1974-01-01

    The embrittlement of Inconel 718 by exposure to 34.5 MN/sq m hydrogen at ambient temperature was found to be a function of both forming operation and heat treatment. The embrittlement, as measured by reduction of notch strength in hydrogen as compared to helium, was decreased by a fine-grain size and was most severe for coarse-grained structures containing a continuous or nearly continuous precipitate tentatively identified as Ni3Cb. Tests performed on unnotched specimens showed that the strain at which surface cracks initiate in 34.5 MN/sq m hydrogen was approximately 3% and was independent of prior forming operation or heat treatment.

  13. Hot tensile tests of Inconel 718

    Science.gov (United States)

    1980-01-01

    The physical metallurgy of near-solidus integranular cracking in Inconel 718 welds was investigated. The data, although inconclusive, suggest at least two mechanisms which might explain intergranular cracking (microfissuring) in the heat-affected zone of several high temperature alloys. One theory is based on the separation of intergranular liquid while the other involves mechanical failure of solid ligaments surrounded by intergranular liquid. Both mechanisms concentrate strain in the grain boundaries resulting in low strain (1%) intergranular brittleness. The mechanisms reported might also pertain to the physical metallurgy of casting, powder metallurgy sintering and hot isostatic pressing.

  14. Cold Spray Forming of Inconel 718

    Science.gov (United States)

    Wong, W.; Irissou, E.; Vo, P.; Sone, M.; Bernier, F.; Legoux, J.-G.; Fukanuma, H.; Yue, S.

    2013-03-01

    Inconel 718 was cold spray formed to a 6-mm thickness on an 8-cm diameter aluminum alloy tube using Sulzer Amdry 1718 powder and the Plasma Giken PCS-1000 cold spray system. The effects of spray particle velocity and post-spray heat treatment were studied. Post-spray annealing was performed from 950 to 1250 °C for 1-2 h. The resulting microstructures as well as the corresponding mechanical properties were characterized. As-sprayed coatings exhibited very low ductility. The tensile strength and ductility of the heat-treated coatings were improved to varying levels depending on the heat-treatment and spray conditions. For coatings sprayed at higher particle velocity and heat treated at 1250 °C for 1 h, an elongation of 24% was obtained. SEM micrographs showed a higher fraction of interparticle metallurgical bonds due to some sintering effect. Corresponding fracture surfaces also revealed a higher fraction of dimple features, typically associated with ductile fracture, in the annealed coatings. The results demonstrate that cold spray forming of Inconel 718 is feasible, and with appropriate heat treatment, metallurgical bonding can be increased. The ductility of the spray-formed samples was comparable to that of the bulk material.

  15. Supersolidus Liquid Phase Sintering Modeling of Inconel 718 Superalloy

    Science.gov (United States)

    Levasseur, David; Brochu, Mathieu

    2016-02-01

    Powder metallurgy of Inconel 718 superalloy is advantageous as a near-net shape process for complex parts to reduce the buy-to-fly ratio and machining cost. However, sintering Inconel 718 requires the assistance of supersolidus liquid formation to achieve near full density and involves the risk of distortion at high temperatures. The present work is focused on modeling the onset of sintering and distortion as a function of temperature, grain size, and part geometry for Inconel 718. Using experimental sintering results and data available in the literature, the supersolidus liquid phase sintering of Inconel 718 was modeled. The model was used to define a processing window where part distortion would be avoided.

  16. Role of hydrogen in the intergranular cracking mechanism by stress corrosion in primary medium of nickel based alloys 600 and 690; Role de l'hydrogene dans le mecanisme de fissuration intergranulaire par corrosion sous contrainte en milieu primaire des alliages base nickel 600, 690

    Energy Technology Data Exchange (ETDEWEB)

    Odemer, G.; Coudurier, A.; Jambon, F.; Chene, J. [CEA Saclay, Dept. de Physico-Chimie (DEN/DANS/DPC/SCCME/LECA), 91 - Gif sur Yvette (France); Odemer, G.; Coudurier, A.; Chene, J. [Evry Univ., UMR 8587 CNRS / CEA, LAMBE, 91 (France)

    2007-07-01

    The aim of this work is to characterize the sensitivity to hydrogen embrittlement of alloys 600 and 690 in order to better understand the eventual role of hydrogen in the stress corrosion mechanism which affects these alloys when they are exposed in PWR primary medium. (O.M.)

  17. Closed Die Hammer Forging of Inconel 718

    Directory of Open Access Journals (Sweden)

    S. Chenna Krishna

    2014-01-01

    Full Text Available A method for the production of Inconel 718 (IN-718 hemispherical domes by closed die hammer forging is proposed. Different combination of operations employed for production are as follows: (i preforging + final forging + air cooling, (ii preforging + final forging + controlled cooling, (iii direct forging + controlled cooling, and (iv direct forging + air cooling. Last three combinations yielded a crack free hemispherical dome. The forged hemispherical domes were solution annealed at 980°C for 1 h and air cooled. The grain size of the domes at all locations was finer than ASTM No 4. Mechanical properties of the forged dome in solution treated and aged condition (STA were better than feedstock used.

  18. A Study on Ultrasonic Elliptical Vibration Cutting of Inconel 718

    Directory of Open Access Journals (Sweden)

    Zhao Haidong

    2016-01-01

    Full Text Available Inconel 718 is a kind of nickel-based alloys that are widely used in the aerospace and nuclear industry owing to their high temperature mechanical properties. Cutting of Inconel 718 in conventional cutting (CC is a big challenge in modern industry. Few researches have been studied on cutting of Inconel 718 using single point diamond tool applying the UEVC method. This paper shows an experimental study on UEVC of Inconel 718 by using polycrystalline diamond (PCD coated tools. Firstly, cutting tests have been carried out to study the effect of machining parameters in the UEVC in terms of surface finish and flank wear during machining of Inconel 718. The tests have clearly shown that the PCD coated tools in cutting of Inconel 718 by the UEVC have better performance at 0.1 mm depth of cut as compared to the lower 0.05 mm depth of cut and the higher 0.12 or 0.15 mm depth of cut. Secondly, like CC method, the cutting performance in UEVC increases with the decrease of the feed rate and cutting speed. The CC tests have also been carried out to compare performance of CC with UEVC method.

  19. Magnetic susceptibility of Inconel alloys 718, 625, and 600 at cryogenic temperatures

    Science.gov (United States)

    Goldberg, Ira B.; Mitchell, Michael R.; Murphy, Allan R.; Goldfarb, Ronald B.; Loughran, Robert J.

    1990-01-01

    After a hydrogen fuel bleed valve problem on the Discovery Space Shuttle was traced to the strong magnetization of Inconel 718 in the armature of the linear variable differential transformer near liquid hydrogen temperatures, the ac magnetic susceptibility of three samples of Inconel 718 of slightly different compositions, one sample of Inconel 625, and on sample of Inconel 600 were measured as a function of temperature. Inconel 718 alloys are found to exhibit a spin glass state below 16 K. Inconel 600 exhibits three different magnetic phases, the lowest-temperature state (below 6 K) being somewhat similar to that of Inconel 718. The magnetic states of the Inconel alloys and their magnetic susceptibilities appear to be strongly dependent on the exact composition of the alloy.

  20. Hardness and electrochemical behavior of ceramic coatings on Inconel

    Directory of Open Access Journals (Sweden)

    C. SUJAYA

    2012-03-01

    Full Text Available Thin films of ceramic materials like alumina and silicon carbide are deposited on Inconel substrate by pulsed laser deposition technique using Q-switched Nd: YAG laser. Deposited films are characterized using UV-visible spectrophotometry and X-ray diffraction. Composite microhardness of ceramic coated Inconel system is measured using Knoop indenter and its film hardness is separated using a mathematical model based on area-law of mixture. It is then compared with values obtained using nanoindentation method. Film hardness of the ceramic coating is found to be high compared to the substrates. Corrosion behavior of substrates after ceramic coating is studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The Nyquist and the Bode plots obtained from the EIS data are fitted by appropriate equivalent circuits. The pore resistance, the charge transfer resistance, the coating capacitance and the double layer capacitance of the coatings are obtained from the equivalent circuit. Experimental results show an increase in corrosion resistance of Inconel after ceramic coating. Alumina coated Inconel showed higher corrosion resistance than silicon carbide coated Inconel. After the corrosion testing, the surface topography of the uncoated and the coated systems are examined by scanning electron microscopy.

  1. Brazing Inconel 625 Using the Copper Foil

    Science.gov (United States)

    Chen, Wen-Shiang; Wang, Cheng-Yen; Shiue, Ren-Kae

    2013-12-01

    Brazing Inconel 625 (IN-625) using the copper foil has been investigated in this research. The brazed joint is composed of nanosized CrNi3 precipitates and Cr/Mo/Nb/Ni quaternary compound in the Cu/Ni-rich matrix. The copper filler 50 μm in thickness is enough for the joint filling. However, the application of Cu foil 100 μm in thickness has little effect on the shear strength of the brazed joint. The specimen brazed at 1433 K (1160 °C) for 1800 seconds demonstrates the best shear strength of 470 MPa, and its fractograph is dominated by ductile dimple fracture with sliding marks. Decreasing the brazing temperature slightly decreases the shear strength of the brazed joint due to the presence of a few isolated solidification shrinkage voids smaller than 15 μm. Increasing the brazing temperature, especially for the specimen brazed at 1473 K (1200 °C), significantly deteriorates the shear strength of the joint below 260 MPa because of coalescence of isothermal solidification shrinkage voids in the joint. The Cu foil demonstrates potential in brazing IN-625 for industrial application.

  2. Ion-irradiation-induced hardening in Inconel 718

    Science.gov (United States)

    Hunn, J. D.; Lee, E. H.; Byun, T. S.; Mansur, L. K.

    2001-07-01

    Inconel 718 is a material under consideration for areas in the target region of the spallation neutron source (SNS), now under construction at Oak Ridge National Laboratory (ORNL) in the US. In these positions, displacement damage from protons and neutrons will affect the mechanical properties. In addition, significant amounts of helium and hydrogen will build up in the material due to transmutation reactions. Nanoindentation measurements of solution-annealed (SA) Inconel 718 specimens, implanted with Fe-, He-, and H-ions to simulate SNS target radiation conditions, have shown that hardening occurs due to ion-induced displacement damage as well as due to the build-up of helium bubbles in the irradiated layer. Precipitation-hardened (PH) Inconel 718 also exhibited hardening by helium build-up but showed softening as a function of displacement damage due to dissolution of the γ ' and γ″ precipitates.

  3. Work Hardening Behavior of Inconel 718%Inconel 718合金的加工硬化行为

    Institute of Scientific and Technical Information of China (English)

    边舫; 苏国跃; 孔凡亚; 杨柯

    2005-01-01

    采用准静态拉伸试验方法研究Inconel 718合金的加工硬化特性.结果表明,Inconel 718合金加工硬化规律基本遵循Hollomon公式.合金在退火态和冷拔态的应变硬化指数n分别为0.476和0.153,拟合方程式的相关系数分别为0.89和0.99.室温条件下,Inconel 718合金塑性变形阶段的真应力-真应变关系可用Voce型公式描述,拟合方程式的相关系数大于0.99.

  4. Development and validation of an experimental procedure for studying the biaxial stress corrosion. Application to the systems: alloy-600/air and 316L/MgCl{sub 2}; Developpement et validation d'une procedure experimentale pour l'etude de la corrosion sous contrainte biaxiale. Application aux couples alliage 600 / air et 316L / MgCl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Farre, M.Th

    1998-07-15

    One of the main preoccupation for maintaining EdF's nuclear pressurised water reactors is intergranular stress corrosion cracking of steam generator tubing (alloy 600: NC 15Fe). The most affected areas (first row U-bend and roll transition zone) are in biaxial stress state. The crack propagation is often axial and sometimes circumferential. The actual life prediction criterion for these structures depends on the maximal principal stress. The purpose of this study is to determine whether it is safe to use such a criterion in a case of biaxial stress state. A procedure is proposed and experimentally validated for designing specimen in a controlled biaxial stress state when submitted to traction. Quadrants I an IV of the stress space are the only ones explored. The aim is to use these specimens in order to realize stress corrosion tests in primary water with alloy 600. The procedure involves studying the biaxial behavior of the material. This shows the effect of hardening on the shape of the yield stress surface. The hardening of alloy 600 is mainly kinematic. The yield stress surface becomes concave in the hardening stress direction and flat in the opposite direction. The geometry of the specimen stems from parameterized shape optimisation. An elasto-viscoplastic behavior law is identified for alloy 600. Use of the law for calculating the strain state of one specimen is experimentally validated. This entire procedure has been successfully validated with biaxial stress corrosion cracking tests, using 316L and MgCl{sub 2} boiling at 154 deg C. In this case it is difficult to determine a life time criterion. It is shown that the criterion of the maximal principal stress is invalid in case of a biaxial stress state. (author)

  5. Weld microfissuring in Inconel 718 minimized by minor elements

    Science.gov (United States)

    Morrison, T. J.; Shira, C. S.; Weisenberg, L. A.

    1968-01-01

    Manganese, silicon, and magnesium markedly reduce the tendency of Inconel 718 to weld microfissuring. By combining a manganese, 0.20 percent by content, with silicon, greater than 0.25 percent content, or by adding 20 ppm of magnesium, the weld microfissuring decreased in the standard alloy.

  6. Tensile and fatigue properties of Inconel 718 at cryogenic temperatures

    Science.gov (United States)

    Malin, C. O.; Schmidt, E. H.

    1969-01-01

    Tests to determine the tensile and fatigue properties of Inconel 718 at cryogenic temperatures show that the alloy increases in strength at low temperatures, with very little change in toughness. The effect of surface finish and grain size on the fatigue properties was also determined.

  7. Stainless steel 301 and Inconel 718 hydrogen embrittlement

    Science.gov (United States)

    Allgeier, R. K.; Forman, R.

    1970-01-01

    Conditions and results of tensile tests of 26 Inconel 718 and four cryoformed stainless steel specimens are presented. Conclusions determine maximum safe hydrogen operating pressure for cryogenic pressure vessels and provide definitive information concerning flaw growth characteristics under the most severe temperature and pressure conditions

  8. Inconel 600及Inconel 718合金晶界偏聚研究进展%Research Progress in Grain Boundary Segregation of Solute Atoms in Inconel 600 and Inconel 718 Superalloys

    Institute of Scientific and Technical Information of China (English)

    郑磊; 董建新; 张麦仓; 孟烨

    2009-01-01

    高温合金中的溶质晶界偏聚是影响合金多方面性能的重要因素.以高温合金Inconel 600和Inconel718为研究对象,总结了合金中溶质晶界偏聚的研究现状,并对已有的研究成果进行了深入分析,结果发现:溶质在Inconel 600合金中的偏聚规律对舍金性能的影响还需要进一步研究晶界偏聚特性、基本物理参量以及晶间腐蚀抗力的作用;溶质在Inconel 718合金中的晶界偏聚对合金性能的影响依然有待于进一步研究其作用机理、偏聚动力学和共偏聚特性.同时,指出今后高温合金中溶质晶界偏聚的研究方向为溶质晶界偏聚动力学以及溶质问晶界共偏聚行为.

  9. Microstructure And Weld Cracking In Inconel 718(R)

    Science.gov (United States)

    Thompson, R. G.

    1988-01-01

    Theories on relationship between metallurgy and microfissuring confirmed. Report describes research on effects of microstructure on cracking of heat-affected zones of welds in Inconel 718(R) alloy. In experimental studies, specimens subjected to various combinations of time-varying thermal and mechanical stresses to simulate welding conditions and to identify physical and chemical effects causing microfissuring.

  10. Solidification paths in modified Inconel 625 weld overlay material

    DEFF Research Database (Denmark)

    Chandrasekaran, Karthik; Tiedje, Niels Skat; Hald, John

    2009-01-01

    Inconel 625 is commonly used for overlay welding to protect the base metal against high temperature corrosion. The efficiency of corrosion protection depends on effective mixing of the overlay weld with the base metal and the subsequent segregation of alloy elements during solidification...

  11. Further Study of near Solidus Intergranular Cracking in Inconel 718

    Science.gov (United States)

    Thompson, R. G.

    1981-01-01

    A series of tests, performed to determine the strain necessary to initiate intergranular cracking in Inconel 718 as a function of temperature, contained enough scatter near the melting temperature that questions remained as to the best curve of curves to fit to the data. Fracture surface analysis showed that the scatter was due to incipient melting in the grain boundary region. The melting contributed to low fracture strain but had only a small on the incipient cracking strain. Gleeble tests, which could be interrupted by water quenching, were used to study the incipient intergranular melting of Inconel 718. This modified weld simulation test provided a sufficiently rapid quench to preserve the intergranular microstructure created during incipient melting. This structure was studied both microscopically and with energy dispensive X-ray analysis. The implications of incipient melting and low-strain incipient cracking on the development of microfissuring envelopes are discussed.

  12. Corrosion fatigue of Inconel 718 and Incoloy 903

    Science.gov (United States)

    Franklin, D. B.; Nelson, E. E.

    1981-01-01

    Corrosion fatigue tests were conducted on Inconel 718 and Incoloy 903 in distilled water, 500 ppm NaCl, and 3.5% NaCl. Results were compared to the endurance limit in air. For Inconel 718, the corrosion fatigue strength (CFS) IN 3.5% NaCl WAS 328 MPa or 75 percent of the endurance limit. For Incoloy 903, the CFS ranged from 234 MPa in distilled water (68 percent of the endurance limit) to 103 MPa in 3.5% NaCl (30 percent of the endurance limit). Results indicate that, for components which have limited fatigue life, an evaluation of the combined effects of fatigue and the corrosive atmosphere must be considered in projecting useful lifetimes.

  13. Investigation on Surface Roughness of Inconel 718 in Photochemical Machining

    Directory of Open Access Journals (Sweden)

    Nitin D. Misal

    2017-01-01

    Full Text Available The present work is focused on estimating the optimal machining parameters required for photochemical machining (PCM of an Inconel 718 and effects of these parameters on surface topology. An experimental analysis was carried out to identify optimal values of parameters using ferric chloride (FeCl3 as an etchant. The parameters considered in this analysis are concentration of etchant, etching time, and etchant temperature. The experimental analysis shows that etching performance as well as surface topology improved by appropriate selection of etching process parameters. Temperature of the etchant found to be dominant parameter in the PCM of Inconel 718 for surface roughness. At optimal etching conditions, surface roughness was found to be 0.201 μm.

  14. Effect of pulse duty cycle on Inconel 718 laser welds

    Science.gov (United States)

    McCay, M. H.; McCay, T. D.; Dahotre, N. B.; Sharp, C. M.; Sedghinasab, A.; Gopinathan, S.

    1989-01-01

    Crack sensitive Inconel 718 was laser pulse welded using a 3.0 kW CO2 laser. Weld shape, structure, and porosity were recorded as a function of the pulse duty cycle. Within the matrix studied, the welds were found to be optimized at a high (17 ms on, 7 ms off) duty cycle. These welds were superior in appearance and lack of porosity to both low duty cycle and CW welds.

  15. Tritium Permeability of Incoloy 800H and Inconel 617

    Energy Technology Data Exchange (ETDEWEB)

    Philip Winston; Pattrick Calderoni; Paul Humrickhouse

    2012-07-01

    Design of the Next Generation Nuclear Plant (NGNP) reactor and its high-temperature components requires information regarding the permeation of fission generated tritium and hydrogen product through candidate heat exchanger alloys. Release of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system represent safety basis and product contamination issues. Of the three potential candidates for high-temperature components of the NGNP reactor design, only permeability for Incoloy 800H has been well documented. Hydrogen permeability data have been published for Inconel 617, but only in two literature reports and for partial pressures of hydrogen greater than one atmosphere, far higher than anticipated in the NGNP reactor. To support engineering design of the NGNP reactor components, the tritium permeability of Inconel 617 and Incoloy 800H was determined using a measurement system designed and fabricated at Idaho National Laboratory. The tritium permeability of Incoloy 800H and Inconel 617, was measured in the temperature range 650 to 950°C and at primary concentrations of 1.5 to 6 parts per million volume tritium in helium. (partial pressures of 10-6 atm)—three orders of magnitude lower partial pressures than used in the hydrogen permeation testing. The measured tritium permeability of Incoloy 800H and Inconel 617 deviated substantially from the values measured for hydrogen. This may be due to instrument offset, system absorption, presence of competing quantities of hydrogen, surface oxides, or other phenomena. Due to the challenge of determining the chemical composition of a mixture with such a low hydrogen isotope concentration, no categorical explanation of this offset has been developed.

  16. Tritium Permeability of Incoloy 800H and Inconel 617

    Energy Technology Data Exchange (ETDEWEB)

    Philip Winston; Pattrick Calderoni; Paul Humrickhouse

    2011-09-01

    Design of the Next Generation Nuclear Plant (NGNP) reactor and its high-temperature components requires information regarding the permeation of fission generated tritium and hydrogen product through candidate heat exchanger alloys. Release of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system represent safety basis and product contamination issues. Of the three potential candidates for high-temperature components of the NGNP reactor design, only permeability for Incoloy 800H has been well documented. Hydrogen permeability data have been published for Inconel 617, but only in two literature reports and for partial pressures of hydrogen greater than one atmosphere, far higher than anticipated in the NGNP reactor. To support engineering design of the NGNP reactor components, the tritium permeability of Inconel 617 and Incoloy 800H was determined using a measurement system designed and fabricated at Idaho National Laboratory. The tritium permeability of Incoloy 800H and Inconel 617, was measured in the temperature range 650 to 950 C and at primary concentrations of 1.5 to 6 parts per million volume tritium in helium. (partial pressures of 10-6 atm) - three orders of magnitude lower partial pressures than used in the hydrogen permeation testing. The measured tritium permeability of Incoloy 800H and Inconel 617 deviated substantially from the values measured for hydrogen. This may be due to instrument offset, system absorption, presence of competing quantities of hydrogen, surface oxides, or other phenomena. Due to the challenge of determining the chemical composition of a mixture with such a low hydrogen isotope concentration, no categorical explanation of this offset has been developed.

  17. Modeling the viscoplastic behavior of Inconel 718 at 1200 F

    Science.gov (United States)

    Abdel-Kader, M. S.; Eftis, J.; Jones, D. L.

    1988-01-01

    A large number of tests, including tensile, creep, fatigue, and creep-fatigue were performed to characterize the mechanical properties of Inconel 718 (a nickel based superalloy) at 1200 F, the operating temperature for turbine blades. In addition, a few attempts were made to model the behavior of Inconel 718 at 1200 F using viscoplastic theories. The Chaboche theory of viscoplasticity can model a wide variety of mechanical behavior, including monotonic, sustained, and cyclic responses of homogeneous, initially-isotropic, strain hardening (or softening) materials. It is shown how the Chaboche theory can be used to model the viscoplastic behavior of Inconel 718 at 1200 F. First, an algorithm was developed to systematically determine the material parameters of the Chaboche theory from uniaxial tensile, creep, and cyclic data. The algorithm is general and can be used in conjunction with similar high temperature materials. A sensitivity study was then performed and an optimal set of Chaboche's parameters were obtained. This study has also indicated the role of each parameter in modeling the response to different loading conditions.

  18. Replacement of alloy 600 by alloy 690 for steam generator tubes and closure heads in PWR; Gains apportes par le changement de materiau dans les generateurs de vapeur et les couvercles de cuve des REP: passage de l'alliage 600 a l'alliage 690

    Energy Technology Data Exchange (ETDEWEB)

    Bioulac, M.; Cipiere, M.F.; Poudroux, G. [FRAMATOME ANP, 92 - Paris-La-Defence (France); Champigny, F.; Mercier, L.; Rouillon, Y.; Vaillant, F. [Electricite de France (EDF), 75 - Paris (France)

    2004-07-01

    The replacement of alloy 600 by alloy 690 for steam generator tubes, tube plugs and closure head penetrations has well fulfilled its expectation concerning resistance to stress corrosion. The first steam generators fitted with tubes in alloy 690 have been operating for 14 years, the first plugs were set more than 20 years ago and the first closure head equipped with adapters in alloy 690 was installed in 1993. The feedback experience on non-destructive testing for these 3 components have shown no cracks. As a consequence the maintenance program has been reduced. A majority of nuclear power plant operators throughout the world have also selected the alloy 690. (A.C.)

  19. Mechanical properties and microstructure evaluation of powder bed fused inconel 625 nickel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Michael J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-19

    The objectives of this report were to optimize and fabricate full density Inconel 625 samples using direct metal laser fusion, an additive manufacturing process; and to compare and evaluate precipitation and solid solution strengthening of Inconel 625 produced by PBF to conventional processed material.

  20. On Electro Discharge Machining of Inconel 718 with Hollow Tool

    Science.gov (United States)

    Rajesha, S.; Sharma, A. K.; Kumar, Pradeep

    2012-06-01

    Inconel 718 is a nickel-based alloy designed for high yield, tensile, and creep-rupture properties. This alloy has been widely used in jet engines and high-speed airframe parts in aeronautic application. In this study, electric discharge machining (EDM) process was used for machining commercially available Inconel 718. A copper electrode with 99.9% purity having tubular cross section was employed to machine holes of 20 mm height and 12 mm diameter on Inconel 718 workpieces. Experiments were planned using response surface methodology (RSM). Effects of five major process parameters—pulse current, duty factor, sensitivity control, gap control, and flushing pressure on the process responses—material removal rate (MRR) and surface roughness (SR) have been discussed. Mathematical models for MRR and SR have been developed using analysis of variance. Influences of process parameters on tool wear and tool geometry have been presented with the help of scanning electron microscope (SEM) micrographs. Analysis shows significant interaction effect of pulse current and duty factor on MRR yielding a wide range from 14.4 to 22.6 mm3/min, while pulse current remains the most contributing factor with approximate changes in the MRR and SR of 48 and 37%, respectively, corresponding to the extreme values considered. Interactions of duty factor and flushing pressure yield a minimum surface roughness of 6.2 μm. The thickness of the sputtered layer and the crack length were found to be functions of pulse current. The hollow tool gets worn out on both the outer and the inner edges owing to spark erosion as well as abrasion due to flow of debris.

  1. Cold-Worked Inconel(R) 718 Bars

    Science.gov (United States)

    Montano, J. W.

    1988-01-01

    Cold working and double aging yield high strength without sacrifice of resistance to corrosion. Report presents data on mechanical properties and stress-corrosion resistance of triple-melted, solution-treated, work-strengthened, direct-double-aged Inconel(R) 718 alloy. Triple melting consists of vacuum induction melting, electro-slag remelting, and vacuum arm remelting. Data indicate advance in processing of large-diameter bars. New process increases yield strength without reducing the elongation, reduction of area, and grain size.

  2. Characterization of Strain-Induced Precipitation in Inconel 718 Superalloy

    Science.gov (United States)

    Calvo, Jessica; Penalva, Mariluz; Cabrera, José María

    2016-08-01

    Inconel 718 presents excellent mechanical properties at high temperatures, as well as good corrosion resistance and weldability. These properties, oriented to satisfy the design requirements of gas turbine components, depend on microstructural features such as grain size and precipitation. In this work, precipitation-temperature-time diagrams have been derived based on a stress relaxation technique and the characterization of precipitates by scanning electron microscopy. By using this methodology, the effect of strain accumulation during processing on the precipitation kinetics can be determined. The results show that the characteristics of precipitation are significantly modified when plastic deformation is applied, and the kinetics are slightly affected by the amount of total plastic deformation.

  3. Considerations on repeated repairing of weldments in Inconel 718 alloy

    Science.gov (United States)

    Bayless, E. O.; Lovoy, C. V.; Mcilwain, M. C.; Munafo, P.

    1981-01-01

    The effects of repeated weld repairs on the metallurgical characteristics, high cycle fatigue (HCF), and tensile properties of Inconel 718 butt weld joints were determined. A 1/4 in thick plate and a 1/2 in thick plate were used as well as tungsten inert gas welding, and Inconel 718 filler wire. Weld panels were subjected to 2, 6, and 12 repeated repairs and were made in a highly restrained condition. Post weld heat treatments were also conducted with the welded panel in the highly restrained condition. Results indicate that no significant metallurgical anomaly is evident as a result of up to twelve repeated weld repairs. No degradation in fatigue life is noted for up to twelve repeated repairs. Tensile results from specimens which contained up to twelve repeated weld repairs revealed no significant degradation in UTS and YS. However, a significant decrease in elongation is evident with specimens (solution treated and age hardened after welding) which contained twelve repeated repairs. The elongation loss is attributed to the presence of a severe notch on each side (fusion line) of the repair weld bead reinforcement.

  4. Influence of hydrogen environments on crack growth in Inconel 718

    Science.gov (United States)

    Walter, R. J.; Chandler, W. T.

    1978-01-01

    The effect of hydrogen environments on sustained-load and cyclic-load crack growth in Inconel 718 was investigated using fracture-mechanics-type specimens. The sustained-load crack growth was determined to be a function of heat-treatment condition, temperature, and hydrogen pressure. The threshold stress intensity for subcritical crack growth was independent of hydrogen pressure at pressures greater than 21 MN/sq m (3000 psi). The cyclic-load crack growth rate in Inconel 718 at low and moderate stress intensity ranges increased with increasing hydrogen pressure. Decreasing the cyclic frequency from 1.0 to 0.1 Hz considerably increased the cyclic crack growth rate at 0.069 MN/sq m (10 psi) and at 68.9 MN/sq m (10,000 psi) hydrogen pressure. A series of measurements performed between 1.0 and 0.1 Hz showed that the crack growth rate increased as a complex function of the time per cycle.

  5. Surface Integrity of Inconel 718 by Ball Burnishing

    Science.gov (United States)

    Sequera, A.; Fu, C. H.; Guo, Y. B.; Wei, X. T.

    2014-09-01

    Inconel 718 has wide applications in manufacturing mechanical components such as turbine blades, turbocharger rotors, and nuclear reactors. Since these components are subject to harsh environments such as high temperature, pressure, and corrosion, it is critical to improve the functionality to prevent catastrophic failure due to fatigue or corrosion. Ball burnishing as a low plastic deformation process is a promising technique to enhance surface integrity for increasing component fatigue and corrosion resistance in service. This study focuses on the experimental study on surface integrity of burnished Inconel 718. The effects of burnishing ball size and pressure on surface integrity factors such as surface topography, roughness, and hardness are investigated. The burnished surfaces are smoother than the as-machined ones. Surface hardness after burnishing is higher than the as-machined surfaces, but become stable over a certain burnishing pressure. There exists an optimal process space of ball sized and burnishing pressure for surface finish. In addition, surface hardness after burnishing is higher than the as-machined surfaces, which is confirmed by statistical analysis.

  6. Structure-Property Correlations in Microwave Joining of Inconel 718

    Science.gov (United States)

    Bansal, Amit; Sharma, Apurbba Kumar; Kumar, Pradeep; Das, Shantanu

    2015-09-01

    The butt joining of Inconel 718 plates at 981°C solution treated and aged (981STA) condition was carried out using the microwave hybrid heating technique with Inconel 718 powder as a filler material. The developed joints were free from any microfissures (cracks) and were metallurgically bonded through complete melting of the powder particles. The as-welded joints were subjected to postweld heat treatments, including direct-aged, 981STA and 1080STA. The microstructural features of the welded joints were investigated using a field emission-scanning electron microscope equipped with x-ray elemental analysis. Microhardness and room-temperature tensile properties of the welded joints were evaluated. The postweld heat-treated specimens exhibited higher microhardness and tensile strength than the as-welded specimens due to the formation of strengthening precipitates in the microstructure after postweld heat treatments. The microhardness of the fusion zone of the joint in 1080STA condition was higher than all welded conditions due to the complete dissolution of Laves phase after 1080STA treatment. However, the tensile strength of the welded specimen in 981STA condition was higher than all welded conditions. The tensile strength in 1080STA condition was lower than that in 981STA condition because of the grain coarsening that took place after 1080STA condition. The fractography of the fractured surfaces was carried out to determine the structure-property-fracture correlation.

  7. Field assisted hot pressing of sintering Inconel 718 MIM samples

    Science.gov (United States)

    Dugauguez, Olivier; Torralba, Jose Manuel; Barriere, Thierry; Gelin, Jean-Claude

    2016-10-01

    In this investigation on samples obtained by Metal Injection Molding (MIM), the conventional way of sintering in a furnace will be compared to Field Assisted Hot pressing (FAHP) sintering. The difficulty of this method is to be able to control the shrinkage of the sample and so its shape. It has yet not been investigated with a super alloy powder and so, the effects of a high sintering rate. By accelerating the sintering kinetics, the thermal behavior may be modified. Hence, the behavior of the Inconel 718 sintered by FAHP has been investigated. The sintered samples were all injected from a feedstock composed of a fine particle Inconel powder and a binder principally composed of Cellulose Acetate Butyrate CAB and Poly-Ethylene Glycol PEG. The effects of the two methods on the microstructure and the mechanical properties are then compared. There was no difference in distribution of pores between the conventional sintering and the FAHP sintering but a finer grain size showed better hardness.

  8. Structural Performance of Inconel 625 Superalloy Brazed Joints

    Science.gov (United States)

    Chen, Jianqiang; Demers, Vincent; Cadotte, Eve-Line; Turner, Daniel; Bocher, Philippe

    2016-12-01

    The purpose of this work was to investigate tensile and fatigue behaviors of Inconel 625 superalloy brazed joints after transient liquid-phase bonding process. Brazing was performed in a vacuum furnace using a nickel-based filler metal in a form of paste to join wrought Inconel 625 plates. Mechanical tests were carried out on single-lap joints under various lap distance-to-thickness ratios. The fatigue crack initiation and crack growth modes were examined via metallographic analysis, and the effect of local stress on fatigue life was assessed by finite element simulations. The fatigue results show that fatigue strength and endurance limit increase with overlap distance, leading to a relatively large scatter of results. Fatigue cracks nucleated in the high-stressed region of the weld fillets from brittle eutectic phases or from internal brazing cavities. The present work proposes to rationalize the results by using the local stress at the brazing fillet. When using this local stress, all fatigue-obtained results find themselves on a single S-N curve, providing a design curve for any joint configuration in fatigue solicitation.

  9. Interfacial Microstructure of Diffusion Bonded Inconel 738 and Ferritic Stainless Steel Couple

    Institute of Scientific and Technical Information of China (English)

    Bulent Kurt; Mustafa Ulutan

    2009-01-01

    In this study, Inconel 738 alloy was diffusion bonded to a ferritic stainless steel. The effect of bonding temperature on the microstructural development across the joint region was investigated. Following the diffusion bonding, conventional characterization techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and microhardness were used to examine the interfacial microstructure. It was seen that bonding temperature was effective on the diffusion of Ni from Inconel 738 to ferritic stainless steel that affected the microstructure of the interface. Austenite phase was formed at the interface as a result of Ni diffusion from the Inconel 738 to the interface.

  10. A Review of Optimization of Surface Roughness of Inconel 718 in End Milling using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Vishal Kumar Mall

    2014-12-01

    Full Text Available Nickel based super alloy, Inconel 718 is a very hard material (46 HRC. Because of its hardness, work hardening and low thermal conductivity, its machining is very difficult. End milling is an effective method for machining, drilling, slotting, and making key ways of Inconel 718. Tensile residual stress takes place during machining of Inconel 718. It is a critical problem, which is minimized to obtain better quality. Residual stress becomes more in the presence of rough machined surface. In this paper we optimize the surface roughness of Inconel 718 in end milling under dry condition. The surface roughness is optimized using four parameter nose radius, depth of cut, feed rate and cutting speed by using a cemented carbide tool. L27 orthogonal array of Taguchi method uses to analyse the result. 27 experimental runs based on L27 orthogonal array of Taguchi method.

  11. Residual stresses in an Inconel-718-clad tungsten tube processed by hot iso-static pressing

    Energy Technology Data Exchange (ETDEWEB)

    Parker, R.B.; Brown, D.W.; Rangaswamy, P. [Los Alamos National Lab., NM (United States)

    2000-07-01

    We have completed a comparative X-ray diffraction (XRD) and finite element analysis (FEA) study of Inconel 718 clad tungsten tubes, of relevance to the accelerator production of tritium (APT) program at the Los Alamos National Laboratory (LANL). Because the Inconel cladding must be in intimate contact with the tungsten at operating temperatures, the materials are diffusion bonded by hot iso-static pressing (HIP) at 1080 C. However, the difference in thermal expansion coefficients of Inconel 718 and tungsten produce large residual stresses upon cooling. The classical XRD (d vs. sin{sup 2}{psi}) technique was used to determine the stresses in the outer layer of inconel 718. These results are used to benchmark finite element analysis (FEA) calculations, and a direct comparison is made in this paper. (orig.)

  12. Dissolution kinetics and behavior of δ phase in Inconel 718

    Institute of Scientific and Technical Information of China (English)

    蔡大勇; 张伟红; 聂璞林; 刘文昌; 姚枚

    2003-01-01

    Dissolution kinetics of δ phase in Inconel 718 at 980,1000 and 1020℃ respectively was established using the quantitative X-ray diffraction(XRD)method.Microstructure evolution during dissolution process was analyzed with scanning electron microscopy(SEM).Dissolution rate of δ phase during high temperature heating keeps at a high level at the beginning stage,and then decreases gradually with the increase of heating time.A dynamic equilibrium state approaches after being heated at 980℃ for more than 30 min and at 1000℃ for more than 2 h,and the equilibrium mass fraction are 3% and 0.6% respectively.δ phase fully dissolves into the austenitic matrix after being heated at 1020℃ for more than 2 h.The dissolution and fracture effects cause the morphology evolution of δphase from long needle shape to short bars or particles at high temperature.

  13. The effect of laser pulse tailored welding of Inconel 718

    Science.gov (United States)

    Mccay, T. Dwayne; Mccay, Mary Helen; Sharp, C. Michael; Womack, Michael G.

    1990-01-01

    Pulse tailored laser welding has been applied to wrought, wrought grain grown, and cast Inconel 718 using a CO2 laser. Prior to welding, the material was characterized metallographically and the solid state transformation regions were identified using Differential Scanning Calorimetry and high temperature x-ray diffraction. Bead on plate welds (restrained and unrestrained) were then produced using a matrix of pulse duty cycles and pulsed average power. Subsequent characterization included heat affected zone width, penetration and underbead width, the presence of cracks, microfissures and porosity, fusion zone curvature, and precipitation and liquated region width. Pedigree welding on three selected processing conditions was shown by microstructural and dye penetrant analysis to produce no microfissures, a result which strongly indicates the viability of pulse tailored welding for microfissure free IN 718.

  14. Trials to manufacture and test castings from Inconel alloy

    Directory of Open Access Journals (Sweden)

    W. Uhl

    2010-07-01

    Full Text Available The article describes the methods of producing and testing the Inconel 740 nickel alloy in as-cast state. An assumption has been made that the obtained alloy should be characterised by a normative chemical composition and mechanical properties similar to those that are obtained in the process of plastic forming. The alloy was fabricated by conventional process and vacuum metallurgy in the form of pilot castings enabling various types of tests to be carried out. Within the test and investigations programme, moulding materials were chosen, castings were poured and subjected to the process of heat treatment, followed by tests and examinations of alloy properties (mechanical tests, cooling curves. The outcome of the investigations was cast alloy characterised by chemical composition close to the normative one but of the mechanical properties inferior to those obtained by plastic forming.

  15. RESPONSE SURFACE METHODOLOGY IN FINISH TURNING INCONEL 718

    Directory of Open Access Journals (Sweden)

    M. Aruna,

    2010-09-01

    Full Text Available Machining of hard materials used in aerospace applications require hard and tough cutting tools. Ceramic tools and cermets are used in machining of nickel alloys for such applications. In this study finish turning of Inconel 718 is carried out with cermet tools. Cutting parameters are designed using Taguchi’s DOE and the experiments are conducted for the designed parameters. The surface finish measurement is carried for the various conditions and data obtained are used to build up the mathematical surface model using response surface methodology. The adequacy of the developed mathematical model is proved by ANOVA. The findings of this study show new results and the second order model was quite adequate.

  16. Effects of Internal and External Hydrogen on Inconel 718

    Science.gov (United States)

    Walter, R. J.; Frandsen, J. D.

    1999-01-01

    Internal hydrogen embrittlement (IHE) and hydrogen environment embrittlement (HEE) tensile and bend crack growth tests were performed on Inconel 718. For the IHE tests, the specimens were precharged to approximately 90 ppm hydrogen by exposure to 34.5 MPa H2 at 650 C. The HEE tests were performed in 34.5 MPa H2. Parameters evaluated were test temperature, strain rate for smooth and notch specimen geometries. The strain rate effect was very significant at ambient temperature for both IHE and HEE and decreased with increasing temperatures. For IHE, the strain rate effect was neglible at 260'C, and for HEE the strain rate effect was neglible at 400 C. At low temperatures, IHE was more severe than HEE, and at high temperatures HEE was more severe than IHE with a cross over temperature about 350 C. At 350 C, the equilibrium hydrogen concentration in Inconel 718 is about 50% lower than the hydrogen content of the precharged IHE specimens. Dislocation hydrogen sweeping of surface absorbed hydrogen was the likely transport mechanism for increasing the hydrogen concentration in the HEE tests sufficiently to produce the same degree of embrittlement as that of the more highly hydrogen charged IHE specimens. The main IHE fracture characteristic was formation of large, brittle flat facets, which decreased with increasing test temperature. The IHE fracture matrix surrounding the large facets ranged between brittle fine faceted to microvoid ductility depending upon strain rate, specimen geometry as well as temperature. The HEE fractures were characteristically fine featured, transgranular and brittle with a significant portion forming a "saw tooth" crystallographic pattern. Both IHE and HEE fractures were predominantly along the {1 1 1) slip and twin boundaries. With respect to embrittlement mechanism, it was postulated that dislocation hydrogen sweeping and hydrogen enhanced localized plasticity were active in HEE and IHE for concentrating hydrogen along (1 1 1) slip and twin

  17. Mechanical properties of hot deformed Inconel 718 and X750

    Directory of Open Access Journals (Sweden)

    A. Nowotnik

    2012-02-01

    Full Text Available Purpose: Variations of a flow stress vs. true strain illustrate behavior of material during plastic deformation. Stress-strain relationship is generally evaluated by a torsion, compression and tensile tests.Design/methodology/approach: Compression tests were carried out on precipitations hardenable nickel based superalloys of Inconel 718 and X750 at constant true strain rates of 10-4, 4x10-4s-1 within temperature through which precipitation hardening phases process occurred (720-1150°C using thermomechanical simulator Gleeble and dilatometer Baehr 850D/L equipped with compression unit. True stress-true strain curves analysis of hot deformed alloys were described.Findings: On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (σpl -T i σpl - ε and compression data were used to determine material’s constants. These constants allow to derive a formula that describes the relationship between strain rate (ε, deformation temperature (T and flow stress σpl.Research limitations/implications: Study the flow stress will be continued on the samples after the aging process.Practical implications: The results of high-temperature deformation of the examined Inconel alloys may possibly find some practical use in the workshop practice to predict a flow stress values, but only within particular temperature and strain rate ranges. The results of the study can be used in the aerospace industry to produce blades for jet engines.Originality/value: The results of the study can be used in the aerospace industry to produce blades for jet engines.

  18. Microstructure and properties of laser-borided Inconel 600-alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kulka, M., E-mail: michal.kulka@put.poznan.pl; Dziarski, P.; Makuch, N.; Piasecki, A.; Miklaszewski, A.

    2013-11-01

    Nickel-based superalloys are used extensively for a variety of industrial applications involving high temperatures and aggressive environments. However, under conditions of appreciable mechanical wear (adhesive or abrasive), these materials have to be distinguished by suitable wear protection. The diffusion boronizing is the thermo-chemical treatment, which improves the tribological properties of nickel and its alloys. Nevertheless, the long duration of this process is necessary in order to obtain the layers of the thickness up to about 100 μm. Instead of the diffusion process, in this study the laser boriding is used for producing boride layer on Inconel 600-alloy. During the laser alloying, the external cylindrical surface of base material is coated by paste, including amorphous boron. Then the surface is re-melted by a laser beam. The high overlapping of multiple laser tracks (86%) causes the formation of uniform laser-alloyed layer in respect of the thickness. Laser re-melted zone, heat-affected zone and the substrate characterize the microstructure. In the re-melted zone, the three areas are observed: compact borides zone consisting of nickel, chromium and iron borides (close to the surface), zone of increased percentage of Ni–Cr–Fe-matrix (appearing in the greater distance from the surface) and zone of dominant Ni–Cr–Fe-matrix percentage (at the end of the layer). The hardness obtained is comparable to that-obtained in case of diffusion boriding. Simultaneously, the laser-borided layers are significantly thicker (about 346 or 467 μm depending on the laser power used). The significant increase in their abrasive wear resistance is observed. The wear intensity factors, as well as the relative mass loss of the laser-borided samples, are ten times smaller in comparison with untreated Inconel 600-alloy.

  19. Microstructure and properties of laser-borided Inconel 600-alloy

    Science.gov (United States)

    Kulka, M.; Dziarski, P.; Makuch, N.; Piasecki, A.; Miklaszewski, A.

    2013-11-01

    Nickel-based superalloys are used extensively for a variety of industrial applications involving high temperatures and aggressive environments. However, under conditions of appreciable mechanical wear (adhesive or abrasive), these materials have to be distinguished by suitable wear protection. The diffusion boronizing is the thermo-chemical treatment, which improves the tribological properties of nickel and its alloys. Nevertheless, the long duration of this process is necessary in order to obtain the layers of the thickness up to about 100 μm. Instead of the diffusion process, in this study the laser boriding is used for producing boride layer on Inconel 600-alloy. During the laser alloying, the external cylindrical surface of base material is coated by paste, including amorphous boron. Then the surface is re-melted by a laser beam. The high overlapping of multiple laser tracks (86%) causes the formation of uniform laser-alloyed layer in respect of the thickness. Laser re-melted zone, heat-affected zone and the substrate characterize the microstructure. In the re-melted zone, the three areas are observed: compact borides zone consisting of nickel, chromium and iron borides (close to the surface), zone of increased percentage of Ni-Cr-Fe-matrix (appearing in the greater distance from the surface) and zone of dominant Ni-Cr-Fe-matrix percentage (at the end of the layer). The hardness obtained is comparable to that-obtained in case of diffusion boriding. Simultaneously, the laser-borided layers are significantly thicker (about 346 or 467 μm depending on the laser power used). The significant increase in their abrasive wear resistance is observed. The wear intensity factors, as well as the relative mass loss of the laser-borided samples, are ten times smaller in comparison with untreated Inconel 600-alloy.

  20. Pulsed laser-assisted machining of Inconel 718 superalloy

    Science.gov (United States)

    Azhdari Tadavani, Soheila; Shoja Razavi, Reza; Vafaei, Reza

    2017-01-01

    Nickel-based superalloys including Inconel 718(IN718) are widely used in aerospace industries due to their superior high temperature strength, toughness, and corrosion resistance. These alloys are difficult to machine mainly because of their low thermal conductivity and high work hardening rate, which cause steep temperature gradient and high cutting forces at the tool edge. The application of laser assisted machining is the subject of many new researches since shear forces; surface coarsening and tool wear are reduced. The aim of this investigation was to evaluate laser assisted machining behavior of a 718 Inconel superalloy from the view point of machining specific energy, surface roughness, tool wear and chip appearance. Experimental apparatuses used included optical and scanning electron microscopy, spark emission spectroscopy, and EDS analysis. The results indicated that increasing the temperature to about 540 °C just ahead of primary shear zone, can result in 35% reduction of machining specific energy, in comparison with conventional machining. Furthermore, surface coarsening and tool wear were reduced by 22% and 23% respectively. Flank wear was the main deteriorating factor on cutting tools during laser assisted machining. SEM micrographs indicated that increase in temperature has no noticeable effect on finished workpiece surface. Analysis of variance obtained from regression analysis indicated that frequency of laser beam has the most influential effect on temperature. The optimum conditions for laser assisted machining of 718 superalloy is suggested as follows: 80 Hz frequency, 400 W power, 24 m/min cutting speed, and 0.052 mm/rev feed rate along with 540 °C temperature, 2.51 J/mm2 machining specific energy and 130 N cutting force.

  1. Research Progress of Effects of Heat Treatment on Microstructure and Properties of Inconel718 Alloy%热处理对Inconel718合金组织与性能影响的研究进展

    Institute of Scientific and Technical Information of China (English)

    葛锋; 张玉碧; 王春光; 何壁; 李念

    2013-01-01

    The effects of heat treatment process on the microstructure,mechanical properties,hydrogen embrittlement features and corrosion resistance of Inconel alloy 718 were reviewed.Then the applications of Inconel alloy 718 were prospected under high temperature and high pressure wet H2S corrosion environment.%综述了热处理对Inconel718合金的组织、力学性能、氢脆特性及耐蚀性能的影响;并展望了Inconel718合金在高温高压湿H2S腐蚀环境下的应用前景.

  2. 激光熔覆Inconel 718合金铌偏聚%Segregation of niobium in laser cladding Inconel 718 superalloy

    Institute of Scientific and Technical Information of China (English)

    龙怡彤; 聂璞林; 李铸国; 黄坚; 李想; 徐昕媚

    2016-01-01

    Inconel 718 superalloy is widely used in the aerospace and turbine industry. Segregation of niobium appears in the laser cladding Inconel 718 superalloy and consequently influences the phase transformation during the rapid solidification. In order to control the microstructure and improve the mechanical properties of the deposited coating, the the influence of solidification conditions on the segregation of niobium and the resultant formation of Nb-rich Laves phase was studied using the microstructure observation and EDS analysis. The results show that the cooling rate has considerable influence on the microstructure of the deposited coating. High cooling rate is beneficial for suppressing the segregation of Nb and reducing the formation of Laves phase, which is believed to be detrimental to the performance of the Inconel 718 alloy.%Inconel 718高温合金被广泛地应用于航空航天和汽轮机领域。在激光熔覆Inconel 718合金中存在铌的偏聚现象,而铌偏聚会影响到合金在快速凝固过程中的相变。为了控制熔覆层的显微组织并提高其力学性能,采用组织观察和能谱分析研究凝固条件对铌偏聚及富铌Laves相形成的影响规律。结果表明冷却速度对熔覆组织具有显著影响。高的冷却速度有利于抑制铌的偏聚,减少对Inconel 718合金力学性能有害的Laves相的析出。

  3. Twinning Mechanism of Inconel 718 Alloy During Creeping%Inconel 718 合金的蠕变孪晶机制

    Institute of Scientific and Technical Information of China (English)

    黄历锋; 孙文儒; 郭守仁; 胡壮麒

    2007-01-01

    通过TEM研究了固溶态及直接时效态Inconel 718合金的蠕变变形组织.结果表明:固溶态Inconel 718合金,在550℃/220 MPa条件下达到1%变形量时,蠕变组织的特征为位错交滑移;而直接时效态Inconel 718合金,在680℃/650 MPa条件下达到1%变形量时,蠕变组织中既有位错滑移后形成的变形带,又存在位错攀移,并且存在少量的孪晶变形.讨论了Inconel 718合金中发生蠕变孪晶的机制,着重从y″强化相的晶体学特征来解释该现象.研究结果认为:具有特殊结构的y″强化相是影响合金蠕变变形机制的根源.

  4. Fatigue Behavior and Deformation Mechanisms in Inconel 718 Superalloy Investigated

    Science.gov (United States)

    2005-01-01

    The nickel-base superalloy Inconel 718 (IN 718) is used as a structural material for a variety of components in the space shuttle main engine (SSME) and accounts for more than half of the total weight of this engine. IN 718 is the bill-of-material for the pressure vessels of nickel-hydrogen batteries for the space station. In the case of the space shuttle main engine, structural components are typically subjected to startup and shutdown load transients and occasional overloads in addition to high-frequency vibratory loads from routine operation. The nickel-hydrogen battery cells are prooftested before service and are subjected to fluctuating pressure loads during operation. In both of these applications, the structural material is subjected to a monotonic load initially, which is subsequently followed by fatigue. To assess the life of these structural components, it is necessary to determine the influence of a prior monotonic load on the subsequent fatigue life of the superalloy. An insight into the underlying deformation and damage mechanisms is also required to properly account for the interaction between the prior monotonic load and the subsequent fatigue loading. An experimental investigation was conducted to establish the effect of prior monotonic straining on the subsequent fatigue behavior of wrought, double-aged, IN 718 at room temperature. First, monotonic strain tests and fully-reversed, strain-controlled fatigue tests were conducted on uniform-gage-section IN 718 specimens. Next, fully reversed fatigue tests were conducted under strain control on specimens that were monotonically strained in tension. Results from this investigation indicated that prior monotonic straining reduced the fatigue resistance of the superalloy particularly at the lowest strain range. Some of the tested specimens were sectioned and examined by transmission electron microscopy to reveal typical microstructures as well as the active deformation and damage mechanisms under each of

  5. Contribution of the low cycle fatigue on ultra high purity Ni-Cr-Fe alloys and on Ni monocrystals to the understanding of the hydrogen role in stress corrosion cracking for the alloys 600 and 690; Apport de la fatigue oligocyclique sur alliages Ni-Cr-Fe d'ultra haute purete et sur monocristaux de Ni a la comprehension sous contrainte des alliages 600 et 69O

    Energy Technology Data Exchange (ETDEWEB)

    Renaudot, N

    1999-06-01

    We discuss the role of hydrogen in cracking of Ni base alloys used for pressurised water reactor (PWR) primary tubes (alloy 600 and 690). Cracking can be explained by a Stress Corrosion Cracking (SCC) phenomenon. For this purpose, Low cycle fatigue (R = - 1) under cathodic charging at room temperature is conducted to study hydrogen effects on propagation of cracks mechanically initiated by the formation of Persistent Slip Bands (PSB). Low cycle fatigue on Ultra High Purity specimens (Ni, alloy 600 and 690) reveals the very important hydrogen effect on crack propagation rate, whatever the Cr content in the Ni base alloy. If Cr seems to have an effect over-hydrogen penetration in specimens (by a protective film formation), it have no beneficial effect when hydrogen have diffused ahead of a crack tip. Propagation rates (transgranular or intergranular) are highly increased, no matter of the absence of impurities like sulphur. Then, in PWR, the difference in the behaviour of alloy 600 and 690 could be due to a slower microcrack propagation rate for alloy 690. Protective films could play an important role in this difference, which is to study. Low cycle fatigue on Ni single crystals oriented for single slip shows, for the first time on bulk specimen, a macroscopic softening which can be explained. by hydrogen-dislocation interactions. Moreover, a simple quantitative model based on these interactions results in the same softening as the one observed experimentally. These results allow to validate experimentally one of the most important steps in the 'Corrosion Enhanced Plasticity (CEP) model', i.e. the softening ahead of a stress corrosion crack tip by hydrogen dislocation interactions. This is of importance because this model can explain cracking in numerous FCC materials-environment couple. (author)

  6. Low-temperature embrittlement of Ti-6Al-4V and Inconel-718 by high pressure hydrogen

    Science.gov (United States)

    Chandler, W. T.; Walter, R. J.

    1970-01-01

    Notched specimens of titanium alloy and Inconel-718 exhibit little reduction of notch strength at certain low temperatures under 2000 lb/sq in. hydrogen, unnotched specimens are not embrittled at these temperatures. The degree of Inconel-718 embrittlement is lower than earlier observations under 1000 lb/sq in. hydrogen.

  7. Friction Freeform Fabrication of Superalloy Inconel 718: Prospects and Problems

    Science.gov (United States)

    Dilip, J. J. S.; Janaki Ram, G. D.

    2013-12-01

    Friction Freeform Fabrication is a new solid-state additive manufacturing process. The present investigation reports a detailed study on the prospects of this process for additive part fabrication in superalloy Inconel 718. Using a rotary friction welding machine and employing alloy 718 consumable rods in solution treated condition, cylindrical-shaped multi-layer friction deposits (10 mm diameter) were successfully produced. In the as-deposited condition, the deposits showed very fine grain size with no grain boundary δ phase. The deposits responded well to direct aging and showed satisfactory room-temperature tensile properties. However, their stress rupture performance was unsatisfactory because of their layered microstructure with very fine grain size and no grain boundary δ phase. The problem was overcome by heat treating the deposits first at 1353 K (1080 °C) (for increasing the grain size) and then at 1223 K (950 °C) (for precipitating the δ phase). Overall, the current study shows that Friction Freeform Fabrication is a very useful process for additive part fabrication in alloy 718.

  8. Experimental Investigations during Dry EDM of Inconel - 718

    Science.gov (United States)

    BHANDARE, A. S.; DABADE, U. A.

    2016-02-01

    Dry EDM is a modification of the conventional EDM process in which the liquid dielectric is replaced by a gaseous medium. Tubular tool electrodes are used and as the tool rotates, high velocity gas is supplied through it into the discharge gap. The flow of high velocity gas into the gap facilitates removal of debris and prevents excessive heating of the tool and work piece at the discharge spots. It is now known that apart from being an environment- friendly process, other advantages of the dry EDM process are low tool wear, lower discharge gap, lower residual stresses, smaller white layer and smaller heat affected zone. Keeping literature review into consideration, in this paper, an attempt has been made by selecting compressed air as a dielectric medium, with Inconel - 718 as a work piece material and copper as a tool electrode. Experiments are performed using Taguchi DoE orthogonal array to observe and analyze the effects of different process parameters to optimize the response variables such as material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). In the current work, a unit has been developed to implement dry EDM process on existing oil based EDM machine.

  9. Investigation of failure to separate an Inconel 718 frangible nut

    Science.gov (United States)

    Hoffman, William C., III; Hohmann, Carl

    1994-01-01

    The 2.5-inch frangible nut is used in two places to attach the Space Shuttle Orbiter to the External Tank. It must be capable of sustaining structural loads and must also separate into two pieces upon command. Structural load capability is verified by proof loading each flight nut, while ability to separate is verified on a sample of a production lot. Production lots of frangible nuts beginning in 1987 experienced an inability to reliably separate using one of two redundant explosive boosters. The problems were identified in lot acceptance tests, and the cause of failure has been attributed to differences in the response of the Inconel 718. Subsequent tests performed on the frangible nuts resulted in design modifications to the nuts along with redesign of the explosive booster to reliably separate the frangible nut. The problem history along with the design modifications to both the explosive booster and frangible nut are discussed in this paper. Implications of this failure experience impact any pyrotechnic separation system involving fracture of materials with respect to design margin control and lot acceptance testing.

  10. [INVITED] Laser treatment of Inconel 718 alloy and surface characteristics

    Science.gov (United States)

    Yilbas, B. S.; Ali, H.; Al-Aqeeli, N.; Karatas, C.

    2016-04-01

    Laser surface texturing of Inconel 718 alloy is carried out under the high pressure nitrogen assisting gas. The combination of evaporation and melting at the irradiated surface is achieved by controlling the laser scanning speed and the laser output power. Morphological and metallurgical changes in the treated surface are analyzed using the analytical tools including optical, electron scanning, and atomic force microscopes, energy dispersive spectroscopy, and X-ray diffraction. Microhardnes and friction coefficient of the laser treated surface are measured. Residual stress formed in the surface region is determined from the X-ray diffraction data. Surface hydrophobicity of the laser treated layer is assessed incorporating the sessile drop method. It is found that laser treated surface is free from large size asperities including cracks and the voids. Surface microhardness increases significantly after the laser treatment process, which is attributed to the dense layer formation at the surface under the high cooling rates, dissolution of Laves phase in the surface region, and formation of nitride species at the surface. Residual stress formed is compressive in the laser treated surface and friction coefficient reduces at the surface after the laser treatment process. The combination of evaporation and melting at the irradiated surface results in surface texture composes of micro/nano-poles and pillars, which enhance the surface hydrophobicity.

  11. Effects on stress rupture life and tensile strength of tin additions to Inconel 718

    Science.gov (United States)

    Dreshfield, R. L.; Johnson, W.

    1982-01-01

    Because Inconel 718 represents a major use of columbium and a large potential source of columbium for aerospace alloys could be that of columbium derived from tin slags, the effects of tin additions to Inconel 718 at levels which might be typical of or exceed those anticipated if tin slag derived columbium were used as a melting stock were investigated. Tin was added to 15 pound Inconel 718 heats at levels varying from none added to approximately 10,000 ppm (1 wt%). Limited 1200 F stress rupture testing was performed at stresses from 68,000 to 115,000 psi and a few tensile tests were performed at room temperature, 800 and 1200 F. Additions of tin in excess of 800 ppm were detrimental to ductility and stress rupture life.

  12. On relationship between microfissuring and microstructure in the HAZ of Inconel 718

    Science.gov (United States)

    Thompson, R. G.

    1982-01-01

    Inconel 718, as well as many other metals, is susceptible to intergranular hot cracking in the weld heat-affected-zone (HAZ). These cracks form near the solidus temperature of the metal during the welding process. This problem is of particular concern to NASA/MSFC because the SSME is primarily constructed of welded Inconel 718. The present program studied microfissuring in the weld HAZ of Inconel 718 by simulating HAZ thermal cycles with the Gleeble machine. Previous researchers have studied the instantaneous mechanical properties of the HAZ using the Gleeble. The present study examines the instantaneous microstructure of the HAZ. This approach showed that second phase structures, high in niobium, melt and wet the grain boundaries in the HAZ during welding. It is postulated that the resultant HAZ grain boundaries, enriched in niobium, act as preferred sites for microfissure nucleation as the weld zone cools.

  13. High Temperature Corrosion of Inconel 600 in NaCl-KCl Molten Salts

    Directory of Open Access Journals (Sweden)

    G. Salinas-Solano

    2014-01-01

    Full Text Available In this work the corrosion resistance of a high content nickel alloy, Inconel 600, was investigated in mixed NaCl-KCl salts at 700, 800, and 900°C for 100 hours in static air. Investigation was carried out using electrochemical techniques such as polarization curves, rest potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy. Corroded specimens were analyzed by scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. Electrochemical measurements showed an increased degradation rate of Inconel 600 with increasing test temperature. SEM and EDS analysis show that the damage experienced by Inconel 600 is greater than that determined by electrochemical measurements. This damage was identified as internal corrosion due to the reaction of Cl2 with the alloying elements (Cr and Fe; however, at 900°C the internal damage was minor and it was associated with the nickel content in the alloy.

  14. 合金设计和Inconel 718型合金的发展

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Inconel 718是一种镍基时效强化型高温合金,其主要强化相为Ni3Nb型的γ'相和部分Ni3A1型的γ'相。Inconel718合金以其优异的机械性能和工作稳定性被广泛应用于各种高温领域,是世界上用量最多的高温合金。然而,由于Inconel718合金的强化相γ'相的不稳定性,该合金通常在650℃以下的工作环境中使用。

  15. Effects of tin on microstructure and mechanical behavior of Inconel 718

    Science.gov (United States)

    Dreshfield, R. L.; Johnson, W. A.; Maurer, G. A.

    1984-01-01

    Columbium, for which the United States is 100 percent import reliant, is of strategic importance to the U.S. aerospace industry. A major amount of the Cb is used in Inconel 718. Should Cb sources be disrupted, it may be desired to use a grade of Cb melting stock having greater Sn content then the preferred vacuum rade. Additions of Sn to Inconel 718 were varied from none added to 1 wt %. The Sn additions below 800 ppm had no detrimental effects on 650 C stress rupture behavior; however, 1-wt % Sn severely degraded both life and ductility. Additions of Sn in excess of 200 ppm were slightly detrimental to the 425 C tensile yield strength and ductility. The Sn additions had no effect on the microstructure of Inconel 718 even after stress rupture testing for over 6000 hr at 650 C.

  16. Study on Inconel 718 Laser Treatment%Inconel 718合金激光处理的研究

    Institute of Scientific and Technical Information of China (English)

    梁晨; 俞海良; 楼松年

    2003-01-01

    采用Nd∶YAG固体激光器在连续激光能量输入方式下对Inconel 718镍基超耐热合金进行表面激光处理,研究了激光处理工艺参数对该合金的微观组织、表面残余应力状态及疲劳性能的影响.结果表明:合金经激光处理后,原基体内弥散分布的γ″强化相及晶间片状δ相会溶解于基体γ相内,使得合金表面硬度下降,下降幅度约为50%;经低角度XRD检测,x、y方向表面残余应力均为拉应力;经激光处理的带缺口试样疲劳强度低于母材.

  17. Application of FEM to Hot Continuous Rolling Process for Inconel 718 Alloy Round Rod

    Institute of Scientific and Technical Information of China (English)

    SUI Feng-li; CHEN Li-qing; LIU Xiang-hua; XU Li-xia

    2009-01-01

    A finite element model for coupled thermo-mechanical analysis has been developed in hot continuous rolling process for Inconel 718 alloy round rod with diameter of 45 ram. The stability of this alloy is discussed by integration of FEM and processing map reported in literatures. The result shows that the stability of Inconel 718 alloy is analyzed effectively during that process and good stability appears as the initial temperature is 960 ℃ and the initial velocity is from 0. 15 to 0. 45 m · s-1 or the initial temperature is 980 "C and the initial velocity is from 0. 15 to 0. 25 m · s-1.

  18. Phase transformation and liquid density redistribution during solidification of Ni-based superalloy Inconel 718

    Directory of Open Access Journals (Sweden)

    Wang Ling

    2012-08-01

    Full Text Available The influences of chemical segregation and phase transformation on liquid density variation during solidification of Ni-based supperalloy Inconel 718 were investigated using SEM and EDS. It was found that significant segregation in liquid prompts high Nb phase to precipitate directly from liquid, which results in the redistribution of alloy elements and liquid density in their vicinity. The term “inter-precipitate liquid density” is therefore proposed and this concept should be applied to determine the solidification behavior of superalloy Inconel 718.

  19. Fabrication and Optimization of Ni Superalloy Inconel 600 Microtruss Materials

    Science.gov (United States)

    Devatha Venkatesh, Balaji

    Microtruss materials are multifunctional cellular hybrids composed of an interconnected arrangement of internal struts that can offer enhanced strength and stiffness at low densities. This study looks at the potential of Ni-based superalloys as microtruss materials. The potential of using the in-situ plastic strain imparted during stretch forming to grain boundary engineer the internal struts of Inconel 600 (IN600) cellular hybrids was also explored. In order to examine this question, a combination of experimental and finite element (FE) methods were employed. The non-uniform plastic deformation imparted to the microtruss struts during fabrication was modeled by FE and the local changes in grain boundary character in the fabricated trusses were mapped by electron backscattered diffraction. This study also examined the distribution of plastic strain over the microtruss architecture. A mechanical press with various pin geometries was employed to experimentally validate the FE models. Standard pin geometry results in substantially non-uniform plastic strain, which limits the maximum formability of the starting sheet material. Importantly, pins designed with tapers and spheres were shown to impart plastic strain along the entire length of the microtruss. This opened up possibility of new design strategies for facilitating grain boundary engineering over the entire truss. It may also present opportunities for enhancing the energy absorption performance of microtruss materials. Finally, this study examined the mechanical properties of IN600 microtrusses, in particular focusing on the significance of strut end constraints in determining the overall mechanical performance. While it is straightforward to analytically determine the inelastic buckling resistance of plastically deformed struts, there is no simple way to determine the rotational end constraint of the struts deformed to varying truss angles. It was seen that end constraint rigidity k could be determined using a

  20. Tensile properties of Inconel 718 after low temperature neutron irradiation

    Science.gov (United States)

    Byun, T. S.; Farrell, K.

    2003-05-01

    Tensile properties of Inconel 718 (IN718) have been investigated after neutron irradiation to 0.0006-1.2 dpa at 60-100 °C in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). The alloy was exposed in solution-annealed (SA) and precipitation-hardened (PH) conditions. Before irradiation, the yield strength of PH IN718 was about 1170 MPa, which was 3.7 times higher than that of SA IN718. In the SA condition, an almost threefold increase in yield strength was found at 1.2 dpa, but the alloy retained a positive strain-hardening capability and a uniform ductility of more than 20%. Comparisons showed that the strain-hardening behavior of the SA IN718 is similar to that of a SA 316LN austenitic stainless steel. In the PH condition, the IN718 displayed no radiation-induced hardening in yield strength and significant softening in ultimate tensile strength. The strain-hardening capability of the PH IN718 decreased with dose as the radiation-induced dissolution of precipitates occurred, which resulted in the onset of plastic instability at strains less than 1% after irradiation to 0.16 or 1.2 dpa. An analysis on plastic instability indicated that the loss of uniform ductility in PH IN718 was largely due to the reduction in strain-hardening rate, while in SA IN718 and SA 316LN stainless steel it resulted primarily from the increase of yield stress.

  1. Inconel 718十二角头螺栓制造工艺技术研究%Study on Manufacturing Technology for Inconel 718 Twelve-Point Bolt

    Institute of Scientific and Technical Information of China (English)

    王玉凤; 刘风雷; 庄宝潼

    2015-01-01

    The material and structure features of Inconel 718 twelve-point bolt are introduced, and key manufacturing technologies, such as hot heading, heat treatment, warm rolling, etc. are analyzed, and optimal technological parameters are obtained. Dimensional in-spection and qualiifcation tests are carried out. The results show that technology designing is rational..%介绍了Inconel 718十二角头螺栓的材料和结构特点,分析了关键制造加工技术,如热镦锻、热处理、滚压螺纹等,确定了合理的工艺参数,并对研制件的尺寸和性能进行了评估,结果表明工艺技术设计合理。

  2. Metallurgical and mechanical properties of Inconel 600 and stellite; Estudio del comportamiento mecanico-metalurgico de alceacion inconel 600 y estelita

    Energy Technology Data Exchange (ETDEWEB)

    Cstillo, Martin; Villa, Gabriel; Vite, Manuel [Instituto Politecnico Nacional, Mexico D.F. (Mexico); Palacios, Francisco [Instituto Nacional de Investigacion Nuclear (ININ), Estado de Mexico (Mexico); Hernandez, Luis H; Urriolagoita, Guillermo [Instituto Politecnico Nacional, Mexico D.F. (Mexico)

    2005-01-15

    The present work studies the metallurgical and mechanical properties of two alloys, Inconel 600 and stellite, which are within the group of high hardness alloys or superalloys, which are deposited through the electrical weld process to the metallic arc with coated electrode (SMAW) and thereinafter analyzed through electron microscopy, diffractometry and abrasion, Impact and hardness test. The relationship between the microstructure and the final properties of the coating (hardness and abrasion wear resistance) was observed. [Spanish] Este trabajo presenta el estudio sobre las propiedades metalurgicas y mecanicas de dos aleaciones, inconel 600 y estelita, clasificadas dentro del grupo de aleaciones de alta dureza o superaleaciones; las cuales fueron depositadas mediante el proceso de soldadura electrica al arco metalico con electrodo revestido (SMAW) y fueron analizadas mediante microscopia electronica (SEM), difractometria pruebas de abrasion, impacto y dureza. Se observo la relacion entre la microstructura y las propiedades del recubrimiento, como son: dureza, resistencia a la abrasion, resistencia al impacto, ente otras.

  3. Application of Non-Equilibrium Grain Boundary Segregation Theory to INCONEL 718%INCONEL 718合金中硼的非平衡晶界偏聚

    Institute of Scientific and Technical Information of China (English)

    徐庭栋; 郑磊

    2003-01-01

    介绍了用溶质非平衡偏聚理论研究INCONEL 718合金中硼的晶界偏聚所取得的最新进展.这些进展包括用非平衡晶界偏聚动力学理论预报热处理工艺对合金晶界脆性的影响.

  4. Effect of Deformation Process on Superplasticity of Inconel 718 Alloy%变形工艺对Inconel 718合金超塑性的影响

    Institute of Scientific and Technical Information of China (English)

    董洪波; 王高潮

    2015-01-01

    Inconel 718合金经过热锻、δ相析出处理及再结晶热处理后,分别采用最大m值法和基于最大m值的应交诱发超塑性法进行高温拉伸试验,研究形变热处理及拉伸工艺对材料超塑性能的影响.结果表明,经过热变形、δ相析出及再结晶退火处理后,有效细化了Inconel 718合金的组织.析出的δ相可以在再结晶退火及热变形中起到控制晶界的作用.在950℃变形,采用上述两种方法拉伸变形得到的延伸率分别为566%和340%,说明基于最大m值的形变诱发超塑法可以进一步提高Inconel 718合金的延伸率.

  5. Hot-cracking studies of Inconel 718 weld- heat-affected zones

    Science.gov (United States)

    Thompson, E. G.

    1969-01-01

    Hot ductility tests, gas-tungsten-arc fillerless fusion tests, and circle patch-weld-restraint tests were conducted on Inconel 718 to better understand and correlate the weldability /resistance to hot cracking/ of the alloy. A correlation of the test results with composition, heat-treat condition, grain size, and microstructure was made.

  6. Effect of reduction of strategic columbium additions in Inconel 718 alloy on the structure and properties

    Science.gov (United States)

    Ziegler, K.; Wallace, J. F.

    1982-01-01

    The amount of columbium which can be removed from Inconel alloy 718 without degrading its high temperature properties was determined. The elements that are substituted are: vanadium and tungsten together and separately; increasing the molybdenum level from 3.0% to 5.8% and increasing the boron to 0.04%.

  7. Microstructure, Fatigue Behavior, and Failure Mechanisms of Direct Laser-Deposited Inconel 718

    Science.gov (United States)

    Johnson, Alex S.; Shao, Shuai; Shamsaei, Nima; Thompson, Scott M.; Bian, Linkan

    2017-03-01

    Inconel 718 is considered to be a superalloy with a series of superior properties such as high strength, creep resistance, and corrosion resistance at room and elevated temperatures. Additive manufacturing (AM) is particularly appealing to Inconel 718 because of its near-net-shape production capability for circumventing the poor machinability of this superalloy. Nevertheless, AM parts are prone to porosity, which is detrimental to their fatigue resistance. Thus, further understanding of their fatigue behavior is required before their widespread use in load-bearing applications. In this work, the microstructure and fatigue properties of AM Inconel 718, produced in a Laser Engineered Net Shaping (LENS™) system and heat treated with a standard heat treatment schedule, are evaluated at room temperature. Fully reversed strain controlled fatigue tests were performed on cylindrical specimens with straight gage sections at strain amplitudes ranging from 0.001 mm/mm to 0.01 mm/mm. The fracture surfaces of fatigue specimens were inspected with a scanning electron microscope. The results indicate that the employed heat treatment allowed the large, elongated grains and dendritic structure of the as-built material to break down into smaller, equiaxed grains, with some dendritic structures remaining between layers. The AM specimens were found to possess lower fatigue resistance than wrought Inconel 718, and this is primarily attributed to the presence of brittle metal-carbide/oxide inclusions or pores near their surface.

  8. The sectional size effect on the deformation behaviour of Inconel 718 at different temperatures

    Directory of Open Access Journals (Sweden)

    Zhao R.

    2015-01-01

    Full Text Available Inconel 718, as a multiphase super-alloy, is widely used in aeronautics and astronautics industries. In this field, a modified Hall-Petch equation was used to describe the grain size effect on the deformation behaviour of Inconel 718 sheet in uniaxial tension test. There is a piecewise linearity in the σ-d−1 curve: With the thickness t is a constant, the slope changes obviously after a critical t/d ratio, which increases with strain. Moreover, the influence on sectional curve caused by temperature is also an interesting issue. To address that, the sectionalized curve was fitted at different strains and temperatures, and the phenomena of grain size effect in piecewise curve at different temperatures were further explained. A surface model of Inconel 718 was proposed to explain the intrinsic mechanism of different slopes. The research provided an in-depth understanding of the size effect on the deformation behaviour of Inconel 718 at different hot working temperatures.

  9. Incompatibility between Zircaloy-2 and Inconel X-750 during Temperature Transients

    DEFF Research Database (Denmark)

    Warren, M. R.; Rørbo, Kaj; Adolph, Eivind

    1975-01-01

    The incompatibility of Zircaloy-2 and Inconel X-750 has been investigated between 1000°C and 1200°C (1200°C being the currently allowable maximum temperature in the acceptance criteria for ECCS for water reactors). It has been found for the temperatures of 1000°C and 1200°C that oxide thicknesses...

  10. Microstructure, Fatigue Behavior, and Failure Mechanisms of Direct Laser-Deposited Inconel 718

    Science.gov (United States)

    Johnson, Alex S.; Shao, Shuai; Shamsaei, Nima; Thompson, Scott M.; Bian, Linkan

    2016-12-01

    Inconel 718 is considered to be a superalloy with a series of superior properties such as high strength, creep resistance, and corrosion resistance at room and elevated temperatures. Additive manufacturing (AM) is particularly appealing to Inconel 718 because of its near-net-shape production capability for circumventing the poor machinability of this superalloy. Nevertheless, AM parts are prone to porosity, which is detrimental to their fatigue resistance. Thus, further understanding of their fatigue behavior is required before their widespread use in load-bearing applications. In this work, the microstructure and fatigue properties of AM Inconel 718, produced in a Laser Engineered Net Shaping (LENS™) system and heat treated with a standard heat treatment schedule, are evaluated at room temperature. Fully reversed strain controlled fatigue tests were performed on cylindrical specimens with straight gage sections at strain amplitudes ranging from 0.001 mm/mm to 0.01 mm/mm. The fracture surfaces of fatigue specimens were inspected with a scanning electron microscope. The results indicate that the employed heat treatment allowed the large, elongated grains and dendritic structure of the as-built material to break down into smaller, equiaxed grains, with some dendritic structures remaining between layers. The AM specimens were found to possess lower fatigue resistance than wrought Inconel 718, and this is primarily attributed to the presence of brittle metal-carbide/oxide inclusions or pores near their surface.

  11. Additive manufacturing of Inconel 718 using electron beam melting: Processing, post-processing, & mechanical properties

    Science.gov (United States)

    Sames, William James, V.

    Additive Manufacturing (AM) process parameters were studied for production of the high temperature alloy Inconel 718 using Electron Beam Melting (EBM) to better understand the relationship between processing, microstructure, and mechanical properties. Processing parameters were analyzed for impact on process time, process temperature, and the amount of applied energy. The applied electron beam energy was shown to be integral to the formation of swelling defects. Standard features in the microstructure were identified, including previously unidentified solidification features such as shrinkage porosity and non-equilibrium phases. The as-solidified structure does not persist in the bulk of EBM parts due to a high process hold temperature (˜1000°C), which causes in situ homogenization. The most significant variability in as-fabricated microstructure is the formation of intragranular delta-phase needles, which can form in samples produced with lower process temperatures (Inconel 718. Traditional post-processing methods of hot isostatic pressing (HIP) and solution treatment and aging (STA) were found to result in variability in grain growth and phase solution. Recrystallization and grain structure are identified as possible mechanisms to promote grain growth. These results led to the conclusion that the first step in thermal post-processing of EBM Inconel 718 should be an optimized solution treatment to reset phase variation in the as-fabricated microstructure without incurring significant grain growth. Such an optimized solution treatment was developed (1120°C, 2hr) for application prior to aging or HIP. The majority of as-fabricated tensile properties met ASTM AM Inconel 718 standards for yield stress and ultimate tensile strength, and STA yield stress, ultimate tensile strength, and elongation exceeded the ASTM standards for AM Inconel 718.

  12. Microstructure and Microsegregation of an Inconel 625 Weld Overlay Produced on Steel Pipes by the Cold Metal Transfer Technique

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2014-10-01

    Full Text Available The aim of this work was to investigate the development of microstructure and variations in chemical composition in commercial Inconel 625 coatings on a ferritic-pearlitic steel overlaid by the CMT method.

  13. Effect of Orientation on Tensile Properties of Inconel 718 Block Fabricated with Electron Beam Freeform Fabrication (EBF3)

    Science.gov (United States)

    Bird, R. Keith; Atherton, Todd S.

    2010-01-01

    Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate an Inconel 718 bulk block deposit. Room temperature tensile properties were measured as a function of orientation and location within the block build. This study is a follow-on activity to previous work on Inconel 718 EBF3 deposits that were too narrow to allow properties to be measured in more than one orientation

  14. Strength Differential Measured in Inconel 718: Effects of Hydrostatic Pressure Studied

    Science.gov (United States)

    Lewandowski, John J.; Wesseling, Paul; Prabhu, Nishad S.; Larose, Joel; Lissenden, Cliff J.; Lerch, Bradley A.

    2003-01-01

    Aeropropulsion components, such as disks, blades, and shafts, are commonly subjected to multiaxial stress states at elevated temperatures. Experimental results from loadings as complex as those experienced in service are needed to help guide the development of accurate viscoplastic, multiaxial deformation models that can be used to improve the design of these components. During a recent study on multiaxial deformation (ref. 1) on a common aerospace material, Inconel 718, it was shown that the material in the aged state exhibits a strength differential effect (SDE), whereby the uniaxial compressive yield and subsequent flow behavior are significantly higher than those in uniaxial tension. Thus, this material cannot be described by a standard von Mises yield formulation. There have been other formulations postulated (ref. 2) that involve other combinations of the stress invariants, including the effect of hydrostatic stress. The question remained as to which invariants are necessary in the flow model. To capture the physical mechanisms occurring during deformation and reflect them in the plasticity formulation, researchers examined the flow of Inconel 718 under various amounts of hydrostatic stress to determine whether or not hydrostatic stress is needed in the formulation. Under NASA Grant NCC3-464, monitored by the NASA Glenn Research Center, a series of tensile tests were conducted at Case Western Reserve University on aged (precipitation hardened) Inconel 718 at 650 C and with superimposed hydrostatic pressure. Dogbone shaped tensile specimens (3-mm-diameter gauge by 16-mm gauge length) and cylindrical compression specimens (3-mm-diameter gauge by 6-mm gauge length) were strain gauged and loaded in a high-pressure testing apparatus. Hydrostatic pressures were obtained with argon and ranged from 210 to 630 MPa. The aged Inconel 718 showed a pronounced difference in the tension and compression yield strength (i.e., an SDE), as previously observed. Also, there were

  15. Quality Requirements Put On The Inconel 625 Austenite Layer Used On The Sheet Pile Walls Of The Boiler’s Evaporator To Utilize Waste Thermally

    Directory of Open Access Journals (Sweden)

    Słania J.

    2015-06-01

    Full Text Available Quality requirements and tests taken on the surfacing layer Inconel 625 are presented in the article. The reasons of using surfacing layer Inconel 625 and technologies of its making with a particular emphasis on the CMT method are described. Quality requirements for the surfacing weld Inconel 625 are provided. Basic requirements included in the Merkblatt 1166, as well as additional requirements, which are reflected in the technical specifications of the boilers’ producers are specified.

  16. Inconel690合金高温高速热变形行为研究%High-Temperature High-Speed Hot Deformation Behavior of Inconel 690 Alloy

    Institute of Scientific and Technical Information of China (English)

    王彬; 程明; 张士宏; 宋鸿武

    2011-01-01

    在Gleeble-3800热模拟试验机上,采用热压缩实验研究了不同变形条件下Inconel 690合金的高温变形行为与组织演变特点.实验中采用的变形温度为1000~1200℃,变形量为70%,变形速率为1.0 ~80.0 s-1.根据实验结果获得了该合金的应力-应变关系,并对峰值应力进行了线性回归,由此得到了该合金的高温材料常数,激活能Q =417.6 kJ.mo1-1,α =0.003196 MPa-1,n=7.51,并最终得到了Incone1690合金的高温变形本构方程.通过金相显微镜研究了合金动态再结晶规律与温度和应变速率的关系,结果表明:变形温度对Inconel 690合金组织的影响很大,随温度的升高,动态再结晶百分数逐渐增加,且伴随着晶粒的长大;而提高应变速率,变形的时间缩短,位错密度迅速增大,动态再结晶的驱动力增加,也可以使再结晶后的晶粒细化;当温度为1150℃左右,应变速率50~80 s-1时,能够得到均匀细晶组织.%The hot deformation characteristics of Inconel 690 alloy were investigated on the Gleeble-3800 thermal mechanical simulator. The testing temperatures were in the range of 1000 ~ 1200 ℃, the deformation degree was 70% , and the strain rates were from 1.0 to 80.0 s-1. The true stress-strain curves were obtained and the material constants, the activation energy Q of 417.6 kJ·mol-1, α of 0.0031% Mpa-1, and re of 7.51, of high-temperature deformation of Inconel 690 alloy were obtained by the linear regression of peak stress. The constitutive equation of inconel 690 alloy was established finally. The relationship between the law of dynamic recrys-tallization and temperature, strain rate was studied by metallurgical microscope. The results showed that the microstructures of inconel 690 alloy were greatly affected by temperature, the percentage of dynamic recrystallization increased with the increasing of temperature, and accompanied by grain growth. The deformation time shortened while the strain rate

  17. Rapid assessment of anisotropic surface processes: experiments on the corrosion of Inconel 600

    Science.gov (United States)

    Schuh, Christopher A.; Anderson, Kelly; Orme, Christine

    2003-10-01

    We present a general experimental method for rapid characterization of surface processes on crystals of many orientations. By correlating maps of crystallographic orientation (obtained by electron backscatter diffraction methods) with those of surface topography (obtained by atomic force microscopy), we illustrate how a surface property can be elucidated on many off-principle crystal surfaces from a single polycrystalline specimen. For the corrosion of Inconel 600 in a dilute aqueous solution of HCl, we find that corrosion rates scale with the deviation angle of the surface normal from an ideal direction. The use of atomic force microscopy can also provide mechanistic details about the surface process in question. For Inconel 600, we correlate the surface oxide morphology directly to the orientation of the underlying crystal.

  18. Investigation of Machine-ability of Inconel 800 in EDM with Coated Electrode

    Science.gov (United States)

    Karunakaran, K.; Chandrasekaran, M.

    2017-03-01

    The Inconel 800 is a high temperature application alloy which is classified as a nickel based super alloy. It has wide scope in aerospace engineering, gas Turbine etc. The machine-ability studies were found limited on this material. Hence This research focuses on machine-ability studies on EDM of Inconel 800 with Silver Coated Electrolyte Copper Electrode. The purpose of coating on electrode is to reduce tool wear. The factors pulse on Time, Pulse off Time and Peck Current were considered to observe the responses of surface roughness, material removal rate, tool wear rate. Taguchi Full Factorial Design is employed for Design the experiment. Some specific findings were reported and the percentage of contribution of each parameter was furnished

  19. Fatigue behavior of two alloys for Space Shuttle applications. [Inconel 903 and 718 for main engine

    Science.gov (United States)

    Adsit, N. R.; Block, S. J.

    1978-01-01

    Two superalloys used extensively in the Space Shuttle main engine are Incoloy 903 and Inconel 718. The fatigue behavior of the two alloys under varying conditions is considered. Three heats of Incoloy 903 and two of Inconel 718 were used in the study. Material was tested in several conditions, including mill polish, longitudinal mill polish, transverse mill polish, chemically milled, chemically milled plus shotpeened on one side and on both sides, gas tungsten arc welded, and electron beam welded. Both round and flat tensile specimens were tested in universal test machines. It was found that surface condition influences test results. Transverse scratches resulting from polishing and rougher surfaces lower the stress at runout in relation to that obtained on longitudinally polished and/or smooth-surfaced specimens.

  20. Extrusion Honed Surface Characteristics of Inconel 625 Fabricated By EDM for Square Shape

    Directory of Open Access Journals (Sweden)

    N.L. Murali Krishna

    2014-07-01

    Full Text Available Extrusion Honing (EH is also known as Abrasive flow machining (AFM is an effective method that is used to deburr, clean, polish, remove recast layer and micro cracks by flowing pressurized semisolid abrasive laden visco-elastic media over those surfaces. Inconel 625 is one of the most difficult-to-cut materials because of its low thermal diffusive property, high hardness and high strength at elevated temperature. In this paper, the influence of the process parameters on surface roughness is investigated on Inconel 625 material of square shape fabricated by Electric discharge machining (EDM. The processed surfaces were measured and analyzed with the help of surface roughness tester and Scanning Electron Microscope (SEM. Results show a significant improvement in surface finish and EH/AFM is capable of removing the micro cracks and recast layer.

  1. Nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel and stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.G.; Sorensen, N.R.

    1998-02-01

    This report presents a nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel alloys from stainless steel alloys as well as an evaluation of cleaning techniques to remove a thermal oxide layer on aircraft exhaust components. The results of this assessment are presented in terms of how effective each technique classifies a known exhaust material. Results indicate that either inspection technique can separate inconel and stainless steel alloys. Based on the experiments conducted, the electrochemical spot test is the optimum for use by airframe and powerplant mechanics. A spot test procedure is proposed for incorporation into the Federal Aviation Administration Advisory Circular 65-9A Airframe & Powerplant Mechanic - General Handbook. 3 refs., 70 figs., 7 tabs.

  2. STUDY OF THE MECHANICAL PROPERTIES OF INCONEL 718 SUPERALLOY AFTER HOT TENSILE TESTS

    Directory of Open Access Journals (Sweden)

    Tarcila Sugahara

    2014-10-01

    Full Text Available This research work investigated some important mechanical properties of Inconel 718 superalloy using hot tensile tests like conventional yield strength to 0.2% strain (σe , ultimate strength (σr , and specific elongation (εu . Samples were strained to failure at temperatures of 600°C, 650°C, 700°C, 750°C, 800°C and 850°C and strain rate of 0.5 mm/min (2 × 10–4 s–1 according to ASTM E-8. The results showed higher values σe of yield strength at 700°C, this anomalous behavior can be attributed to the presence of hardening precipitates as observed in the TTT diagram of superalloy Inconel 718. Examination of the sample’s surfaces tensile fracture showed that with increasing temperature test the actuating mechanism changes from intergranular fracture to coalescence of the microcavities.

  3. Microsegregation and Rayleigh number variation during the solidification of superalloy Inconel 718

    Institute of Scientific and Technical Information of China (English)

    Ling Wang; Jianxin Dong; Yuliang Tian; Lei Zhang

    2008-01-01

    The microstructure and composition of the residual liquid at different temperatures were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX) associated with the Thermo-calc software calculation of the equilibrium phase diagrams of Inconel 718 and segregated liquid. The liquid density difference and Rayleigh number variation dur-ing solidification were estimated as well. It is found that the heavy segregation of Nb in liquid prompts the precipitation of δ and Laves phase directly from liquid and the resultant quenched liquid microstructure consists of pro-eutectic γ+eutectic, or complete eutectic according to the content of Nb from low to high. The liquid density increases with decreasing temperature during the solidi-fication of Inconel 718 and the liquid density difference is positive. The largest relative Rayleigh number occurs at 1320℃ when the liquid fraction is about 40vol%.

  4. Solute redistribution and Rayleigh number in the mushy zone during directional solidifi cation of Inconel 718

    Directory of Open Access Journals (Sweden)

    Wang Ling

    2009-08-01

    Full Text Available The interdendritic segregation along the mushy zone of directionally solidifi ed superalloy Inconel 718 has been measured by scanning electron microscope (SEM and energy dispersion analysis spectrometry (EDAXtechniques and the corresponding liquid composition profile was presented. The liquid density and Rayleigh number (Ra profi les along the mushy zone were calculated as well. It was found that the liquid density difference increased from top to bottom in the mushy zone and there was no density inversion due to the segregation of Nb and Mo. However carbide formation in the freezing range and the preferred angle of the orientated dendrite array could prompt the fl uid fl ow in the mushy zone although there was no liquid density inversion. The largest relative Rayleigh number appeared at 1,326 篊 for Inconel 718 where the fl uid fl ow most easily occurred.

  5. Solute redistribution and Rayleigh number in the mushy zone during directional solidification of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    Wang Ling; Dong Jianxin; Liu Lin; Zhang Lei

    2009-01-01

    The interdendritic segregation along the mushy zone of directionally solidified superalloy Inconel 718has been measured by scanning electron microscope (SEM) and energy dispersion analysis spectrometry (EDAX)techniques and the corresponding liquid composition profile was presented. The liquid density and Rayleigh number (Ra) profiles along the mushy zone were calculated as well. It was found that the liquid density difference increased from top to bottom in the mushy zone and there was no density inversion due to the segregation of Nb and Mo. However carbide formation in the freezing range and the preferred angle of the odentated dendrite array could prompt the fluid flow in the mushy zone although there was no liquid density inversion. The largest relative Rayleigh number appeared at 1,326℃ for Inconel 718 where the fluid flow most easily occurred.

  6. Effect of δ Phase on Hydrogen Embrittlement of Inconel 718 by Notch Tensile Tests

    Institute of Scientific and Technical Information of China (English)

    Liufa LIU; Chen LU; Wenjiang DING; Akio Hirose; Kojiro F.Kobayashi

    2005-01-01

    The effect of δ phase on the hydrogen embrittlement (HE) sensitivity of Inconel 718 was investigated by conducting notch tensile tests. Notch tensile specimens with various precipitation morphologies of δ phase were prepared with different heat treatments, and hydrogen was charged into the tensile specimens before tensile tests via a cathodic charging process. The loss of notch tensile strength (NTS) due to the charged hydrogen was used to evaluate the hydrogen embrittlement sensitivity. The results show that δ phase has deleterious effect on NTSs, and the fracture of hydrogen-charged specimens initiated near the notch surfaces. The loss of NTS caused by precharged hydrogen can be greatly decreased by dissolving δ phase. δ-free Inconel 718 alloy is proposed for the applications in hydrogen environments.

  7. Friction welding of TiAl intermetallics and structural steel by applying Inconel 718 as interlayer

    Institute of Scientific and Technical Information of China (English)

    Li Jinglong; Wang Zhongping; Xiong Jiangtao; Zhang Fusheng; Wang Yanfang

    2005-01-01

    lnconel 718 with thickness ranged from 0. 1 - 1.7 mm was chosen as interlayer to promote weldability in friction welding of TiAl intermetallics and structural steel such as AISI 4140, in which the welded joint presents single fin showing less welding deformation on TiAl side. The correlations between tensile strength and the interlayer thickness were analyzed and fitted to a model. It indicates an optimum interlayer thickness ranged from 0. 9 - 1.1 mm where the tensile strength reaches as high as 360 MPa. Otherwise, while the interlayer thickness decreases to 0. 1 mm, brittle compounds of TiC, Al2 Ti4 C2 and M7 C3 are formed in the welded zone so that the tensile strength decays. Thicker interlayer should be also avoided as double joints may occur at TiAl - Inconel 718 and Inconel 718 -AISI 4140, respectively, which lowers the tensile strength to some extent.

  8. Laser Additive Melting and Solidification of Inconel 718: Finite Element Simulation and Experiment

    Science.gov (United States)

    Romano, John; Ladani, Leila; Sadowski, Magda

    2016-03-01

    The field of powdered metal additive manufacturing is experiencing a surge in public interest finding uses in aerospace, defense, and biomedical industries. The relative youth of the technology coupled with public interest makes the field a vibrant research topic. The authors have expanded upon previously published finite element models used to analyze the processing of novel engineering materials through the use of laser- and electron beam-based additive manufacturing. In this work, the authors present a model for simulating fabrication of Inconel 718 using laser melting processes. Thermal transport phenomena and melt pool geometries are discussed and validation against experimental findings is presented. After comparing experimental and simulation results, the authors present two correction correlations to transform the modeling results into meaningful predictions of actual laser melting melt pool geometries in Inconel 718.

  9. Studies on the weldability, microstructure and mechanical properties of activated flux TIG weldments of Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Ramkumar, K. Devendranath, E-mail: ramdevendranath@gmail.com; Kumar, B. Monoj; Krishnan, M. Gokul; Dev, Sidarth; Bhalodi, Aman Jayesh; Arivazhagan, N.; Narayanan, S.

    2015-07-15

    This research article addresses the joining of 5 mm thick plates of Inconel 718 by activated flux tungsten inert gas (A-TIG) welding process using SiO{sub 2} and TiO{sub 2} fluxes. Microstructure studies inferred the presence of Nb rich eutectics and/or laves phase in the fusion zone of the A-TIG weldments. Tensile studies corroborated that the ultimate tensile strength of TiO{sub 2} flux assisted weldments (885 MPa) was better compared to SiO{sub 2} flux assisted weldments (815 MPa) and the failure was observed in the parent metal for both the cases. Impact test results portrayed that both the weldments were inferior in toughness as compared to the parent metal, which was due to the presence of oxide inclusions. Also, the study investigated the structure–property relationships of the A-TIG weldments of Inconel 718.

  10. Flow stress behavior of delta-processed Inconel 718 superalloy under hot compression deformation%Delta工艺Inconel718合金热变形条件下的流变行为

    Institute of Scientific and Technical Information of China (English)

    杨平; 赵玉涛; 王安东; 缪栋; 陈刚; 何毅

    2012-01-01

    The flow stress behavior of the delta-processed Inconel 718 superalloy was investigated by the hot compression on Gleeble-3500 test machine. The results of the thermal simulation compression tests show that the flow stress is positively sensitive to the strain rate and the deformation temperature. The peak stress decreases with the decreasing strain rate and increasing deformation temperature. The dynamic recrystallization is the main softening mechanism of the hot deformation of the delta-processed Inconel 718 superalloy. The activation energy (0 of the delta-processed S phase aged Inconel 718 superalloy is 497.407 kJ/mol. The relationships among the flow stress, the deformation temperature and the strain rate for the delta-processed Inconel 718 can be described by the hyperbolic sine-type function.%在Gleeble-3500热模拟实验机上对Delta工艺Inconel 718合金进行高温压缩实验,研究其高温压缩变形的流变应力行为.结果表明:δ相时效态Inconel 718合金在本实验条件下具有正的应变速率敏感性,流变应力随着应变速率的降低和变形温度的升高而减小,动态再结晶是合金重要的软化机制.δ相时效态Inconel 718合金的热变形激活能为497.407kJ/mol,高温压缩峰值流变应力与变形温度和应变速率的关系可用双曲正弦函数表示.

  11. Experimental Study on Cutting Force in High-speed Turning of Inconel 718%高速车削Inconel718切削力的试验研究

    Institute of Scientific and Technical Information of China (English)

    季德生; 黄雪红

    2012-01-01

    为了研究高速切削Inconel 718的切削力经验公式和各切削参数对切削力的影响显著程度,应用涂层硬质合金刀具对Inconel 718进行了正交车削试验,得到了硬质合金刀具车削Inconel 718的切削力经验公式.分析结果表明:对切削力影响最大的因素是进给量,切削深度和切削速度对试验结果的影响依次减弱.用涂层硬质合金刀具KC5510精车Inconel 718时,采用小进给量、小切削深度、高切削速度可以得到小的切削力,取得良好的切削效果.%In order to study the cutting force empirical formula and the influence of every cutting parameter on cutting force of high speed cutting Inconel 718, the orthogonal cutting test of high speed turning nickel - based superalloys Inconel 718 using coated carbide tool is presented. The results show that cutting force is influenced by cutting parameters, feed rate the most, followed by the depth of cut and cutting speed the minimum. So when finish turning Inconel 718 using coated carbide blades, small cutting force can be guaranteed by using low value of feed rate, depth of cut and high cutting speed.

  12. Corrosion resistance of 15Mo3 in steam boiler pipe surfaced with Inconel 625 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Aracic, S.; Samardzic, I.; Krumes, D. [Mechanical Engineering Faculty, Trg Ivane Brlic Mazuranic 18, HR-35000 Slavonski Brod (Croatia)

    2004-07-01

    This paper presents accelerated laboratory corrosion resistant investigation results made on steam boiler 15Mo3 steel pipes surfaced with alloy Inconel 625. Surfacing of 15Mo3 pipes was made due to pipes corrosion resistance increase in exploitation conditions which are present in fire box of trash burning plant. Corrosion resistance investigations were made in fire box simulated atmosphere and in salt spray chamber. (authors)

  13. Beschreibung des Eigenspannungsabbaus in kugelgestrahltem Inconel 718 bei thermischer, quasistatischer und zyklischer Beanspruchung

    OpenAIRE

    Hoffmeister, Jürgen

    2009-01-01

    Für die Nickelbasissuperlegierung Inconel 718 (IN718), die hauptsächlich als Scheibenlegierung für Gasturbinen eingesetzt wird, soll im Rahmen dieser Arbeit die Stabilität von unterschiedlichen, durch Kugelstrahlen erzeugten Randschichtzuständen untersucht und beschrieben werden. Es sollen die für Gasturbinen typischen Beanspruchungen berücksichtigt werden, wobei es sich hierbei um thermische, isotherm quasistatische und isotherm zyklische Beanspruchungen handelt.

  14. Fatigue Crack Growth Rate of Inconel 718 Sheet at Cryogenic Temperatures

    Science.gov (United States)

    Wells, Douglas; Wright, Jonathan; Hastings, Keith

    2005-01-01

    Inconel 718 sheet material was tested to determine fatigue crack growth rate (FCGR) at cryogenic conditions representative of a liquid hydrogen (LH2) environment at -423 degree F. Tests utilized M(T) and ESE(T) specimen geometries and environments were either cold gaseous helium or submersion in LH2. The test results support a significant improvement in the fatigue crack growth threshold at -423 degree F compared to -320 degree F or 70 degree F.

  15. The electrochemical polishing behavior of the Inconel 718 alloy in perchloric-acetic mixed acids

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.A. [Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan (China)], E-mail: gfehu@mail.cgu.edu.tw; Chen, Y.C.; Chang, J.H. [Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan (China)

    2008-02-15

    The electropolishing behavior of the Inconel 718 alloy was studied by using rotating disc electrode (RDE) in the HClO{sub 4}-CH{sub 3}COOH mixed acids with different HClO{sub 4}-concentrations. After electropolishing, surface morphologies of RDE specimens were examined with surface profiler, atomic force microscope and scanning electron microscope. According to the surface morphologies observed, three types of anodic dissolution behavior can be characterized in relation to the HClO{sub 4}-content in mixed acids; namely, leveling without brightening of the surface in the mixed acids with 10 and 20 vol% HClO{sub 4}, leveling and brightening of the surface in the mixed acids with 30 and 40 vol% HClO{sub 4}, and a matt and gray surface in the mixed acids with 50 vol% or more HClO{sub 4}. Anodic dissolution in the first and second dissolution types follows a mass-transfer controlled mechanism, in which a linear relationship between the reciprocal of limiting-current density and the reciprocal of square root of rotating speed of RDE specimen can be detected. Owing to precipitation of salt film on the polished surface of the Inconel 718 material, saturated dissolved metallic ions could be the chemical species for the mass-controlled mechanism. The salt film, in addition, could enhance the corrosion resistance of the Inconel 718 alloy.

  16. Experimental Investigation of process parameters influence on machining Inconel 800 in the Electrical Spark Eroding Machine

    Science.gov (United States)

    Karunakaran, K.; Chandrasekaran, M.

    2016-11-01

    The Electrical Spark Eroding Machining is an entrenched sophisticated machining process for producing complex geometry with close tolerances in hard materials like super alloy which are extremely difficult-to-machine by using conventional machining processes. It is sometimes offered as a better alternative or sometimes as an only alternative for generating accurate 3D complex shapes of macro, micro and nano-features in such difficult-to-machine materials among other advanced machining processes. The accomplishment of such challenging task by use of Electrical Spark Eroding Machining or Electrical Discharge Machining (EDM) is depending upon selection of apt process parameters. This paper is about analyzing the influencing of parameter in electrical eroding machining for Inconel 800 with electrolytic copper as a tool. The experimental runs were performed with various input conditions to process Inconel 800 nickel based super alloy for analyzing the response of material removal rate, surface roughness and tool wear rate. These are the measures of performance of individual experimental value of parameters such as pulse on time, Pulse off time, peak current. Taguchi full factorial Design by using Minitab release 14 software was employed to meet the manufacture requirements of preparing process parameter selection card for Inconel 800 jobs. The individual parameter's contribution towards surface roughness was observed from 13.68% to 64.66%.

  17. Effects of Flux Precoating and Process Parameter on Welding Performance of Inconel 718 Alloy TIG Welds

    Science.gov (United States)

    Lin, Hsuan-Liang; Wu, Tong-Min; Cheng, Ching-Min

    2014-01-01

    The purpose of this study is to investigate the effect of activating flux on the depth-to-width ratio (DWR) and hot cracking susceptibility of Inconel 718 alloy tungsten inert gas (TIG) welds. The Taguchi method is employed to investigate the welding parameters that affect the DWR of weld bead and to achieve optimal conditions in the TIG welds that are coated with activating flux in TIG (A-TIG) process. There are eight single-component fluxes used in the initial experiment to evaluate the penetration capability of A-TIG welds. The experimental results show that the Inconel 718 alloy welds precoated with 50% SiO2 and 50% MoO3 flux were provided with better welding performance such as DWR and hot cracking susceptibility. The experimental procedure of TIG welding process using mixed-component flux and optimal conditions not only produces a significant increase in DWR of weld bead, but also decreases the hot cracking susceptibility of Inconel 718 alloy welds.

  18. Surface Integrity of Inconel 718 by Wire-EDM at Different Energy Modes

    Science.gov (United States)

    Li, L.; Wei, X. T.; Guo, Y. B.; Li, W.; Liu, J. F.

    2014-08-01

    Inconel alloys including IN 718 alloy are widely used in turbomachinery industry due to their superior mechanical properties. Inconel alloys are very difficult to machine using cutting and grinding. Wire electrical discharge machining (W-EDM) is an alternative process to manufacture complex Inconel parts. However, little research has been done on surface integrity by W-EDMed IN 718. This study focuses on surface integrity of IN 718 by W-EDM at different modes of discharge energy. The results show that the EDMed surface topography shows dominant coral reef microstructures at high energy mode, while random microvoids are dominant at low energy modes. The average roughness can be significantly reduced at low energy mode. A thick white layer is predominantly discontinuous and non-uniform at relative high energy modes. Microvoids are confined within the thick white layers and no microcracks were found in the subsurface. A thin white layer by trim cut at low energy mode becomes continuous, uniform, and is free of voids. Compared to the bulk, white layers have dramatic reduction in microhardness. In addition, surface alloying from wire electrode and water dielectric is obvious in main cut, but it can be minimized in trim cuts.

  19. 激光熔覆Inconel 718合金铌偏聚

    Institute of Scientific and Technical Information of China (English)

    龙怡彤; 聂璞林; 李铸国; 黄坚; 李想; 徐昕媚

    2016-01-01

    Inconel 718高温合金被广泛地应用于航空航天和汽轮机领域。在激光熔覆Inconel 718合金中存在铌的偏聚现象,而铌偏聚会影响到合金在快速凝固过程中的相变。为了控制熔覆层的显微组织并提高其力学性能,采用组织观察和能谱分析研究凝固条件对铌偏聚及富铌Laves相形成的影响规律。结果表明冷却速度对熔覆组织具有显著影响。高的冷却速度有利于抑制铌的偏聚,减少对Inconel 718合金力学性能有害的Laves相的析出。

  20. Microstructure Development in Electron Beam-Melted Inconel 718 and Associated Tensile Properties

    Science.gov (United States)

    Kirka, M. M.; Unocic, K. A.; Raghavan, N.; Medina, F.; Dehoff, R. R.; Babu, S. S.

    2016-03-01

    During the electron beam melting (EBM) process, builds occur at temperatures in excess of 800°C for nickel-base superalloys such as Inconel 718. When coupled with the temporal differences between the start and end of a build, a top-to-bottom microstructure gradient forms. Characterized in this study is a microstructure gradient and associated tensile property gradient common to all EBM Inconel 718 builds, the extent of which is dependent on build geometry and the specifics of a build's processing history. From the characteristic microstructure elements observed in EBM Inconel 718 material, the microstructure gradient can be classified into three distinct regions. Region 1 (top of a build) is comprised of a cored dendritic structure that includes carbides and Laves phase within the interdendritic regions. Region 2 is an intermediate transition zone characterized by a diffuse dendritic structure, dissolution of the Laves phase, and precipitation of δ needle networks within the interdendritic regions. The bulk structure (Region 3) is comprised of a columnar grain structure lacking dendritic characteristics with δ networks having precipitated within the grain interiors. Mechanically, at both 20°C and 650°C, the yield strength, ultimate tensile strength, and elongation at failure exhibit the general trend of increasing with increasing build height.

  1. Investigation of low stress rupture properties in Inconel-718 super alloy

    Science.gov (United States)

    Zaman, T.; Farooque, M.; Rizvi, S. A.; Salam, I.; Waseem, M.

    2016-08-01

    Inconel-718 is a Ni-Cr-Fe based super alloy. It is widely utilized in aircraft gas turbines, nuclear power systems, space vehicles and medical applications. Aim of the present study is to evaluate the effect of Ti and Nb content on high temperature stress rupture properties of Inconel718. OM, SEM and TEM were utilized for characterization of microstructure. Inconel718 is unique in that it forms large number of phases due to its composition and variety of heat treatments. γ"+ γ' precipitates and the effect of annealing on these precipitates have been studied using TEM. The main hardening phase was identified as metastable Ni3Nb (γ"). Other phases identified after annealing were secondary carbides (NbC) and stable acicular 5 phase. Effect of γ", 5, primary carbides and NbC on creep behavior was observed using OM and SEM. Higher Ti content(1.25 wt. %) resulted in poor creep properties due to large concentrations of primary carbides (TiC) at grain boundaries.

  2. Inconel 718合金高速切削加工的工艺参数优化%Processing Parameter Optimization for High Speed Turning of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    吴江妙; 杨志强

    2009-01-01

    高温合金Inconel 718(铬镍铁合金)的高速切削加工具有重要意义.对高速切削加工过程中Inconel 718的可切削性进行试验研究,通过对切削力、切削温度、切屑形貌和材料声发射(AE)状态的观察,进行加工参数优化.试验中使用嵌入式碳化钨硬质合金(K20)刀具,在高速精密VDF车床干切削务件下进行Inconel718合金的高速切削.结果表明,能够获得最佳加工质量的切削速度为45~55 m/min,进给量为0.08 mm/r,切削深度为0.5 mm.

  3. Experimental Research on Surface Finish of Cutting Inconel 718%切削Inconel 718表面粗糙度的试验研究

    Institute of Scientific and Technical Information of China (English)

    黄雪红; 季德生

    2013-01-01

    The cutting tests of high speed turning Inconel 718 using coated carbide tool is presented.The influences of cutting parameters and tool abrasion on surface finish are studied.The results show that feeding affected on the surface finish of machined surface has been most,then is cutting depth,cutting speed is minimal.After entering normal wear stage,the surface roughness decreases,and cutting condition is optimum.%利用涂层硬质合金刀具对Inconel 718进行了高速切削试验,对不同切削参数下刀具的切削用量及刀具磨损对工件表面粗糙度的影响进行了研究.分析结果表明进给量对已加工表面的粗糙度影响最大,切削深度次之,切削速度最小;刀具进入正常磨损阶段后,表面粗糙度减小,处于最佳的切削状态.

  4. 镍基合金Inconel 718可切削加工性的试验研究%Research on the influence of carbon content on the machinability of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    徐林红; 江征风; Jan-Eric St(a)hl

    2010-01-01

    Inconel 718是一种高强度耐热镍基合金,具有优良的高温强度、高温硬度和耐蚀性,在高温条件下能长期工作,已被广泛地应用于宇航工业、航空工业的涡轮发动机和相关零件的制造.分析Inconel 718的机械性能、微观组织结构及其对切削加工性能的影响并进行了相关的试验验证,在试验数据的基础上,研究Inconel 718中含碳量对切削过程中刀具磨损的影响.试验结果表明,Inconel 718中含碳量在刀具后刀面磨损中起着非常重要的作用,Inconel 718合金中含碳量越高,合金中所含的细微硬质夹杂物也越多,在切削过程中使刀具产生严重的后刀面磨粒磨损,从而降低材料的切削加工性.

  5. Application of Inconel 718 to produce welding bellows mechanical seal%Inconel 718在热油泵波纹管机械密封中的应用

    Institute of Scientific and Technical Information of China (English)

    李臻

    2004-01-01

    介绍了热油泵机械密封焊接波纹管材料Inconel 718的力学性能、抗腐蚀性能、对0.13mm厚Inconel 718合金钢带采用不同的时效工艺的结果及其焊接波纹管制造工艺. 对0Cr18Ni9Ti、AM350、冷轧和时效Inconel 718材料在减压重脱油介质中进行的抗均匀腐蚀试验表明, Inconel 718与国内焊接波纹管常用材料0Cr18Ni9Ti的抗均匀腐蚀性能没有明显差别.经时效工艺处理的Inconel 718用于某炼油厂高温油泵的焊接型波纹管制造,效果良好.

  6. OXIDATION OF INCONEL 718 IN AIR AT TEMPERATURES FROM 973K TO 1620K.

    Energy Technology Data Exchange (ETDEWEB)

    GREENE,G.A.; FINFROCK,C.C.

    2000-10-01

    As part of the APT project, it was necessary to quantify the release of tungsten from the APT spallation target during postulated accident conditions in order to develop accident source terms for accident consequence characterization. Experiments with tungsten rods at high temperatures in a flowing steam environment characteristic of postulated accidents revealed that considerable vaporization of the tungsten occurred as a result of reactions with the steam and that the aerosols which formed were readily transported away from the tungsten surfaces, thus exposing fresh tungsten to react with more steam. The resulting tungsten release fractions and source terms were undesirable and it was decided to clad the tungsten target with Inconel 718 in order to protect it from contact with steam during an accident and mitigate the accident source term and the consequences. As part of the material selection criteria, experiments were conducted with Inconel 718 at high temperatures to evaluate the rate of oxidation of the proposed clad material over as wide a temperature range as possible, as well as to determine the high-temperature failure limit of the material. Samples of Inconel 718 were inserted into a preheated furnace at temperatures ranging from 973 K to 1620 K and oxidized in air for varying periods of time. After oxidizing in air at a constant temperature for the prescribed time and then being allowed to cool, the samples would be reweighed to determine their weight gain due to the uptake of oxygen. From these weight gain measurements, it was possible to identify three regimes of oxidation for Inconel 718: a low-temperature regime in which the samples became passivated after the initial oxidation, an intermediate-temperature regime in which the rate of oxidation was limited by diffusion and exhibited a constant parabolic rate dependence, and a high-temperature regime in which material deformation and damage accompanied an accelerated oxidation rate above the parabolic

  7. Surface Roughness and Tool Wear on Cryogenic Treated CBN Insert on Titanium and Inconel 718 Alloy Steel

    Science.gov (United States)

    Thamizhmanii, S.; Mohideen, R.; Zaidi, A. M. A.; Hasan, S.

    2015-12-01

    Machining of materials by super hard tools like cubic boron nitride (cbn) and poly cubic boron nitride (pcbn) is to reduce tool wear to obtain dimensional accuracy, smooth surface and more number of parts per cutting edge. wear of tools is inevitable due to rubbing action between work material and tool edge. however, the tool wear can be minimized by using super hard tools by enhancing the strength of the cutting inserts. one such process is cryogenic process. this process is used in all materials and cutting inserts which requires wear resistance. the cryogenic process is executed under subzero temperature -186° celsius for longer period of time in a closed chamber which contains liquid nitrogen. in this research, cbn inserts with cryogenically treated was used to turn difficult to cut metals like titanium, inconel 718 etc. the turning parameters used is different cutting speeds, feed rates and depth of cut. in this research, titanium and inconel 718 material were used. the results obtained are surface roughness, flank wear and crater wear. the surface roughness obtained on titanium was lower at high cutting speed compared with inconel 718. the flank wear was low while turning titanium than inconel 718. crater wear is less on inconel 718 than titanium alloy. all the two materials produced saw tooth chips.

  8. Experimental Investigation on High-speed Turning of Inconel 718 with Tungsten Carbide Tool%碳化钨刀具对Inconel 718合金的高速切削实验研究

    Institute of Scientific and Technical Information of China (English)

    吴江妙; 杨志强

    2010-01-01

    利用碳化钨硬质合金刀具为Inconel 718合金进行高速切削,研究单位切削力、工件表面粗糙度、加工表面微观结构和刀具磨损在切削过程中随加工参数的变化,以寻找最佳切削条件,提出适当切削方法克服Inconel 718合金的加工障碍.同时,利用碳化钨刀具替代昂贵的PCD或CBN刀具进行切削,也为高速切削Inconel 718合金提供了较为经济的方案.

  9. 切削速度对Inconel718加工表面完整性的影响%Effects of Cutting Speed on Surface Integrity of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    曹成铭; 刘战强; 杨奇彪

    2011-01-01

    As one kind of high strength and thermal resistant nickel-based alloys, Inconel 718 has been used extensively in aerospace industries. To satisfy the instant requirements of higher material removal rate and good surface integrity from engineering practice, high speed machining of Inconel 718 is an inevitable trend. The influences of cutting speed on surface integrity were investigated through the experimental study with high-speed milling Inconel 718 using Sialon ceramic tool. The results showed that higher cutting speed could exploit to give excellent surface integrity. The best surface integrity was obtained in the investigation at the highest cutting speed of 1 400 m/min in the applied cutting speed range.%随着机械加工对于更快的材料去除率和更好的表面完整性的需求,高速切削高强度镍基高温合金Inconel 718的应用是必然的发展趋势.通过赛阿龙(Sialon)陶瓷刀具高速铣削Inconel 718试验,研究切削速度对Inconel 718加工表面完整性的影响规律.结果表明,随着切削速度的提高加工表面完整性越来越好,在试验条件范围内,当切削速度达到1 400 m/min时,获得的表面完整性最好.

  10. Mechanical properties of Inconel 718 and Nickel 201 alloys after thermal histories simulating brazing and high temperature service

    Science.gov (United States)

    James, W. F.

    1985-01-01

    An experimental investigation was made to evaluate two nickel base alloys (Nickel-201 and Inconel-718) in three heat treated conditions. These conditions were: (1) annealed; (2) after thermal exposure simulating a braze cycle; and (3) after a thermal exposure simulating a braze cycle plus one operational lifetime of high temperature service. For the Nickel-201, two different braze cycle temperatures were evaluated. A braze cycle utilizing a lower braze temperature resulted in less grain growth for Nickel-201 than the standard braze cycle used for joining Nickel-201 to Inconel-718. It was determined, however, that Nickel-201, was marginal for temperatures investigated due to large grain growth. After the thermal exposures described above, the mechanical properties of Nickel-201 were degraded, whereas similar exposure on Inconel-718 actually strengthened the material compared with the annealed condition. The investigation included tensile tests at both room temperature and elevated temperatures, stress-rupture tests, and metallographic examination.

  11. 变形高温合金 INCONEL 718疲劳性能的研究进展%RESEARCH DEVELOPMENT ON FATIGUE PROPERTIES OF FORGED INCONEL 718 SUPERALLOY

    Institute of Scientific and Technical Information of China (English)

    王海瑛

    2008-01-01

    INCONEL 718是目前应用范围最广、用量最大的高温合金,从高周疲劳特性的研究、元素B和P对低周疲劳特性的影响、显微组织对718合金疲劳性能的影响三方面综述了目前国内外对变形高温合金INCONEL 718疲劳性能的研究情况.

  12. 高速成型车削镍基合金Inconel 718的建模和有限元分析%Model and FEM of High - speed Form Turning Nickel Based on Alloy Inconel 718

    Institute of Scientific and Technical Information of China (English)

    杨军; 陈鸣; 陈云; 刘洪; 李发强; 谢勇

    2012-01-01

    The study simulates high speed turning of Inconel 718 forming cutting by software Deform 3D,then analyses the cutting forces, chip shape under different cutting depth process condition and the stress and wear of cutting tool .%利用Deform 3D有限元分析软件,模拟成型车削Inconel 718,分析了不同切削深度和切削速度下的切削力及卷屑排屑状况,并对刀具应力及刀具磨损进行了分析.

  13. Dissolution kinetics of δ phase in Inconel 718 alloy%Inconel 718合金δ相的溶解动力学

    Institute of Scientific and Technical Information of China (English)

    蔡大勇; 张伟红; 刘文昌; 姚枚

    2006-01-01

    采用X射线衍射技术测定了Inconel 718合金中δ相在980、 1 000和1 020 ℃时的溶解动力学, 并采用扫描电镜进行了组织观察. 结果表明: Inconel 718合金在980、 1 000和1 020 ℃保温过程中, δ相含量逐渐降低, 经1 020 ℃保温2 h后, δ相可完全溶入基体;当温度为980和1 000 ℃时, δ相的平衡含量分别约为3%及0.6%. δ相的溶解过程可分为两个阶段, 溶解初期主要表现为长针状δ相长度方向的断裂, 且很快溶解断裂为短棒状及颗粒状, 同时在厚度方向上尺寸逐渐减小;随着溶解过程的进行, 后续的溶解过程主要为短棒状及颗粒状δ相尺寸的减小. δ相溶解动力学过程的控制环节并非Nb或Ni原子的长程扩散过程, 而为δ相分解的界面反应过程.

  14. A Comparison of Weld-Repaired and Base Metal for Inconel 718 and CRES 321 at Cryogenic and Room Temperatures

    Science.gov (United States)

    Newman, John A.; Smith, Stephen W.; Willard, Scott A.; Piascik, Robert S.

    2004-01-01

    Fatigue crack growth tests were conducted to characterize the performance of Inconel 718 and CRES 321 welds, weld heat-affect-zone and parent metal at room temperature laboratory air and liquid nitrogen (-196oC) environments. The results of this study were required to predict the damage tolerance behavior of proposed orbiter main engine hydrogen fuel liner weld repairs. Experimental results show that the room and cryogenic temperature fatigue crack growth characteristics of both alloys are not significantly degraded by the weld repair process. However, both Inconel 718 and CRES 321 exhibited lower apparent toughness within the weld repair region compared to the parent metal.

  15. 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF and its load response

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The 3-sheet structure of Inconel 718 superalloy will be used in flying vehicles as heat resisting and shielding structure due to its lightweight, high strength and stiffness. The 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF (laser beam welding/superplastic forming) technology exhibited good configuration and uniform thickness distribution. The LBW parameters for 3-sheet structure were as follows: Pulse frequency was 32 Hz, impulse duration 3 ms, peak power per pulse 4500 W, and welding speed 180 mm/min. The SPF parameters were as follows: Temperature T=965 ℃, forming pressure P=4.2 MPa, and forming time t=130 min. The microstructure in weld fusion zone was consti- tuted of austenite dendritics and Laves phase precipitated in interdendritics. After the SPF process, austenite dendritics in the weld fusion became coarser and most of Laves phases were dissolved and turned into δ precipitated phase, but a few of Laves phases were still reserved. And Nb concentration in dendritics increased to 5.42% compared to 2.82% in as-weld condition. Weld metal Vickers-hardness increased from 331.63 in as-weld condition to 391.74 in post-SPF condition which was closed to the base material Vickers-hardness of post-SPF. Grain size of base material grew slightly and an amount of precipitated phase appeared in the base material undergoing SPF process. The tensile test results of base material showed that tensile strength increased obviously and the ductility decreased slightly after SPF process. Load response test results indicated that the 3-sheet structure possessed good resistance to compression and bending load. Accordingly, the LBW/SPF technology is an appropriate forming technique for the 3-sheet structure of Inconel 718 superalloy.

  16. 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF and its load response

    Institute of Scientific and Technical Information of China (English)

    QU FengSeng; ZHANG KaiFeng

    2009-01-01

    The 3-sheet structure of Inconel 718 superalloy will be used in flying vehicles as heat resisting and shielding structure due to its lightweight,high strength and stiffness.The 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF(laser beam welding/superplastic forming)technology exhibited good configuration and uniform thickness distribution.The LBW parameters for 3-sheet structure were as follows:Pulse frequency was 32 Hz,impulse duration 3 ms,peak power per pulse 4500 W,and welding speed 180 mm/min.The SPF parameters were as follows:Temperature T=965℃,forming pressure P=-4.2 MPa,and forming time t=130 min.The microstructure in weld fusion zone was constituted of austenite dendritics and Laves phase precipitated in interdendritics.After the SPF process,austenite dendritics in the weld fusion became coarser and most of Laves phases were dissolved and turned into δprecipitated phase,but a few of Laves phases were still reserved.And Nb concentration in dendritics increased to 5.42% compared to 2.82% in as-weld condition.Weld metal Vickers-hardness increased from 331.63 in as-weld condition to 391.74 in post-SPF condition which was closed to the base material Vickers-hardness of post-SPF.Grain size of base material grew slightly and an amount of precipitated phase appeared in the base material undergoing SPF process.The tensile test results of base material showed that tensile strength increased obviously and the ductility decreased slightly after SPF process.Load response test results indicated that the 3-sheet structure possessed good resistance to compression and bending load.Accordingly,the LBW/SPF technology is an appropriate forming technique for the 3-sheet structure of inconel 718 superalloy.

  17. Industrial Process Design for Manufacturing Inconel 718 Extremely Large Forged Rings

    Science.gov (United States)

    Ambielli, John F.

    2011-12-01

    Inconel 718 is a Ni-Fe-based superalloy that has been central to the gas turbine industry since its discovery in 1963. While much more difficult to process than carbon or stainless steels, among its superalloy peers Inconel 718 has relatively high forgeability and has been used to make discs, rings, shells, and structural components. A metal forming process design algorithm is presented to incorporate key criteria relevant to superalloy processing. This algorithm was applied to conceptual forging and heat treating extremely large rings of Inconel 718 of diameter 1956 mm (77in) and weight 3252 kg (7155 lb). A 3-stage standard thermomechanical (TMP) processing was used, where Stage 1 strain varied from 0.1190 to 0.2941, Stage 2 from 0.0208 to 0.0357 and Stage 3 from 0.0440 to 0.0940. This was followed by heat treatment of a solution anneal (954°C/1750°F for 4 hour hold), air cool, then a double aging (718°C/1325°F for 8 hour hold; furnace cool to 621°C/1150°F 56°C/100°F per hr; 18 hour total time for both steps). Preliminary mechanical testing was performed. Average yield strength of 951 MPa/138 ksi (longitudinal) and 979 MPa/142 ksi (axial) was achieved. Tensile strengths were 1276 MPa/185 ksi (longitudinal) and 1255 MPa/182 ksi (axial). Elongations and reduction of areas attained were, respectively, 18 (long) and 25 (axial) and 28 (long) and 27 (axial).

  18. Normal spectral emittance of Inconel 718 aeronautical alloy coated with yttria stabilized zirconia films

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Campo, L. del [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.es [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Emittance of Inconel 718 coated with plasma sprayed yttria stabilized zirconia. Black-Right-Pointing-Pointer The coating is opaque for {lambda} > 9 {mu}m and semi-transparent for {lambda} < 9 {mu}m. Black-Right-Pointing-Pointer In the semi-transparent region the emittance decreases with coating thickness. Black-Right-Pointing-Pointer 300 {mu}m thick coatings are still semi-transparent. Black-Right-Pointing-Pointer In the opaque region the surface roughness determines the emittance level. - Abstract: Knowledge of the radiative behaviour of the yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) is needed to perform radiative heat transfer calculations in industrial applications. In this paper, normal spectral emittance experimental data of atmospheric plasma sprayed (PS) YSZ films layered on Inconel 718 substrates are shown. The spectral emittance was measured between 2.5 and 22 {mu}m on samples with film thicknesses ranging from 20 to 280 {mu}m. The samples were heated in a controlled environment, and the emittance was measured for several temperatures between 330 and 730 Degree-Sign C. The dependence of the spectral emittance with film thickness, surface roughness and temperature has been studied and compared with the available results for YSZ TBCs obtained by electron-beam physical vapour deposition. The PS-TBC samples show a Christiansen point at {lambda} = 12.8 {mu}m. The films are semi-transparent for {lambda} < 9 {mu}m, and opaque for {lambda} > 9 {mu}m. In the semi-transparent region, the contribution of the radiation emitted by the Inconel 718 substrate to the global emittance of the samples is analysed. In addition, the influence of the roughness in the emittance values in the opaque spectral region is discussed. Finally, the total normal emittance is obtained as a function of the TBC thickness.

  19. 激光快速成形Inconel718超合金拉伸力学性能研究%Research on Tensile Properties of Inconel 718 Superalloy Fabricated by Laser Rapid Forming Process

    Institute of Scientific and Technical Information of China (English)

    席明哲; 高士友

    2012-01-01

    研究了激光快速成形Inconel 718超合金试样3个相互垂直方向的拉伸力学性能,以及热处理对激光快速成形凝固组织与3个相互垂直方向拉伸力学性能的影响.结果表明,激光快速成形Inconel 718超合金试样3个相互垂直方向的拉伸力学性能均明显低于其锻件拉伸力学性能,且表现出明显的各向异性.经过热处理的Inconel 718超合金试样,其沿沉积高度方向定向外延生长的柱状枝晶组织转变为晶粒粗大且不均匀的等轴状再结晶组织,随Laves相固溶消失及强化相γ"和γ'大量析出,3个相互垂直方向上的拉伸力学性能均大幅度提高,其中,与基板平行的两个相互垂直方向上的拉伸力学性能均达到Inconel 718超合金锻件拉伸力学性能标准,但沿成形件高度方向,出现拉伸力学性低于Inconel 718超合金锻件拉伸力学性能标准的试样.%The tensile mechanical properties in three mutually perpendicular directions of Inconel 718 superalloy sample fabricated by laser rapid forming (LRF) are studied. The influences of heat treatment on both the solidification microstructures of and the tensile mechanical properties in three mutually perpendicular directions of Inconel 718 superalloy sample are investigated. It is shown that the tensile mechanical properties of all test specimens are clearly inferior to that of wrought Inconel 718 superalloy. After being heat treated, the coarse columnar dendrites growing epitaxially along the deposition direction of as-deposited Inconel 718 superalloy change to the coarse and non-uniform equiaxed grains due to recrystallization. With the dissolution of Laves phase and precipitation of a large number of strengthening phase γ" and γ' the tensile mechanical properties in three mutually directions increase substantially. The tensile properties of tested specimens whose tensile directions are parallel with the base plate reach the tensile properties standard of wrought

  20. Crack-growth behavior in thick welded plates of Inconel 718 at room and cryogenic temperatures

    Science.gov (United States)

    Forman, R. G.

    1974-01-01

    Results of mechanical-properties and axial-load fatigue and fracture tests performed on thick welded plates of Inconel 718 superalloy are presented. The test objectives were to determine the tensile strength properties and the crack-growth behavior in electron-beam, plasma-arc, and gas tungsten are welds for plates 1.90 cm (0.75 in) thick. Base-metal specimens were also tested to determine the flaw-growth behavior. The tests were performed in room-temperature-air and liquid nitrogen environments. The experimental crack-growth-rate data are correlated with theoretical crack-growth-rate predictions for semielliptical surface flaws.

  1. Effect of Plasma Nitriding Parameters on the Wear Resistance of Alloy Inconel 718

    Science.gov (United States)

    Kovací, Halim; Ghahramanzadeh ASL, Hojjat; Albayrak, Çigdem; Alsaran, Akgün; Çelik, Ayhan

    2016-11-01

    The effect of the temperature and duration of plasma nitriding on the microstructure and friction and wear parameters of Inconel 718 nickel alloy is investigated. The process of plasma nitriding is conducted in a nitrogen-hydrogen gaseous mixture at a temperature of 400, 500 and 600°C for 1 and 4 h. The modulus of elasticity of the nitrided layer, the micro- and nanohardness, the surface roughness, the friction factor and the wear resistance of the alloy are determined prior to and after the nitriding. The optimum nitriding regime providing the best tribological characteristics is determined.

  2. PCBN刀具在Inconel 718加工中的应用

    Institute of Scientific and Technical Information of China (English)

    王魄

    2006-01-01

    Inconel 718应用简介 术语“超级合金”描述了一个范围广泛的专门用于通常在高温下苛求优异的机械和化学特性而开发的镍、铁和钻基合金。大约2/3的超级合金被用于航空工业的动力涡轮机和相关零件的制造。

  3. ANALYSIS OF THE SURFACE PROFILE AND ITS MATERIAL SHARE DURING THE GRINDING INCONEL 718 ALLOY

    Directory of Open Access Journals (Sweden)

    Martin Novák

    2015-05-01

    Full Text Available Grinding is still an important method for surface finishing. At FPTM JEPU research, which deals with this issue is conducted. Experiments are carried out with grinding various materials under different conditions and then selected components of the surface integrity are evaluated. They include roughness Ra, Rm and Rz, Material ratio curve (Abbott Firestone curve and also the obtained roundness. This article deals with grinding nickel Inconel 718 alloy, when selected cutting grinding conditions were used and subsequently the surface profile and the material ratio curve were measured and evaluated.

  4. Spectral Emittance of Uncoated and Ceramic-Coated Inconel and Type 321 Stainless Steel

    Science.gov (United States)

    Richmond, Joseph C.; Stewart, James E.

    1959-01-01

    The normal spectral emittance of Inconel and type 321 stainless steel with different surface treatments was measured at temperatures of 900, 1,200, 1,500, and 1,800 F over a wavelength range of 1.5 to 15 microns. The measurements involved comparison of the radiant energy emitted by the heated specimen with that emitted by a comparison standard at the same temperature by means of a recording double-beam infrared spectrophotometer. The silicon carbide comparison standard had previously been calibrated against a laboratory black-body furnace. Surface treatments included electropolishing, sandblasting, electro-polishing followed by oxidation in air for 1/2 hour at 1,800 F, sandblasting followed by oxidation in air for 1/2 hour at 1,800 F, application of National Bureau of Standards coating A-418, and application of NBS ceramic coating N-143. The normal spectral emittance of both alloys in the electropolished condition was low and decreased very slightly with increasing wavelength while in the sandblasted condition it was somewhat higher and did not vary appreciably with wavelength. The oxidation treatment greatly increased the normal spectral emittance of both the electropolished and sandblasted type 321 stainless steel specimens and of the electropolished Inconel specimens and introduced some spectral selectivity into the curves. The oxidation increased the normal spectral emittance of the sandblasted Inconel specimens only moderately. Of the specimens to which a coating about 0.002 inch thick was applied, those coated with A-418 had higher emittance at all wavelengths than did those coated with N-143, and the coated specimens of Inconel had higher spectral emittance at all wavelengths than did the corresponding specimens of type 321 stainless steel. Both coatings were found to be partially transparent to the emitted energy at this thickness but essentially opaque at a thickness of 0.005 inch. Coated specimens with 0.005 inch or more of coating did not show the effect

  5. Estudo do uso de ferramentas cerâmicas na usinagem de inconel 718

    OpenAIRE

    Santos, Júlio César dos

    2010-01-01

    A usinagem de superligas de níquel e ligas resistentes a altas temperaturas como o inconel 718 sempre representou uma tarefa difícil no chão-de-fábrica. Mas as aplicações industriais desses materiais passaram por rápida evolução nos últimos anos. Na indústria aeroespacial, o crescimento da popularidade destes materiais tem sido evidenciado na forma de palhetas de turbina, peças de compressor, suportes e elementos de conjuntos para aviação. Devido a suas propriedades e aos benefícios que traze...

  6. Nucleation mechanisms of dynamic recrystallization in Inconel 625 superalloy deformed with different strain rates

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The effects of strain rates on the hot working characteristics and nucleation mechanisms of dynamic recrystallization (DRX) were studied by optical microscopy and electron backscatter diffraction (EBSD) technique. Hot compression tests were conducted using a Gleeble-1500 simulator at a true strain of 0.7 in the temperature range of 1000 to 1150 °C and strain rate range of 0.01 to 10.00 s-1. It is found that the size and volume fraction of the DRX grains in hot-deformed Inconel 625 superalloy firstly decreas...

  7. δ相对Inconel 718合金组织与疲劳性能影响的研究进展%Research Progress in Effect of δ Phase on Microstructure and Fatigue Property of Inconel 718 Alloy

    Institute of Scientific and Technical Information of China (English)

    司家勇; 刘锋

    2013-01-01

    It is the key factor to ensure the properties of the product that the quantity and morphology of S phase in Inconel 718 alloy. The research progress in effect of δ phase on microstructure and fatigue property of Inconel 718 alloy are summarized. Three aspects, the formation, precipitation dissolution behavior of δ phase, relationship be tween 8 phase and hot deformation parameters, effect of 8 phase on the fatigue property, are introduced.%Inconel 718合金中δ相数量与形貌的控制是保证产品性能的关键因素.介绍了近年来Inconel 718合金中δ相对其组织与疲劳性能影响的研究进展.综述了合金中δ相的形成与析出、溶解规律,δ相与热变形参数间的对应关系及δ相对疲劳性能的影响.

  8. Development of inconel 718 processing performance under different cooling and lubricating condition%研究不同冷却润滑条件下切削镍基合金Inconel 718的加工性能

    Institute of Scientific and Technical Information of China (English)

    石鹏辉; 冯益华; 贾孝伟; 黄海霞; 李福盟

    2014-01-01

    The research progress of cutting nickel based alloy Inconel 718 machined cooling and lubrication condition was summarized at home and abroad in recent years.By comparing with the cutting force,cutting temperature, tool life, product surface quality, product surface roughness and so on to compare the cutting performance of nicked based alloy under dry cutting,MQL and cryogenic machining condition was introduced .The advantages and disadvantages of various methods and their applicable scope were compared.The development direction of processing method of difficult machining material like nickel base alloy inconel 718 was put forward.%综述了近年来国内外切削镍基合金Inconel 718的加工冷却润滑条件的研究进展,通过比较切削力、刀具寿命、切削温度、表面质量、表面粗糙度等几个方面来比较干式切削、微量润滑和低温冷风等条件下镍基合金的切削性能,介绍并比较了各种切削条件的优缺点和各自的适用范围。提出镍基合金Inconel 718等难加工材料的加工方法的发展方向。

  9. Inconel718高温合金多层夹芯板结构的LBW/SPF技术%Multi-sheet Sandwich Structure of Inconel718 Superalloy Manufactured by LBW/SPF Technology

    Institute of Scientific and Technical Information of China (English)

    董旭刚; 曲凤盛; 张凯锋

    2013-01-01

    Multi-sheet sandwich structure of Inconel718 superalloy will be widely used for low-cost, lightweight rocket engine manufacturing due to its lightweight, high strength and stiffness. Multi-sheet sandwich structure of Inconel718 superalloy was manufactured by LBW/SPF (laser beam welding/superplastic forming) technology. Test results showed; Superplasticity of Inconel718 superalloy was investigated. Under T = 950℃ and initial strain rate with ε = 1. 6 × 10-4 /s,the elongation of Inconel718 superalloy was 483. 6%. The multi-sheet sandwich structure manufactured by laser LBW/SPF technology had good shape, uniform wall thickness distribution. The laser penetration welding parameters of face plate and core plate were as follows:Power 1050W,welding speed 1000mm/min,defocusing amount -0. 80mm,shield gas flow 0. 6L/min. The laser penetration welding parameters between the core plates were as follows: Power 900W, welding speed l000mm/min, defocusing amount - 1. 00mm, shield gas flow 0. 6L/min. The parameters for superplastic forming were as follows; temperature Tf = 965℃,pressure Pf =4. 2MPa,time tf = 130min. Superplastic forming process was favorable to improving the microstructure and mechanical properties of laser welding joints. Accordingly, LBW/SPF technology is an appropriate forming technology for multi-sheet sandwich structure of Inconel718 superalloy.%Inconel718高温合金多层夹心板结构具有高强度、高刚度、轻量化结构的特点,已用于低成本、轻质火箭发动机的制造.采用LBW/SPF技术制造了Inconel718合金多层夹芯结构件,并对其超塑成形前后的微观组织进行了分析.试验结果表明:超细晶Inconel718合金板材具有优良的超塑性能,在T=950℃,初始应变速率为1.6×10-4/s的条件下,延伸率达到483.6%.LBW/SPF技术制造出的Inconel718高温合金多层夹芯构件具有外观形状良好、壁厚分布均匀等特点.面板与芯板激光焊接参数为:功率1050W,焊接速度1000mm

  10. GRAIN GROWTH MODEL OF INCONEL 718 ALLOY FORGED SLAB IN REHEATING PROCESS PRIOR TO ROUGH ROLLING%Inconel 718合金方坯粗轧加热过程晶粒长大模型

    Institute of Scientific and Technical Information of China (English)

    陈礼清; 隋凤利; 刘相华

    2009-01-01

    The Inconel 718 superalloy is extensively used to manufacture critical parts in aero-nautical, astronautical, oil and chemical industries due to its excellent mechanical, physical and anti-corrosion behavior. Usually, these parts are shaped by hot forging or rolling in open-train mills. Recently, the tandem hot rolling has been applied to form superalloy bar products. In some cases, it can replace the traditional rolling, since it has higher productivity and product quality. In order to obtain the most favorable microstructure and the best mechanical properties of Inconel 718 alloy in tandem hot rolling, it is necessary to control its microstructural evolution in every step of the whole rolling process. With the aid of computer modeling, it is possible to make such a controlling process possible. As the first step in tandem hot rolling, reheating process of a forged slab prior to rough rolling plays a predominant role in predicting the grain size change or even the microstructural evo-lution. Thus, in this study, an Inconel 718 alloy forged slab was used as the experimental material and the effects of reheating temperature and holding time on its grain growth were investigated. A universal model was developed and verified for the grain growth of Inconel 718 alloy forged slab in reheating process prior to rough rolling. With the increase of holding time, the grain size shows no remarkable change up to 1173 K. The grain growth presents a linear trend in the range from 1173 to 1323 K. A parabolic trend of grain growth can be observed when reheating temperature is higher than 1323 K. The established grain growth model of Inconel 718 alloy would be suitable to calculate the grain size evolution under the both isothermal and non-isothermal reheating conditions. This could also provide a basis in formulating the technological parameters for tandem hot rolling of Inconel 718 superalloy.%以Inconel 718合金锻坯为研究对象,在1173-1423 K的温度范围内,研究了加热温度和时间对Inconel

  11. Microstructural analysis of ion-irradiation-induced hardening in inconel 718

    Science.gov (United States)

    Hashimoto, N.; Hunn, J. D.; Byun, T. S.; Mansur, L. K.

    2003-05-01

    As an assessment for a possible accelerator beam line window material for the US Spallation Neutron Source (SNS) target, performance, radiation-induced hardening and microstructural evolution in Inconel 718 were investigated in both solution annealed (SA) and precipitation hardened (PH) conditions. Irradiations were carried out using 3.5 MeV Fe +, 370 keV He + and 180 keV H + either singly or simultaneously at 200 °C to simulate the damage and He/H production in the SNS target vessel wall. This resulted in systematic hardening in SA Inconel and gradual net softening in the PH material. TEM microstructural analysis showed the hardening was associated with the formation of small loop and faulted loop structures. Helium-irradiated specimens included more loops and cavities than Fe + ion-irradiated specimens. Softening of the PH material was due to dissolution of the γ '/γ ″ precipitates. High doses of helium were implanted in order to study the effect of high retention of gaseous transmutation products. Simultaneous with the hardening and/or softening due to the displacement damage cascade, helium filled cavities produced additional hardening at high concentrations.

  12. Multi-criteria decision making in the selection of machining parameters for Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Thirumalai, R. [SNS College of Technology, Coimbatore (India); Senthilkumaar, J. S. [Bharathithasan Engineering College, Nattrampalli (India)

    2013-04-15

    Taguchi's methods and design of experiments are invariably used and adopted as quality improvement techniques in several manufacturing industries as tools for offline quality control. These methods optimize single-response processes. However, Taguchi's method is not appropriate for optimizing a multi-response problem. In other situations, multi-responses need to be optimized simultaneously. This paper presents multi-response optimization techniques. A set of non-dominated solutions are obtained using non-sorted genetic algorithm for multi-objective functions. Multi-criteria decision making (MCDM) is proposed in this work for selecting a single solution from nondominated solutions. This paper addresses a new method of MCDM concept based on technique for order preference by similarity to ideal solution (TOPSIS). TOPSIS determines the shortest distance to the positive-ideal solution and the greatest distance from the negative-ideal solution. This work involves the high-speed machining of Inconel 718 using carbide cutting tool with six objective functions that are considered as attributes against the process variables of cutting speed, feed, and depth of cut. The higher-ranked solution is selected as the best solution for the machining of Inconel 718 in its respective environment.

  13. Mechanical Behaviour of Inconel 718 Thin-Walled Laser Welded Components for Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Enrico Lertora

    2014-01-01

    Full Text Available Nickel alloys are very important in many aerospace applications, especially to manufacture gas turbines and aero engine components, where high strength and temperature resistance are necessary. These kinds of alloys have to be welded with high energy density processes, in order to preserve their high mechanical properties. In this work, CO2 laser overlap joints between Inconel 718 sheets of limited thickness in the absence of postweld heat treatment were made. The main application of this kind of joint is the manufacturing of a helicopter engine component. In particular the aim was to obtain a specific cross section geometry, necessary to overcome the mechanical stresses found in these working conditions without failure. Static and dynamic tests were performed to assess the welds and the parent material fatigue life behaviour. Furthermore, the life trend was identified. This research pointed out that a full joint shape control is possible by choosing proper welding parameters and that the laser beam process allows the maintenance of high tensile strength and ductility of Inconel 718 but caused many liquation microcracks in the heat affected zone (HAZ. In spite of these microcracks, the fatigue behaviour of the overlap welds complies with the technical specifications required by the application.

  14. Influence of Process Parameters in n-PMEDM of Inconel 800 with Electrode and Coated Electrodes

    Directory of Open Access Journals (Sweden)

    Karunakaran K.

    2017-01-01

    Full Text Available By considering the unique performances, the Powder Mixed Electrical Discharge Machining (PMEDM mostly encounter choice for machining the hard materials with job features like intricate shapes with grater accuracy and those materials are difficult to cut in conventional machining processes. This Research aimed to prepare parameter index chart for machining nickel based super alloy - Inconel 800 for various requirements. To achieve the aim, In this experimental study on machining of Inconel 800 in PMEDM with electrolyte copper electrode as well as silver coated electrolyte copper electrode is focused. Taguchi full factorial design derived from MINITAB release-16 software was used to design the experimentation. The factors like pulse off time, Current and Pulse on Time were considered. The responses like amount of Tool Wear, Quantity of material removal, surface finishes were noted against each case. In the same experimental conditions the coated electrode increased the MRR by 36.67% with minor increment of maximum surface roughness to 16.11%.

  15. Laser post-processing of Inconel 625 made by selective laser melting

    Science.gov (United States)

    Witkin, David; Helvajian, Henry; Steffeney, Lee; Hansen, William

    2016-04-01

    The effect of laser remelting of surfaces of as-built Selective Laser Melted (SLM) Inconel 625 was evaluated for its potential to improve the surface roughness of SLM parts. Many alloys made by SLM have properties similar to their wrought counterparts, but surface roughness of SLM-made parts is much higher than found in standard machine shop operations. This has implications for mechanical properties of SLM materials, such as a large debit in fatigue properties, and in applications of SLM, where surface roughness can alter fluid flow characteristics. Because complexity and netshape fabrication are fundamental advantages of Additive Manufacturing (AM), post-processing by mechanical means to reduce surface roughness detracts from the potential utility of AM. Use of a laser to improve surface roughness by targeted remelting or annealing offers the possibility of in-situ surface polishing of AM surfaces- the same laser used to melt the powder could be amplitude modulated to smooth the part during the build. The effects of remelting the surfaces of SLM Inconel 625 were demonstrated using a CW fiber laser (IPG: 1064 nm, 2-50 W) that is amplitude modulated with a pulse profile to induce remelting without spallation or ablation. The process achieved uniform depth of melting and improved surface roughness. The results show that with an appropriate pulse profile that meters the heat-load, surface features such as partially sintered powder particles and surface connected porosity can be mitigated via a secondary remelting/annealing event.

  16. Dynamic mechanical behaviour and dislocation substructure evolution of Inconel 718 over wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woei-Shyan, E-mail: wslee@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Chi-Feng [National Center for High-Performance Computing, Hsin-Shi Tainan County 744, Taiwan (China); Chen, Tao-Hsing [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan (China); Chen, Hong-Wei [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2011-07-25

    A compressive split-Hopkinson pressure bar and transmission electron microscope (TEM) are used to investigate the mechanical behaviour and microstructural evolution of Inconel 718 at strain rates ranging from 1000 to 5000 s{sup -1} and temperatures between -150 and 550 deg. C. The results show that the flow stress increases with an increasing strain rate or a reducing temperature. The strain rate effect is particularly pronounced at strain rates greater than 3000 s{sup -1} and a deformation temperature of -150 deg. C. A significant thermal softening effect occurs at temperatures between -150 and 25 deg. C. The microstructural observations reveal that the strengthening effect in deformed Inconel 718 alloy is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature. By contrast, the dislocation cell size decreases with increasing strain rate, but increases with increasing temperature. It is shown that the correlation between the flow stress, the dislocation density and the dislocation cell size is well described by the Bailey-Hirsch constitutive equations.

  17. Microstructure Stability of Inconel 740H Alloy After Long Term Exposure at 750℃

    Directory of Open Access Journals (Sweden)

    DANG Ying-ying

    2016-09-01

    Full Text Available Unstressed exposure tests of Inconel 740H alloy tube were carried out at 750℃ for 500-3000h. The microstructure evolution and microhardness were studied by means of thermodynamic simulation, OM, FEG-SEM and microhardness testing. The results show that the tube is qualified if both chemical composition and tensile properties of the as-received alloy meet the corresponding requirements of ASME. After long term exposure, the main precipitates are γ' and M23C6, and no η and σ phase. With the prolonging of exposure time, the coarsening of γ' becomes faster and the law of relationship between the radius of γ' and time accords with LSW Ostwald ripening law; meanwhile, the change in size of M23C6 is not so obvious. During the whole process, microhardness increases firstly and then decreases, but the fluctuation is slight. The changes of microstructure and hardness indicate that, after long time exposure, the domestic Inconel 740H has good stability and can be used for further carrying out the investigation on the mechanical property of creep-rupture.

  18. Development and Characterization of a Metal Injection Molding Bio Sourced Inconel 718 Feedstock Based on Polyhydroxyalkanoates

    Directory of Open Access Journals (Sweden)

    Alexandre Royer

    2016-04-01

    Full Text Available The binder plays the most important role in the metal injection molding (MIM process. It provides fluidity of the feedstock mixture and adhesion of the powder to keep the molded shape during injection molding. The binder must provide strength and cohesion for the molded part and must be easy to remove from the molded part. Moreover, it must be recyclable, environmentally friendly and economical. Also, the miscibility between polymers affects the homogeneity of the injected parts. The goal of this study is to develop a feedstock of superalloy Inconel 718 that is environmentally friendly. For these different binders, formulations based on polyethylene glycol (PEG, because of his water solubility property, and bio sourced polymers were studied. Polyhydroxyalkanoates (PHA were investigated as a bio sourced polymer due to its miscibility with the PEG. The result is compared to a standard formulation using polypropylene (PP. The chemical and rheological behavior of the binder formulation during mixing, injection and debinding process were investigated. The feedstock was characterized in the same way as the binders and the interactions between the powder and the binders were also studied. The results show the well adapted formulation of polymer binder to produce a superalloy Inconel 718 feedstock.

  19. Surface Integrity and Structural Stability of Broached Inconel 718 at High Temperatures

    Science.gov (United States)

    Chen, Z.; Peng, R. Lin; Moverare, J.; Avdovic, P.; Zhou, J. M.; Johansson, S.

    2016-07-01

    The current study focused on the surface integrity issues associated with broaching of Inconel 718 and the structural stability of the broached specimen at high temperatures, mainly involving the microstructural changes and residual stress relaxation. The broaching operation was performed using similar cutting conditions as that used in turbo machinery industries for machining fir-tree root fixings on turbine disks. Thermal exposure was conducted at 723 K, 823 K, and 923 K (450 °C, 550 °C, and 650 °C) for 30, 300, and 3000 hours, respectively. Surface cavities and debris dragging, sub-surface cracks, high intensity of plastic deformation, as well as the generation of tensile residual stresses were identified to be the main issues in surface integrity for the broached Inconel 718. When a subsequent heating was applied, surface recrystallization and α-Cr precipitation occurred beneath the broached surface depending on the applied temperature and exposure time. The plastic deformation induced by the broaching is responsible for these microstructural changes. The surface tension was completely relaxed in a short time at the temperature where surface recrystallization occurred. The tensile layer on the sub-surface, however, exhibited a much higher resistance to the stress relief annealing. Oxidation is inevitable at high temperatures. The study found that the surface recrystallization could promote the local Cr diffusion on the broached surface.

  20. ANALYSIS OF PITTING CORROSION ON AN INCONEL 718 ALLOY SUBMITTED TO AGING HEAT TREATMENT

    Directory of Open Access Journals (Sweden)

    Felipe Rocha Caliari

    2014-10-01

    Full Text Available Inconel 718 is one of the most important superalloys, and it is mainly used in the aerospace field on account of its high mechanical strength, good resistance to fatigue and creep, good corrosion resistance and ability to operate continuously at elevated temperatures. In this work the resistance to pitting corrosion of a superalloy, Inconel 718, is analyzed before and after double aging heat treatment. The used heat treatment increases the creep resistance of the alloy, which usually is used up to 0.6 Tm. Samples were subjected to pitting corrosion tests in chloride-containing aqueous solution, according to ASTM-F746-04 and the procedure described by Yashiro et al. The results of these trials show that after heat treatment the superalloy presents higher corrosion resistance, i.e., the pitting corrosion currents of the as received surfaces are about 6 (six times bigger (~0.15 mA than those of double aged surfaces (~0.025 mA.

  1. Experimental Investigation into the Effect of Ball End Milling Parameters on Surface Integrity of Inconel 718

    Science.gov (United States)

    Bhopale, Nandkumar N.; Joshi, Suhas S.; Pawade, Raju S.

    2015-02-01

    In machining of Inconel 718, various difficulties such as increased tool wear and poor machined surface quality are frequently encountered due to its high temperature strength and poor thermal properties. This work considers the effect of number of passes and the machining environment on the machined surface quality in ball end milling of Inconel 718, which hitherto has not been adequately understood. To this effect, extensive experimentation has been carried out to analyze machined surface quality and integrity in terms of surface roughness, surface damage, and microhardness variation in the machined surfaces. The machined surfaces show formation of distinct bands as a function of instantaneous machining parameters along the periphery of cutting tool edge. A distinct variation is also observed in the measured values of surface roughness and microhardness in these regions. The minimum surface roughness is obtained in the stable cutting zone and it increases toward the periphery of the cutter on band #2 and band #3. Microhardness of depth beneath the machined surface shows that the machining affected zone varies from 60 to 100 µm in ball end milling under various machining conditions.

  2. Effect of thermal exposure on microstructure and nano-hardness of broached Inconel 718

    Directory of Open Access Journals (Sweden)

    Chen Zhe

    2014-01-01

    Full Text Available Inconel 718 is a high strength, heat resistant superalloy that is used extensively for components in hot sections of gas turbine engines. This paper presents an experimental study on the thermal stability of broached Inconel 718 in terms of microstructure and nano-hardness. The broaching process used in this study is similar to that used in gas turbine industries for machining fir-tree root fixings on turbine discs. Severe plastic deformation was found under the broached surface. The plastic deformation induces a work-hardened layer in the subsurface region with a thickness of ∼50 μm. Thermal exposure was conducted at two temperatures, 550 ∘C and 650 ∘C respectively, for 300 h. Recrystallization occurs in the surface layer during thermal exposure at 550 ∘C and α-Cr precipitates as a consequence of the growth of recrystallized δ phases. More recrystallized grains with a larger size form in the surface layer and the α-Cr not only precipitates in the surface layer, but also in the sub-surface region when the thermal exposure temperature goes up to 650 ∘C. The thermal exposure leads to an increase in nano-hardness both in the work-hardened layer and in the bulk material due to the coarsening of the main strengthening phase γ′′.

  3. Performance of PVD-Coated Carbide Tools When Turning Inconel 718 in Dry Machining

    Directory of Open Access Journals (Sweden)

    Gusri Akhyar Ibrahim

    2011-01-01

    Full Text Available Inconel 718 has found its niche in many industries, owing to its unique properties such as high oxidation resistance and corrosion resistance even at very high temperatures. Coated carbide tool with hard layer of PVD TiAlN is used to turn Inconel 718. Taguchi method with the orthogonal array L9 is applied in this experiment with the parameter cutting speed of 60–80 m/min, feed rate of 0.2–0.3 mm/rev, and depth of cut of 0.3–0.5 mm. The results show that depth of cut is a significant influence to the tool life. Cutting speed of 60 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm are the optimum parameters. The flank wear, crater wear, notch wear, and nose wear are the wear mechanisms on the carbide tool. Through the SEM, abrasion, attrition, and adhesion are the wear mechanisms which can be seen on the cutting tool.

  4. Analysis of Deformation in Inconel 718 When the Stress Anomaly and Dynamic Strain Aging Coexist

    Science.gov (United States)

    Follansbee, Paul S.

    2016-09-01

    Deformation in Inconel 718 in the presence of combined effects of the stress anomaly and dynamic strain aging is analyzed according to an internal state variable model formulation. The analysis relies on the availability of experimental data in regimes of behavior where both the stress anomaly and dynamic strain aging are absent. A model that introduces two internal state variables—one characterizing interactions of dislocations with solute atoms and one characterizing interaction of dislocations with precipitates—is shown to adequately describe the temperature and strain-rate dependence of the yield stress in several superalloy systems. Strain hardening is then added with a third internal state variable to enable description of the full stress-strain curve. These equations are extrapolated into regimes where the stress anomaly and dynamic strain aging are present to identify signatures of their effects and to compare to similar analyses in a variety of metal systems. Dynamic strain aging in Inconel 718 follows similar trends to those observed previously. The magnitude of the stress anomaly tracks measurements of stress vs test temperature in pure Ni3Al. Several trends in the strain-rate sensitivity of elevated temperature deformation in superalloys are identified based on limited availability of measurements over a wide range of strain rates or tests using strain-rate changes.

  5. Discontinuous Dynamic Recrystallization of Inconel 718 Superalloy During the Superplastic Deformation

    Science.gov (United States)

    Huang, Linjie; Qi, Feng; Hua, Peitao; Yu, Lianxu; Liu, Feng; Sun, Wenru; Hu, Zhuangqi

    2015-09-01

    The superplastic behavior of Inconel 718 superalloy with particular emphasis on the microstructural evolution has been systematically investigated through tensile tests at the strain rate of 10-3 s-1 and the temperatures ranging from 1223 K to 1253 K (950 °C to 980 °C). Its elongations exceeded 300 pct under all of the experimental conditions and peaked a maximum value of 520 pct at 1223 K (950 °C). Moreover, the stress reached the top value at the strain of 0.3, and then declined until the tensile failure. In addition, we have found that the grain size reduced after deformation while the δ phase precipitation increased. Microstructural evolution during the superplasticity was characterized via transmission electron microscope, and the randomly distributed dislocation, dislocation network, dislocation arrays, low-angled subgrains, and high-angled recrystallized new grains were observed in sequence. These new grains were found to nucleate at the triple junction, twin boundary, and near the δ phase. Based on these results, it is deemed that the discontinuous dynamic recrystallization occurred as the main mechanism for the superplastic deformation of Inconel 718 alloy.

  6. An experimental assessment on the performance of different lubrication techniques in grinding of Inconel 751

    Directory of Open Access Journals (Sweden)

    A.S.S. Balan

    2016-09-01

    Full Text Available The application of emulsion for combined heat extraction and lubrication requires continuous monitoring of the quality of emulsion to sustain a desired grinding environment; this is applicable to other grinding fluids as well. Thus to sustain a controlled grinding environment, it is necessary to adopt an effectively lubricated wheel-work interface. The current study was undertaken to assess experimentally the ​ effects of different grinding environments such as dry, minimum quantity lubrication (MQL and Cryo-MQL on performance, such as grinding force, temperature, surface roughness and chip morphology on Inconel 751, a higher heat resistance material posing thermal problems and wheel loading. The results show that grinding with the combination of both liquid nitrogen (LN2 and MQL lowers temperature, cutting forces, and surface roughness as compared with MQL and dry grinding. Specific cutting energy is widely used as an inverse measure of process efficiency in machining. It is found from the results that specific cutting energy of Cryo-MQL assisted grinding is 50–65% lower than conventional dry grinding. The grindability of Inconel 751 superalloy can be enhanced with Cryo-MQL condition.

  7. WEAR ANALYSIS OF CERAMIC CUTTING TOOLS IN FINISH TURNING OF INCONEL 718

    Directory of Open Access Journals (Sweden)

    M. ARUNA,

    2010-09-01

    Full Text Available The demand for heat resistant Nickel based super alloys are increasing because of their excellent mechanical properties. Nickel based alloy, Inconel 718 is useful in aerospace applications. In this work, finish turning of Inconel 718 using ceramic tools is carried out under high pressure coolant supply. The approach is based on Taguchi’s method and the analysis of variance (ANOVA. A series of experiments are conducted by varying the process parameters and their effects on surface finish and tool wear are measured. It is found that the surface roughness is well below the rejection criteria. The experimental results indicate that the cutting speed is the most significant factor to the overall performance. The correlation etween cutting speed and feed with the tool wear and surface roughness are obtained by multi-variable linear regression and is compared with the experimental results. In addition, SEM analysis is carried out to study the wear of ceramic tools under varying processparameters. The results of the work provide recommendations to give the best quality surface combined with less tool wear.

  8. Laser brazing of inconel 718 alloy with a silver based filler metal

    Science.gov (United States)

    Khorram, A.; Ghoreishi, M.; Torkamany, M. J.; Bali, M. M.

    2014-03-01

    In the presented study laser brazing of an inconel 718 alloy with silver based filler metal using 400 W pulsed Nd:YAG laser is investigated. Laser brazing was performed with varying laser frequency, pulse width, process speed and gap distance. The effect of preheating on wetting and spreading also was studied. Brazing geometrical images were observed using an optical microscope. The composition analysis and microstructure of the filler metal and brazed joints were examined using X-ray diffraction analyzer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Micro-hardness and tensile test were performed for investigation of mechanical properties. The experimental observations show that filler metal consist of α-Ag solid solution, ά-Cu solid solution surround by the α-Ag solid solution and eutectic structure. Phases of the brazed joint are similar to the filler metal. The results indicate that the filler metal has adequate wetting and spreading on inconel 718 and the wetting angle depends on the heat input significantly. Interdiffusion occurs in laser brazing and the average thickness of reaction layer is approximately 2.5 μm. Whenever the gap is big, it is needed to use longer pulse width in order to have a better melting flow. Preheating has significant influence on wetting and spreading of the filler metal.

  9. Effect of service exposure on fatigue crack propagation of Inconel 718 turbine disc material at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Dae-Ho [Department of Materials Science and Engineering, RECAPT, Gyeongsang National University, Chinju (Korea, Republic of); Choi, Myung-Je [Korea Aerospace Industry, Sacheon (Korea, Republic of); Goto, Masahiro [Department of Mechanical Engineering, Oita University, Oita (Japan); Lee, Hong-Chul [Republic of Korea Air Force (Korea, Republic of); Kim, Sangshik, E-mail: sang@gnu.ac.kr [Department of Materials Science and Engineering, RECAPT, Gyeongsang National University, Chinju (Korea, Republic of)

    2014-09-15

    In this study, the fatigue crack propagation behavior of Inconel 718 turbine disc with different service times from 0 to 4229 h was investigated at 738 and 823 K. No notable change in microstructural features, other than the increase in grain size, was observed with increasing service time. With increasing service time from 0 to 4229 h, the fatigue crack propagation rates tended to increase, while the ΔK{sub th} value decreased, in low ΔK regime and lower Paris' regime at both testing temperatures. The fractographic observation using a scanning electron microscope suggested that the elevated temperature fatigue crack propagation mechanism of Inconel 718 changed from crystallographic cleavage mechanism to striation mechanism in the low ΔK regime, depending on the grain size. The fatigue crack propagation mechanism is proposed for the crack propagating through small and large grains in the low ΔK regime, and the fatigue crack propagation behavior of Inconel 718 with different service times at elevated temperatures is discussed. - Highlights: • The specimens were prepared from the Inconel 718 turbine disc used for 0 to 4229 h. • FCP rates were measured at 738 and 823 K. • The ΔK{sub th} values decreased with increasing service time. • The FCP behavior showed a strong correlation with the grain size of used turbine disc.

  10. Tensile Properties and Microstructure of Inconel 718 Fabricated with Electron Beam Freeform Fabrication (EBF(sup 3))

    Science.gov (United States)

    Bird, R. Keith; Hibberd, Joshua

    2009-01-01

    Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate two Inconel 718 single-bead-width wall builds and one multiple-bead-width block build. Specimens were machined to evaluate microstructure and room temperature tensile properties. The tensile strength and yield strength of the as-deposited material from the wall and block builds were greater than those for conventional Inconel 718 castings but were less than those for conventional cold-rolled sheet. Ductility levels for the EBF3 material were similar to those for conventionally-processed sheet and castings. An unexpected result was that the modulus of the EBF3-deposited Inconel 718 was significantly lower than that of the conventional material. This low modulus may be associated with a preferred crystallographic orientation resultant from the deposition and rapid solidification process. A heat treatment with a high solution treatment temperature resulted in a recrystallized microstructure and an increased modulus. However, the modulus was not increased to the level that is expected for Inconel 718.

  11. Effect of Double Aging Heat Treatment on the Short-Term Creep Behavior of the Inconel 718

    Science.gov (United States)

    Caliari, Felipe Rocha; Candioto, Kátia Cristiane Gandolpho; Couto, Antônio Augusto; Nunes, Carlos Ângelo; Reis, Danieli Aparecida Pereira

    2016-06-01

    This research studies the effect of double aging heat treatment on the short-term creep behavior of the superalloy Inconel 718. The superalloy, received in the solution treated state, was subjected to an aging treatment which comprises a solid solution at 1095 °C for 1 h, a first aging step of 955 °C for 1 h, then aged at 720 and 620 °C, 8 h each step. Creep tests at constant load mode, under temperatures of 650, 675, 700 °C and stress of 510, 625 and 700 MPa, were performed before and after heat treatment. The results indicate that after the double aging heat treatment creep resistance is increased, influenced by the presence of precipitates γ' and γ″ and its interaction with the dislocations, by grain size growth (from 8.20 to 7.23 ASTM) and the increase of hardness by approximately 98%. Creep parameters of primary and secondary stages have been determined. There is a breakdown relationship between dot{\\upvarepsilon }_{{s}} and stress at 650 °C of Inconel 718 as received, around 600 MPa. By considering the internal stress values, effective stress exponent, effective activation energy, and TEM images of Inconel 718 double aged, it is suggested that the creep mechanism is controlled by the interaction of dislocations with precipitates. The fracture mechanism of Inconel 718 as received is transgranular (coalescence of dimples) and mixed (transgranular-intergranular), whereas the Inconel 718 double aged condition crept surfaces evidenced the intergranular fracture mechanism.

  12. The performance of Inconel 693 electrodes for processing an iron phosphate glass melt containing 26 wt.% of a simulated low activity waste

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Jen-Hsien; Newkirk, Joseph W. [Department of Material Science and Engineering, Missouri University of Science and Technology, 101 Straumanis-James Hall 401 W. 16th St., Rolla, MO 65409-0330 (United States); Kim, Cheol-Woon [MO-SCI Corporation, 4040 HyPoint North, Rolla, MO 65401 (United States); Brow, Richard K., E-mail: brow@mst.edu [Department of Material Science and Engineering, Missouri University of Science and Technology, 101 Straumanis-James Hall 401 W. 16th St., Rolla, MO 65409-0330 (United States); Schlesinger, Mark E.; Ray, Chandra S.; Day, Delbert E. [Department of Material Science and Engineering, Missouri University of Science and Technology, 101 Straumanis-James Hall 401 W. 16th St., Rolla, MO 65409-0330 (United States)

    2014-01-15

    Iron phosphate glass is a candidate fixation medium for storing radioactive waste. The Department of Energy supported a program to assess the viability of using Fe-phosphate glass for vitrifying low activity waste in a Joule Heated Melter (JHM). In this study, Inconel 693 electrodes were tested in a research-scale joule-heated melter (RSM) at Pacific Northwest National Laboratory. After a 10-day test at 1030 °C that yielded 124 kg of glass, the electrodes exhibited a dimensional loss rate of ∼1.6 mm/year, which is comparable to that of Inconel 690 electrodes used in a JHM for processing borosilicate melts. Microstructural changes occurred within the outermost 700 μm of the electrodes and are consistent with an earlier study of Inconel coupons in Fe-phosphate melts. The results indicate that Inconel 693 should have an acceptable corrosion resistance as the electrode for JHM processing of iron phosphate melts.

  13. Inconel 718合金中δ相的溶解行为%Dissolution Behavior of Phase δ in Inconel 718

    Institute of Scientific and Technical Information of China (English)

    蔡大勇; 张伟红; 刘文昌; 姚枚; 孙贵东; 陈宗霖; 王少刚; 高玉魁

    2002-01-01

    用金相显微镜及X线衍射技术研究了Inconel 718合金中δ相在不同温度下的溶解行为.结果发现:在980 ℃、1 000 ℃、1 020 ℃保温过程中,合金中δ相的含量逐渐降低,且形状由长针状变为短棒状或颗粒状;1 020 ℃保温2 h后δ相可完全溶入基体;980 ℃、1 000 ℃保温时,δ相的平衡含量分别约为3 %及0.6 %;保温开始阶段,δ相的溶解速度较快并近似为常数.随着保温时间的延长,溶解速度逐渐降低,980 ℃保温30 min及1 000 ℃保温2 h后,δ相的溶解速度趋于零.

  14. Delta工艺中Inconel 718合金中δ相的演变机制%EVOLUTION OF δ PHASE IN INCONEL 718 ALLOY DURING DELTA PROCESS

    Institute of Scientific and Technical Information of China (English)

    张海燕; 张士宏; 程明

    2009-01-01

    针对Inconel 718合金的Delta工艺,采用金相显微镜、扫描电镜和定量X射线衍射技术研究了变形温度为950℃,应变速率为0.005 s~(-1)的等温压缩变形中δ相的演变机制.结果表明:在变形前的加热和保温阶段,时效处理过程中晶内析出的颗粒/短棒状δ相全部溶解消失,δ相含量由8.14%降低为7.05%;在变形过程中δ相发生了溶解,含量由7.05%进一步降低为5.14%;由于变形断裂和溶解断裂的综合作用,片层/长针状δ相发生球化,由片层/长针状δ相转变为颗粒/短棒状δ相;在变形量最大的芯部,片层/长针状δ相全部消失,颗粒/短棒状δ相分布于晶内与晶界.

  15. Analysis of Crack Generation Reason of Inconel 718 Alloy%Inconel 718合金件裂纹产生原因分析

    Institute of Scientific and Technical Information of China (English)

    樊建勋

    2013-01-01

    Inconel 718合金件在使用过程中裂纹产生的原因进行分析.结果表明:合金件在服役过程中主要受冷热应力与O、S元素的影响,过渡区域的棱边为应力集中区域,在热应力作用下为最容易破坏的位置.合金在服役过程中O和S扩散进基体,产生了氧化及硫化作用,使基体产生了氧化物和硫化物产物的的U型凹坑,加剧了应力集中区域的缺口敏感性,从而在冷热应力的作用下产生裂纹.裂纹的产生更易于O、S等有害元素向基体扩散,在应力作用下促使裂纹进一步扩展.在腐蚀、动态应力开裂、再腐蚀、冷热应力的作用下裂纹进一步扩展,是导致合金件失效的原因.

  16. Supersolidus liquid phase sintering of Inconel 718 powder alloy%超固相线液相烧结Inconel 718合金

    Institute of Scientific and Technical Information of China (English)

    汤春峰; 潘峰; 曲选辉; 贾成厂; 段柏华; 何新波

    2008-01-01

    以惰性气体雾化粉末为原料,采用超固相线液相烧结方法制备了Inconel 718粉末高温合金,研究了粉末合金的烧结温度和热处理制度对合金组织和力学性能的影响. 实验结果表明:在1240℃真空烧结120min可以制备出相对密度为98.5%的粉末合金,后续的热等静压处理可以将其相对密度提高到99.7%;经热处理后,合金的抗拉强度和延伸率分别为1280MPa和9%;析出相为球形γ′相、针状γ″相以及粗大的碳化物,平均晶粒大小在50μm以下.

  17. 热处理对Inconel718合金组织及力学性能的影响%Effects of heat treatment on microstructure and mechanical properties of Inconel 718 alloy

    Institute of Scientific and Technical Information of China (English)

    魏先平; 郑文杰; 宋志刚; 雷霆; 谢清程; 易小东

    2012-01-01

    针对Inconel 718合金的不同用途,分析研究了4种常用热处理工艺对Inconel 718合金组织和力学性能的影响。结果表明:固溶温度超过1020℃时,奥氏体晶粒显著长大。合金中主要析出相有MC、δ、γ'和γ″相。δ相沿晶界分布,1025℃固溶时呈颗粒状少量析出;950℃固溶时呈块状大量析出;直接时效时呈网状不连续分布。同时,δ相对合金的晶粒度影响较大,且其析出数量和形态决定了合金的韧塑性,γ″、γ'相的析出量和尺寸与晶粒尺寸决定了合金的强度变化。%In view of different applications of Inconel 718 alloy, the influence of four kinds of heat treatment on mierostructure and mechanical performance of the alloy was investigated. The results indicate that the austenite grains grow observably when solution temperature exceeds 1020 %. The main precipitated phases of Inconel 718 alloy are MC,δ,γ' and γ". It is found that a few of blocky phase are formed along grain boundaries when the solution temperature is 1025 ℃ ,a large amount of blocky 8 phase are observable in the alloy solution-treated at 950 ℃ , and some net-liked 8 phase precipitates discontinuously under directly aging treatment. The precipitation of 8 phase significantly influences the grain size of the alloy and toughness and ductility of Inconel 718 alloy depend on the morphology and quantity of 8 phase. The morphological characteristics of γ", γ' phases and grain size of Inconel 718 alloy greatly affect its strength.

  18. Electron Backscatter Diffraction Analysis of Inconel 718 Parts Fabricated by Selective Laser Melting Additive Manufacturing

    Science.gov (United States)

    Wang, Xiaoqing; Chou, Kevin

    2017-02-01

    In this study, the crystallographic texture of an Inconel 718 part fabricated by selective laser melting was investigated. The front surface (X-Z plane) microstructure is characterized by the columnar grains growing along the build direction, and the width of columnar grains is in the range of about 75-150 µm, with the bottom layers having narrower grains as a result of a higher cooling rate. In addition to equiaxed grains, the top surface (X-Y plane) has a feature of patch patterns resulting from the laser scanning strategy. Based on the electron backscatter diffraction results, there appears only weak crystallographic texture in both the X-Z plane and the X-Y plane of the part. From the grain boundary map, the microstructures are composed of high-angle boundaries with a larger fraction of subgrain boundaries.

  19. Laser controlled melting of pre-prepared inconel 718 alloy surface

    Science.gov (United States)

    Abdul Aleem, B. J.; Hashmi, M. S. J.; Yilbas, B. S.

    2011-11-01

    Laser treatment of Inconel 718 alloy surface is carried out. The alloy surface is coated with a carbon layer containing 7% TiC particles prior to the laser treatment. The carbon coating provides increased absorption of the incident laser beam and holds TiC particles. The microstrutural and morphological changes in the laser treated region are examined using optical and scanning electron microscopes, energy dispersive spectroscopy, and X-ray diffraction. The microhardness of the surface is measured and the residual stress formed at the surface vicinity is determined from the XRD technique. It is found that partial dissolution of carbide particles takes place at the surface. The composition of fine grains at the surface vicinity, nitride compounds formed, and dissolution of Laves phase at the surface region enhances the hardness at the treated surface. In addition, laser treated surface is free from the micro-crack network and cavities.

  20. Deformation characteristics of {delta} phase in the delta-processed Inconel 718 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y., E-mail: haiyanzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, S.H., E-mail: shzhang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Cheng, M. [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Z.X. [Beijing Institute of Aeronautica1 Materials, Beijing 100095 (China)

    2010-01-15

    The hot working characteristics of {delta} phase in the delta-processed Inconel 718 alloy during isothermal compression deformation at temperature of 950 deg. C and strain rate of 0.005 s{sup -1}, were studied by using optical microscope, scanning electron microscope and quantitative X-ray diffraction technique. The results showed that the dissolution of plate-like {delta} phase and the precipitation of spherical {delta} phase particles coexisted during the deformation, and the content of {delta} phase decreased from 7.05 wt.% to 5.14 wt.%. As a result of deformation breakage and dissolution breakage, the plate-like {delta} phase was spheroidized and transferred to spherical {delta} phase particles. In the center with largest strain, the plate-like {delta} phase disappeared and spherical {delta} phase appeared in the interior of grains and grain boundaries.

  1. Sliding wear and friction behavior of zirconium alloy with heat-treated Inconel718

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H., E-mail: kimjhoon@cnu.ac.kr [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.M. [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.K.; Jeon, K.L. [Nuclear Fuel Technology Department, Korea Nuclear Fuel, 1047 Daedukdae-ro, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2014-04-01

    In water-cooled nuclear reactors, the sliding of fuel rod can lead to severe wear and it is an important issue to sustain the structural integrity of nuclear reactor. In the present study, sliding wear behavior of zirconium alloy in dry and water environment using Pin-On-Disk sliding wear tester was investigated. Wear resistance of zirconium alloy against heat-treated Inconel718 pin was examined at room temperature. Sliding wear tests were carried out at different sliding distance, axial load and sliding speed based on ASTM (G99-05). The results of these experiments were verified with specific wear rate and coefficient of friction. The micro-mechanisms responsible for wear in zirconium alloy were identified to be microcutting and microcracking in dry environment. Moreover, micropitting and delamination were observed in water environment.

  2. Segregation of B, P, and C in the Ni-Based Superalloy, Inconel 718

    Science.gov (United States)

    Alam, Talukder; Felfer, Peter J.; Chaturvedi, Mahesh; Stephenson, Leigh T.; Kilburn, Matthew R.; Cairney, Julie M.

    2012-07-01

    Small additions of B, P, and C can result in dramatic changes in the mechanical performance and welding behavior of Inconel 718. Although additions of B and P improve the mechanical properties, they have a detrimental effect on weldability. Adding C mitigates the negative effect on welding while retaining the improvements in mechanical performance. In this study, precise observations of the segregation of B, P, and C to the grain boundaries are made using site-specific atom probe tomography and NanoSIMS. Changes in the segregation behavior provide a quantitative explanation for the welding response, where hot cracking is attributed to the formation of a eutectic film. Calculations of the relative positions of the B, P, and C revealed that these atoms were less likely to cluster together in the presence of C, providing insight into the likely mechanisms behind the segregation behavior in this complex, multicomponent alloy.

  3. Intercrystalline Stress Corrosion of Inconel 600 Inspection Tubes in the Aagesta Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Groenwall, B.; Ljungberg, L.; Huebner, W.; Stuart, W.

    1966-08-15

    Intercrystalline stress corrosion cracking has occurred in the Aagesta reactor in three so-called inspection tubes made of Inconel 600. The tubes had been exposed to 217 deg C light water, containing 1-4 ppm LiOH (later KOH) but only small amounts of oxygen, chloride and other impurities. Some of the circumferential cracks developed in or at crevices on the outside surface. At these positions constituents dissolved in the water may have concentrated. The crevices are likely to have contained a gas phase, mainly nitrogen. Local boiling in the crevices may also have occurred. Some few cracks were also found outside the crevice region. Irradiation effects can be neglected. No surface contamination could be detected except for a very minor fluoride content (1 {mu}g/cm{sup 2}). The failed tubes had been subjected to high stresses, partly remaining from milling, partly induced by welding operations. The possibility that stresses slightly above the 0.2 per cent offset yield strength have occurred at the operating temperature cannot be excluded. The cracked tube material contained a large amount of carbide particles and other precipitates, both at grain boundaries and in the interior of grains. The particles appeared as stringers in circumferential zones. Zones depleted in precipitates were found along grain boundaries. The failed tube turned out to have an unusually high mechanical strength, likely due to a combination of some kind of ageing process and cold work (1.0 - 1.3 per cent plastic strain). Laboratory exposures of stressed surplus material in high purity water and in 1 M LiOH at 220 deg C showed some pitting but no cracking after 6800 h and 5900 h respectively. Though the encountered failures may have developed because of influence of some few or several of the above-mentioned detrimental factors, the actual cause cannot be stated with certainty. In the literature information is given concerning intercrystalline stress corrosion cracking of Inconel 600 both in

  4. Rationalization of Microstructure Heterogeneity in INCONEL 718 Builds Made by the Direct Laser Additive Manufacturing Process

    Science.gov (United States)

    Tian, Yuan; McAllister, Donald; Colijn, Hendrik; Mills, Michael; Farson, Dave; Nordin, Mark; Babu, Sudarsanam

    2014-09-01

    Simulative builds, typical of the tip-repair procedure, with matching compositions were deposited on an INCONEL 718 substrate using the laser additive manufacturing process. In the as-processed condition, these builds exhibit spatial heterogeneity in microstructure. Electron backscattering diffraction analyses showed highly misoriented grains in the top region of the builds compared to those of the lower region. Hardness maps indicated a 30 pct hardness increase in build regions close to the substrate over those of the top regions. Detailed multiscale characterizations, through scanning electron microscopy, electron backscattered diffraction imaging, high-resolution transmission electron microscopy, and ChemiSTEM, also showed microstructure heterogeneities within the builds in different length scales including interdendritic and interprecipitate regions. These multiscale heterogeneities were correlated to primary solidification, remelting, and solid-state precipitation kinetics of γ″ induced by solute segregation, as well as multiple heating and cooling cycles induced by the laser additive manufacturing process.

  5. Texture-Induced Anisotropy in an Inconel 718 Alloy Deposited Using Electron Beam Freeform Fabrication

    Science.gov (United States)

    Tayon, W.; Shenoy, R.; Bird, R.; Hafley, R.; Redding, M.

    2014-01-01

    A test block of Inconel (IN) 718 was fabricated using electron beam freeform fabrication (EBF(sup 3)) to examine how the EBF(sup 3) deposition process affects the microstructure, crystallographic texture, and mechanical properties of IN 718. Tests revealed significant anisotropy in the elastic modulus for the as-deposited IN 718. Subsequent tests were conducted on specimens subjected to a heat treatment designed to decrease the level of anisotropy. Electron backscatter diffraction (EBSD) was used to characterize crystallographic texture in the as-deposited and heat treated conditions. The anisotropy in the as-deposited condition was strongly affected by texture as evidenced by its dependence on orientation relative to the deposition direction. Heat treatment resulted in a significant improvement in modulus of the EBF(sup 3) product to a level nearly equivalent to that for wrought IN 718 with reduced anisotropy; reduction in texture through recrystallization; and production of a more homogeneous microstructure.

  6. Temperature field analysis and its application in hot continuous rolling of Inconel 718 superalloy

    Institute of Scientific and Technical Information of China (English)

    Fengli SUI; Liqing CHEN; Xianghua LIU; Lintao WANG; Wei LI

    2009-01-01

    A coupled thermo-mechanical model containing metal flow and temperature field for calculating temperature variation has been developed on fourteen-pass hot continu-ous rolling of round rod for Inconel 718 alloy using 3D elastic-plastic finite element method (FEM). The temperature of characteristic analysis points in the intermedi-ate cross-section of the workpiece has been simulated at initial temperature ranging nite element analysis and microstructural observation in cylindrical hot compression experiments, the appropriate hot continuous rolling technologies have been designed for rod products with different diameters. For a real rolling practice, the simulated surface temperature was examined and is in good agreement with the measured one.

  7. Performance of Silicon carbide whisker reinforced ceramic inserts on Inconel 718 in end milling process

    Science.gov (United States)

    Reddy, M. M.; Joshua, C. X. H.

    2016-03-01

    An experimental investigation is planned in order to study the machinability of Inconel 718 with silicon carbide whisker reinforced ceramic inserts in end milling process. The relationship between the cutting speed, feed rate, and depth of cut against the response factors are studied to show the level of significance of each parameter. The cutting parameters are optimized by using Taguchi method. Implementing analysis of variance, the parameter which influences the surface roughness the most is determined to be the cutting speed, followed by the feed rate and depth of cut. Meanwhile, the optimal cutting condition is determined to have high cutting speed, low feed rate, and high depth of cut in the range of selected parameters.

  8. Processing and Characterization of Sub-delta Solvus Forged Hemispherical Forgings of Inconel 718

    Science.gov (United States)

    Chenna Krishna, S.; Rao, G. Sudarasana; Singh, Satish Kumar; Narayana Murty, S. V. S.; Venkatanarayana, G.; Jha, Abhay K.; Pant, Bhanu; Venkitakrishnan, P. V.

    2016-12-01

    In this paper, microstructure and mechanical properties of 200 mm diameter Inconel 718 hemispherical domes processed at 1025 °C through closed die hammer forging have been investigated. Microstructure and mechanical properties of the forgings in radial and tangential directions were characterized using optical microscopy, scanning electron microscopy, impact testing, and tensile testing. Grain size of the forgings at three different locations was fine with an average grain size of ASTM No. 8-9. The typical tensile properties of the forgings in solution-treated and aged condition were ultimate tensile strength-1450 MPa, yield strength-1240 MPa, and ductility-25%. The fine grain size achieved in forgings has been attributed to delta phase present at grain boundaries which pinned the grains during forging and prevented grain coarsening.

  9. Effect of machining parameters on surface finish of Inconel 718 in end milling

    Directory of Open Access Journals (Sweden)

    Sarkar Bapi

    2017-01-01

    Full Text Available Surface finish is an important criteria in machining process and selection of proper machining parameters is important to obtain good surface finish. In the present work effects of the machining parameters in end milling of Inconel 718 were investigated. Central composite design was used to design the total number of experiments. A Mathematical model for surface roughness has been developed using response surface methodology. In this study, the influence of cutting parameters such as cutting speed, feed rate and depth of cut on surface roughness was analyzed. The study includes individual effect of cutting parameters on surface roughness as well as their interaction. The analysis of variance (ANOVA was employed to find the validity of the developed model. The results show that depth of cut mostly affected the surface roughness. It is also observed that surface roughness values are comparable in both dry and wet machining conditions.

  10. Processing and Microstructural Evolution of Superalloy Inconel 718 during Hot Tube Extrusion

    Institute of Scientific and Technical Information of China (English)

    Shihong ZHANG; Zhongtang WANG; Bing QIAO; Yi XU; Tingfeng XU

    2005-01-01

    The processing parameters of tube extrusion for superalloy Inconel 718 (IN 718), such as slug temperature, tools temperature, choice of lubricant, extrusion ratio and extrusion speed, were determined by experiment in this paper. An appropriate temperature range recommended for the slug is 1080~1120℃, and the temperature range recommended for the tools is 350~500℃. The microstructural evolution of superalloy IN 718 during tube extrusion was analyzed.With the increase of the deformation the cross crystal grains were slightly refined. While the vertical crystal grain is elongated evidently and the tensile strength increased along the axial rake. Glass lubricants have to be spread on the slug surface after being heated to 150~200℃, vegetable oil or animal oil can be used as the lubricant on the surface of the tools to reduce the extrusion force remarkably.

  11. Preliminary study on pressure brazing and diffusion welding of Nb-1Zr to Inconel 718

    Science.gov (United States)

    Moore, T. J.

    1990-01-01

    Future space power systems may include Nb-1Zr/Inconel 718 dissimilar metal joints for operation at 1000 K for 60,000 h. The serviceability of pressure-brazed and diffusion-welded joints was investigated. Ni-based metallic glass foil filler metals were used for brazing. Ni and Fe foils were used as diffusion welding inter-layers. Joint soundness was determined by metallographic examination in the as-brazed and as-welded condition, after aging at 1000 K, and after thermal cycling. Brazed joints thermally cycled in the as-brazed condition and diffusion-welded joints were unsatisfactory because of cracking problems. Brazed joints may meet the service requirements if the joints are aged at 1000 K prior to thermal cycling.

  12. Study of delta phase on static recrystallization behavior of Inconel 718 alloy.

    Science.gov (United States)

    Lee, Hwa-Teng; Hou, Wen-Hsin

    2012-09-01

    The mechanical properties of Inconel 718 alloy depend on its microstructural features. Controlling the grain size during manufacturing is currently achieved through the use of a powerful hot forming process performed at a temperature sufficiently high to induce dynamic recrystallization. The present study proposes an alternative technique to achieve a uniform fine grain structure by using static recrystallization and a proper control of delta precipitation. The results show that a fine structure with an average grain size of ASTM No. 7 can be achieved. And in this study the finest grains yet achievable is ca. 200 nm. As a result, the proposed technique provides a feasible means of controlling the grain size without the need for an energy consumption and technically sophisticated hot forming process.

  13. Rotary bending fatigue properties of Inconel 718 alloys by ultrasonic nanocrystal surface modification technique

    Directory of Open Access Journals (Sweden)

    Jun-Hyong Kim

    2015-08-01

    Full Text Available This study investigates the influence of ultrasonic nanocrystal surface modification (UNSM technique on fatigue properties of SAE AMS 5662 (solution treatment of Inconel 718 alloys. The fatigue properties of the specimens were investigated using a rotary bending fatigue tester. Results revealed that the UNSM-treated specimens showed longer fatigue life in comparison with those of the untreated specimens. The improvement in fatigue life of the UNSM-treated specimens is attributed mainly to the induced compressive residual stress, increased hardness, reduced roughness and refined grains at the top surface. Fractured surfaces were analysed using a scanning electron microscopy (SEM in order to give insight into the effectiveness of UNSM technique on fracture mechanisms and fatigue life.

  14. Electron Backscatter Diffraction Analysis of Inconel 718 Parts Fabricated by Selective Laser Melting Additive Manufacturing

    Science.gov (United States)

    Wang, Xiaoqing; Chou, Kevin

    2016-11-01

    In this study, the crystallographic texture of an Inconel 718 part fabricated by selective laser melting was investigated. The front surface (X-Z plane) microstructure is characterized by the columnar grains growing along the build direction, and the width of columnar grains is in the range of about 75-150 µm, with the bottom layers having narrower grains as a result of a higher cooling rate. In addition to equiaxed grains, the top surface (X-Y plane) has a feature of patch patterns resulting from the laser scanning strategy. Based on the electron backscatter diffraction results, there appears only weak crystallographic texture in both the X-Z plane and the X-Y plane of the part. From the grain boundary map, the microstructures are composed of high-angle boundaries with a larger fraction of subgrain boundaries.

  15. Inter- and intragranular delta phase quantitative characterization in Inconel 718 by means of image analysis.

    Science.gov (United States)

    Vanderesse, N; Anderson, M; Bridier, F; Bocher, P

    2015-01-01

    This paper describes an image processing method for discriminating the inter- and intragranular delta phase precipitates in Inconel 718 (IN 718). The successive practical operations and the motivations of their choices are presented in detail. The method was applied to IN 718 specimens heat treated with different parameters to produce microstructures containing various amounts of both types of precipitates. They were characterized by electron microscopy in backscattered electron imaging. The main difficulty arose from the fact that the brightness distributions of inter- and intragranular precipitates partially overlap. Additional information on their morphology and their spatial distribution had to be exploited in order to differentiate them. The shape and the orientation of the precipitates were evaluated using the structure tensor, an operator that quantifies the directionality of the intensity distribution in an image. The distance between parallel precipitates was also used as an additional property to identify clusters of intragranular precipitates.

  16. The effects of multiple repairs on Inconel 718 weld mechanical properties

    Science.gov (United States)

    Russell, C. K.; Nunes, A. C., Jr.; Moore, D.

    1991-01-01

    Inconel 718 weldments were repaired 3, 6, 9, and 13 times using the gas tungsten arc welding process. The welded panels were machined into mechanical test specimens, postweld heat treated, and nondestructively tested. Tensile properties and high cycle fatigue life were evaluated and the results compared to unrepaired weld properties. Mechanical property data were analyzed using the statistical methods of difference in means for tensile properties and difference in log means and Weibull analysis for high cycle fatigue properties. Statistical analysis performed on the data did not show a significant decrease in tensile or high cycle fatigue properties due to the repeated repairs. Some degradation was observed in all properties, however, it was minimal.

  17. Aging Thermal Treatment in the Inconel 725 Brazed Incorporating Tungsten Nanoparticles

    Directory of Open Access Journals (Sweden)

    H. M. Hdz-García

    2016-01-01

    Full Text Available Fractures in blade sections of Inconel 725 were impregnated with tungsten nanoparticles and jointed by the brazing process. In order to evaluate their effect over the microstructure, aging thermal treatments at 750°C for 2, 6, 10, and 14 h were done. BNi-9 was selected as brazing filler metal and was characterized by scanning electron microscopy and X-ray fluorescence. Before brazing, the fractures were impregnated with a mixture of tungsten NPs in ethanol. Measurements of Vickers microhardness showed an increase in the melting zone of samples with aging thermal treatment for 14 h, which is attributed to the precipitation of the γ′ phase with a typical size of ca. 100 nm. Likewise, the tungsten NPs modified the size and morphology of Cr-Ni eutectics into finer and uniformly distributed microstructures.

  18. EXPERIMENTAL INVESTIGATION AND THERMODYNAMIC CALCULATION ON PHASE PRECIPITATION OF INCONEL 740

    Institute of Scientific and Technical Information of China (English)

    S.Q. Zhao; Y. Jiang; J.X. Dong; X.S. Xie

    2006-01-01

    A novel nickel-based superalloy INCONEL 740 was under development for application in ultra-supercritical superheater tubers above 750℃. The precipitation behaviors of η phase andγ′ particles of the alloy were investigated through experimental study and phase computation.Experimental results showed that η phase formed a Widmanst(a)tten pattern structure following long-term exposure at elevated temperatures and that the coarsening of γ′ particle follows a cube rate law: (r)3 ∝t. Thermodynamic calculation results showed that Al and Ti had an important effect on the precipitation behavior of γ′ and η phases. Two suggested novel modified alloys, wherein the Al and Ti contents were modified, were designed and melted for the experimental study. The preliminary results indicated that the modified alloys exhibited higher structural stability following long-term exposure at 750℃ till 5000h.

  19. High-rate laser metal deposition of Inconel 718 component using low heat-input approach

    Science.gov (United States)

    Kong, C. Y.; Scudamore, R. J.; Allen, J.

    Currently many aircraft and aero engine components are machined from billets or oversize forgings. This involves significant cost, material wastage, lead-times and environmental impacts. Methods to add complex features to another component or net-shape surface would offer a substantial cost benefit. Laser Metal Deposition (LMD), currently being applied to the repair of worn or damaged aero engine components, was attempted in this work as an alternative process route, to build features onto a base component, because of its low heat input capability. In this work, low heat input and high-rate deposition was developed to deposit Inconel 718 powder onto thin plates. Using the optimised process parameters, a number of demonstrator components were successfully fabricated.

  20. Microstructural evolution of CANDU spacer material Inconel X-750 under in situ ion irradiation

    Science.gov (United States)

    Zhang, He Ken; Yao, Zhongwen; Judge, Colin; Griffiths, Malcolm

    2013-11-01

    Work on Inconel®Inconel® is a registered trademark of Special Metals Corporation that refers to a family of austenitic nickel-chromium-based superalloys.1 X-750 spacers removed from CANDU®CANDU® is a registered trademark of Atomic Energy of Canada Limited standing for ''CANada Deuterium Uranium''.2 reactors has shown that they become embrittled and there is development of many small cavities within the metal matrix and along grain boundaries. In order to emulate the neutron irradiation induced microstructural changes, heavy ion irradiations (1 MeV Kr2+ ions) were performed while observing the damage evolution using an intermediate voltage electron microscope (IVEM) operating at 200 kV. The irradiations were carried out at various temperatures 60-400 °C. The principal strengthening phase, γ‧, was disordered at low doses (˜0.06 dpa) during the irradiation. M23C6 carbides were found to be stable up to 5.4 dpa. Lattice defects consisted mostly of stacking fault tetrahedras (SFTs), 1/2 perfect loops and small 1/3 faulted Frank loops. The ratio of SFT number density to loop number density for each irradiation condition was found to be neither temperature nor dose dependent. Under the operation of the ion beam the SFT production was very rapid, with no evidence for further growth once formed, indicating that they probably formed as a result of cascade collapse in a single cascade. The number density of the defects was found to saturate at low dose (˜0.68 dpa). No cavities were observed regardless of the irradiation temperature between 60 °C and 400 °C for doses up to 5.4 dpa. In contrast, cavities have been observed after neutron irradiation in the same material at similar doses and temperatures indicating that helium, produce during neutron irradiation, may be essential for the nucleation and growth of cavities.

  1. Microstructural characterization and some mechanical properties of gas-borided Inconel 600-alloy

    Energy Technology Data Exchange (ETDEWEB)

    Makuch, N.; Kulka, M., E-mail: michal.kulka@put.poznan.pl

    2014-09-30

    Graphical abstract: - Highlights: • Two-stage gas boriding was proposed to produce the boride layer on Inconel 600-alloy. • The microstructure of diffusion zone consisted of compact borides zone and borides at grain boundaries. • The identification of nickel and chromium borides required the use of a special etching solution. • The diffusion along grain boundaries was indicated as a predominant mechanism of boron diffusion. • The increased hardness and improved wear resistance of gas-borided layer were obtained. - Abstract: The excellent resistance of Ni-based alloys to corrosion and oxidation is well-known. Boriding can be applied to these alloys in order to obtain suitable wear protection. In this paper, two-stage gas boronizing in N{sub 2}–H{sub 2}–BCl{sub 3} atmosphere is proposed for the producing the boride layer on Inconel{sup ®}600-alloy. This process consists in two stages alternately repeated: saturation by boron and diffusion annealing. Such a gas boriding is applied in order to accelerate the saturation by boron and its diffusion. It turns out to be more effective because of eliminating the excess of boron, diffusing into the substrate, during the second stage. Microstructure and some mechanical properties of the produced layer are presented. Microstructural characterization is studied with using an optical microscope, scanning electron microscope, energy-dispersive x-ray microanalysis and x-ray diffraction. The diffusion zone consists of the mixture of nickel and chromium borides, occurring in the compact boride zone and in the area located beneath, at grain boundaries. The improved hardness and wear resistance characterize the layer. The formed boride layer is significantly thicker than those-obtained by the pack-boronizing or paste process at comparable temperature and time. Simultaneously, the measured depth of layer is slightly smaller than that-reported for electrolytic boriding.

  2. Influence of Feed Per Tooth on Surface Quality of Inconel 718 Alloy When Broaching%拉刀齿升量对Inconel 718合金拉削表面质量的影响

    Institute of Scientific and Technical Information of China (English)

    庞丽君; 段宝

    2004-01-01

    Inconel 718合金是一种综合机械性能优良的高温合金,在国内外应用非常广泛。在国内主要用于制造多种先进发动机的涡轮盘、机匣、涡轮叶片等重要零件。由于高温合金塑性大,韧性高,导热性差,给切削加工带来了困难,如在拉削加工Inconel 718合金时,拉刀齿升量的大小就直接影响着合金表面质量,本课题对此进行了试验研究。

  3. Inconel718合金压铸模力学性能的神经网络预测%Prediction of Mechanical Properties of Die-casting Mould of Inconel 718 Alloy Based on Neural Network

    Institute of Scientific and Technical Information of China (English)

    樊爱珍

    2013-01-01

    研究了不同热处理工艺条件下Inconel 718合金压铸模的显微组织,并测试了该合金的力学性能.结果表明:随着热处理温度的降低,合金塑韧性减小,强度增大.基于BP神经网络构建了Inconel 718合金力学性能模型,并对合金抗拉强度、屈服强度、伸长率和断面收缩率进行了预测.预测相关性达到0.999 93,误差均在5%以内.

  4. Research on Stress Threshold of Stress Corrosion Cracking of Inconel 718 Alloy Hold-down Spring%Inconel 718合金压紧弹簧应力腐蚀开裂的应力阈值研究

    Institute of Scientific and Technical Information of China (English)

    陈亮; 庞华; 宋小明; 刘丽莉

    2015-01-01

    采用适当的热处理时效工艺,可以避免板状压紧弹簧的Inconel 718镍基合金在晶界上产生有害的δ相,从而对压水堆一回路水质条件具有较低的应力腐蚀开裂敏感性.为防止镍基合金发生应力腐蚀开裂(sCC),其承受的应力不应超过该合金屈服强度的75%~ 80%.对于采用Inconel 718材料的板状压紧弹簧,其设计应力阈值设为931 MPa(135 ksi)在合理范围内,且其数值并不保守.

  5. Inconel718与硬质合金摩擦磨损特性的实验研究%Experimental Study on the Friction and Wear Properties of Inconel 718/Carbide

    Institute of Scientific and Technical Information of China (English)

    黄雪红; 季德生; 赵军

    2011-01-01

    利用UMT-2多功能摩擦磨损试验机对镍基合金Inconel 718与硬质合金刀具对偶时的摩擦磨损特性进行研究,揭示法向载荷和滑动速度对摩擦副摩擦因数的影响,通过SEM观察试样摩擦形貌并分析磨损机制.研究结果表明:摩擦副的摩擦因数随着法向载荷的增大而减小,随滑动速度的增大而增大;Inconel 718镍基合金与硬质合金对偶时的磨损机制主要为黏着磨损、磨粒磨损和氧化磨损.%The friction and wear properties of Inconel 718/carbide tool were studied on a UMT-2 type wear tester, revealed the effects of normal load and sliding velocity on friction coefficient, surface topographies of pin sample and wear mechanism were analysed by SEM. The results show that the friction coefficient is decreased with the increase of load and increased with the increase of sliding velocity. The wear mechanisms are mainly adhesive wear,abration wear and oxidation wear.

  6. Influence of carbon and niobium on microstructures and properties of Inconel 718 alloy deposit coating%碳、铌对Inconel 718合金熔敷层组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    毛萍莉; 李红军; 耿新; 孔凡亚; 都祥远; 边舫

    2007-01-01

    为了提高Inconel 718合金焊接接头的塑、韧性,开发了具有良好力学性能和热加工性能的镍基高温合金焊接材料.通过适当调整Inconel 718高温合金中的碳、铌含量,并在一定工艺参数下进行熔敷,然后再进行扩散退火和固溶、时效处理;研究了C、Nb含量变化对Inconel 718高温合金熔敷层的组织和性能的影响.实验结果表明:焊后熔敷层的组织主要由γ固溶体构成,枝晶间出现白色的Laves相;经扩散退火处理后,Laves相发生溶解;在相同的处理条件下,熔敷层的屈服强度和硬度对碳、铌成分的变化比较敏感.

  7. Microstructures and Microfissuring in the HAZ of Inconel 718 Welds by Laser Welding%Inconel718激光焊接接头组织与热影响区裂纹研究

    Institute of Scientific and Technical Information of China (English)

    张冬梅; 崔海超; 杨尚磊; 庹文海

    2016-01-01

    采用CO2激光器对板厚为11mm的Inconel 718合金进行激光焊接,并利用金相分析和扫描电镜对Inconel 718激光焊接接头各区域组织以及热影响区显微裂纹产生的原因进行了分析.研究发现:利用激光对Inconel 718进行焊接,可以获得成形良好的焊接接头;焊缝区域组织为铸造组织,从熔合线到焊缝中心由较长的树枝晶逐步变为等轴晶;热影响区因受循环热输入的影响,晶界较母材出现粗化现象,且在钉头缩颈处出现沿粗化的晶界扩展的液化裂纹,裂纹两侧存在低熔点共晶体,主要富集Nb及Mo元素,低熔点共晶体在热输入影响下发生液化是裂纹产生的主要原因.

  8. Experimental Study of Direct Laser Deposition of Ti-6Al-4V and Inconel 718 by Using Pulsed Parameters

    Directory of Open Access Journals (Sweden)

    Kamran Shah

    2014-01-01

    Full Text Available Laser direct metal deposition (LDMD has developed from a prototyping to a single metal manufacturing tool. Its potential for creating multimaterial and functionally graded structures is now beginning to be explored. This work is a first part of a study in which a single layer of Inconel 718 is deposited on Ti-6Al-4V substrate. Single layer tracks were built at a range of powder mass flow rates using a coaxial nozzle and 1.5 kW diode laser operating in both continuous and pulsed beam modes. This part of the study focused on the experimental findings during the deposition of Inconel 718 powder on Ti-6Al-4V substrate. Scanning electron microscopy (SEM and X-ray diffraction analysis were performed for characterization and phase identification. Residual stress measurement had been carried out to ascertain the effects of laser pulse parameters on the crack development during the deposition process.

  9. Experimental study of direct laser deposition of Ti-6Al-4V and Inconel 718 by using pulsed parameters.

    Science.gov (United States)

    Shah, Kamran; Izhar Ul Haq; Shah, Shaukat Ali; Khan, Farid Ullah; Khan, Muhammad Tahir; Khan, Sikander

    2014-01-01

    Laser direct metal deposition (LDMD) has developed from a prototyping to a single metal manufacturing tool. Its potential for creating multimaterial and functionally graded structures is now beginning to be explored. This work is a first part of a study in which a single layer of Inconel 718 is deposited on Ti-6Al-4V substrate. Single layer tracks were built at a range of powder mass flow rates using a coaxial nozzle and 1.5 kW diode laser operating in both continuous and pulsed beam modes. This part of the study focused on the experimental findings during the deposition of Inconel 718 powder on Ti-6Al-4V substrate. Scanning electron microscopy (SEM) and X-ray diffraction analysis were performed for characterization and phase identification. Residual stress measurement had been carried out to ascertain the effects of laser pulse parameters on the crack development during the deposition process.

  10. Determination of Constitutive Equation for Thermo-mechanical Processing of INCONEL 718 Through Double Multivariate Nonlinear Regression Analysis

    Science.gov (United States)

    Hussain, Mirza Zahid; Li, Fuguo; Wang, Jing; Yuan, Zhanwei; Li, Pan; Wu, Tao

    2015-07-01

    The present study comprises the determination of constitutive relationship for thermo-mechanical processing of INCONEL 718 through double multivariate nonlinear regression, a newly developed approach which not only considers the effect of strain, strain rate, and temperature on flow stress but also explains the interaction effect of these thermo-mechanical parameters on flow behavior of the alloy. Hot isothermal compression experiments were performed on Gleeble-3500 thermo-mechanical testing machine in the temperature range of 1153 to 1333 K within the strain rate range of 0.001 to 10 s-1. The deformation behavior of INCONEL 718 is analyzed and summarized by establishing the high temperature deformation constitutive equation. The calculated correlation coefficient ( R) and average absolute relative error ( AARE) underline the precision of proposed constitutive model.

  11. Recyclability Study on Inconel 718 and Ti-6Al-4V Powders for Use in Electron Beam Melting

    Science.gov (United States)

    Nandwana, Peeyush; Peter, William H.; Dehoff, Ryan R.; Lowe, Larry E.; Kirka, Michael M.; Medina, Francisco; Babu, Sudarsanam S.

    2016-02-01

    Powder bed-based additive manufacturing technologies offer a big advantage in terms of reusability of the powders over multiple cycles that result in cost savings. However, currently there are no standards to determine the factors that govern the powder reuse times. This work presents the results from a recyclability study conducted on Inconel 718 and Ti-6Al-4V powders. It has been found that the Inconel 718 powders are chemically stable over a large number of cycles and their reuse time is limited by physical characteristics of powders such as flowability. Ti-6Al-4V, on the other hand, finds its reuse time governed by the oxygen pick up that occurs during and in between build cycles. The detailed results have been presented.

  12. Ultrasonic measurements for in-service assessment of wrought Inconel 625 cracker tubes of heavy water plants

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Anish [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Rajkumar, K.V. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)]. E-mail: tjk@igcar.ernet.in; Raj, Baldev [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Mishra, B. [Heavy Water Board, Mumbai 400 085 (India)

    2006-05-01

    The degradation in mechanical properties of Inconel 625 ammonia cracker tubes occurs during the service for long duration in heavy water plants. The present study brings out the possibility of using Poisson's ratio (derived from measurement of time of flight of ultrasonic waves) in combination with hardness measurements, as an effective non-destructive tool for assessment of in-service degradation of Inconel 625 cracker tubes and qualification of re-solution annealing heat treatment for their rejuvenation. Further, the study also indicates the feasibility of extending the life of some of the tubes beyond the presently followed 120 000 h, before they are taken up for re-solution annealing, without affecting their serviceability. However, further studies are required to identify quantitative criterion for Poisson's ratio and hardness values, for deciding on the basis for removal of the tubes for rejuvenation.

  13. Verification of the stability lobes of Inconel 718 milling by recurrence plot applications and composite multiscale entropy analysis

    Science.gov (United States)

    Krzysztof, Kecik; Borowiec, Marek; Rafał, Rusinek

    2016-01-01

    Correctness verification of the stability lobe diagrams of milling process determined by commercial software CutPro 9 is the aim of this work. The analysis is performed for nickel superalloy Inconel 718 which is widely used in aviation industry. A methodology of stability analysis which bases on advanced nonlinear methods such as recurrence plot, recurrence quantifications analysis and composite multiscale entropy analysis are applied to the experimental data. Additionally, a new criterion for the determination of the unstable areas is proposed.

  14. Laser Rapid Manufacturing of Stainless Steel 316L/Inconel718 Functionally Graded Materials: Microstructure Evolution and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Dongjiang Wu

    2010-01-01

    Full Text Available Two patterns of functionally graded materials (FGMs were successfully fabricated whose compositions gradually varied from 100% stainless steel 316L to 100% Inconel718 superalloy using laser engineered net shaping process. The microstructure characterization, composition analysis, and microhardness along the graded direction were investigated. The comparison revealed the distinctions in solidification behavior, microstructure evolution of two patterns. In the end, the abrasive wear resistance of the material was investigated.

  15. Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects

    Science.gov (United States)

    Bast, Callie Corinne Scheidt

    1994-01-01

    This thesis presents the on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes four effects that typically reduce lifetime strength: high temperature, mechanical fatigue, creep, and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for four variables, namely, high temperature, mechanical fatigue, creep, and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using the current version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of mechanical fatigue, creep, and thermal fatigue was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

  16. Selective laser melting additive manufactured Inconel 718 superalloy parts: High-temperature oxidation property and its mechanisms

    Science.gov (United States)

    Jia, Qingbo; Gu, Dongdong

    2014-10-01

    This work presented a comprehensive study of high-temperature oxidation behaviors and mechanisms of Selective laser melting (SLM) processed Inconel 718 superalloy parts using different methods including isothermal oxidation testing, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The experimental results revealed that the oxidation process of the tested parts processed at a lower volumetric laser energy density experienced the severe spallation. On reasonably increasing the applied volumetric laser energy density, the oxidation kinetics of the as-produced parts obeyed a parabolic law, exhibiting the significantly improved oxidation resistance performance. The constitutional phases within the oxidation film were identified and the corresponding formation mechanisms were elucidated in detail according to the thermodynamic principles. The cross-sectional morphologies of oxidized Inconel 718 parts indicated that the oxidation microstructure mainly consisted of an external oxidation layer and an internal oxidation zone. The oxidation process was controlled by the outward diffusion of oxide forming elements and inward penetration of oxygen, by which the interaction mechanisms between the microstructures and internal oxidation zones were clarified. On the basis of the experimental results and theoretical analyses, the physical oxidation mechanisms were accordingly established to illustrate the oxidation behaviors of SLM-processed Inconel 718 parts at elevated operative temperatures.

  17. Effect of cold rolling and first precipitates on the coarsening behavior of γ″-phases in Inconel 718 alloy

    Science.gov (United States)

    Zhang, Jing-ling; Guo, Qian-ying; Liu, Yong-chang; Li, Chong; Yu, Li-ming; Li, Hui-jun

    2016-09-01

    The coarsening behaviors of γ″-phase particles in Inconel 718 alloy aged at 750, 800, and 850°C were investigated by scanning electron microscopy (SEM). Detailed observations and quantitative measurements were conducted to characterize the coarsening behavior of the γ?-phase under various aging conditions. The experimental results indicate that the existence of the δ-phase retards the formation and coarsening of the γ″-phase, without influencing its final particle size or amount. Moreover, when cold rolled with a reduction of 50%, the dimensions of the γ″ particles in Inconel 718 alloy decrease with increasing aging time. Furthermore, the coarsening behavior of the γ″-phase in the Inconel 718 alloy after a normal aging treatment (sample A) and that of the primary δ-phase (sample B) follow the Lifshitz-Slyozov-Wagner (LSW) diffusion-controlled growth theory; the thus-obtained activation energies for the γ″-phase are 292 kJ·mol-1 and 302 kJ·mol-1, respectively.

  18. Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: maqomer@yahoo.com [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan); Ali, G.; Ahmed, Ejaz; Haq, M.A.; Akhter, J.I. [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan)

    2011-06-15

    Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy.

  19. Étude du comportement structural de l'alliage NC 19 Fe Nb (Inconel 718)

    Science.gov (United States)

    Slama, C.; Cizeron, G.

    1997-03-01

    In the as-received state (following a double treatment at 720 and 620 °C), the structure of INC 718 consists of a γ matrix, intergranular β precipitates and (Nb,Ti)C carbides; moreover, γ{'} and γ{''} phases have precipitated in the matrix. Using different methods, the structural behaviour was analyzed which led to distinguish the temperature ranges in which occurs precipitation or dissolution of β, γ{'} and γ{''} phases on heating and to define the optimum conditions of homogeneization. Furthermore a CCT diagram for INC 718 has been drawn showing the respective precipitation of γ{'}, γ{''} and β phases as a function of the cooling rate applied from 990 °C. L'étude de l'alliage Inconel 718 (NC 19 Fe Nb) a permis de montrer que sa structure, dans l'état de livraison (après double revenu à 720 puis 620 °C), consiste en une matrice γ avec des précipités β intergranulaires et des carbures du type (Nb,Ti) C ; en outre, la matrice contient des précipités des phases γ{''} et γ{'}. L'analyse du comportement structural de l'alliage à l'aide de différentes méthodes physiques a conduit à délimiter les domaines de température dans lesquels interviennent, au chauffage, la précipitation ou la dissolution des phases β, γ{'}, γ{''} et de définir les conditions optimales d'homogénéisation. Le diagramme T.R.C. de l'Inconel 718 a ensuite été tracé : les intervalles de température dans lesquels interviennent les précipitations respectives des phases γ{'}, γ{''} et β en fonction de la vitesse de refroidissement imposée depuis 990 °C, ont ainsi pu être précisés.

  20. DP处理Inconel 718合金δ相静态溶解行为%Dissolution behavior of δ phase in Inconel 718 alloy

    Institute of Scientific and Technical Information of China (English)

    廖晓航; 司家勇; 宋思远; 谢利强

    2016-01-01

    对经δ相时效处理(DP)后的Inconel 718合金中δ相的静态溶解行为进行了研究,分析了不同热处理温度和保温时间下δ相含量、晶粒尺寸和硬度变化,发现了δ相在静态溶解过程中的组织和性能演变规律.结果表明:静态溶解过程中针状δ相形貌特征变化可分为两个阶段,初期主要为长针状δ相溶解成为短针状乃至球状,后期主要是短针状δ相溶解成球状及部分球状δ相;随着保温时间的延长,δ相的溶解量与保温时间的关系由溶解初期的线性关系变为溶解后期的近似抛物线关系,溶解速度逐渐降低;在950、980和1000℃时,δ相的溶解量在保温一段时间后达到稳定值,而在温度为1020℃和1060℃时,δ相可持续溶解,最终完全溶解;溶解初期δ相体积分数的迅速降低是界面反应起主要作用,溶解后期主要是受扩散过程控制;δ相溶解初期,硬度值下降较快,后期趋于稳定;随着保温时间的延长,热处理温度的提高,硬度值不断降低.

  1. Microhardness and microstructure evolution of TiB2 reinforced Inconel 625/TiB2 composite produced by selective laser melting

    Science.gov (United States)

    Zhang, Baicheng; Bi, Guijun; Nai, Sharon; Sun, Chen-nan; Wei, Jun

    2016-06-01

    In this study, micron-size TiB2 particles were utilized to reinforce Inconel 625 produced by selective laser melting. Exceptional microhardness 600-700 HV0.3 of the composite was obtained. In further investigation, the microstructure and mechanical properties of Inconel 625/TiB2 composite can be significantly influenced by addition of TiB2 particles during SLM. It was found that the long directional columnar grains observed from SLM-processed Inconel 625 were totally changed to fine dendritic matrix due to the addition of TiB2 particles. Moreover, with laser energy density (LED) of 1200 J/m, a Ti, Mo rich interface around TiB2 particles with fine thickness can be observed by FESEM and EDS. The microstructure evolution can be determined by different laser energy density (LED): under 1200 J/m, γ phase in dendrite grains; under 600 J/m, γ phase in combination of dendritic and acicular grains; under 400 J/m, γ phase acicular grains. Under optimized LED 1200 J/m, the dynamic nanohardness (8.62 GPa) and elastic modulus (167 GPa) of SLM-processed Inconel 625/TiB2 composite are higher compared with those of SLM-processed Inconel 625 (3.97 GPa and 135 GPa, respectively).

  2. Reactivity Studies of Inconel 625 with Sodium, and Lunar Regolith Stimulant

    Science.gov (United States)

    Gillies, Donald; Salvail, Pat; Reid, Bob; Colebaugh, James; Easterling, Greg

    2008-01-01

    In the event of the need for nuclear power in exploration, high flux heat pipes will be needed for heat transfer from space nuclear reactors to various energy conversion devices, and to safely dissipate excess heat. Successful habitation will necessitate continuous operation of alkali metal filled heat pipes for 10 or-more years in a hostile environment with little maintenance. They must be chemical and creep resistant in the high vacuum of space (lunar), and they must operate reliably in low gravity conditions with intermittent high radiation fluxes. One candidate material for the heat pipe shell, namely Inconel 625, has been tested to determine its compatibility with liquid sodium. Any reactivity could manifest itself as a problem over the long time periods anticipated. In addition, possible reactions with the lunar regolith will take place, as will evaporation of selected elements at the external surfaces of the heat pipes, and so there is a need for extensive long-term testing under simulated lunar conditions.

  3. Laser surface annealing technique of aged Inconel 718 by laser beam irradiation

    Science.gov (United States)

    Liu, Liufa; Hirose, Akio; Kobayashi, Kojiro F.

    2003-03-01

    Laser was employed to anneal a thin surface layer of aged Inconel 718 by dissolving the strengthening phase, γ". The HE (Hydrogen Embrittlement) resistance of the alloy was improved via such laser surface annealing (LSA) processes. To establish a general LSA technique for engineer applications, experimental LSA processes were conducted to study the effects of the laser process parameters on the formation of the annealed surface layers, and applicable process parameter ranges were obtained. Next, a numerical method was developed for predicting the formation of the laser annealed surface layers in the following steps. Because only the γ" phase was dissolved in the LSA process, the dissolution kinetics of this phase was studied via thermal cycling experiments, and it was proved to follow an Avrami equation. FEM (Finite Element Method) simulations were conducted to calculate the thermal distribution in each laser annealed surface layer, and thermal history data were extracted every certain depth. The volume fractions of the γ" phase at these depths were calculated using these thermal history data based on the deduced Avrami equation. Using a developed relationship between the hardness variation of the alloy and the volume fraction variation of the γ" phase, the hardness distribution in the annealed surface layer and this layer's thickness were calculated. The predicted applicable laser process parameter ranges were obtained. These calculated results were compared with their corresponding experimental results. The good agreements between the calculated and measured results suggested that this numerical prediction approach is feasible for engineer applications.

  4. Addition of a nickel aluminide coating to Inconel 600 using a solar furnace

    Energy Technology Data Exchange (ETDEWEB)

    Rawers, J.C.; Alman, D.E.; Lewandowski, A.; Petty, A.V.; Pitts, J. (Bureau of Mines, Albany, OR (United States). Albany Research Center)

    1994-11-15

    Three different coating application techniques have been investigated for placing a nickel-aluminium coating onto an Inconel 600 substrate using a solar furnace. In the first, a sheet of pure aluminium was melted onto the substrate. A duplex sheet of pure aluminium was melted onto the substrate. A duplex surface coating resulted, the outer layer being a mixture of pure aluminium and NiAl[sub 3], the inner layer being pure NiAl[sub 3] firmly bonded to the substrate. The second method involved melting pre-alloyed NiAl powder onto the substrate and gave a firmly bonded composite mixture of NiAl and Ni[sub 2]Al[sub 3] intermetallics. The third method was less successful. Elemental Al and Ni powders did not wet the substrate when melted and resulted only in poorly bonded intermetallic balls. Given the right technique, however, it has been demonstrated that solar radiation can be very effective in rapidly heating and melting a surface coating onto a processed bulk material with minimal thermal damage. (5 figures, 7 references). (UK)

  5. Laser Metal Deposition as Repair Technology for a Gas Turbine Burner Made of Inconel 718

    Science.gov (United States)

    Petrat, Torsten; Graf, Benjamin; Gumenyuk, Andrey; Rethmeier, Michael

    Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.

  6. Investigation of electron-beam welding in wrought Inconel 706--experimental and numerical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ferro, Paolo [Department of Management and Engineering, University of Padova, Stradella S. Nicola, 3 I-36100 Vicenza (Italy)]. E-mail: ferro@gest.unipd.it; Zambon, Andrea [DIMEG, University of Padova, Via Marzolo, 9 I-35131 Padova (Italy); Bonollo, Franco [Department of Management and Engineering, University of Padova, Stradella S. Nicola, 3 I-36100 Vicenza (Italy)

    2005-02-15

    Electron-beam welding (EBW) is commonly employed in the aeroengine industry for the welding of high integrity components, fabricated from high-strength superalloys. For such applications, it is important to predict distortions and residual stresses induced by the process. Melt run trials have been carried out on nickel-base superalloy Inconel 706 plates using the EBW technique in order to analyse the effects of welding parameters on geometrical characteristics and microstructure of the bead. Butt-welded plates have been then investigated by means of tensile tests, microstructural analysis, and X-ray diffraction measurements. A finite element model of the process has been set up using an uncoupled thermal-mechanical analysis. The heat source was modelled using a superimposition of a spherical and a conical shape heat source with Gaussian power density distribution in order to reproduce the nail shape of the fusion zone (FZ). The parameters of the source were chosen so that the model would match with experimentally determined weld pool shape and temperatures, measured with thermocouples. Subsequently, the thermal analysis was used to drive the non-linear mechanical analysis. The predicted residual stresses were then compared with X-ray diffraction measurements. It was found that the correct thermal and residual stresses prediction is influenced by the shape of the fusion zone, the highest thermal tensile stress arising under the nailhead of the fusion zone where microfissuring can be observed.

  7. CO2 laser cut quality of Inconel 718 nickel - based superalloy

    Science.gov (United States)

    Hasçalık, Ahmet; Ay, Mustafa

    2013-06-01

    This paper experimentally investigates the cut quality of laser cutting for the age hardened Inconel 718 nickel based super alloy, with the use of a continuous CO2 4.0 kW laser cutting system. The quality of the cut has been monitored by measuring the kerf taper ratio, the recast layer thickness and the surface roughness of the cut specimens. The effects of processing parameters, such as the laser power, the cutting speed and the assisting gas pressure were evaluated. Scanning electron microscopy (SEM), Energy Dispersive Spectrography (EDS), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Knoop hardness tests are carried out to examine the cutting defects, the kerf size variation and formed carbide on the surfaces. A statistical analysis of the results has been performed in order for the effect of each parameter on the cutting quality to be determined. The regression analysis has been used for the development of empirical models able to describe the effect of the process parameters on the quality of laser cutting.

  8. Carbide and nitride precipitation during laser cladding of Inconel 718 alloy coatings

    Science.gov (United States)

    Zhang, Yaocheng; Li, Zhuguo; Nie, Pulin; Wu, Yixiong

    2013-11-01

    The microstructure of the laser clad Inconel 718 alloy coating was observed by scanning electron microscope (SEM). The chemical composition of precipitation phases was investigated by energy dispersive spectrometer (EDS) and solid phase microextraction (SPME). The crystal structure and lattice constants of precipitation are determined by transmission electron microscope (TEM). Vickers hardness of the coatings and the nanohardness of the interstitial phases were measured. The insular carbide (MC) and the tetragonal nitride (MN) with face-centered cubic (FCC) structure are rich in Ti and Nb but depleted in Ni, Fe and Cr due to the interdiffusion and redistribution of alloying elements between MC and MN and supersaturated matrix. MC and MN were precipitated in the forms of (Nb0.12Ti0.88)C1.5 and (Nb0.88Ti0.12)N1.5, and the Gibbs free energies of formation can be expressed as Δ G [ (Nb0.12Ti0.88)C1.5 ] 0 = - 122.654 - 3.1332 T (kJ /mol) and Δ G [ (Nb0.88Ti0.12)N1.5 ] 0 = - 157.814 - 3.0251 T (kJ /mol). The nanohardness and Young's modulus of the MC and MN were much higher than the matrix, and the plastic deformation energy of interstitial phases was lower than the matrix. The precipitation of MC and MN is beneficial to the mechanical properties of coating.

  9. Biaxial thermal creep of Inconel 617 and Haynes 230 at 850 and 950 °C

    Science.gov (United States)

    Tung, Hsiao-Ming; Mo, Kun; Stubbins, James F.

    2014-04-01

    The biaxial thermal creep behavior of Inconel 617 and Haynes 230 at 850 and 950 °C was investigated. Biaxial stresses were generated using the pressurized tube technique. The detailed creep deformation and fracture mechanism have been studied. Creep curves for both alloys showed that tertiary creep accounts for a greater portion of the materials' life, while secondary creep only accounts for a small portion. Fractographic examinations of the two alloys indicated that nucleation, growth, and coalescence of creep voids are the dominant micro-mechanisms for creep fracture. At 850 °C, alloy 230 has better creep resistance than alloy 617. When subjected to the biaxial stress state, the creep rupture life of the two alloys was considerably reduced when compared to the results obtained by uniaxial tensile creep tests. The Monkman-Grant relation proves to be a promising method for estimating the long-term creep life for alloy 617, whereas alloy 230 does not follow the relation. This might be associated with the significant changes in the microstructure of alloy 230 at high temperatures.

  10. A Comparative Study on the Hot Working Behavior of Inconel 718 and ALLVAC 718 Plus

    Science.gov (United States)

    Momeni, Amir; Abbasi, Seyed Mehdi; Morakabati, Maryam; Badri, Hasan

    2017-03-01

    Hot compression tests were performed on Inconel 718 and ALLVAC 718 PLUS (718+) at temperatures and strain rates in ranges of 1223 K to 1373 K (950 °C to 1100 °C) and 0.001-1 s-1, respectively. Discontinuous yield behavior was observed in the flow curves of both alloys. For both alloys, the drop in stress at the yield point (yield drop) was maximized at 0.01 to 1 s-1. The alloy 718+ showed larger yield drop than 718 over the studied deformation conditions. The different yield behaviors were attributed to the various chemical compositions. The peak strain for both alloys increased in temperature range of 1223 K to 1273 K (950 to 1000 °C) and strain rates of 0.01 to 1 s-1. This uncommon behavior was ascribed to the change in the mechanism of microstructural evolution from continuous to discontinuous dynamic recrystallization (DRX). The kinetics of DRX was described by the Avrami equation and the exponent was determined at different deformation conditions. The Avrami exponent increased in the middle values of Zener-Hollomon ( Z) parameters, i. e., 29.3 < ln Z < 32.9 for 718 and 31.4 < ln Z < 34.5 for 718+. The unusual variation of the Avrami exponent was attributed to the change in the mechanism of DRX.

  11. Effect of electric discharge machining on the fatigue life of Inconel 718

    Science.gov (United States)

    Jeelani, S.; Collins, M. R.

    1988-01-01

    The effect of electric discharge machining on the fatigue life of Inconel 718 alloy at room temperature was investigated. Data were generated in the uniaxial tension fatigue mode at ambient temperature using flat 3.175 mm thick specimens. The specimens were machined on a wire-cut electric discharge machine at cutting speeds ranging from 0.5 to 2 mm per minute. The specimens were fatigued at a selected stress, and the resulting fatigue lives compared with that of the virgin material. The surfaces of the fatigued specimens were examined under optical and scanning electron microscopes, and the roughness of the surfaces was measured using a standard profilometer. From the results of the investigation, it was concluded that the fatigue life of the specimens machined using EDM decreased slightly as compared with that of the virgin material, but remained unchanged as the cutting speed was changed. The results are explained using data produced employing microhardness measurements, profilometry, and optical and scanning microscopy.

  12. Microstructural evolution and mechanical properties of Inconel 718 after thermal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z.S., E-mail: yuzaisong@tpri.com.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China); Zhang, J.X. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Yuan, Y.; Zhou, R.C.; Zhang, H.J.; Wang, H.Z. [Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China)

    2015-05-14

    Inconel 718 was subjected to various heat treatments, i.e., solution heat treatment, standard ageing treatment and standard ageing plus 700 °C thermal exposure. The mechanical properties of the alloys were determined using tensile tests and Charpy pendulum impact tests at 650 °C and room temperature, respectively. The highest yield strength of 988 MPa was attained in the standard aged specimen, whereas a maximum impact toughness of 217 J cm{sup −2} was attained in the solution-treated specimen. After thermal exposure, the mechanical properties of the specimens degrade. Both the yield strength and impact toughness decreased monotonically with increasing thermal exposure time. Subjected to a 10000-h long-term thermal exposure, the yield strength dramatically decreased to 475 MPa (almost 50% of the maximum strength), and the impact toughness reduced to only 18 J cm{sup −2}. The microstructures of the specimens were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Coarsening of γ′ and γ″ and the transformation of γ″ to δ-Ni{sub 3}Nb was observed after thermal exposure. However, a complete transformation from metastable γ″ to δ-Ni{sub 3}Nb was never accomplished, even after the 10000-h long-term thermal exposure. Based on the obtained experimental results, the effects of the microstructural evolution on the mechanical properties are discussed.

  13. Grain Size Effect on Fracture Behavior of the Axis-Tensile Test of Inconel 718 Sheet

    Science.gov (United States)

    Liu, B. B.; Han, J. Q.; Zhao, R.; Liu, W.; Wan, M.

    2016-11-01

    Change in mechanical parts from macro-size to micro-size has become a trend in the metal- and alloy-forming process, with an increasing demand on micro-parts in the last decades. The material mechanical behaviors of micro-size parts are quite different from the conventional ones of macro-size parts due to size effect. It is necessary to further investigate the effects of grain size on material mechanisms in micro-scales, especially fracture behaviors. The fracture behaviors of Inconel 718 sheet with the thickness of 300 μm are studied by uniaxial tensile tests in different grain sizes ranging from 18 to 130 μm. The results show that fracture stress and strain decrease with the increase of grain size. A critical value in the specimen thickness (t) to grain size (d) ratio divides the strength levels into separate stages on the basis of an increase of the inverse of grain size. In addition, the grain size-dependent fracture morphology is changed in the number of dimples and micro-voids decreasing on the fracture surfaces and the sizes of micro-voids changing larger with the increase of grain size.

  14. Influence of overloads on dwell time fatigue crack growth in Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Saarimäki, Jonas, E-mail: jonas.saarimaki@liu.se [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Moverare, Johan [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Siemens Industrial Turbomachinery AB, Materials Technology, SE-61283 Finspång (Sweden); Eriksson, Robert; Johansson, Sten [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden)

    2014-08-26

    Inconel 718 is one of the most commonly used superalloys for high temperature applications in gasturbines and aeroengines and is for example used for components such as turbine discs. Turbine discs can be subjected to temperatures up to ∼700 °C towards the outer radius of the disc. During service, the discs might start to develop cracks due to fatigue and long dwell times. Additionally, temperature variations during use can lead to large thermal transients during start-up and shutdown which can lead to overload peaks in the normal dwell time cycle. In this study, tests at 550 °C with an overload prior to the start of each dwell time, have been performed. The aim of the investigation was to get a better understanding of the effects of overloads on the microstructure and crack mechanisms. The microstructure was studied using electron channelling contrast imaging (ECCI). The image analysis toolbox in Matlab was used on cross sections of the cracks to quantify: crack length, branch length, and the number of branches in each crack. It was found that the amount of crack branching increases with an increasing overload and that the branch length decreases with an increasing overload. When the higher overloads were applied, the dwell time effect was almost cancelled out. There is a strong tendency for an increased roughness of the crack path with an increasing crack growth rate.

  15. Optimization of WEDM process parameters using deep cryo-treated Inconel 718 as work material

    Directory of Open Access Journals (Sweden)

    Bijaya Bijeta Nayak

    2016-03-01

    Full Text Available The present work proposes an experimental investigation and optimization of various process parameters during taper cutting of deep cryo-treated Inconel 718 in wire electrical discharge machining process. Taguchi's design of experiment is used to gather information regarding the process with less number of experimental runs considering six input parameters such as part thickness, taper angle, pulse duration, discharge current, wire speed and wire tension. Since traditional Taguchi method fails to optimize multiple performance characteristics, maximum deviation theory is applied to convert multiple performance characteristics into an equivalent single performance characteristic. Due to the complexity and non-linearity involved in this process, good functional relationship with reasonable accuracy between performance characteristics and process parameters is difficult to obtain. To address this issue, the present study proposes artificial neural network (ANN model to determine the relationship between input parameters and performance characteristics. Finally, the process model is optimized to obtain a best parametric combination by a new meta-heuristic approach known as bat algorithm. The results of the proposed algorithm show that the proposed method is an effective tool for simultaneous optimization of performance characteristics during taper cutting in WEDM process.

  16. Application of laser ultrasonics to monitor microstructure evolution in Inconel 718 superalloy

    Directory of Open Access Journals (Sweden)

    Garcin Thomas

    2014-01-01

    Full Text Available Laser ultrasonics for metallurgy is an innovative sensor dedicated to the measurement of microstructure evolution during thermomechanical processing. In this technique, broadband ultrasound pulses are generated and detected with lasers. The properties of the ultrasounds are then related to the characteristics of the microstructure. Ultrasound attenuation is primary originated by the scattering at grain boundaries and its frequency dependence can be related to the grain size. The present work aims to introduce this technology as an exciting tool for metallurgists. As an illustration of its capability, the evolution of the grain size during isothermal annealing from a fine grained structure is in-situ monitored in an Inconel 718 superalloy. Laser ultrasonic measurements are compared with ex-situ metallography observations. Indication of heterogeneous grain growth is observed, correlated to the dissolution of δ-phase particles present in the initial structure. This preliminary study illustrates the potential of this new technique to monitor microstructure evolution in more complex scenarios including recrystallization during simulation of hot forging processes.

  17. Effect of Grain Size Distribution on Processing Maps for Isothermal Compression of Inconel 718 Superalloy

    Science.gov (United States)

    Wang, Jianguo; Liu, Dong; Hu, Yang; Yang, Yanhui; Zhu, Xinglin

    2016-02-01

    Cylindrical specimens of Inconel 718 alloys with three types of grain size distribution were used in the compression tests and processing maps were developed in 940-1040 °C and 0.001-10 s-1. The equiaxed fine grain is more effective on the dynamic softening behavior. For partial recrystallized microstructure, the peak efficiency of power dissipation occurs at the strain rate of 0.001 s-1, and the temperature range of 1000-1020 °C. In order to obtain homogeneous microstructure with fine grains, the partial recrystallized microstructure should be deformed at the low temperature and slow strain rates. The area fraction of instability domains decreases with strain increasing. The peak efficiency of power dissipation increases with average grain size decreasing. The efficiency of power dissipation will be stimulated by the precipitation of δ phase at slow strain rate of 0.001-0.01 s-1, and the initial deformed substructure at the strain rate of 0.1-1 s-1. Equiaxed fine grain is the optimum state for forging process and dynamic recrystallization. The grain size distribution has slight influence on the microstructure evolution at high temperatures.

  18. Mechanical Characterization of an Additively Manufactured Inconel 718 Theta-Shaped Specimen

    Science.gov (United States)

    Cakmak, Ercan; Watkins, Thomas R.; Bunn, Jeffrey R.; Cooper, Ryan C.; Cornwell, Paris A.; Wang, Yanli; Sochalski-Kolbus, Lindsay M.; Dehoff, Ryan R.; Babu, Sudarsanam S.

    2016-02-01

    Two sets of "theta"-shaped specimens were additively manufactured with Inconel 718 powders using an electron beam melting technique with two distinct scan strategies. Light optical microscopy, mechanical testing coupled with a digital image correlation (DIC) technique, finite element modeling, and neutron diffraction with in situ loading characterizations were conducted. The cross-members of the specimens were the focus. Light optical micrographs revealed that different microstructures were formed with different scan strategies. Ex situ mechanical testing revealed each build to be stable under load until ductility was observed on the cross-members before failure. The elastic moduli were determined by forming a correlation between the elastic tensile stresses determined from FEM, and the elastic strains obtained from DIC. The lattice strains were mapped with neutron diffraction during in situ elastic loading; and a good correlation between the average axial lattice strains on the cross-member and those determined from the DIC analysis was found. The spatially resolved stresses in the elastic deformation regime are derived from the lattice strains and increased with applied load, showing a consistent distribution along the cross-member.

  19. Multipass forging of Inconel 718 in the delta-Supersolvus domain: assessing and modeling microstructure evolution

    Directory of Open Access Journals (Sweden)

    Zouari Meriem

    2014-01-01

    Full Text Available This work is focused on the evolution of the microstructure of Inconel 718 during multi-pass forging processes. During the forming process, the material is subjected to several physical phenomena such as work-hardening, recovery, recrystallization and grain growth. In this work, transformation kinetics are modeled in the δ-Supersolvus domain (T>Tsolvus where the alloy is single-phase, all the alloying elements being dissolved into the FCC matrix. Torsion tests were used to simulate the forging process and recrystallization kinetics was modeled using a discontinuous dynamic recrystallization (DDRX two-site mean field model. The microstructure evolution under hot forging conditions is predicted in both dynamic and post-dynamic regimes based on the initial distribution of grain size and the evolution of dislocation density distribution during each step of the process. The model predicts recrystallization kinetics, recrystallized grain size distribution and stress–strain curve for different thermo-mechanical conditions and makes the connection between dynamic and post-dynamic regimes.

  20. TEM Study of High-Temperature Precipitation of Delta Phase in Inconel 718 Alloy

    Directory of Open Access Journals (Sweden)

    Moukrane Dehmas

    2011-01-01

    Full Text Available Inconel 718 is widely used because of its ability to retain strength at up to 650∘C for long periods of time through coherent metastable  Ni3Nb precipitation associated with a smaller volume fraction of  Ni3Al precipitates. At very long ageing times at service temperature,  decomposes to the stable Ni3Nb phase. This latter phase is also present above the  solvus and is used for grain control during forging of alloy 718. While most works available on precipitation have been performed at temperatures below the  solvus, it appeared of interest to also investigate the case where phase precipitates directly from the fcc matrix free of  precipitates. This was studied by X-ray diffraction and transmission electron microscopy (TEM. TEM observations confirmed the presence of rotation-ordered domains in plates, and some unexpected contrast could be explained by double diffraction due to overlapping phases.

  1. Molding Properties of Inconel 718 Feedstocks Used in Low-Pressure Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Fouad Fareh

    2016-01-01

    Full Text Available The impact of binders and temperature on the rheological properties of feedstocks used in low-pressure powder injection molding was investigated. Experiments were conducted on different feedstock formulations obtained by mixing Inconel 718 powder with wax-based binder systems. The shear rate sensitivity index and the activation energy were used to study the degree of dependence of shear rate and temperature on the viscosity of the feedstocks. The injection performance of feedstocks was then evaluated using an analytical moldability model. The results indicated that the viscosity profiles of feedstocks depend significantly on the binder constituents, and the secondary binder constituents play an important role in the rheological behavior (pseudoplastic or near-Newtonian exhibited by the feedstock formulations. Viscosity values as low as 0.06 to 2.9 Pa·s were measured at high shear rates and high temperatures. The results indicate that a feedstock containing a surfactant agent exhibits the best moldability characteristics.

  2. Experimental Investigation and Optimization of Response Variables in WEDM of Inconel - 718

    Science.gov (United States)

    Karidkar, S. S.; Dabade, U. A.

    2016-02-01

    Effective utilisation of Wire Electrical Discharge Machining (WEDM) technology is challenge for modern manufacturing industries. Day by day new materials with high strengths and capabilities are being developed to fulfil the customers need. Inconel - 718 is similar kind of material which is extensively used in aerospace applications, such as gas turbine, rocket motors, and spacecraft as well as in nuclear reactors and pumps etc. This paper deals with the experimental investigation of optimal machining parameters in WEDM for Surface Roughness, Kerf Width and Dimensional Deviation using DoE such as Taguchi methodology, L9 orthogonal array. By keeping peak current constant at 70 A, the effect of other process parameters on above response variables were analysed. Obtained experimental results were statistically analysed using Minitab-16 software. Analysis of Variance (ANOVA) shows pulse on time as the most influential parameter followed by wire tension whereas spark gap set voltage is observed to be non-influencing parameter. Multi-objective optimization technique, Grey Relational Analysis (GRA), shows optimal machining parameters such as pulse on time 108 Machine unit, spark gap set voltage 50 V and wire tension 12 gm for optimal response variables considered for the experimental analysis.

  3. High productivity machining of holes in Inconel 718 with SiAlON tools

    Science.gov (United States)

    Agirreurreta, Aitor Arruti; Pelegay, Jose Angel; Arrazola, Pedro Jose; Ørskov, Klaus Bonde

    2016-10-01

    Inconel 718 is often employed in aerospace engines and power generation turbines. Numerous researches have proven the enhanced productivity when turning with ceramic tools compared to carbide ones, however there is considerably less information with regard to milling. Moreover, no knowledge has been published about machining holes with this type of tools. Additional research on different machining techniques, like for instance circular ramping, is critical to expand the productivity improvements that ceramics can offer. In this a 3D model of the machining and a number of experiments with SiAlON round inserts have been carried out in order to evaluate the effect of the cutting speed and pitch on the tool wear and chip generation. The results of this analysis show that three different types of chips are generated and also that there are three potential wear zones. Top slice wear is identified as the most critical wear type followed by the notch wear as a secondary wear mechanism. Flank wear and adhesion are also found in most of the tests.

  4. A Comparative Study on the Hot Working Behavior of Inconel 718 and ALLVAC 718 Plus

    Science.gov (United States)

    Momeni, Amir; Abbasi, Seyed Mehdi; Morakabati, Maryam; Badri, Hasan

    2017-01-01

    Hot compression tests were performed on Inconel 718 and ALLVAC 718 PLUS (718+) at temperatures and strain rates in ranges of 1223 K to 1373 K (950 °C to 1100 °C) and 0.001-1 s-1, respectively. Discontinuous yield behavior was observed in the flow curves of both alloys. For both alloys, the drop in stress at the yield point (yield drop) was maximized at 0.01 to 1 s-1. The alloy 718+ showed larger yield drop than 718 over the studied deformation conditions. The different yield behaviors were attributed to the various chemical compositions. The peak strain for both alloys increased in temperature range of 1223 K to 1273 K (950 to 1000 °C) and strain rates of 0.01 to 1 s-1. This uncommon behavior was ascribed to the change in the mechanism of microstructural evolution from continuous to discontinuous dynamic recrystallization (DRX). The kinetics of DRX was described by the Avrami equation and the exponent was determined at different deformation conditions. The Avrami exponent increased in the middle values of Zener-Hollomon (Z) parameters, i.e., 29.3 < lnZ < 32.9 for 718 and 31.4 < lnZ < 34.5 for 718+. The unusual variation of the Avrami exponent was attributed to the change in the mechanism of DRX.

  5. Microstructures, Forming Limit and Failure Analyses of Inconel 718 Sheets for Fabrication of Aerospace Components

    Science.gov (United States)

    Sajun Prasad, K.; Panda, Sushanta Kumar; Kar, Sujoy Kumar; Sen, Mainak; Murty, S. V. S. Naryana; Sharma, Sharad Chandra

    2017-02-01

    Recently, aerospace industries have shown increasing interest in forming limits of Inconel 718 sheet metals, which can be utilised in designing tools and selection of process parameters for successful fabrication of components. In the present work, stress-strain response with failure strains was evaluated by uniaxial tensile tests in different orientations, and two-stage work-hardening behavior was observed. In spite of highly preferred texture, tensile properties showed minor variations in different orientations due to the random distribution of nanoprecipitates. The forming limit strains were evaluated by deforming specimens in seven different strain paths using limiting dome height (LDH) test facility. Mostly, the specimens failed without prior indication of localized necking. Thus, fracture forming limit diagram (FFLD) was evaluated, and bending correction was imposed due to the use of sub-size hemispherical punch. The failure strains of FFLD were converted into major-minor stress space (σ-FFLD) and effective plastic strain-stress triaxiality space (ηEPS-FFLD) as failure criteria to avoid the strain path dependence. Moreover, FE model was developed, and the LDH, strain distribution and failure location were predicted successfully using above-mentioned failure criteria with two stages of work hardening. Fractographs were correlated with the fracture behavior and formability of sheet metal.

  6. Microstructural characterization and some mechanical properties of gas-borided Inconel 600-alloy

    Science.gov (United States)

    Makuch, N.; Kulka, M.

    2014-09-01

    The excellent resistance of Ni-based alloys to corrosion and oxidation is well-known. Boriding can be applied to these alloys in order to obtain suitable wear protection. In this paper, two-stage gas boronizing in N2-H2-BCl3 atmosphere is proposed for the producing the boride layer on Inconel®600-alloy. This process consists in two stages alternately repeated: saturation by boron and diffusion annealing. Such a gas boriding is applied in order to accelerate the saturation by boron and its diffusion. It turns out to be more effective because of eliminating the excess of boron, diffusing into the substrate, during the second stage. Microstructure and some mechanical properties of the produced layer are presented. Microstructural characterization is studied with using an optical microscope, scanning electron microscope, energy-dispersive x-ray microanalysis and x-ray diffraction. The diffusion zone consists of the mixture of nickel and chromium borides, occurring in the compact boride zone and in the area located beneath, at grain boundaries. The improved hardness and wear resistance characterize the layer. The formed boride layer is significantly thicker than those-obtained by the pack-boronizing or paste process at comparable temperature and time. Simultaneously, the measured depth of layer is slightly smaller than that-reported for electrolytic boriding.

  7. Analisis Kegagalan Retak dan Teknologi Perbaikan Sudu Turbin Jenis Inconel 792 pada Pesawat Terbang

    Directory of Open Access Journals (Sweden)

    Suharno .

    2013-01-01

    Full Text Available Penelitian untuk melakukan analisis terhadap kegagalan retak telah dilakukan pada sudu turbin dari Auxiliary Power Unit (APU pesawat terbang. Bahan sudu turbin adalah paduan super  Inconel 792. Pengujian yang dilakukan meliputi inspeksi visual, pengujian komposisi kimia, fractography, pengujian kekerasan, dan metalografi.Hasilnya menunjukkan bahwa patah dimulai dari celah dan retak makro dan kemudian menjalar/merambat menjadi retak terbuka di permukaan.Hal ini kemungkinan disebabkan oleh mekanisme retak panas selama perbaikan las sebelumnya. Kandungan Aluminium dan Titanium yang tinggi pada logam las, menjadikan material menjadi rapuh, hal ini ditunjukkan oleh fitur intergranular dibandingkan dengan aspek pembelahan transgranular menunjukkan bahwa keuletan pada lasan rendah. Dibandingkan dengan sudu yang tidak rusak (gagal, ukuran butir dari sudu turbin yang rusak adalah sangat berbeda menunjukkan eksposisi terhadap panas baik dari siklus termal pengelasan atau lingkungan operasi normal pada suhu tinggi.Teknik perbaikan lebih lanjut dikembangkan berdasarkan keberhasilan PQTR yang di uji dengan kekerasan mikro, destructive dan non destructive test.Untuk tujuan ini maka dipilih las GTAW yang diikuti dengan solution dan aging treatment.

  8. Characterization of the Microstructures and the Cryogenic Mechanical Properties of Electron Beam Welded Inconel 718

    Science.gov (United States)

    Kwon, Soon Il; Bae, Sang Hyun; Do, Jeong Hyeon; Jo, Chang Yong; Hong, Hyun Uk

    2016-02-01

    The microstructures and the cryogenic mechanical properties of electron beam (EB) welds between cast and forged Inconel 718 superalloys with a thickness of 10 mm were investigated in comparison with gas tungsten arc (GTA) welds. EB welding with a heat input lower than 250 J/mm caused the formation of liquation microfissuring in the cast-side heat-affected-zone (HAZ) of the EB welds. HAZ liquation microfissuring appeared to be associated with the constitutional liquation of primary NbC carbides at the grain boundaries. Compared with the GTA welding process, the EB welding produced welds with superior microstructure, exhibiting fine dendritic structure associated with the reduction in size and fraction of the Laves phase due to the rapid cooling rate. This result was responsible for the superior mechanical properties of the EB welds at 77 K (-196 °C). Laves particles in both welds were found to provide the preferential site for the crack initiation and propagation, leading to a significant decrease in the Charpy impact toughness at 77 K (-196 °C). Crack initiation and propagation induced by Charpy impact testing were discussed in terms of the dendrite arm spacing, the Laves size and the dislocation structure ahead of the crack arisen from the fractured Laves phase in the two welds.

  9. Low Cycle Fatigue Behaviors of Alloy 617 (INCONEL 617 Weldments for High Temperature Applications

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    Rando Tungga Dewa

    2016-04-01

    Full Text Available In this study, we comparatively investigate the low cycle fatigue behavior of Alloy 617 (INCONEL 617 weldments by gas tungsten arc welding process at room temperature and 800 °C in the air to support the qualification in high temperature applications of the Next Generation-IV Nuclear Plant. Axial total-strain controlled tests have been performed with the magnitude of strain ranges with a constant strain ratio (Rε = −1. The results of fatigue tests consistently show lower fatigue life with an increase in total strain range and temperature at all testing conditions. The reduction in fatigue life may result from the higher cyclic plastic strain accumulation and the material ductility at high temperature conditions. A constitutive behavior of high temperature by some cyclic hardening was observed. The occurrence of serrated yielding in the cyclic stress response was also observed, suggesting the influence of dynamic strain aging during high temperature. We evaluated a well-known life prediction model through the Coffin-Manson relationship. The results are well matched with the experimental data. In addition, low cycle fatigue cracking occurred in the weld metal region and initiated transgranularly at the free surface.

  10. Self-organization of Coated Carbide Insert in Turning of Inconel 718%车削Inconel 718时涂层硬质合金刀具自组织过程

    Institute of Scientific and Technical Information of China (English)

    宋新玉; 刘永洪

    2015-01-01

    根据不可逆热力学的非平衡态下结构稳定与失效原理,当系统熵产生数达到一定值时,系统将会出现“行为临界点”.越过这种临界点后系统将离开原来的热力学无序分支,形成稳定的有序的自组织结构.采用硬质合金刀具对镍基合金Inconel 718进行了车削试验,分析了不同切削条件下形成积屑瘤、切屑流动带、氧化层和粘结层的磨损机理.通过热力学刀具磨损自组织原理,对金属切削工程中刀具的摩擦、磨损进行研究.研究结果表明高速切削镍基高温合金Inconel 718的过程中,积屑瘤、切屑流动带、氧化层和粘结层是刀具形成新的有序的自组织结构的体现.试验和理论分析证实,高速切削镍基高温合金Inconel 718过程中刀具的磨损过程就是非平衡态热力学结构稳定与失效的演变过程.

  11. Optimization of micro milling electrical discharge machining of Inconel 718 by Grey-Taguchi method%田口-灰关联法应用于Inconel718微放电铣削参数最佳化

    Institute of Scientific and Technical Information of China (English)

    林茂用; 曾中丞; 许春耀; 邱(薆)蕙; 黄鹏丞; 林裕城

    2013-01-01

    应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响.实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6× 10-9 mm3/min降低到5.2×10-9 mm3/min,材料去除率由0.47× 10 8 mm3/min增加到1.68× 10-8 mm3/min,扩口量由1.27 μm降低到1.19μm.研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性.%The optimization of micro milling electrical discharge machining (EDM) process parameters of Inconel 718 alloy to achieve multiple performance characteristics such as low electrode wear,high material removal rate and low working gap was investigated by the Grey-Taguchi method.The influences of peak current,pulse on-time,pulse off-time and spark gap on electrode wear (EW),material removal rate (MRR) and working gap (WG) in the micro milling electrical discharge machining of Inconel 718 were analyzed.The experimental results show that the electrode wear decreases from 5.6× 10-9 to 5.2× 10 9 mm3/min,the material removal rate increases from 0.47x 10-8 to 1.68x 10-8 mm3/min,and the working gap decreases from 1.27 to 1.19 μm under optimal micro milling electrical discharge machining process parameters.Hence,it is clearly shown that multiple performance characteristics can be improved by using the Grey-Taguchi method.

  12. Microsegregation and Precipitates in Inconel 625 Arc Weld Overlay Coatings on Boiler Pipes / Mikrosegregacja I Wydzielenia W Powłokach Ze Stopu Inconel 625 Napawanych Łukowo Na Rury Kotłowe

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2015-12-01

    Full Text Available The aim of this work was to investigate the microsegregation and precipitates formed due to segregation in Inconel 625 arc weld overlay coatings on boiler pipes. Examination of microsegregation and precipitates were carried out by means of a scanning electron microscope (SEM equipped with an EDS detector as well as a transmission electron microscope (TEM equipped with a HAADF (STEM and an EDS detectors. The presence of precipitations in the weld overlay was also confirmed with X-ray diffraction analysis (XRD of residue in the form of powder that remained after the electrolytic dissolution of weld overlay matrix.

  13. Predictive Tool Life Model of Ultra High Speed Turning Inconel 718 and Cutting Parameter Optimization%超高速切削Inconel 718刀具寿命研究及切削参数优化

    Institute of Scientific and Technical Information of China (English)

    赵军; 郑光明; 李安海; 崔晓斌

    2011-01-01

    Inconel 718 is a difficult to machine alloy with low cutting efficiency and server tool wear. A series of orthogonal turning tests with sialon ceramic tools in ultra high speed scale was carried out to study tool life and wear mechanism. At the same time, the cutting parameters were optimized based on tool life-efficiency contour analysis.The experiential functions of tool life were developed. The main wear mechanisms of sialon ceramic tool involve adhesion and abrasion. In the same cutting efficiency, the higher cutting speed and small depth of cut are the better selection. For the selested tool, the optimized cutting parameter are cutting speed 150 ~ 250 m/min, depth of cut 0. 05 ~0.2 mm, feed rate 0. 1 ~ 0.2 mm, and the predietve tool life is about 5 ~ 20 min in this cutting condition.%针对Inconel 718加工时,切削效率低和刀具磨损严重,通过角正交试验对Sialon陶瓷刀具超高速切削Inconel 718的刀具寿命及磨损机理进行了研究,同时利用等效率-等寿命响应曲面法,对切削参数进行了优化,获得了干切削状态下刀具寿命的经验公式,得到陶瓷刀具超高速切削Inconel 718主要的磨损机理是粘结磨损和磨粒磨损,在效率不变的情况下,适当的降低切削速度,增大切削深度,可以提高刀具寿命,试验刀具的切削参数优化结果为:切削速度150~250 m/min、切削深度0.05~0.2 mm、进给量0.1~0.2 mm,在该建议切削参数下刀具寿命约在5~20 min.

  14. Effects of Al and Ti Contents on the Microstructure and Solidification Behavior of Cast Inconel 718%Al、Ti含量对Inconel 718合金铸造组织和凝固行为的影响

    Institute of Scientific and Technical Information of China (English)

    王立红; 刘子利; 刘希琴; 孙楠; 温宸

    2016-01-01

    采用差热分析(DSC)、光学显微镜、扫描电镜(SEM)、电子能谱(EDS)和X射线衍射分析(XRD)测试手段,结合JMatPro模拟计算分析研究了Al、Ti含量对Inconel 718铸锭组织和凝固行为的影响.结果表明,不同Al、Ti含量Inconel 718合金的铸态组织均呈典型树枝状结构,枝晶间析出相主要由(γ+ Laves)共晶相和少量M(C,N)构成.随着Al/Ti原子比的升高,铸态组织中黑色枝晶间区域数量明显增加,Laves相形态由块状向共晶筛网状转变,同时Laves相周围析出的针状一次δ相和枝晶间γ"相数量减少;Inconel 718合金的凝固次序没有改变,合金的液相线由1363.5℃(合金Ⅰ)降低至1358.7℃(合金Ⅲ),而Laves相初熔温度和MC相固溶温度变化不大(不超过1.4℃);Nb,Mo,Ti元素在枝晶间的偏析程度随着Al/Ti原子比的升高而减轻.热力学计算结果显示,增加Al/Ti原子比可以提高γ'相数量,降低γ"相的数量.改型合金的硬度值随着Al/Ti原子比的提高而增加,当Al/Ti=4.32且(Al+Ti)=3.1 at.%时,硬度值达到了345HV,比Inconel 718母合金硬度提高了23.7%.

  15. Chemical phase analysis of Inconel 718 after long time thermal exposure%高温长期时效后Inconel 718合金的化学相分析

    Institute of Scientific and Technical Information of China (English)

    王改莲; 吴翠微; 董建新; 谢锡善; 卢翠芬

    2001-01-01

    采用化学相分析的方法研究了经过高温长期时效后标准Incone l 718合金中的析出相,确认了Inconel 718合金中α-Cr相的析出,同时也分析了α-Cr,γ′+γ″,δ相以及MC数量随时效时间和时效温度的变化情况.

  16. 切削参数与刀具几何形状对Inconel 718加工残余应力的影响%Effect of Cutting Parameters and Tool Geometry on Residual Stress in Cutting of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    翁孟超; 杨志强

    2009-01-01

    Inconel 718高速切削加工过程中合金加工表面的残余应力进行研究,为优化材料切削参数提供参考.由试验结果可知,最大切削速度、最小进给量、中等切削深度和使用珩磨切削刃可以确保减少加工表面的残余应力,相应的表面也没有划痕区和粘附的碎屑.

  17. Influence of Strengthening Elements on Precipitation of Thermodynamic Equilibrium Phases in Inconel Alloy 740H%Inconel 740H主要强化元素对热力学平衡相析出行为的影响

    Institute of Scientific and Technical Information of China (English)

    符锐; 林富生; 赵双群; 迟成宇

    2013-01-01

    Thermodynamic calculation was carried out on the Ni-based Inconel alloy 740H for 700 ℃ advanced ultra supercritical (A-USC) superheaters and reheaters,so as to study the influence of the main strengthening elements on precipitation of the equilibrium phases.Results show that both γ' and M23C6 in the alloy have a good stability in a wide temperature range.Elements Al,Ti and Nb affect much but element Co influences little on the precipitation of phases γ',ηand σ,in which Al promotes the precipitation and stabilization of γ' and σ,but suppresses the precipitation of η,while Ti and Nb promote precipitation of all the phases γ',ηand σ.Elements C and Cr respectively affect much on the precipitation quantity and temperature of M23C6.The composition of Inconel alloy 740H can be optimized by reasonably control the mass fractions of elements Al,Ti,Nb,C,Cr and Co.%对700℃等级超超临界电站过热器/再热器管材所用镍基高温合金Inconel 740H进行热力学相计算并研究了主要析出强化元素对其平衡析出相析出行为的影响.结果表明:合金中γ '相和M23C6碳化物稳定温度范围较宽;Al、Ti和Nb3种元素对γ'相、η相和σ相的析出行为影响较大,而Co元素对其影响不大,其中Al对γ'相和σ相的析出和稳定有促进作用,对η相却有抑制作用,Ti和Nb对γ'相、η相和σ相均有促进作用;C对M23C6碳化物析出量的影响显著,而Cr对M23C6的析出温度影响显著.将Al、Ti、Nb、C和Cr的质量分数控制在一定范围内并适当减小Co的质量分数,可以使Inconel 740H合金的成分范围得到一定的优化.

  18. Infrared Brazing of Ti50Ni50 Shape Memory Alloy and Inconel 600 Alloy with Two Ag-Cu-Ti Active Braze Alloys

    Science.gov (United States)

    Shiue, Ren-Kae; Wu, Shyi-Kaan; Yang, Sheng-Hao

    2017-02-01

    Infrared brazing of Ti50Ni50 SMA and Inconel 600 alloy using Cusil-ABA and Ticusil filler metals has been investigated. The joints were dominated by Ag-Cu eutectic with proeutectic Cu in the Cusil-ABA brazed joint and with proeutectic Ag in the Ticusil one. A continuous curved belt composed of a Ni3Ti layer and a (Cu x Ni1- x )2Ti layer formed in the brazed Ti50Ni50/Ticusil/Inconel 600 joint. On the Ti50Ni50 SMA side, an intermetallic layer of (Cu x Ni1- x )2Ti formed in all joints, with x values around 0.81 and 0.47. Layers of (Cu x Ni1- x )2Ti, Ni3Ti, and mixed Ni3Ti and Ni2Cr intermetallics were observed next to the Inconel 600 substrate in the brazed Ti50Ni50/Cusil-ABA/Inconel 600 joint. The maximum shear strengths of the joints using the Cusil-ABA filler metal and the Ticusil filler metal were 324 and 300 MPa, respectively. In the Cusil-ABA brazed joint, cracks with cleavage-dominated fracture propagated along the (Cu x Ni1- x )2Ti interfacial layer next to the Ti50Ni50 SMA substrate. In the Ticusil brazed joint, ductile dimple fracture occurred in the Ag-rich matrix near the Inconel 600 alloy substrate. The absence of a detrimental Ti-Fe-(Cu) layer on the Inconel 600 substrate side can effectively improve the shear strength of the joint.

  19. 磷硼复合添加对Inconel718合金铸态组织及均匀化处理参数的影响%Effects of P and B addition on as-cast microstructure and homogenization parameter of Inconel 718 alloy

    Institute of Scientific and Technical Information of China (English)

    缪竹骏; 单爱党; 吴元彪; 卢俊; 胡莹; 刘俊亮; 宋洪伟

    2012-01-01

    研究磷硼复合添加对Inconel 718高温合金铸态组织及均匀化处理参数的影响.结果表明:磷硼的加入促进块状Laves相的形成.由于硼在最后残余液相中大量富集,形成一种富含Nb、Mo和Cr的含硼相.根据DSC和电子探针分析结果,确定磷硼复合添加Inconel 718高温合金的凝固顺序为L→L+γ→L+γ+MC→L+γ+MC+Laves→γ+MC+Laves+含硼相.由于低熔点含硼相的存在,磷硼复合添加Inconel 718高温合金的均匀化处理温度应比标准Inconel 718合金低至少40℃.%The effects of phosphorus and boron addition on the as-cast microstructure and homogenization parameters of Inconel 718 were studied.The results indicate that the addition of phosphorus and boron promotes the formation of blocky Laves phase.Due to the strong segregation behavior of boron in the final residual liquid,a low melting B-bearing phase enriched in Nb,Mo and Cr is observed.According to the differential scanning calorimeter results and electron probe micro-analysis characterization,the solidification sequence of Inconel 718 with phosphorus and boron addition in best combination is determined as L→L+γ→L+γ+MC→L+γ+MC+Laves→γ+MC+Laves+B-bearing phase.Accordingly,the homogenization temperature is recommended to be adjusted at least 40℃ lower than that of standard Inconel 718 due to the existence of low melting B-bearing phase.

  20. Relationship of mechanical characteristics and microstructural features to the time-dependent edge notch sensitivity of inconel 718 sheet

    Science.gov (United States)

    Wilson, D. J.

    1971-01-01

    Time-dependent notch sensitivity of Inconel 718 sheet was observed at 900 F to 1200 F (482 - 649 C). It occurred when edge-notched specimens were loaded below the yield strength and smooth specimen tests showed that small amounts of creep consumed large rupture life fractions. The severity of the notch sensitivity was reduced by decreasing the solution temperature, increasing the time and/or temperature of aging and increasing the test temperature to 1400 F (760 C). Elimination of time-dependent notch sensitivity correlated with a change in dislocation motion mechanism from shearing to by-passing precipitate particles.

  1. Inconel crucibles - an alternative to quartz glass crucibles when analysing problematic samples by EA-IRMS

    Science.gov (United States)

    Meier-Augenstein, Wolfram; Kemp, Helen; Neal, Ken

    2013-04-01

    Anecdotal evidence as well as observations made in our own stable isotope laboratory suggest for samples with either a high halogen content (such as marine samples) or a high carbon and oxygen content (such as carbohydrates) to result in flash combustion temperatures exceeding temperature or burn time or both of flash combustion under typical conditions. Whatever the exact circumstances during combustion of such samples, they weaken the wall of the quartz glass reactors in the combustion zone and ultimately lead to pin-prick holes being formed through which carrier gas escapes thus resulting in a dramatic loss of carrier gas flow. Occasionally these pin-prick holes get plugged or "sealed" by molten tin thus restoring carrier gas flow but at the other end of the spectrum these pin-prick holes can become so wide for molten tin being able to pass through and to run down the outside of the reactor tube. In the latter event, a catastrophic failure of the reactor tube is inevitable with carrier gas flow downstream of the holes dropping to almost zero. While pin-prick holes (going unnoticed during an autosampler run of a large batch of samples) typically result in the loss of 3 or 4 samples until the hole/s "self-sealed" with molten tin, in a worst case scenario a catastrophic failure of the reactor tube can result in the loss of 40 or more samples (depending on number of samples in a batch run and when the failure occurred). Here we present examples of combustion reactor failure as well as observations made with crucibles made of quartz glass, stainless steel or inconel alloy during experiments to see if crucible design can mitigate against the effects of problematic samples.

  2. Mechanical Properties Anisotropy of Isothermally Forged and Precipitation Hardened Inconel 718 Disk

    Science.gov (United States)

    Khaja, Shaik; Mehta, K. K.; Veera Babu, R.; Sri Rama Devi, R.; Singh, A. K.

    2015-03-01

    The present work describes the tensile and cyclic flow behavior of the as-received disk of Inconel 718 in solution treated and precipitation hardened condition at different locations and orientations. The disk shows moderately high values of anisotropy index indicating significant difference in uniform true strain along radial and tangential orientations. The tensile true stress-plastic strain curves exhibit two slopes defined by Ludwigson relation []. The low-strain regime during tensile test is associated with low-strain localization between broad annealing twins and slips, while high-strain regime is related to the presence of large volume fraction of deformation twins and high-strain localization between narrow deformation twins. It appears that both the γ' and γ″ play a critical role during low deformation regime while the role of γ″ precipitates becomes significant in high-strain regime. The stabilized cyclic true stress-plastic strain curves follow Ludwik relationship ( σ = Kɛ n ) similar to that of high-strain regime of two-slope tensile curves. The true stress-strain curves show softening during cyclic test in comparison to that of monotonic condition and are independent of sample orientations and locations. The lower degree of cyclic softening associated with radial-oriented sample can be attributed to the alignment of δ-phase precipitates normal to the loading direction. The low ductility and low work-hardening exponent of radial-oriented sample in web region have been explained based on the dislocation storage capacity and dynamic recovery coefficient using Kock-Mecking-Estrin analysis.

  3. Microstructural characterization of thermal barrier coating on Inconel 617 after high temperature oxidation

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-06-01

    Full Text Available A turbine blade was protected against high temperature corrosion and oxidation by thermal barrier coatings (TBCsusing atmospheric plasma spraying technique (APS on a Ni-based superalloy (Inconel 617. The coatings (NiCr6AlY/ YSZ and NiCr10AlY/YSZ consist of laminar structure with substantial interconnected porosity transferred oxygen from Yittria stabilized Zirconia (YSZ layer toward the bond coat (NiCrAlY. Hence, a thermally grown oxide layer (TGO was formed on the metallic bond coat and internal oxidation of the bond coat occurred during oxidation. The TBC systems were oxidized in a normal electrically heated furnace at 1150 °C for 18, 22, 26, 32 and 40h.Microstructural characterization of coatings demonstrated that the growth of the TGO layer on the nickel alloy with 6wt. % Al is more rapid than TGO with 10wt. % Al. In addition, many micro-cracks were observed at the interface of NiCr6AlY/YSZ. X-ray diffraction analysis (XRD showed the existence of detrimental oxides such as NiCr2O4, NiCrO3 and NiCrO4 in the bond coat containing 6wt. % Al, accompanied by rapid volume expansion causing the destruction of TBC. In contrast, in the bond coat with 10wt. % Al, NiO, Al2O3and Cr2O3 oxides were formed while very low volume expansion occurred. The oxygen could not penetrate into the TGO layer of bond coat with 10 wt. % Al during high temperature oxidation and the detrimental oxides were not extensively formed within the bond coat as more oxygen was needed. The YSZ with higher Al content showed higher oxidation resistance.

  4. Parametric modeling and optimization of laser scanning parameters during laser assisted machining of Inconel 718

    Science.gov (United States)

    Venkatesan, K.; Ramanujam, R.; Kuppan, P.

    2016-04-01

    This paper presents a parametric effect, microstructure, micro-hardness and optimization of laser scanning parameters (LSP) on heating experiments during laser assisted machining of Inconel 718 alloy. The laser source used for experiments is a continuous wave Nd:YAG laser with maximum power of 2 kW. The experimental parameters in the present study are cutting speed in the range of 50-100 m/min, feed rate of 0.05-0.1 mm/rev, laser power of 1.25-1.75 kW and approach angle of 60-90°of laser beam axis to tool. The plan of experiments are based on central composite rotatable design L31 (43) orthogonal array. The surface temperature is measured via on-line measurement using infrared pyrometer. Parametric significance on surface temperature is analysed using response surface methodology (RSM), analysis of variance (ANOVA) and 3D surface graphs. The structural change of the material surface is observed using optical microscope and quantitative measurement of heat affected depth that are analysed by Vicker's hardness test. The results indicate that the laser power and approach angle are the most significant parameters to affect the surface temperature. The optimum ranges of laser power and approach angle was identified as 1.25-1.5 kW and 60-65° using overlaid contour plot. The developed second order regression model is found to be in good agreement with experimental values with R2 values of 0.96 and 0.94 respectively for surface temperature and heat affected depth.

  5. Neutron Imaging for Selective Laser Melting Inconel Hardware with Internal Passages

    Science.gov (United States)

    Tramel, Terri L.; Norwood, Joseph K.; Bilheux, Hassina

    2014-01-01

    Additive Manufacturing is showing great promise for the development of new innovative designs and large potential life cycle cost reduction for the Aerospace Industry. However, more development work is required to move this technology into space flight hardware production. With selective laser melting (SLM), hardware that once consisted of multiple, carefully machined and inspected pieces, joined together can be made in one part. However standard inspection techniques cannot be used to verify that the internal passages are within dimensional tolerances or surface finish requirements. NASA/MSFC traveled to Oak Ridge National Lab's (ORNL) Spallation Neutron Source to perform some non-destructive, proof of concept imaging measurements to assess the capabilities to understand internal dimensional tolerances and internal passages surface roughness. This presentation will describe 1) the goals of this proof of concept testing, 2) the lessons learned when designing and building these Inconel 718 test specimens to minimize beam time, 3) the neutron imaging test setup and test procedure to get the images, 4) the initial results in images, volume and a video, 4) the assessment of using this imaging technique to gather real data for designing internal flow passages in SLM manufacturing aerospace hardware, and lastly 5) how proper cleaning of the internal passages is critically important. In summary, the initial results are very promising and continued development of a technique to assist in SLM development for aerospace components is desired by both NASA and ORNL. A plan forward that benefits both ORNL and NASA will also be presented, based on the promising initial results. The initial images and volume reconstruction showed that clean, clear images of the internal passages geometry are obtainable. These clear images of the internal passages of simple geometries will be compared to the build model to determine any differences. One surprising result was that a new cleaning

  6. Microstructural Evolution and Mechanical Properties of Inconel 625 Alloy during Pulsed Plasma Arc Deposition Process

    Institute of Scientific and Technical Information of China (English)

    Fujia Xu; Yaohui Lv; Yuxin Liu; Fengyuan Shu; Peng He; Binshi Xu

    2013-01-01

    Pulsed plasma arc deposition (PPAD),which combines pulsed plasma cladding with rapid prototyping,is a promising technology for manufacturing near net shape components due to its superiority in cost and convenience of processing.In the present research,PPAD was successfully used to fabricate the Ni-based superalloy Inconel 625 components.The microstructures and mechanical properties of deposits were investigated by scanning electron microscopy (SEM),optical microscopy (OM),transmission electron microscopy (TEM) with energy dispersive spectrometer (EDS),microhardness and tensile testers.It was found that the as-deposited structure exhibited homogenous columnar dendrite structure,which grew epitaxially along the deposition direction.Moreover,some intermetallic phases such as Laves phase,minor MC (NbC,TiC) carbides and needle-like δ-Ni3Nb were observed in γ-Ni matrix.Precipitation mechanism and distribution characteristics of these intermetallic phases in the as-deposited 625 alloy sample were analyzed.In order to evaluate the mechanical properties of the deposits,microhardness was measured at various location (including transverse plane and longitudinal plane).The results revealed hardness was in the range of 260-285 HVo.2.In particular,microhardness at the interface region between two adjacent deposited layers was slightly higher than that at other regions due to highly refined structure and the disperse distribution of Laves particles.Finally,the influence of precipitation phases and fabrication strategies on the tensile properties of the as-deposited samples was investigated.The failure modes of the tensile specimens were analyzed with fractography.

  7. Identifying and Understanding Environment-Induced Crack propagation Behavior in Ni-based Superalloy INCONEL 617

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Longzhou

    2012-11-30

    The nickel-based superalloy INCONEL 617 is a candidate material for heat exchanger applications in the next-generation nuclear plant (NGNP) system. This project will study the crack propagation process of alloy 617 at temperatures of 650°C-950°C in air under static/cyclic loading conditions. The goal is to identify the environmental and mechanical damage components and to understand in-depth the failure mechanism. Researchers will measure the fatigue crack propagation (FCP) rate (da/dn) under cyclic and hold-time fatigue conditions, and sustained crack growth rates (da/dt) at elevated temperatures. The independent FCP process will be identified and the rate-controlled sustained loading crack process will be correlated with the thermal activation equation to estimate the oxygen thermal activation energy. The FCP-dependent model indicates that if the sustained loading crack growth rate, da/dt, can be correlated with the FCP rate, da/dn, at the full time dependent stage, researchers can confirm stress-accelerated grain-boundary oxygen embrittlement (SAGBOE) as a predominate effect. Following the crack propagation tests, the research team will examine the fracture surface of materials in various cracking stages using a scanning electron microscope (SEM) and an optical microscope. In particular, the microstructure of the crack tip region will be analyzed in depth using high resolution transmission electron microscopy (TEM) and electron energy loss spectrum (EELS) mapping techniques to identify oxygen penetration along the grain boundary and to examine the diffused oxygen distribution profile around the crack tip. The cracked sample will be prepared by focused ion beam nanofabrication technology, allowing researchers to accurately fabricate the TEM samples from the crack tip while minimizing artifacts. Researchers will use these microscopic and spectroscopic results to interpret the crack propagation process, as well as distinguish and understand the environment or

  8. Cast microstructure of Inconel 713C and its dependence on solidification variables

    Energy Technology Data Exchange (ETDEWEB)

    Bhambri, A.K.; Kattamis, T.Z.; Morral, J.E.

    1975-03-01

    The dependence of cast microstructure of Inconel 713C on solidification variables was investigated over a wide range of local cooling rates, epsilon, and thermal gradients in the liquid at the solid-liquid interface, G. The shape of MC carbide particles was found to depend greatly on: 1) the G/R ratio at the solid-liquid interface, where R is growth rate, through the effect of this ratio on the solid phase, ..gamma../sub g/, growth morphology. Under planar front growth conditions the carbide particles were octahedral, under cellular growth conditions they were plate-like, elongated along the cellular growth direction, and under dendritic growth conditions they were irregularly shaped; 2) the local cooling rate, epsilon, when ..gamma.. was dendritic, with a transition from octahedral to dendritic with increasing epsilon. The size of MC carbide particles was found to be controlled by coarsening and to become finer with increasing epsilon. In this alloy the composition of the MC carbide was established as (Nb/sub 0/./sub 63/Ti/sub 0/./sub 31/M0/sub 0/./sub 06/)C and was practically independent of local cooling rate. Other observations were that the precipitation of ..gamma.., d the formation of nonequilibrium eutectics, such as MC-..gamma.., ..gamma..-..gamma..' or MC-..gamma..-..gamma..' were suppressed at splat-cooling rates. Also, microsegregation of all alloying elements with the exception of aluminum was normal, with concentration increasing from the dendrite center-line to the dendrite arm boundary. Aluminum behaved in the opposite manner. Within the cooling rate range used herein, this variable had only a slight effect on microsegregation.

  9. Wear Patterns and Wear Mechanisms of Tool in High Speed Cutting of Inconel 718%高速切削Inconel 718刀具磨损形态和机理分析

    Institute of Scientific and Technical Information of China (English)

    黄雪红; 赵军

    2013-01-01

    The dry-cutting tests of high speed turning Inconel 718 using coated carbide tool is presented.The worn surface morphology of tool and its abrasion mechanism are studied by scanning electronic microscope (SEM) and energy disperse spectrum (EDS).The results show that the failure modes are rake wear,flake wear,flaking and chipping and the main failure mechanisms of tool are adhesive wear,abrasion wear,oxidation wear,diffusive wear and so on.%利用涂层硬质合金刀具对Inconel 718进行了高速干切削试验,采用扫描电子显微镜SEM和能量分散光谱EDS扫描,对不同切削参数下刀具的损坏形态和损坏机理进行了研究.分析结果表明刀具损坏形式主要有前刀面磨损、后刀面磨损、剥落和崩刃.刀具损坏机理主要是粘结磨损、磨粒磨损、氧化磨损和扩散磨损等.

  10. Three-dimension finite element simulation of inertia friction welding temperature field Inconel 718 superalloy%Inconel 718合金惯性摩擦焊温度场三维有限元数值模拟

    Institute of Scientific and Technical Information of China (English)

    卜文德; 刘金合; 贾中振

    2009-01-01

    根据能量守恒定律,在考虑摩擦面上周向摩擦对转速影响的基础上,提出了惯性摩擦焊的热输入模型,建立了Inconel 718合金惯性摩擦焊的三维有限元热力耦合模型,通过计算获得了其焊接过程中温度场的空间分布和时间分布,并分析了其变化特点.用基于热电偶的温度场检测系统对焊接过程中温度进行了实时检测,结果表明计算数据和试验结果基本吻合,这说明了该模型的可靠性,可以为Inconel 718惯性摩擦焊工艺参数的优化提供有效的依据.

  11. Precipitation of γ" Phase and Residual Stress Relaxation in Shot Peened Inconel 718%Inconel 718合金喷丸层γ"相的析出及应力松弛

    Institute of Scientific and Technical Information of China (English)

    蔡大勇; 聂璞林; 单佳萍; 刘文昌; 姚枚

    2003-01-01

    Incnel 718合金喷丸后分别在700℃和740℃进行时效处理,采用应力分析仪研究喷丸层的应力分布及应力松弛规律,并通过X射线衍射(XRD)定量分析喷丸层及基体中γ"相的析出动力学.喷丸处理在Inconel 718合金表层形成残余压应力场,表面压应力约为-530MPa,最大压应力距表面约为0.1mm,约-620MPa.喷丸后的时效过程中,表面残余压应力逐渐发生松弛,应力松弛的动力学过程满足Zener-Wert-Avrami关系.700℃和740℃时效时,Inconel 718合金喷丸层及基体中γ"相的析出动力学过程明显不同,喷丸处理促进了γ"相的析出.

  12. Studies of Standard Heat Treatment Effects on Microstructure and Mechanical Properties of Laser Net Shape Manufactured INCONEL 718

    Science.gov (United States)

    Qi, H.; Azer, M.; Ritter, A.

    2009-10-01

    Laser net shape manufacturing (LNSM) is a laser cladding/deposition based technology, which can fabricate and repair near-net-shape high-performance components directly from metal powders. Characterizing mechanical properties of the laser net shape manufactured components is prerequisite to the applications of LNSM in aircraft engine industrial productions. Nickel-based superalloys such as INCONEL 718 are the most commonly used metal materials in aircraft engine high-performance components. In this study, the laser deposition process is optimized through a set of designed experiments to reduce the porosity to less than 0.03 pct. It is found that the use of plasma rotating electrode processed (PREP) powder and a high energy input level greater than 80 J/mm are necessary conditions to minimize the porosity. Material microstructure and tensile properties of laser-deposited INCONEL 718 are studied and compared under heat treatment conditions of as deposited, direct aged, solution treatment and aging (STA), and full homogenization followed by STA. Tensile test results showed that the direct age heat treatment produces the highest tensile strength equivalent to the wrought material, which is followed by the STA-treated and the homogenization-treated tensile strengths, while the ductility exhibits the reverse trend. Finally, failure modes of the tensile specimens were analyzed with fractography.

  13. Electrical discharge machining (EDM) of Inconel 718 by using copper electrode at higher peak current and pulse duration

    Science.gov (United States)

    Ahmad, S.; Lajis, M. A.

    2013-12-01

    This experimental work is an attempt to investigate the performance of Copper electrode when EDM of Nickel Based Super Alloy, Inconel 718 is at higher peak current and pulse duration. Peak current, Ip and pulse duration (pulse on-time), ton are selected as the most important electrical pulse parameters. In addition, their influence on material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra) are experimentally investigated. The ranges of 10 mm diameter of Copper electrode are used to EDM of Inconel 718. After the experiments, MRR, EWR, and Ra of the machined surfaces need to be measured in order to evaluate the performance of the EDM process. In order to obtain high MRR, higher peak current in range of 20A to 40A and pulse duration in range of 200μs to 400μs were used. Experimental results have shown that machining at a highest peak current used of 40A and the lowest pulse duration of 200μs used for the experiment yields the highest material removal rate (MRR) with value 34.94 mm3/min, whereas machining at a peak current of 20A and pulse duration of 400μs yields the lowest electrode wear rate (EWR) with value -0.0101 mm3/min. The lowest surface roughness (Ra) is 8.53 μm achieved at a lowest peak current used of 20A and pulse duration of 200μs.

  14. Inconel 718合金在初期时效中沉淀相的变化

    Institute of Scientific and Technical Information of China (English)

    孟南

    2015-01-01

    由于在高温时具有良好的机械性能和蠕变抗力,Inconel 718合金在高温领域有着广泛地应用,特别是在航空工业以及核工业等部门。这种沉淀强化型合金的主要强化相是γ′相和γ″相经过形核阶段后,γ′相和γ″相在基体中的体积分数分别约为4%和3%,其尺寸与时效处理的温度和时间有关。瑞典的科研人员研究了Inconel718合金在时效处理时强化相的形核和长大及对合金性能的影响。

  15. Study on the microstructure, mechanical property and residual stress of SLM Inconel-718 alloy manufactured by differing island scanning strategy

    Science.gov (United States)

    Lu, Yanjin; Wu, Songquan; Gan, Yiliang; Huang, Tingting; Yang, Chuanguang; Junjie, Lin; Lin, Jinxin

    2015-12-01

    Inconel-718 has received an extensive using in mold industry. The selective laser melting (SLM) is providing an ideal means for manufacturing mold insert with complex geometrical features and internal architecture. During the manufacturing of high quality mold inserts with conformal cooling channel, the parameters play a vital role in the SLM process. In the study, the Inconel-718 alloys were manufactured by SLM with 2×2 mm2, 3×3 mm2, 5×5 mm2, and 7×7 mm2 island scanning strategies. The microstructure, mechanical property, and residual stress were investigated by optical microscope, tensile test and Vickers micro-indentation, respectively. It can be found that the relative density increased with enlarging the island size; the results on the microstructure indicated that the cracks and more pores were detected in the 22-specimen; whilst the microstructures of all specimens were composed of fine dendritic grains, cellular, and columnar structures; the tensile testing suggested that the ultimate tensile strength and yield strength of all samples was similar; while the outcome of the residual stress showed that the value of residual stress was ranked in the following sequence: 22-specimen<55-specimen<77-specimen<33-specimen. Although the 22-specimen had lower residual stress compared with the other groups, the occurrence of cracks limited its processing application in SLM. Through integrated into account, the 55-scanning strategy is a promising candidate for manufacturing of mold inserts.

  16. Ultrasonic Sensor Signals and Optimum Path Forest Classifier for the Microstructural Characterization of Thermally-Aged Inconel 625 Alloy

    Directory of Open Access Journals (Sweden)

    Victor Hugo C. de Albuquerque

    2015-05-01

    Full Text Available Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ'' and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 \\(^\\circ\\C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms and accurate (accuracy of 88.75% and harmonic mean of 89.52 for the application proposed.

  17. Ultrasonic sensor signals and optimum path forest classifier for the microstructural characterization of thermally-aged inconel 625 alloy.

    Science.gov (United States)

    de Albuquerque, Victor Hugo C; Barbosa, Cleisson V; Silva, Cleiton C; Moura, Elineudo P; Filho, Pedro P Rebouças; Papa, João P; Tavares, João Manuel R S

    2015-05-27

    Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ'' and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF) classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 °C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms) and accurate (accuracy of 88.75%" and harmonic mean of 89.52) for the application proposed.

  18. Quality-productivity decision making when turning of Inconel 718 aerospace alloy: A response surface methodology approach

    Directory of Open Access Journals (Sweden)

    Hamid Tebassi

    2017-06-01

    Full Text Available Inconel 718 is among difficult to machine materials because of its abrasiveness and high strength even at high temperature. This alloy is mainly used in aircraft and aerospace industries. Therefore, it is very important to reveal and evaluate cutting tools behavior during machining of this kind of alloy. The experimental study presented in this research work has been carried out in order to elucidate surface roughness and productivity mathematical models during turning of Inconel 718 superalloy (35 HRC with SiC Whisker ceramic tool at various cutting parameters (depth of cut, feed rate, cutting speed and radius nose. A small central composite design (SCCD including 16 basics runs replicated three times (48 runs, was adopted and graphically evaluated using Fraction of design space (FDS graph, completed by a statistical analysis of variance (ANOVA. Mathematical models for surface roughness and productivity were developed and normality was improved using the Box-Cox transformation. Results show that surface roughness criterion Ra was mainly influenced by cutting speed, radius nose and feed rate, and that the depth of cut had major effect on productivity. Finally, ranges of optimized cutting conditions were proposed for serial industrial production. Industrial benefit was illustrated in terms of high surface quality accompanied with high productivity. Indeed, results show that the use of optimal cutting condition had an industrial benefit to 46.9 % as an improvement in surface quality Ra and 160.54 % in productivity MRR.

  19. Effect of Wire Material on Productivity and Surface Integrity of WEDM-Processed Inconel 706 for Aircraft Application

    Science.gov (United States)

    Sharma, Priyaranjan; Chakradhar, D.; Narendranath, S.

    2016-09-01

    Inconel 706 is a recently developed superalloy for aircraft application, particularly in turbine disk which is among the most critical components in the gas turbine engines. Recently, wire electrical discharge machining (WEDM) attained success in machining of gas turbine components which require complex shape profiles with high precision. To achieve the feasibility in machining of these components, the research work has been conducted on Inconel 706 superalloy using WEDM process. And, the effect of different wire materials (i.e., hard brass wire, diffused wire, and zinc-coated wire) on WEDM performance characteristics such as cutting speed, surface topography, surface roughness, recast layer formation, residual stresses, and microstructural and metallurgical alterations have been investigated. Even though, zinc-coated wire exhibits improved productivity, hard brass wire was found to be beneficial in terms of improved surface quality of the machined parts. Additionally, lower tensile residual stresses were obtained with hard brass wire. However, diffused wire has a moderate effect on productivity and surface quality. Under high discharge energy, higher elemental changes were observed and also the white layer was detected.

  20. Measurement of desorption energies of H 2 and CO from SS-304 LN and inconel 625 surfaces by laser induced thermal desorption

    Science.gov (United States)

    Tagle, J. A.; Pospieszczyk, A.

    Stainless steel (AISI 304 LN) and Inconel 625 surfaces have been exposed to different pressures of H 2 and CO in the temperature range of 300-473 K. A laser heating technique for studying fast surface processes was applied to determine the desorption energies of these gasses from SS 304 LN and Inconel 625 surfaces. The Clausius-Clapeyron plots give a desorption energy value of 97 kJ mol -1 for H 2/SS 304 LN and 77.4 kJ mol -1 for H 2/Inconel 625. The adsorption of CO on these surfaces is drastically affected by the fast growing of a chromium oxide layer at the surface during the laser shots. In this case the desorption energy was determined by fitting both the experimental recoverage times and the equilibrium coverage curves. The oxide passivation layer produces a decrease of the desorption energy from 92.8 to 72.8 kJ mol -1 for CO/SS 304 LN and from 91.8 to 77.9 kJ mol -1 for CO/Inconel 625 when the oxygen surface concentration increases to 14%.

  1. INCONEL 690 CORROSION IN WTP (WASTE TREATMENT PLANT) HLW (HIGH LEVEL WASTE) GLASS MELTS RICH IN ALUMINUM & BISMUTH & CHROMIUM OR ALUMINUM/SODIUM

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; FENG Z; GAN H; PEGG IL

    2009-11-05

    Metal corrosion tests were conducted with four high waste loading non-Fe-limited HLW glass compositions. The results at 1150 C (the WTP nominal melter operating temperature) show corrosion performance for all four glasses that is comparable to that of other typical borosilicate waste glasses, including HLW glass compositions that have been developed for iron-limited WTP streams. Of the four glasses tested, the Bi-limited composition shows the greatest extent of corrosion, which may be related to its higher phosphorus content. Tests at higher suggest that a moderate elevation of the melter operating temperature (up to 1200 C) should not result in any significant increase in Inconel corrosion. However, corrosion rates did increase significantly at yet higher temperatures (1230 C). Very little difference was observed with and without the presence of an electric current density of 6 A/inch{sup 2}, which is the typical upper design limit for Inconel electrodes. The data show a roughly linear relationship between the thickness of the oxide scale on the coupon and the Cr-depletion depth, which is consistent with the chromium depletion providing the material source for scale growth. Analysis of the time dependence of the Cr depletion profiles measured at 1200 C suggests that diffusion of Cr in the Ni-based Inconel alloy controls the depletion depth of Cr inside the alloy. The diffusion coefficient derived from the experimental data agrees within one order of magnitude with the published diffusion coefficient data for Cr in Ni matrices; the difference is likely due to the contribution from faster grain boundary diffusion in the tested Inconel alloy. A simple diffusion model based on these data predicts that Inconel 690 alloy will suffer Cr depletion damage to a depth of about 1 cm over a five year service life at 1200 C in these glasses.

  2. Effects of Various Heat Treatments on the Ballistic Impact Properties of Inconel 718 Investigated

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2000-01-01

    Uncontained failures of aircraft engine fan blades are serious events that can cause equipment damage and loss of life. Federal Aviation Administration (FAA) certification requires that all engines demonstrate the ability to contain a released fan blade with the engine running at full power. However, increased protection generally comes at the expense of weight. Proper choice of materials is therefore imperative to an optimized design. The process of choosing a good casing material is done primarily through trial and error. This costly procedure could be minimized if there was a better understanding of the relationships among static material properties, impact properties, and failure mechanisms. This work is part of a program being conducted at the NASA Glenn Research Center at Lewis Field to study these relationships. Ballistic impact tests were conducted on flat, square sheets of Inconel 718 that had been subjected to different heat treatments. Two heat treatments and the as-received condition were studied. In addition, results were compared with those from an earlier study involving a fourth heat treatment. The heat treatments were selected on the basis of their effects on the static tensile properties of the material. The impact specimens used in this study were 17.8-cm square panels that were centered and clamped over a 15.2-cm square hole in a 1.27-cm-thick steel plate. Three nominal plate thickness dimensions were studied, 1.0, 1.8, and 2.0 mm. For each thickness, all the specimens were taken from the same sheet of material. The projectile was a Ti-6Al-4V cylinder with a length of 25.4 mm, a diameter of 12.7 mm, and a mass ranging from 14.05 to 14.20 g. The projectiles were accelerated toward the specimens at normal incidence using a gas gun with a 2-m-long, 12.7-mm inner-diameter barrel. The ballistic limit for each heat treatment condition and thickness was determined by conducting a number of impact tests that bracketed as closely as possible the velocity

  3. Oxidation Resistance of Inconel 740 in Static Air or Air-Steam Mixture%Inconel 740合金在空气和含有水蒸气的空气中的氧化研究

    Institute of Scientific and Technical Information of China (English)

    赵双群; 谢锡善; 董建新

    2011-01-01

    利用热重分析法、X射线衍射仪和扫描电镜与能谱分析仪研究了Inconel 740合金在空气和含有水蒸气的空气中的高温氧化行为,并分析了该合金的氧化机制.结果表明:Inconel 740合金在950℃的静态空气中氧化时,氧化动力学遵循抛物线规律,氧化膜黏附性能良好,表面氧化膜完整,外层由Cr2O3和少量的(Ni,Co)Cr2O4、TiO2组成,中间层为SiO2和Al2O3,内层氧化物为Al2O3和TiO2;合金在750℃含有10%水蒸气的空气中的腐蚀动力学也近似遵从抛物线规律,表面氧化膜很薄且致密性较差,表面氧化层主要为Cr2O3,内层氧化物为Al2O3和TiO2.%By means of TGA,XRD,SEM and EDX,high temperature oxidation behavior of nickel base superalloy,Inconel 740,was investigated in static air or air-steam mixture,while its oxidation mechanism analyzed.Results indicate that the oxidation kinetic curve of Alloy 740 at 950 ℃ in static air obeys the parabolic rate law;the oxidation film is adhesive and compact;the surface layer consists of Cr2O3 mainly and small amount of(Ni,Co)Cr2O4 and TiO2;the medium layer is made up of SiO2 and Al2O3,and the internal layer consists of TiO2 and Al2O3.The oxidation kinetic curve of the alloy at 750 ℃ in air with 10 % water vapor also obeys the parabolic rate law;the oxidation film is thin and poor;the surface layer is mainly composed of Cr2O3 and the internal oxides are Al2O3 and TiO2.

  4. Influence of microstructure in corrosion behavior of an Inconel 600 commercial alloy in 0.1 M sodium thiosulfate solution; Influencia de la microestructura en el comportamiento a la corrosion de una aleacion comercial Inconel 600 en solucion de Tiosulfato de sodio 0.1 M

    Energy Technology Data Exchange (ETDEWEB)

    Granados, J.; Rodriguez, F.J.; Arganis, C. [Facultad de Quimica, UNAM, C.P. 04510 Mexico D.F. (Mexico)

    1999-07-01

    The Inconel 600 is used in diverse components of BWR and PWR type reactors, where diverse cases of intergranular stress corrosion have been presented. It has been reported susceptibility to the corrosion of this alloy, in presence of thiosulfates, which come from the degradation of the ion exchange resins of water treatments that use the reactors. The objective of this work is to study the influence of metallurgical condition in the corrosion velocity of Inconel 600 commercial alloy, in a 0.1 M thiosulfates solution. (Author)

  5. Capacitive behaviour and electronic structure of passive films formed on nickel base alloy type Inconel 600; influence of Cr and Fe. Comportement capacitif et structure electronique des films passifs formes sur l'alliage a base de nickel du type Inconel 600 (75Ni-16Cr-8Fe); influence du chrome et du fer

    Energy Technology Data Exchange (ETDEWEB)

    Hakiki, N.E.; Da Cunha Belo, M. (Centre National de la Recherche Scientifique (CNRS), 94 - Vitry-sur-Seine (France). Centre d' Etudes de Chimie Metallurgique)

    1994-08-01

    The study of passive films formed on a nickel base alloy type Inconel 600 is performed by capacitance measurements (Mott-Schottky approach). This research is supported by the passivation study of the alloying elements Ni, Cr, Fe and high purity alloys Ni-Cr, Ni-Fe, Ni-Cr-Fe. The results obtained show that the capacitive behaviour of the Inconel 600 in the passive state is similar to that on a p-n heterojunction to which a barrier zone of nickel oxide is added. The individual or combined action of alloying elements on the development of this kind of electronic structure is discussed. (authors). 5 refs., 6 figs.

  6. Inconel718合金摩擦焊接头析出相溶解机制研究%Precipitation Phrases Dissolution Mechanism of Inconel 718 Inertia Friction Welding Joint

    Institute of Scientific and Technical Information of China (English)

    王传杰; 杨军; 薛锦

    2006-01-01

    Inconel 718高温合金惯性摩擦焊接接头焊缝的γ'、γ"及δ等相的溶解行为进行了研究,场发射扫描电镜和透射电镜观察发现,焊缝中的γ'和γ"在焊接热循环和摩擦剪应力作用下全部溶解,并呈现突变现象,即γ'和γ"量的减少呈陡降趋势;δ相部分溶解,且滞后于γ'、γ"相的溶解.

  7. Ti3SiC2/Inconel718摩擦副的高温摩擦学性能%Tribological Properties of Ti3SiC2-Inconel 718 Couple at Elevated Temperatures

    Institute of Scientific and Technical Information of China (English)

    李慧; 任书芳; 商剑; 吕晋军

    2013-01-01

    The tribological properties of Ti3SiC2 sliding against Ni — based alloy Inconel 718 from ambient temperature to 800 ℃ were investigated. The experiment results indicated that the tribological behaviors of the couple were improved with the increase of temperatures. The Ti3SiC2 —Inconel 718 couple presented excellent tribological properties at 800 ℃. The friction coefficient was 0. 81 at ambient temperature and wear rate of Ti3SiC2 was 4 x 10 mm /( N · m) . In contrast, the friction coefficient was 0.37 at 800 ℃ and the wear rate of Ti3SiC2 reduced to 10~5 mmV(N · m). The deformation at elevated temperature and the tribo -oxidation led to the decrease of friction coefficient. The high wear rate of Ti3SiC2 was determined by the fracture and pullout of Ti3SiC2 grains and material transfer to the counterbody alloy during the sliding process below 300 ℃ , while at 400 -800 t ,the fracture and pull - out of Ti3SiC2 grains were inhibited which resulted in the very low wear rate.%本文考察了Ti3SiC2-Inconel 718摩擦副从室温到800 ℃范围内的摩擦磨损性能.结果表明:温度的升高有利于改善Ti3 SiC2-Inconel 718摩擦副的摩擦磨损性能,在800℃时,其摩擦磨损性能优异.随着温度的升高,摩擦系数从室温的0.71降至800℃时的0.37,Ti3SiC2的磨损率从4×10-3 mm3/(N·m)降至10-5mm3/(N·m)以下.高温塑性变形和摩擦氧化物层的形成导致摩擦系数的降低,300℃以下,晶粒的断裂、拔出与脱落以及材料向合金的转移造成了Ti3SiC2高的磨损率,从400℃至800℃,Ti3 SiC2晶粒的断裂与脱落受到明显抑制,其磨损率显著降低.

  8. Effect of Combined Addition of Phosphorus and Boron on Inconel 718 Alloy%复合添加磷和硼对Inconel718合金的影响

    Institute of Scientific and Technical Information of China (English)

    宋洪伟; 郭守仁; 卢德忠; 徐岩; 王玉兰; 胡壮麒

    1999-01-01

    研究了磷和硼对Inconel 718合金持久和蠕变性能的影响.结果表明,单独添加0.02%磷对性能明显有益,单独提高硼含量至0.01%对性能有害,复合添加磷和硼的效果最佳.磷和硼复合作用显著有益的原因在于磷与硼之间存在强烈有益的交互作用,其机制可能与磷、硼和基体原子的晶界集团扩散有关.

  9. Turning Simulation of Nickel-based Alloy Inconel 718 Based on Deform-3D%基于Deform-3D的Inconel 718镍基合金的车削仿真

    Institute of Scientific and Technical Information of China (English)

    王作超; 李淑娟; 程结结

    2012-01-01

    Inconel 718镍基高温合金的力学、抗氧化、抗热变形的性能好,但是加工性能差,材料塑性大、导热系数低、加工硬化严重等问题制约了镍基高温合金的广泛使用.文中运用有限元软件分析和研究材料的切削性能、刀具选择以及切削参数等问题,对解决镍基高温合金难加工的现状提供了参考价值.

  10. 球头铣刀高速切削Inconel 718的刀具磨损研究%Study on Tool Wear in High Speed Cutting of Inconel 718 with Spherical Milling Cutters

    Institute of Scientific and Technical Information of China (English)

    何磊; 李亮; 戚宝运

    2010-01-01

    为了实现航空高温合金的高速高效加工,通过对Inconel 718的铣削试验,分析了涂层球头铣刀切削高温合金时的加工性能.试验结果表明,乳化液在90m/min的切削速度下仍然具有较好的冷却润滑作用.通过对TiAIN涂层和TiAIN+Al2O3涂层刀具的对比试验,证明TiAIN涂层具有优异的耐磨性,可显著提高加工高温合金时的刀具寿命.

  11. DP工艺Inconel 718合金高温流变曲线修正及应变本构模型%Revised hot deformation behavior and strain constitutive modeling of delta-processed Inconel 718 alloy

    Institute of Scientific and Technical Information of China (English)

    司家勇; 廖晓航; 黄再旺; 江亮

    2015-01-01

    采用等温热压缩实验研究DP工艺Inconel 718合金在变形温度为900~1060℃,应变速率为0.001~0.5 s-1条件下的高温流变行为,分析摩擦因数和绝热温升对真应力-真应变曲线的影响,并对摩擦引起的流变应力误差进行了修正,建立了基于应变量的应变本构模型.结果表明:随着应变速率的增大和变形温度的降低,摩擦因数的影响趋于明显,变形激活能和材料常数是应变量的函数.对引入应变量参数建立的用于预测工艺处理的Inconel718合金不同变形量时的流变应力本构模型进行误差分析,其实验值与预测值的相关性系数为0.998,平均相对误差绝对值为3.87%,能够用于准确预测不同变形量时合金的流变应力值.

  12. Review of INCONEL 718 Alloy: Its History,Properties, Processing and Developing Substitutes%INCONEL 718(GH4169)高温合金的发展与工艺

    Institute of Scientific and Technical Information of China (English)

    齐欢

    2012-01-01

    Since its invention and initial application in gas turbine components in the early 60's of 20th century at INCO Huntington Alloys (now called Special Metals Co. ), INCONEL 718 alloy (IN718) has become the most widely used nickel based superalloy in the aircraft engine industry. It was used in many critical aircraft engine components, accounting for over 30% of the total finished component mass of a modern aircraft engine. This article reviews IN718 alloy development history, its mechanical properties, long-term thermal stabilities, industrial processing methods, and current developing substitute alloys for enhanced thermal stability.%INCONEL 718合金(IN718)自从20世纪60年代初在美国的INCO Huntington Alloys(现为Special Metals Co.)被发明并应用于涡轮零部件制造后,已成为航空发动机历史上应用最为广泛的镍基高温合金材料.现代飞机发动机上超过30%(质量分数)的关键零部件由718合金制成.本文回顾了718合金在航空发动机上的应用历史,对该合金的基本力学性能、高温稳定性,以及目前国外应用的铸、锻制造工艺现状做了综述.对国外正在研究的新型IN718衍生替代合金的发展现状进行了介绍.

  13. 高速铣削 Inconel718已加工表面残余应力的有限元分析%Finite Element Analysis of Residual Stress for High Speed Orthogonal Milling of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    曹成铭; 刘战强; 林琪

    2011-01-01

    Cutting forces, cutting temperature and residual stress of high-speed orthogonal milling nickel-based superalloy Incone1718 are simulated through FEM. The results show the peak temperature of tool tip increases with the increase of cutting speed. However, the cutting forces decrease with the increase of cutting speed due to workpiece being soften induced by elevated temperature. Residual stress layer presents in the sub-surface beneath the machined surface 0.5mm, the maximum residual stress are tensile stress. At the cutting speed of 2000m/min, residual stresses have the small magnitude along two directions. Thus, from the point of improving the fatigue life of machined parts, this speed is the most optimum one in machining lnconel 718.%利用有限元法对镍基高温合金Inconel 718的高速正交铣削进行模拟仿真,获得切削力、切削温度和残余应力.结果表明在仿真切削速度100-3000m/min范围内,刀尖峰值温度随切削速度提高而增大,由于高温造成工件软化,从而使切削力随切削速度增大而减小;残余应力层深度在已加工表面O.5mm以下,最大表面残余应力为拉应力.当切削速度在2000m/min时,加工表面两个方向上的最大残余应力都较小.因此,从有利于提高零件的疲劳寿命角度分析,该速度为铣削Inconel 718的最优加工速度.

  14. Microstructure and fractal characteristics of the solid-liquid interface forming during directional solidification of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel718, under different cooling rates during directional solidification, ware investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing (PDAS) was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100 μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate, but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.

  15. (Al, Ti) Gamma Prime Precipitates in a Nickel-Based Superalloy Inconel X-750 Under Heavy Ion Irradiation

    Science.gov (United States)

    Zhang, He K.; Yao, Zhongwen; Kirk, Marquis A.; Daymond, Mark R.

    2014-07-01

    Phase stability of Ni3(Al, Ti) precipitates in Inconel X-750 under cascade damage was studied using heavy ion irradiation with transmission electron microscope (TEM) in situ observations. From 333 K to 673 K (60 °C to 400 °C), ordered Ni3(Al, Ti) precipitates became completely disordered at low irradiation dose of 0.06 displacement per atom (dpa). At higher dose, a trend of precipitate dissolution occurring under disordered state was observed, which is due to the ballistic mixing effect by irradiation. However, at temperatures greater than 773 K (500 °C), the precipitates stayed ordered up to 5.4 dpa, supporting the view that irradiation-induced disordering/dissolution and thermal recovery reach a balance between 673 K and 773 K (400 °C and 500 °C). Effects of Ti/Al ratio and irradiation dose rate are also discussed.

  16. Sensitivity analysis of tool-chip contact parameters when predicting residual stresses in turning of Inconel 718

    Science.gov (United States)

    Torrano, I.; Barbero, O.; Kortabarria, A.; Arrazola, P. J.

    2012-04-01

    Heat-resistant alloys like Inconel 718 are used in critical components such as aircraft engine turbine discs. Due to the extreme thermo-mechanical solicitations that must suffer during their lifetime, reliability is essential, even more if its failure could lead to loss of human lives. Surface integrity is a critical issue in this kind of components and specially residual stresses are a key aspect. Currently, the development and optimization of the machining process with regards to the residual stresses is done through expensive experimental trial and error methods. This article shows the research work made on the simulation of a machining model in three dimensions with the Deform TM commercial program. The results obtained show the influence of contact parameters (friction coefficient, heat transfer coefficient) not only on the cutting forces and temperatures, but also in the generation of residual stresses.

  17. Study of Radiographic Linear Indications and Subsequent Microstructural Features in Gas Tungsten Arc Welds of Inconel 718

    Science.gov (United States)

    Walley, J. L.; Nunes, A. C.; Clounch, J. L.; Russell, C. K.

    2007-01-01

    This study presents examples and considerations for differentiating linear radiographic indications produced by gas tungsten arc welds in a 0.05-in-thick sheet of Inconel 718. A series of welds with different structural features, including the enigma indications and other defect indications such as lack of fusion and penetration, were produced, radiographed, and examined metallographically. The enigma indications were produced by a large columnar grain running along the center of the weld nugget occurring when the weld speed was reduced sufficiently below nominal. Examples of respective indications, including the effect of changing the x-ray source location, are presented as an aid to differentiation. Enigma, nominal, and hot-weld specimens were tensile tested to demonstrate the harmlessness of the enigma indication. Statistical analysis showed that there is no difference between the strengths of these three weld conditions.

  18. Effect of nanostructured composite powders on the structure and strength properties of the high-temperature inconel 718 alloy

    Science.gov (United States)

    Cherepanov, A. N.; Ovcharenko, V. E.

    2015-12-01

    The experimental results of the effect of powder nanomodifiers of refractory compounds on the strength properties, the macro- and microstructure of the high-temperature Inconel 718 alloy have been presented. It has been shown that the introduction of powder modifiers into the melt leads to a decrease in the average grain size by a factor of 1.5-2 in the alloy. The long-term tensile strength of the alloy at 650°C increases 1.5-2 times, and the number of cycles at 482°C before fracture grows by more than three times. The effect of nanoparticles on the grain structure and strength properties of the alloy is due to an increase in the number of generated crystallization centers and the formation of nanoparticle clusters of refractory compounds at boundaries and junctions in the formed grain structure, which hinder the development of recrystallization processes in the alloy.

  19. Microstructure and fractal characteristics of the solid-liquid interface forming during directional solidification of Inconel 718

    Directory of Open Access Journals (Sweden)

    WANG Ling

    2007-08-01

    Full Text Available The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718, under different cooling rates during directional solidification, were investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing (PDAS was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100 μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate, but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.

  20. The influence of microstructure and operating temperature on the fatigue endurance of hot forged Inconel{sup ®} 718 components

    Energy Technology Data Exchange (ETDEWEB)

    Maderbacher, H., E-mail: hermann.maderbacher@unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Oberwinkler, B., E-mail: bernd.oberwinkler@bohler-forging.com [Böhler Schmiedetechnik GmbH and Co KG, Mariazellerstraße 25, 8605 Kapfenberg (Austria); Gänser, H.-P., E-mail: hans-peter.gaenser@mcl.at [Materials Center Leoben Forschung GmbH, Roseggerstraße 12, 8700 Leoben (Austria); Tan, W., E-mail: wen.tan@unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Rollett, M., E-mail: mathias.rollett@stud.unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Stoschka, M., E-mail: michael.stoschka@stud.unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

    2013-11-15

    The dependence of the fatigue behavior of hot-forged Inconel{sup ®} 718 aircraft components on the operating temperature and the material microstructure is investigated. To this purpose, possible correlations between a variety of tested microstructural parameters and the results from low-cycle fatigue (LCF) testing are analyzed using statistical methods. To identify the prevailing damage mechanisms, failure analyses are carried out on specimens tested at different temperatures. Optical and scanning electron microscopy are used for the inspection of surface crack networks and of the final fracture surface. In addition, energy dispersive X-ray (EDX) analyses are performed at the crack initiation sites to track down possible accumulations of alloying elements. The results are critically reviewed and used to propose a temperature and microstructure dependent fatigue model for predicting LCF ε⧸N-curves.

  1. Comparison of Residual Stresses in Inconel 718 Simple Parts Made by Electron Beam Melting and Direct Laser Metal Sintering

    Science.gov (United States)

    Sochalski-Kolbus, L. M.; Payzant, E. A.; Cornwell, P. A.; Watkins, T. R.; Babu, S. S.; Dehoff, R. R.; Lorenz, M.; Ovchinnikova, O.; Duty, C.

    2015-03-01

    Residual stress profiles were mapped using neutron diffraction in two simple prism builds of Inconel 718: one fabricated with electron beam melting (EBM) and the other with direct laser metal sintering. Spatially indexed stress-free cubes were obtained by electrical discharge machining (EDM) equivalent prisms of similar shape. The (311) interplanar spacings from the EDM sectioned sample were compared to the interplanar spacings calculated to fulfill stress and moment balance. We have shown that applying stress and moment balance is a necessary supplement to the measurements for the stress-free cubes with respect to accurate stress calculations in additively manufactured components. In addition, our work has shown that residual stresses in electron beam melted parts are much smaller than that of direct laser metal sintered parts most likely due to the powder preheating step in the EBM process.

  2. TEM, HRTEM, electron holography and electron tomography studies of gamma' and gamma'' nanoparticles in Inconel 718 superalloy.

    Science.gov (United States)

    Dubiel, B; Kruk, A; Stepniowska, E; Cempura, G; Geiger, D; Formanek, P; Hernandez, J; Midgley, P; Czyrska-Filemonowicz, A

    2009-11-01

    The aim of the study was the identification of gamma' and gamma'' strengthening precipitates in a commercial nickel-base superalloy Inconel 718 (Ni-19Fe-18Cr-5Nb-3Mo-1Ti-0.5Al-0.04C, wt %) using TEM dark-field, HRTEM, electron holography and electron tomography imaging. To identify gamma' and gamma'' nanoparticles unambiguously, a systematic analysis of experimental and theoretical diffraction patterns were performed. Using HRTEM method it was possible to analyse small areas of precipitates appearance. Electron holography and electron tomography techniques show new possibilities of visualization of gamma' and gamma'' nanoparticles. The analysis by means of different complementary TEM methods showed that gamma'' particles exhibit a shape of thin plates, while gamma' phase precipitates are almost spherical.

  3. Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718

    Directory of Open Access Journals (Sweden)

    N.N. Bhopale

    2012-12-01

    Full Text Available The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting parameters. It is observed that at large cutting speed as well as feeds, thicker work piece with larger work piece inclination shows higher micro hardness as compared to the other machining conditions.

  4. Age-hardening and precipitation phenomena in the Inconel-713C superalloy studied by means of positron lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Somoza, A.; Santos, G.; Ges, A. [Buenos Aires Univ. Nacional (Argentina). Facultad de Ciencias Exactas y Naturales; Versaci, R.; Plazaola, F.

    1999-07-16

    Specimens of the commercial superalloy Inconel-713C were heat treated by using isothermal artificial ageing treatments in order to obtain information on the process of precipitation of the {gamma}'-phase which is an intermetallic compound with a composition of Ni{sub 3}(Al, Ti) having a L1{sub 2}-ordered structure. The experimental information was basically obtained by means of positron lifetime spectroscopy and Vickers microhardness. In some specific cases, transmission electron microscopy was also used. From the positron results it was possible to analyze the influence of the homogenization and quenching procedures on the microstructure and to follow the coarsening of the smallest {gamma}'-particles during the very early stage of artificial ageing at 950 C. For long ageing times, when the overageing condition of the superalloy was clearly observed by a hardness decrease, the positron lifetime evolution reaches a stable maximum value and different annihilation mechanisms were discussed. (orig.)

  5. Heat transfer coefficient distribution over the inconel plate cooled from high temperature by the array of water jets

    Science.gov (United States)

    Malinowski, Z.; Telejko, T.; Cebo-Rudnicka, A.; Szajding, A.; Rywotycki, M.; Hadała, B.

    2016-09-01

    The industrial rolling mills are equipped with systems for controlled water cooling of hot steel products. A cooling rate affects the final mechanical properties of steel which are strongly dependent on microstructure evolution processes. In case of water jets cooling the heat transfer boundary condition can be defined by the heat transfer coefficient. In the present study one and three dimensional heat conduction models have been employed in the inverse solution to heat transfer coefficient. The inconel plate has been heated to about 900oC and then cooled by one, two and six water jets. The plate temperature has been measured by 30 thermocouples. The heat transfer coefficient distributions at plate surface have been determined in time of cooling.

  6. Characterization and heat flux testing of beryllium coatings on Inconel for JET ITER-like wall project

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, T [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425 Juelich (Germany); Linke, J [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425 Juelich (Germany); Sundelin, P [Alfven Laboratory, Association EURATOM-VR, 100 44 Stockholm (Sweden); Rubel, M [Alfven Laboratory, Association EURATOM-VR, 100 44 Stockholm (Sweden); Kuehnlein, W [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425 Juelich (Germany); Wessel, E [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425 Juelich (Germany); Coad, J P [Culham Science Centre, EURATOM-UKAEA Fusion Association, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Lungu, C P [National Institute of Lasers, Plasma and Radiation Physics, Association EURATOM-MEdC, Bucharest (Romania); Matthews, G F [Culham Science Centre, EURATOM-UKAEA Fusion Association, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Pedrick, L [Culham Science Centre, EURATOM-UKAEA Fusion Association, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Piazza, G [EFDA, CSU, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

    2007-03-15

    In order to perform a fully integrated material test, JET has launched the ITER-like wall project with the aim of installing a full metal wall during the next major shutdown. The material foreseen for the main chamber wall is bulk Be at the limiters and Be coatings on inconel tiles elsewhere. R and D process comprises global characterization (structure, purity etc) of the evaporated films and testing of their performance under heat loads. The major results are (i) the layers have survived energy loads of 20 MJ m{sup -2} which is significantly above the required level of 5-10 MJ m{sup -2} (ii) melting limit of beryllium coating would be at the energy level of 30 MJ m{sup -2} (iii) cyclic thermal load of 10 MJ m{sup -2} for up to 50 cycles have not induced any noticeable damage such as flaking or detachment.

  7. Stability of machining induced residual stresses in Inconel 718 under quasi-static loading at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Madariaga, A., E-mail: amadariaga@mondragon.edu [Mechanical and Industrial Production Department, Faculty of Engineering, Mondragon Unibertsitatea, Loramendi 4, Mondragon 20500 Gipuzkoa (Spain); Esnaola, J.A.; Arrazola, P.J. [Mechanical and Industrial Production Department, Faculty of Engineering, Mondragon Unibertsitatea, Loramendi 4, Mondragon 20500 Gipuzkoa (Spain); Ruiz-Hervias, J.; Muñoz, P. [Departamento Ciencia de Materiales, ETSI Caminos, Universidad Politécnica de Madrid, c/Profesor Aranguren s/n, Madrid 28040 (Spain); Ostolaza, K. [Materials and Processes Technology Department, ITP S.A., Parque Tecnológico, Edificio 300, 48170 Zamudio (Spain)

    2015-01-03

    Tensile residual stresses are very often generated on the surface when machining nickel alloys. In order to determine their influence on the final mechanical behaviour of the component residual stress stability should be considered. In the present work the evolution of surface residual stresses induced by machining in Inconel 718 under static loading at room temperature was studied experimentally and numerically. An Inconel 718 disc was face turned employing industrial working conditions and specimens for tensile tests were extracted from the disc. Surface residual stresses were measured by X-ray diffraction for initial state and after applying different loads over the material's yield stress. Then, a finite element model based on the surface–core approach was fitted to experimental results and the study was extended to analyse the influence of load level, degree of work-hardening and initial surface conditions. For the studied case, initial tensile surface residual stress (776 MPa) became even more tensile when applying loads higher than the material yield stress, but a shift was observed at the highest applied load (1350 MPa) and initial residual stress was relaxed about 170 MPa. This particular behaviour is associated to the modified stress–strain properties of the machined affected surface layer which was strongly work-hardened. Moreover, if the work-hardened properties are not considered in the finite element model results differ substantially from experiments. Surface residual stress stability also depends on the initial surface residual stress, but the degree of work-hardening induced by the machining process must be considered as well. If the difference between the yield stress of the surface and the yield stress of the core is lower than the initial surface residual stress, the surface begins yielding first and consequently the surface residual stress is decreased. In contrast, if the difference between the yield stress of the surface and the

  8. Influence of modified processing on structure and properties of hot isostatically pressed superalloy Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Rao, G. Appa [Defence Metallurgical Research Laboratory, Kanchanbagh (P.O.), Hyderabad 500 058 (India)]. E-mail: gouduapparao@rediffmail.com; Srinivas, M. [Defence Metallurgical Research Laboratory, Kanchanbagh (P.O.), Hyderabad 500 058 (India); Sarma, D.S. [Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India)

    2006-02-25

    Inert gas atomized (IGA) superalloy Inconel 718 powder was consolidated by hot isostatic pressing (HIPing) at 1200 deg. C under 120 MPa pressure for 3 h. The HIPed alloy heat treated as per the aerospace materials specification (AMS) 5662J standard schedule, viz. solution treatment (ST) at 980 deg. C for 1 h/water quenching (WQ) to room temperature (RT) and a two-step ageing treatment (AT) at 720 deg. C for 8 h/furnace cooling (FC) at 55 deg. C h{sup -1} to 620 deg. C and holding at 620 deg. C for 8 h and air cooling (AC) to room temperature has exhibited the yield strength (YS) and ultimate tensile strength (UTS) comparable to that of the conventionally processed (forged and heat treated) IN 718. However, its ductility and stress rupture properties at 650 deg. C were found to be poor due to the presence of prior particle boundary (PPB) networks decorated with highly stable oxides (Al{sub 2}O{sub 3} and TiO{sub 2}) and brittle MC (Nb, Ti)C carbides. To mitigate this problem, the HIPed alloy was subjected to solution treatment at 1270 deg. C for 1 h followed by re-HIPing at 1100 deg. C/130 MPa/3 h before heat-treating it as per AMS 5662J standard schedule. Optical and scanning electron microscopy (SEM) of the alloy processed under modified HIPing and heat treatment conditions have shown the dissolution of MC-carbides, breaking up of PPB networks and formation of equiaxed grains with an average diameter of about 50 {mu}m. Transmission electron microscopy (TEM) of this alloy has revealed uniform distribution of {gamma}'' and {gamma}' strengthening precipitates in the {gamma}-matrix and the presence of {delta}(Ni{sub 3}Nb) phase as well as very fine oxide particles near the grain boundaries. The tensile properties of the alloy processed under modified conditions have shown quite satisfactory levels of YS and UTS combined with a significantly improved elongation (EL) values at room temperature (19.5%) and at 650 deg. C (8.0%). The improvement in alloy

  9. J-resistance curves for Inconel 690 and Incoloy 800 nuclear steam generators tubes at room temperature and at 300 °C

    Science.gov (United States)

    Bergant, Marcos A.; Yawny, Alejandro A.; Perez Ipiña, Juan E.

    2017-04-01

    The structural integrity of steam generator tubes is a relevant issue concerning nuclear plant safety. In the present work, J-resistance curves of Inconel 690 and Incoloy 800 nuclear steam generator tubes with circumferential and longitudinal through wall cracks were obtained at room temperature and 300 °C using recently developed non-standard specimens' geometries. It was found that Incoloy 800 tubes exhibited higher J-resistance curves than Inconel 690 for both crack orientations. For both materials, circumferential cracks resulted into higher fracture resistance than longitudinal cracks, indicating a certain degree of texture anisotropy introduced by the tube fabrication process. From a practical point of view, temperature effects have found to be negligible in all cases. The results obtained in the present work provide a general framework for further application to structural integrity assessments of cracked tubes in a variety of nuclear steam generator designs.

  10. Effect of pulsed current micro plasma arc welding process parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 sheets

    Institute of Scientific and Technical Information of China (English)

    Kondapalli Siva Prasad; Chalamalasetti Srinivasa Rao; Damera Nageswara Rao

    2012-01-01

    The paper focuses on developing mathematical models to predict grain size and ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 nickel alloy.Four factors,five levels,central composite rotatable design matrix is used to optimize the number of experiments.The mathematical models have been developed by response surface method.The adequacy of the models is checked by analysis of variance technique.By using the developed mathematical models,grain size and ultimate tensile strength of the joints can be predicted with 99%0 confidence level.Contour plots are drawn to study the interaction effect of pulsed current micro plasma arc welding parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 weld ioints.

  11. Time-Dependent Fatigue Crack Propagation Behavior of Two Solid-Solution-Strengthened Ni-Based Superalloys—INCONEL 617 and HAYNES 230

    Science.gov (United States)

    Ma, Longzhou; Roy, Shawoon K.; Hasan, Muhammad H.; Pal, Joydeep; Chatterjee, Sudin

    2012-02-01

    The fatigue crack propagation (FCP) as well as the sustained loading crack growth (SLCG) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 (Special Metals Corporation Family of Companies) and HAYNES 230 (Haynes International, Inc., Kokomo, IN), were studied at increased temperatures in laboratory air under a constant stress-intensity-factor ( K) condition. The crack propagation tests were conducted using a baseline cyclic triangular waveform with a frequency of 1/3 Hz. Various hold times were imposed at the maximum load of a fatigue cycle to study the hold time effect. The results show that a linear elastic fracture mechanics (LEFM) parameter, stress intensity factor ( K), is sufficient to describe the FCP and SLCG behavior at the testing temperatures ranging from 873 K to 1073 K (600 °C to 800 °C). As observed in the precipitation-strengthened superalloys, both INCONEL 617 and HAYNES 230 exhibited the time-dependent FCP, steady SLCG behavior, and existence of a damage zone ahead of crack tip. A thermodynamic equation was adapted to correlate the SLCG rates to determine thermal activation energy. The fracture modes associated with crack propagation behavior were discussed, and the mechanism of time-dependent FCP as well as SLCG was identified. Compared with INCONEL 617, the lower crack propagation rates of HAYNES 230 under the time-dependent condition were ascribed to the different fracture mode and the presence of numerous W-rich M6C-type and Cr-rich M23C6-type carbides. Toward the end, a phenomenological model was employed to correlate the FCP rates at cycle/time-dependent FCP domain. All the results suggest that an environmental factor, the stress assisted grain boundary oxygen embrittlement (SAGBOE) mechanism, is mainly responsible for the accelerated time-dependent FCP rates of INCONEL 617 and HAYNES 230.

  12. 氢化物发生-原子荧光光谱法测定Inconel 718合金中痕量硒

    Institute of Scientific and Technical Information of China (English)

    向祥蓉; 刘虹; 王佼

    2011-01-01

    本文采用氢化物发生-原子荧光光谱法测定Inconel718合金中痕量硒。对影响其测定的负高压、灯电流、载气流量、屏蔽气流量、载流酸类酸度、硼氢化钾等因素进行了较为洋细的研究,优化了测定条件,考察了Inconel718合金主要组成元素和基体元素对硒测定的影响。结果表明,用氟化氨溶液络合,柠檬酸溶液作干扰抑制剂能基本消除基体元素和主要组成元素的干扰。硒浓度在0~100ug/L与荧光强度有良好的线性关系,方法的检出限为0.0083ug/L。对铁镍基高温合金标准样品和Inconel 718合金样品进行9次测定,相对标准偏差为1.6%~3.5%。

  13. NDT of a Nickel Coated Inconel Specimen Using by the Complex Induced Current - Magnetic Flux Leakage Method and Linearly Integrated Hall Sensor Array

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Jong Woo; Lee, Jin Yi [Chosun University, Gwangju (Korea, Republic of); Park, Duk Keun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-10-15

    Nondestructive testing (NDT) by using the electromagnetic methods are useful for detecting cracks on the surface and subsurface of the metal. However, when the material contains both ferromagnetic and paramagnetic materials, it is difficult for NDT to detect and analyze cracks using this method. In addition the existence of a partial ferromagnetic material can be incorrectly characterized as a crack in the several cases. On the other hand a large crack has sometimes been misunderstood as a partially magnetized region. Inconel 600 is an important material in atomic energy plant. A nickel film is coated when a crack a appears on an Inconel substrate. Cracks are difficult to detect on the combined material of an Inconel substrate with a nickel film, which are paramagnetic and ferromagnetic material respectively. In this paper, a scan type magnetic camera, which uses a complex induced current-magnetic flux leakage (CIC-MFL) method as a magnetic source and a linearly integrated Hall sensor array (LIHaS) on a wafer as the magnetic sensors, was examined for its ability to detect cracks on the combined material. The evaluation probability of a crack is discussed. In addition the detection probability of the minimum depth was reported

  14. Effect of Al content on delta phase microstructure evolution in Inconel 718 alloys%Al含量对Inconel 718合金中δ相组织演变的影响

    Institute of Scientific and Technical Information of China (English)

    周喜顺; 何亚斌; 刘建辉; 辛士进; 王东; 崔艳芳; 李鹏; 董莹

    2012-01-01

    The dissolution mechanism and morphology feature of 8 phase in standard as-heated 718 alloys with three different Al contents for different holding times were investigated by scanning electron microscopy (SEM) and Thermo-Calc software. The fraction of 8 phase was counted using the Photoshop software. The results indicate that the dissolution of 8 phase in 718 alloy with lower Al content is mainly characterized as the dissolution from long needle shape to short rod or granule, and the 8 phase in the grains of 718 alloys with higher Al content dissolves firstly while the dissolution of 8 phase at grain boundaries is slower. So the migration of grain boundary is inhibited, the grain size of 718 alloys can be controlled effectively to some extent. The fraction of 8 phase decreases gradually with the increase of temperature. The dissolution temperature of 8 phase can be increased with the increase of Al content in 718 alloys but the dissolution velocity decreases with it.%采用扫描电子显微镜和Thermo-Calc热力学计算等方法,研究3种不同Al含量的Inconel 718合金在标准热处理和不同保温时间下δ相的形貌特征、溶解行为及3种合金中δ相含量的变化.结果表明:A1含量低的合金中δ相溶解特征主要表现为沿针状δ相的长度方向断开,在短时间内溶解为短棒状及颗粒状;Al含量高的合金中δ相溶解优先从晶内开始,其晶界上的δ相溶解缓慢,对抑制晶界迁移,控制奥氏体晶粒长大有重要作用;Inconel 718合金中δ相含量随溶解温度的提高而降低,Al含量提高使合金中δ相的溶解速度减慢,溶解温度提高.

  15. Crack growth threshold under hold time conditions in DA Inconel 718 – A transition in the crack growth mechanism

    Directory of Open Access Journals (Sweden)

    E. Fessler

    2016-01-01

    Full Text Available Aeroengine manufacturers have to demonstrate that critical components such as turbine disks, made of DA Inconel 718, meet the certification requirements in term of fatigue crack growth. In order to be more representative of the in service loading conditions, crack growth under hold time conditions is studied. Modelling crack growth under these conditions is challenging due to the combined effect of fatigue, creep and environment. Under these conditions, established models are often conservative but the degree of conservatism can be reduced by introducing the crack growth threshold in models. Here, the emphasis is laid on the characterization of crack growth rates in the low ΔK regime under hold time conditions and in particular, on the involved crack growth mechanism. Crack growth tests were carried out at high temperature (550 °C to 650 °C under hold time conditions (up to 1200 s in the low ΔK regime using a K-decreasing procedure. Scanning electron microscopy was used to identify the fracture mode involved in the low ΔK regime. EBSD analyses and BSE imaging were also carried out along the crack path for a more accurate identification of the fracture mode. A transition from intergranular to transgranular fracture was evidenced in the low ΔK regime and slip bands have also been observed at the tip of an arrested crack at low ΔK. Transgranular fracture and slip bands are usually observed under pure fatigue loading conditions. At low ΔK, hold time cycles are believed to act as equivalent pure fatigue cycles. This change in the crack growth mechanism under hold time conditions at low ΔK is discussed regarding results related to intergranular crack tip oxidation and its effect on the crack growth behaviour of Inconel 718 alloy. A concept based on an “effective oxygen partial pressure” at the crack tip is proposed to explain the transition from transgranular to intergranular fracture in the low ΔK regime.

  16. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Directory of Open Access Journals (Sweden)

    Rojas-Morín, A.

    2011-04-01

    Full Text Available A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almería (PSA in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF® plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF region at the operational temperatures of both 650 °C and 900 °C.

    En el concentrador solar de disco parabólico DISTAL-I, situado en la Plataforma Solar de Almería (PSA, en España, se ha instalado un sistema para pruebas de ciclado térmico de materiales. Este sistema permite realizar pruebas abruptas de calentamiento y enfriamiento, en materiales para receptores solares de torre central, al exponerlos a radiación solar concentrada. Estas pruebas se realizan para simular las condiciones de operación de un receptor solar, las condiciones críticas y las condiciones normales. Con este sistema se ha estimado el tiempo de vida bajo fatiga térmica, en una placa de INCONEL 626LCF®, cuando es sometida a radiación solar concentrada. Asimismo, hemos desarrollado un modelo numérico que evalúa el desarrollo térmico en el material de la placa: adicionalmente, el modelo obtiene los esfuerzos de tensión-compresión en la placa, los cuales permiten la estimaciónde las curvas de fatiga vidaesfuerzo (S-N. Estas curvas

  17. Study on Localized Corrosion Cracking of Alloy 600 using EN-DCPD Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeonju; Kim, Sungwoo; Kim, Hongpyo; Hwang, Seongsik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-02-15

    The object of this work is to establish an electrochemical noise(EN) measurement technique combined with a direct current potential drop(DCPD) method for monitoring of localized corrosion cracking of nickel-based alloy, and to analyze its mechanism. The electrochemical current and potential noises were measured under various conditions of applied stress to a compact tension specimen in a simulated primary water chemistry of a pressurized water reactor. The amplitude and frequency of the EN signals were evaluated in both time and frequency domains based on a shot noise theory, and then quantitatively analyzed using statistical Weibull distribution function. From the spectral analysis, the effect of the current application in DCPD was found to be effectively excluded from the EN signals generated from the localized corrosion cracking. With the aid of a microstructural analysis, the relationship between EN signals and the localized corrosion cracking mechanism was investigated by comparing the shape parameter of Weibull distribution of a mean time-to-failure.

  18. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    Science.gov (United States)

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  19. Dissolution Kinetics of δ Phase and Effect on Notch Sensitivity of Inconel 718%Inconel 718合金中δ相溶解动力学及对缺口敏感性的影响

    Institute of Scientific and Technical Information of China (English)

    蔡大勇; 张伟红; 刘文昌; 肖福仁; 姚枚; 孙贵东; 陈宗霖; 王少刚

    2003-01-01

    通过X-射线衍射及高温持久试验研究Inconel 718中δ相在不同温度下溶解的动力学过程,以及δ相含量对缺口敏感性的影响.结果表明,在980,1000和1020℃保温过程中,δ相含量逐渐降低.1020℃保温2h后δ相可完全溶入基体,980℃保温30min、1000℃保温2h后δ相趋于平衡含量3%和0.6%.保温开始阶段,δ相的溶解速度较快且近似为常数,随着时间延长,溶解速度降低.δ相含量在0.62%~2.98%,合金无缺口敏感性,含量低于0.43%时导致缺口敏感.1000℃固溶合金的高温持久性能最佳.

  20. 低温形变热处理对Inconel718合金组织的影响%Effects of Low Temperature Deforming Treatment on Inconel 718 Alloy Structure

    Institute of Scientific and Technical Information of China (English)

    杨若凡

    2006-01-01

    利用透射电子显微镜(TEM)和X射线衍射仪研究了低温形变热处理时冷轧变形道次及不同变形量对Inconel 718合金中金属间化合物γ"相和δ相的分布、形貌和数量的影响.结果表明:随着变形量的增加,析出相由晶内和晶界析出逐渐转变到形变带及位错墙处析出,δ相形状由针状过渡到短棒状或颗粒状,γ"相的尺寸逐渐减小.形变既促进γ"相的析出又促进γ"相向δ相的转变.γ"、δ相的含量随变形量的增加而增加,两道次冷轧的低温形变热处理工艺提高了δ相的含量,却减少了γ"相的量.

  1. Inconel 718镍基合金管道焊接残余应力的数值模拟%Numerical Simulation on Residual Stress for Inconel 718 Nickel-based Alloy Tube Welding

    Institute of Scientific and Technical Information of China (English)

    姬丽森; 凌泽民; 何建; 杨贤飞

    2015-01-01

    Inconel 718镍基合金管道的对接接头为研究对象,建立了热-力学耦合的三维有限元模型,采用SYSWELD焊接模拟软件对其环焊缝在不同预热温度和焊接顺序下的残余应力进行数值模拟,分析了预热温度和焊接顺序对外表面轴向和环向残余应力分布的影响.并与实验结果进行对比,验证了模型的准确性.结果表明:管道外表面轴向残余应力在焊缝及近缝区表现为压应力,而远离焊缝中心的区域表现为拉应力;焊缝与近缝区环向残余应力为拉应力,随着距焊缝中心距离的增加,拉应力逐渐转化为压应力;随着预热温度的增加,管道外表面轴向和环向残余应力降低;焊接顺序的改变不能有效降低管道焊接残余应力.

  2. STRAIN-INDUCED γ" PHASE PRECIPITATION AND γ" →δ TRANSFORMATION IN INCONEL 718 ALLOY%应变诱发Inconel 718合金γ″相析出和γ″→δ转变

    Institute of Scientific and Technical Information of China (English)

    陈宗霖; 刘文昌

    2000-01-01

    采用X射线衍射技术测定了冷轧Inconel 718合金在810℃时效温度下γ"相和δ相的含量,研究了冷轧变形对γ″相析出和γ″→δ转变的影响.结果表明,在810℃时效,γ″相的析出达到饱和状态此时γ"→δ的转变即将发生;应变可诱发γ″相析出以及γ″→δ转变;δ相的数量与时间的关系符合Avrami方程,随冷轧变形量增加,时间指数减小,δ相析出速率增加;γ"→δ转变的数量与时间的关系也可以用Avrami方程描述.

  3. Elastic and Plastic Behavior of O-ring Specimens of Inconel 718 Alloy under Side-compressing at Elevated Temperatures%Inconel 718合金O形环的高温压扁弹塑性行为

    Institute of Scientific and Technical Information of China (English)

    蔡力勋; 叶裕明; 左国

    2005-01-01

    Inconel 718合金O形环试样进行了压扁-回弹试验研究,考察了本构模型各参数对O形环回弹量的影响.结果表明,先前低压缩比的加载历史对O形环后继高压缩比的回弹量没有影响;温度对O形环回弹量有一定程度影响;在压缩比为6%~30%,O形环回弹量与压缩比呈抛物律关系.运用ANSYS程序的接触分析功能,基于NLISO非线性等向强化本构模型对常温下O形环压扁-回弹过程的数值模拟结果与试验结果吻合较好.

  4. The wear of the carbide cutting tools coated with TiN during the milling of Inconel 738

    Science.gov (United States)

    Sebhi, A.; Douib, N.

    2017-02-01

    The machining of superalloy parts still an area not very clear in mechanical manufacturing. It is found to be used in particular areas such as gas turbine, rocket engine, space ships, nuclear reactors, and pumps. The machining of Inconel 738 superalloy has been studied in this context, with the aim to understand the wear behavior with carbide inserts coated with TiN and in order to optimize the cutting parameters before starting the production. The wear behavior of the inserts during the machining process of a very tough austenitic superalloy is unclear, and requires a series of well determined tests. The life of the insert under high stress such as pressure, cutting speed, high temperature, in a hostile zone and in contact with a very tough and harder material is determined. The generated process of wear is very complex, because it is followed by physico-chemical phenomenon appearing on the contact surfaces between the active part of the tool and workpiece.The lifetime of machine tools often depends on the tribological characteristics of the material couples (cutting tool / material to be machined). It has been shown that the most influential parameter is the coating, then comes the sliding speed. A relationship between the wear VB and the roughness Ra is proposed to collect information on the cutting edge and the quality of the tool by measuring the roughness. For wear measurement, an indirect method is used in coupling a Touptek photonics camera to capture and Ttoupview analysis software.

  5. High-temperature-oxidation-induced ordered structure in Inconel 939 superalloy exposed to oxy-combustion environments

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jingxi; Wise, Adam; Nuhfer, Thomas; Holcomb, Gordon R; Jablonski, Paul D; Sridhar, Seetharaman; Laughlin, David E

    2013-04-20

    In the integrated oxy-fuel combustion and turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO2 and O2. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation that results in the loss of the strengthening precipitates. In an earlier study of the oxidation of Inconel 939 Ni-based superalloy exposed to oxy-fuel combustion environment for up to 1000 hours, a high-temperature-oxidation-induced phase transformation in the sub-surface region was noticed and a two-phase region formed at the expense of strengthening γ' phase. While one of the two phases was identified as the Ni-matrix (γ solid solution, face-center-cubic) phase, the other product phase remained unidentified. In this study, the crystal structure of the unknown phase and its orientation relationship with the parent Ni-matrix phase was investigated through electron diffraction and high-resolution transmission electron microscopy. It was determined that the crystal structure of the unknown phase could be modeled as a ternary derivative of the ordered η-Ni3Ti phase (D024) structure with lattice parameters of a = 0.5092 nm and c = 0.8336 nm, α = 90º, β = 90º and γ = 120º.

  6. Investigation into the influence of post-weld heat treatment on the microstructure and hardness of Inconel X-750

    Directory of Open Access Journals (Sweden)

    Prachya Peasura

    2015-04-01

    Full Text Available This work describes a post-weld heat treatment for a precipitation-hardened nickel alloy. Inconel X-750 is a nickel-based superalloy for gas tungsten arc welding processes. The materials were heat-treated in two steps: solution and aging. The post-weld heat treatment variables examined in this study included post-weld heat treatment temperatures of 705°C, 775°C, and 845°C and post-weld heat treatment time of 2–24 h in 2-h increments. The resulting materials were examined using the full factorial design of experiments to determine the resulting material hardness and observed with optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy in the fusion zone and heat-affected zone. The results show that a longer post-weld heat treatment time corresponds to larger γ′ precipitates and a smaller amount of Cr23C6 at the grain boundaries, which can decrease the overall hardness. The post-weld heat treatment analysis indicates that an increase in the amount of γ′ results in better mechanical properties for particles with octagonal shapes and a small size. A factorial analysis, which was conducted on the relationship between the post-weld heat treatment temperature and time to the hardness of the fusion zone, had a 95% confidence level.

  7. Microstructural Features Controlling the Variability in Low-Cycle Fatigue Properties of Alloy Inconel 718DA at Intermediate Temperature

    Science.gov (United States)

    Texier, Damien; Gómez, Ana Casanova; Pierret, Stéphane; Franchet, Jean-Michel; Pollock, Tresa M.; Villechaise, Patrick; Cormier, Jonathan

    2016-03-01

    The low-cycle fatigue behavior of two direct-aged versions of the nickel-based superalloy Inconel 718 (IN718DA) was examined in the low-strain amplitude regime at intermediate temperature. High variability in fatigue life was observed, and abnormally short lifetimes were systematically observed to be due to crack initiation at (sub)-surface non-metallic inclusions. However, crack initiation within (sub)-surface non-metallic inclusions did not necessarily lead to short fatigue life. The macro- to micro-mechanical mechanisms of deformation and damage have been examined by means of detailed microstructural characterization, tensile and fatigue mechanical tests, and in situ tensile testing. The initial stages of crack micro-propagation from cracked non-metallic particles into the surrounding metallic matrix occupies a large fraction of the fatigue life and requires extensive local plastic straining in the matrix adjacent to the cracked inclusions. Differences in microstructure that influence local plastic straining, i.e., the δ-phase content and the grain size, coupled with the presence of non-metallic inclusions at the high end of the size distribution contribute strongly to the fatigue life variability.

  8. Swept frequency eddy current (SFEC) measurements of Inconel 718 as a function of microstructure and residual stress

    Science.gov (United States)

    Chandrasekar, Ramya

    The goal of this thesis was to determine the dependency of swept frequency eddy current (SFEC) measurements on the microstructure of the Ni-based alloy, Inconel 718 as a function of heat treatment and shot peening. This involved extensive characterization of the sample using SEM and TEM coupled with measurements and analysis of the eddy current response of the various sample conditions using SFEC data. Specific objectives included determining the eddy current response at varying depths within the sample, and this was accomplished by taking SFEC measurements in frequencies ranging from 100 kHz to 50 MHz. Conductivity profile fitting of the resulting SFEC signals was obtained by considering influencing factors (such as surface damage). The problems associated with surface roughness and near surface damage produced by shot peening were overcome by using an inversion model. Differences in signal were seen as a result of precipitation produced by heat treatment and by residual stresses induced due to the shot peening. Hardness of the material, which is related both to precipitation and shot peening, was seen to correlate with the measured SFEC signal. Surface stress measurement was carried out using XRD giving stress in the near surface regions, but not included in the calculations due to shallow depth information provided by the technique compared to SFEC. By comparing theoretical SFEC signal computed using the microstructural values (precipitate fraction) and experimental SFEC data, dependency of the SFEC signals on microstructure and residual stress was obtained.

  9. Flank wear and I-kaz 3D correlation in ball end milling process of Inconel 718

    Directory of Open Access Journals (Sweden)

    M.A.S.M. Tahir

    2015-12-01

    Full Text Available Tool wear may deteriorate the machine product quality due to high surface roughness, dimension exceeding tolerance and also to machine tool itself. Tool wear monitoring system is vital to be used in machining process to achieve high quality of the machined product and at the same time improve the productivity. Nowadays, many monitoring system developed using various sensor and statistical technique to analyze the signals being used. In this paper, I-kaz 3D method is used to analyze cutting force signal in milling process of Inconel 718 for monitoring the status of tool wear in milling process. The results from analyzing cutting force show that I-kaz 3D coefficient has a correlation with cutting tool condition. Tool wear will generate high value of I-kaz 3D coefficient than the sharp cutting tool. Furthermore, the three dimension graphical representation of I-kaz 3D for all cutting condition shown that the degree of scattering data increases with tool wear progression.

  10. Characterization and Evaluation of Cyclic Hot Corrosion Resistance of Detonation-Gun Sprayed Ni-5Al Coatings on Inconel-718

    Science.gov (United States)

    Saladi, Sekar; Menghani, Jyoti V.; Prakash, Satya

    2015-06-01

    The high temperature hot corrosion behavior of bare and detonation-gun-sprayed Ni-5Al coatings on Ni-based superalloy Inconel-718 is comparatively discussed in the present study. Hot corrosion studies were carried out at 900 °C for 100 cycles in Na2SO4-60% V2O5 molten salt environment under cyclic heating and cooling conditions. The thermo-gravimetric technique was used to establish the kinetics of hot corrosion. X-ray diffraction, SEM/EDAX, and X-ray mapping techniques were used to analyze the hot corrosion products of bare and coated superalloys. The results indicate that Ni-5Al-coated superalloy showed very good hot corrosion resistance. The overall weight gain and parabolic rate constant of Ni-5Al-coated superalloy were less in comparison with the bare superalloy. The D-gun-sprayed Ni-5Al coating was found to be uniform, adherent, and dense in hot corrosion environment. The formation of nickel- and aluminum-rich oxide scale might have contributed for the better hot corrosion resistance of the coated superalloy.

  11. Determination of Yield in Inconel 718 for Axial-Torsional Loading at Temperatures up to 649 C

    Science.gov (United States)

    Gil, Christopher M.; Lissenden, Cliff J.; Lerch, Bradley A.

    1998-01-01

    An experimental program has been implemented to determine small offset yield loci under axial-torsional loading at elevated temperatures. The nickel-base superalloy Inconel 718 (IN718) was chosen for study due to its common use in aeropropulsion applications. Initial and subsequent yield loci were determined for solutioned IN718 at 23, 371, and 454 C and for aged (precipitation hardened) IN718 at 23 and 649 C. The shape of the initial yield loci for solutioned and aged IN718 agreed well with the von Mises prediction. However, in general, the centers of initial yield loci were eccentric to the origin due to a strength-differential (S-D) effect that increased with temperature. Subsequent yield loci exhibited anisotropic hardening in the form of translation and distortion of the locus. This work shows that it is possible to determine yield surfaces for metallic materials at temperatures up to at least 649 C using multiple probes of a single specimen. The experimental data is first-of-its-kind for a superalloy at these very high temperatures and will facilitate a better understanding of multiaxial material response, eventually leading to improved design tools for engine designers.

  12. Inconel 718金属注射成形制品的X-射线分析

    Institute of Scientific and Technical Information of China (English)

    孙世杰

    2004-01-01

    Inconel 718母合金粉与羰基镍粉、羰基铁粉及粘结剂混合,以金属注射成形方法成形并烧结,取一些试样在稀硫酸溶液介质中,以4.5V电压电解10~20s,电解后的试样用于电镜分析,用X-射线能谱分析选区化学成分的变化。在背散射电子的成像中观察到一个大的沉淀区,X-射线能谱分析表明这是一个钛富集区,沉淀区的树枝形态与沉淀相的晶体结构有关,可能是具有面心立方结构的TiN,

  13. Long-Term Creep of a Thin-Walled Inconel 718 Stirling Power-Convertor Heater Head Assessed

    Science.gov (United States)

    Bowman, Randy R.

    2002-01-01

    The Department of Energy and NASA have identified Stirling power convertors as candidate power supply systems for long-duration, deep-space science missions. A key element for qualifying the flight hardware is a long-term durability assessment for critical hot section components of the power convertor. One such critical component is the power convertor heater head. The heater head is a high-temperature pressure vessel that transfers heat to the working gas medium of the convertor, which is typically helium. An efficient heater head design is the result of balancing the divergent requirements of thin walls for increased heat transfer versus thick walls to lower the wall stresses and thus improve creep resistance and durability. In the current design, the heater head is fabricated from the Ni-base superalloy Inconel 718 (IN 718, Inco Alloys International, Inc., Huntington, WV). Although IN 718 is a mature alloy system (patented in 1962), there is little long-term (>50,000-hr) creep data available for thin-specimen geometries. Since thin-section properties tend to be inferior to thicker samples, it is necessary to generate creep data using specimens with the same geometry as the actual flight hardware. Therefore, one facet of the overall durability assessment program involves generating relatively short-term creep data using thin specimens at the design temperature of 649 C (1200 F).

  14. Microstructure and strain-stress analysis of the dynamic strain aging in inconel 625 at high temperature

    Science.gov (United States)

    Maj, P.; Zdunek, J.; Mizera, J.; Kurzydlowski, K. J.; Sakowicz, B.; Kaminski, M.

    2017-01-01

    Serrated flow is a result of unstable plastic flow, which occurs during tensile and compression tests on some dilute alloys. This phenomenon is referred as the Portevin Le-Chatelier effect (PLC effect). The aim of this research was to investigate and analyze this phenomenon in Inconel 625 solution strengthened superalloy. The tested material was subjected to tensile tests carried out within the temperature range 200-700 °C, with three different strain rates: 0.002 1/s, 0.01/s, and 0.05 1/s and additional compression tests with high deformation speeds of 0.1, 1, and 10 1/s. The tensile strain curves were analyzed in terms of intensity and the observed patterns of serrations Using a modified stress drop method proposed by the authors, the activation energy was calculated with the assumption that the stress drops' distribution is a direct representation of an average solute atom's interaction with dislocations. Subsequently, two models, the standard vacancy diffusion Bilby-Cottrell model and the realistic cross-core diffusion mechanism proposed by Zhang and Curtin, were compared. The results obtained show that the second one agrees with the experimental data. Additional microstructure analysis was performed to identify microstructure elements that may be responsible for the PLC effect. Based on the results, the relationship between the intensity of the phenomenon and the conditions of the tests were determined.

  15. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Morin, A.; Fernandez-Reche, J.

    2011-07-01

    A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almeria (PSA) in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N) fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF) region at the operational temperatures of both 650 degree centigrade and 900 degree centigrade. (Author) 20 refs.

  16. Particle Size of Gamma Prime as a Result of Vacuum Heat Treatment of INCONEL 738 Super Alloy

    Science.gov (United States)

    Guzman, I.; Granda, E.; Mendez, R.; Lopez, G.; Acevedo, J.; Gonzalez, D.

    2013-04-01

    In this paper, the influence of the cooling rate and cooling media after a standard solution heat treatment on the size and distribution of the gamma prime phase (γ') in the nickel-based super alloy INCONEL 738 in over-aged conditions is described. The volume fraction of the gamma prime depends on the chemical composition of the alloy, the solution treatment temperature and the cooling rate; in over-aged alloys (i.e., with more than 25,000 h of service) the volume fraction of γ' is about 78.8%. However, it has been demonstrated that in order to maintain excellent creep strength a volume fraction of at least 60% or lower is required. In this work the volume fraction was optimized between 40 and 55% by means of a standard solution heat treatment at 1120 °C using different cooling gases. A γ' volume fraction of 54.8% was obtained by using argon as the cooling medium at a cooling rate of 87 °C/min, producing a precipitate of partial distribution of primary and secondary γ'. Better results were obtained in a nitrogen atmosphere at a cooling rate of 287 °C/min, leading to a volume fraction of 40% and obtaining a total re-precipitation of primary and secondary γ'.

  17. The fatigue and corrosion fatigue behavior of welded Inconel 625 alloy employed in off-shore platforms; Avaliacao do comportamento a fadiga e a corrosao-fadiga de juntas soldadas da liga Inconel 625 testada para uso em plaaformas off-shore

    Energy Technology Data Exchange (ETDEWEB)

    Pfingstag, M.E.; Schroeder, R.M.; Mueller, I.L. [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Dept. de Metalurgia. Lab. de Pesquisa em Corrosao], e-mail: maiquel10@walla.com

    2006-07-01

    The fatigue and corrosion fatigue behavior of welded Inconel 625 employed live like risers in off-shore platforms was studied. These risers may be employed integrally of this alloy, or combined with API 52 X60 steel in the form of 'Clads'. One of the most susceptible points in .these structures is the circumferential weld that joint the pipes together. In these regions, stresses and defects are generated by the welding process, and these material remind in contact with aggressive species like, chlorides and Co{sub 2} . Polarization curves, slow strain rate fatigue and corrosion fatigue tests were used to characterize the Inconel alloy behavior. In the welded deposit condition, this alloy shows an excellent resistance corrosion and a good fatigue and corrosion-fatigue behavior.(author)

  18. Solidificação da zona de fusão na soldagem do AISI 304 com inconel 600 por laser de Nd: YAG Microstructure development in Nd: YAG laser welding of AISI 304 and Inconel 600

    Directory of Open Access Journals (Sweden)

    Maurício David M. das Neves

    2009-06-01

    Full Text Available Neste trabalho estudou-se a morfologia de solidificação da zona de fusão, numa junta formada a partir de materiais dissimilares, composta por aço inoxidável austenítico AISI 304 e por liga de níquel Inconel 600, soldada com laser pulsado de Nd:YAG. Os parâmetros do feixe laser e do sistema óptico foram selecionados, visando obter uma solda com penetração total e bom acabamento superficial. A caracterização microestrutural foi realizada por microscopia ótica, onde se observou uma zona de fusão com penetração total do tipo keyhole, a presença de pequenos poros e a ausência de trincas. As juntas soldadas foram caracterizadas também, por meio de microscopia eletrônica de varredura (MEV. Medidas realizadas por espectrometria de raios X por dispersão de energia na zona de fusão indicaram uma distribuição levemente heterogênea de níquel e ferro. Observou-se que o início de solidificação da zona de fusão ocorreu por meio de crescimento epitaxial. A morfologia de solidificação da ZF foi basicamente dendrítica e celular sendo, influenciada pelo gradiente de temperatura, velocidade de solidificação e composição química. As variações de composição química e da morfologia de solidificação não alteraram significativamente os valores de microdureza Vickers na zona de fusão. Resultados obtidos nos ensaios de tração indicaram valores de eficiência de soldagem adequados.An autogenous laser welding of dissimilar materials involving AISI 304 austenitic stainless steels and Inconel 600 nickel alloy was investigated in this study. Hence, the aim of this investigation was to study the solidification and microstructure of fusion zone when using a pulsed Nd:YAG laser. The laser and optical beam parameters were chosen to achieve a good weld with total penetration. Optical microscopy pictures showed a typical keyhole weld with total penetration, small pores and free of cracks. The x-ray spectrometry by energy dispersion

  19. Aspectos metalúrgicos de revestimentos dissimilares com a superliga à base de níquel inconel 625 Metallurgical aspects of dissimilar weld overlays of inconel 625 nickel based superalloys

    Directory of Open Access Journals (Sweden)

    Cleiton Carvalho Silva

    2012-09-01

    Full Text Available Prolongar a vida útil e aumentar a confiabilidade de equipamentos e tubulações de plantas de produção e processamento de petróleo é uma busca constante no setor de petróleo e gás. Tais aspectos dependem essencialmente do uso de ligas resistentes à corrosão. Neste contexto, a soldagem de revestimento com superligas à base de níquel tem sido uma alternativa interessante, pois confere aos equipamentos uma alta resistência à corrosão com um custo inferior, se comparado à fabricação de componentes ou tubulações maciças com superligas. Assim, o objetivo do presente trabalho foi investigar o comportamento metalúrgico de revestimento de superliga à base de níquel do tipo Inconel 625 depositados pelo processo TIG com alimentação de arame frio. As soldagens foram realizadas em uma bancada robotizada, empregando uma fonte eletrônica de soldagem com sistema de aquisição de dados para o monitoramento dos sinais de corrente e tensão. A caracterização microestrutural foi realizada através das técnicas de microscopia eletrônica de varredura (MEV e transmissão (MET, espectroscopia de energia dispersiva de raios-X (EDS. Os resultados mostraram que a microestrutura do metal de solda foi constituída por uma matriz γ com fases secundárias ricas em Nb. Foi encontrada a formação de precipitados complexos de carbonetos/nitretos de Ti e Nb.To extend the life and reliability of pipes and equipment in oil & gas production and processing settings is a continuous demand. These aspects are essentially dependent on corrosion resistant alloys used. In this context, the weld overlay with Ni-based superalloys is a great interesting alternative, since improve the corrosion resistance without increase the cost of manufacture when compared to massive equipment. Thus, the objective of this study was to evaluate the metallurgical aspects of Inconel 625 weld overlays deposited by GTAW cold wire feed process. The welds were performed using a

  20. 金刚石涂层Si3N4刀具高速切削Inconel 718合金实验研究%Experimental Research on Si3N4 Diamond Coated Tools in High Speed Machining of Inconel 718

    Institute of Scientific and Technical Information of China (English)

    宣仲义

    2010-01-01

    在高速切削加工铬镍铁耐热合金(Inconel 718)的过程中,对加工表面质量的严格控制是获得高可靠性、长寿命工件的前提.利用热丝化学气相沉积(HFCVD)法在Si,N4刀具上涂覆一层金刚石薄膜,用于对Inconel 718合金进行加工.通过对Si3N4刀具磨损和工件表面加工硬化程度(DWH)的研究,寻找最优加工条件.结果表明,在切削深度0.75 mm、进给量0.10 mm/r、切削速度55 m/min的加工条件下,Inconel 718合金工件获得较好的加工质量,同时Si3N4刀具的磨损较小.

  1. 反应堆压力容器用Inconel 718合金O形环密封性能%Sealing Characteristics of O-Ring of Inconel 718 Alloy in Reaction Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    沈明学; 谢林君; 赵丽娜; 励行根; 王燕; 彭旭东

    2015-01-01

    基于二维轴对称非线性弹塑性模型,对反应堆压力容器(RPV)用Inconel 718合金O形密封环进行了有限元分析,在实验验证的基础上探讨了O形环压缩率、截面直径、管材壁厚和环外径等关键参数对密封性能的影响.结果表明:压缩率对其密封面接触应力分布、大小以及变形特性有重要影响;增加O形环截面直径可提高其回弹性能,但也会引起密封线比压的下降,而壁厚对回弹量和线比压的影响与截面直径相反,但O形环外径对其回弹量和线比压的影响较小;工程上推荐RPV用O形密封环的压缩率控制为12%~16%、截面直径选择12.7 mm左右、壁厚取1.35~1.65 mm,此时O形环可以达到较好的密封性能.

  2. Understanding the Role of Hot Isostatic Pressing Parameters on the Microstructural Evolution of Ti-6Al-4V and Inconel 718 Fabricated by Electron Beam Melting

    Energy Technology Data Exchange (ETDEWEB)

    Peter, William H [ORNL; Nandwana, Peeyush [ORNL; Kirka, Michael M [ORNL; Dehoff, Ryan R [ORNL; Sames, William [Texas A& M University; ERDMAN III, DONALD L [ORNL; Eklund, Anders [Avure Technologies, Inc.; Howard, Ron [Avure Technologies, Inc.

    2015-04-01

    In this project, Avure and ORNL evaluated the influence of hot isostatic pressing (HIP) and thermal cycling as standalone post processing techniques on the microstructure of electron beam powder bed deposited Ti-6Al-4V and Inconel 718 alloys. Electron beam powder bed deposition is an effective technology for fabricating complex net shape components that cannot be manufactured with conventional processes. However, material deposited by this technology results in columnar grain growth which is detrimental for many applications. For Ti-6Al-4V, it has been found that thermal cycling alone is not sufficient to breakdown the columnar microstructure that is typical of electron beam powder bed technology. HIP, on the other hand, has the potential to be an effective technique to break down the columnar microstructure of Ti-6Al-4V into a more equiaxed and refined β grain structure, and provide a more homogeneous microstructure compared to the thermally cycled samples. Overall, the project showed that hot isostatic pressing reduced/eliminated porosity in both Ti-6Al-4V and Inconel 718 However, based on the unique thermal cycle and the application of pressure in the HIP vessel, Ti-6Al-4V e-beam deposited microstructures were modified from columnar grain growth to equiaxed microstructures; a significant outcome to this collaboration. Inconel 718, on the other hand, shows no change in the macrostructure as a result of the current HIP cycle based on the thermal history, and would require further investigation. Though the results of HIP cycle were very good at changing the microstructure, further development in optimizing the post heat treatments and HIP cycles is required to improve mechanical properties.

  3. Time-dependent edge notch sensitivity of Inconel 718 sheet in the temperature range 900 to 1400 F (482 to 760 C)

    Science.gov (United States)

    Wilson, D. J.

    1972-01-01

    Time-dependent notch sensitivity of Inconel 718 sheet occurred at 900 to 1200 F when notched specimens were loaded below the yield strength, and tests on smooth specimens showed that small amounts of creep consumed large fractions of creep-rupture life. The severity of the notch sensitivity decreased with decreasing solution treatment temperature and increasing time and/or temperature of the aging treatment. Elimination of the notch sensitivity was correlated with a change in the dislocation mechanism from shearing to by-passing precipitate particles.

  4. Comparative Analysis of Properties and Microstructure of the Plastically Deformed Alloy Inconel®718, Manufactured by Plastic Working and Direct Metal Laser Sintering

    Directory of Open Access Journals (Sweden)

    Żaba K.

    2016-03-01

    Full Text Available Nickel superalloys as Inconel® are materials widely used in the aerospace industry among others for diffusers, combustion chamber, shells of gas generators and other. In most cases, manufacturing process of those parts are used metal strips, produced by conventional plastic processing techniques, and thus by hot or cold rolling. An alternative technology allowing for manufacturing components for jet engines is the technique of 3D printing (additive manufacturing, and most of all Direct Metal Laser Sintering, which is one of the latest achievement in field of additive technologies.

  5. Chemistry of glass-ceramic to metal bonding for header applications. I. Effect of treatments on Inconel 718 and Hastelloy C-276 metallic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, D P; Craven, S M; Schneider, R E; Moddeman, W E; Brohard, D W

    1984-02-02

    Auger electron spectroscopy and depth Auger profiling were used to study the surfaces of Inconel 718 and Hastelloy C-276. The metal surfaces were processed in the same manner as is presently being used in the manufacturing of glass-ceramic headers. At each step in the process, samples were studied with Auger spectroscopy to determine their resultant elemental surface composition and film thickness. In addition, the effect of a final plasma cleaning operation on the metal surface was examined. The results show that the type and concentration of surface species and the thickness of the surface oxides are dependent on the processing technique.

  6. Influences of hot-isostatic-pressing temperature on microstructure, tensile properties and tensile fracture mode of Inconel 718 powder compact

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Litao [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); University of Chinese Academy of Sciences, Beijing (China); Sun, Wenru; Cui, Yuyou [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Yang, Rui, E-mail: ryang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2014-04-01

    Inconel 718 powders have been hot-isostatic-pressed (HIPed) at representative temperatures to investigate the variations in microstructure, tensile properties and tensile fracture mode of the powder compact. Microstructure of the powder compacts were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results showed that the interdendritic precipitates inherited from the powders were partially retained in the powder compacts when the powders were HIPed at or below 1210 °C but were eliminated when HIPed at and above 1260 °C. The grain size uniformity of the powder compacts first increases and then decreases with increasing HIPing temperature. Prior particle boundaries (PPBs) were observed in the powder compacts HIPed at and below 1260 °C but was eliminated when HIPed at 1275 °C. The PPBs were decorated with carbide particles, the amount of the carbide particles at the PPBs decreases with increasing HIPing temperature. Most of the PPBs were pinned by the carbide particles in the compacts HIPed at 1140 °C. When the HIPing temperature was increased to 1210 °C and 1260 °C, a large number of PPBs de-pinned and moved beyond the pinning carbide particles, leading to grain growth and leaving carbide particles at the site of the original PPBs within the new grains. With increasing HIPing temperature, the 0.2% yield strength of the powder compacts at 650 °C decreases, the tensile elongation increases, and the tensile fracture mode changed from inter-particle dominant fracture to fully dimple ductile fracture.

  7. Combined strengthening of multi-phase and graded interface in laser additive manufactured TiC/Inconel 718 composites

    Science.gov (United States)

    Gu, Dongdong; Hong, Chen; Jia, Qingbo; Dai, Donghua; Gasser, Andres; Weisheit, Andreas; Kelbassa, Ingomar; Zhong, Minlin; Poprawe, Reinhart

    2014-01-01

    Laser metal deposition (LMD) additive manufacturing of TiC particle reinforced Inconel 718 composite parts was performed. The influence of laser energy density (LED) on densification, microstructures and wear behaviour of LMD-processed composites was studied. It showed that using a LED of 280 J mm-3 produced ˜5% porosity in LMD-processed composites, caused by the aggregation of reinforcing particles. A further increase in LED above 350 J mm-3 yielded near-full densification. Two categories of reinforcing phases, i.e. the substoichiometric TiCx particles and the in situ (Ti,M)C (M = Mo, Nb and Cr) carbide having 7-10 at% Nb and Mo contents, were formed in the matrix of LMD-processed composites. The TiCx reinforcing particles changed from an irregular poly-angular shape to a smoothened and refined structure as the LED increased. An increase in LED resulted in a larger amount of phase formation and an enhanced degree of crystal growth of the in situ (Ti,M)C reinforcement. The interfacial graded layer with thickness of 0.2-1.2 µm, which was identified as (Ti,M)C (M = Mo, Nb and Cr) carbide with 5-6 at% Mo and Nb contents, was tailored between the TiCx particles and the matrix. At an optimal LED of 420 J mm-3, a considerably low coefficient of friction of 0.38 and resultant low wear rate of 1.8 × 10-4 mm3 N-1 m-1 were obtained in sliding tests, due to the combined strengthening of the interfacial graded layer and the multiple reinforcing phases. The wear resistance decreased at an excessive LED because of the coarsening of reinforcement crystals and the decrease in microstructural uniformity of composites.

  8. Effects of Heat Treatment on the Ballistic Impact Properties of Inconel 718 for Jet Engine Fan Containment Applications

    Science.gov (United States)

    Pereira, J. Michael; Lerch, Bradley A.

    2001-01-01

    The effects of heat treating Inconel 718 on the ballistic impact response and failure mechanisms were studied. Two different annealing conditions and an aged condition were considered. Large differences in the static properties were found between the annealed and the aged material, with the annealed condition having lower strength and hardness and greater elongation than the aged. High strain rate tests show similar results. Correspondingly large differences were found in the velocity required to penetrate material in the two conditions in impact tests involving 12.5 mm diameter, 25.4 mm long cylindrical Ti-6-4 projectiles impacting flat plates at velocities in the range of 150 to 300 m/sec. The annealed material was able to absorb over 25 percent more energy than the aged. This is contrary to results observed for ballistic impact response for higher velocity impacts typically encountered in military applications where it has been shown that there exists a correlation between target hardness and ballistic impact strength. Metallographic examination of impacted plates showed strong indication of failure due to adiabatic shear. In both materials localized bands of large shear deformation were apparent, and microhardness measurements indicated an increase in hardness in these bands compared to the surrounding material. These bands were more localized in the aged material than in the annealed material. In addition the annealed material underwent significantly greater overall deformation before failure. The results indicate that lower elongation and reduced strain hardening behavior lead to a transition from shear to adiabatic shear failure, while high elongation and better strain hardening capabilities reduce the tendency for shear to localize and result in an unstable adiabatic shear failure. This supports empirical containment design methods that relate containment thickness to the static toughness.

  9. Influence of cutting parameters on surface characteristics of cut section in cutting of Inconel 718 sheet using CW Nd:YAG laser

    Institute of Scientific and Technical Information of China (English)

    Dong-Gyu AHN; Kyung-Won BYUN

    2009-01-01

    Recently, laser cutting technologies begin to use for manufacturing mechanical parts of lnconel super-alloy sheet due to difficulties of machining of the Inconel material as a results of its extremely tough nature. The objective of this work is to investigate the influence of cutting parameters on surface characteristics of the cut section in the cutting of Inconel 718 super-alloy sheet using CW Nd:YAG laser through laser cutting experiments. Normal cutting experiments were performed using a laser cutting system with six-axis controlled automatic robot and auto-tracking system of the focal distance. From the results of the experiments, the effects of the cutting parameters on the surface roughness, the striation formation and the microstructure of the cut section were examined. In addition, an optimal cutting condition, at which the surface roughness is minimized and both the delayed cutting phenomenon and the micro-cracking are not initiated, is estimated to improve both the part quality and the cutting efficiency.

  10. Artificial Neural Network-Based Constitutive Relationship of Inconel 718 Superalloy Construction and Its Application in Accuracy Improvement of Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Junya Lv

    2017-01-01

    Full Text Available The application of accurate constitutive relationship in finite element simulation would significantly contribute to accurate simulation results, which play critical roles in process design and optimization. In this investigation, the true stress-strain data of an Inconel 718 superalloy were obtained from a series of isothermal compression tests conducted in a wide temperature range of 1153–1353 K and strain rate range of 0.01–10 s−1 on a Gleeble 3500 testing machine (DSI, St. Paul, DE, USA. Then the constitutive relationship was modeled by an optimally-constructed and well-trained back-propagation artificial neural network (ANN. The evaluation of the ANN model revealed that it has admirable performance in characterizing and predicting the flow behaviors of Inconel 718 superalloy. Consequently, the developed ANN model was used to predict abundant stress-strain data beyond the limited experimental conditions and construct the continuous mapping relationship for temperature, strain rate, strain and stress. Finally, the constructed ANN was implanted in a finite element solver though the interface of “URPFLO” subroutine to simulate the isothermal compression tests. The results show that the integration of finite element method with ANN model can significantly promote the accuracy improvement of numerical simulations for hot forming processes.

  11. 田口-灰关联法应用于Inconel 718微放电铣削参数最佳化(英文)

    Institute of Scientific and Technical Information of China (English)

    林茂用; 曹中丞; 许春耀; 邱菱蕙; 黄鹏丞; 林裕城

    2013-01-01

    应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响。实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6×10-9mm3/min降低到5.2×10-9mm3/min,材料去除率由0.47×10-8mm3/min增加到1.68×10-8mm3/min,扩口量由1.27μm降低到1.19μm。研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性。

  12. Galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718 and graphite-epoxy composite material: Corrosion occurrence and prevention

    Science.gov (United States)

    Danford, M. D.; Higgins, R. H.

    1983-01-01

    The effects of galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718, and graphite-epoxy composite material (G/E) in 3.5% NaCl were studied. Measurements of corrosion potentials, galvanic currents and corrosion rates of the bare metals using weight-loss methods served to establish the need for corrosion protection in cases where D6AC steel and 6061-T6 aluminum are galvanically coupled to G/E in salt water while Inconel 718 was shown to be compatible with G/E. Six tests were made to study corrosion protective methods for eliminating galvanic corrosion in the cases of D6AC steel and 6061-T6 aluminum coupled to G/E. These results indicate that, when the G/E is completely coated with paint or a paint/polyurethane resin combination, satisfactory protection of the D6AC steel is achieved with either a coat of zinc-rich primer or a primer/topcoat combination. Likewise, satisfactory corrosion protection of the aluminum is achieved by coating it with an epoxy coating system.

  13. Investigation into the Impact of Hold Time, Thermal Mechanical Fatigue, Shotpeen, and Retardation on Fatigue Crack Growth in Inconel Dovetail Slots in Jet Engines

    Science.gov (United States)

    Joiner, Josiah W.

    2011-12-01

    Current jet engine industry studies are ongoing to develop a generic Inconel dovetail slot test case that will be used for calibrating a manufacturing-induced surface damage anomaly distribution curve for future probabilistic life assessments. The stress and temperature profile during the mission have been defined. This analysis will consist of a design of experiments on the Inconel dovetail slot test data. The test case includes thermal and mechanical stresses, as well as variations in hold time, stress and temperature regimes. Several DOEs will be created and run to help assess the impact of four crack growth mechanisms on the damage tolerance life for the different mission profiles: hold time, thermal mechanical fatigue, shotpeen, and retardation. For the sake of this study a parametric study is considered to be a DOE. Calculations will be completed for both surface and corner cracks. For surface cracks, a 2:1 aspect ratio semicircular initial flaw size of 15 x 30 mils will be used. For corner cracks, a 1:1 aspect ratio semicircular initial flaw size of 15 x 15 mils will be used. The calculations will be completed using a proprietary crack propagation code. The results of this study will reveal the mission profile at which each of the aforementioned effects begins to have a significant impact on the damage tolerance life. These studies are critical to ensuring the final test case adequately addresses each of these critical crack propagation drivers.

  14. 磷硼复合添加对Inconel 718合金铸态组织及均匀化处理参数的影响(英文)

    Institute of Scientific and Technical Information of China (English)

    缪竹骏; 单爱党; 吴元彪; 卢俊; 胡莹; 刘俊亮; 宋洪伟

    2012-01-01

    研究磷硼复合添加对Inconel 718高温合金铸态组织及均匀化处理参数的影响。结果表明:磷硼的加入促进块状Laves相的形成。由于硼在最后残余液相中大量富集,形成一种富含Nb、Mo和Cr的含硼相。根据DSC和电子探针分析结果,确定磷硼复合添加Inconel 718高温合金的凝固顺序为L→L+γ→L+γ+MC→L+γ+MC+Laves→γ+MC+Laves+含硼相。由于低熔点含硼相的存在,磷硼复合添加Inconel 718高温合金的均匀化处理温度应比标准Inconel 718合金低至少40°C。

  15. Risk of Galvanic Corrosion among API X65, 316L and Inconel 625%API X65、316L不锈钢及Inconel 625间电偶腐蚀风险研究

    Institute of Scientific and Technical Information of China (English)

    田永芹; 常炜; 胡丽华; 贾旭; 周晓红; 邢云颖; 余晓毅; 于湉

    2016-01-01

    ABSTRACT:Objective To determine the galvanic corrosion risk among API X65, 316L and inconel 625.Methods Elec-trochemical corrosion test, standard galvanic corrosion evaluation experiment and simulation experiment were carried out to analyze the corrosion risk.Results The corrosion potential of X65 was around-0.75 V, while that of 316L and 625 potential was both around-0.35 V. For standard galvanic corrosion evaluation experiment, in the open solution or 100 kPa and 500 kPa CO2 solution, the galvanic current of X65-316L was the largest, followed by X65-625 and then 316L-625. Galvanic corrosion oc-curred when X65 met either 316L or 625. For simulation experiment, obvious galvanic corrosion occurred among X65, 316L and 625. There was a serious groove corrosion near the weld joint position in X65. The corrosion rate of X65 without galvanic corrosion was 1.24 mm/a. The galvanic corrosion increased this value. The average galvanic corrosion rate of X65-316L was 1.49 mm/a and that of X65-625 was 1.75 mm/a. The local galvanic corrosion rate of X65-316L was 16.8 mm/a and that of X65-625 was 26.4 mm/a, which was over ten times as high as the corrosion rate of X65 without galvanic corrosion. The galvan-ic corrosion rate of X65 and 316L was larger than that of X65 and 625. There was almost no galvanic corrosion between 316L stainless steel and 625 nickel base alloy.ConclusionGalvanic corrosion risk between X65 and 316L was larger than that be-tween X65 and 625. Galvanic corrosion risk between 316L and 625 was very small.%目的:确定API X65、316L不锈钢及inconel625相互偶接后的电偶腐蚀风险。方法采用电化学测试、标准电偶腐蚀评价实验和腐蚀模拟实验对电偶腐蚀进行分析研究。结果在模拟地层水中,经过电化学测试,X65的自腐蚀电位在-0.75 V左右,316L和625的电位在-0.35 V左右。对于标准电偶腐蚀评价实验,敞口溶液及CO2分压分别为100 kPa和500 kPa的溶液中,X65与316L之间的

  16. 高温水中添加微量Zn(2+)对Inconel600合金氧化膜半导体性质的影响%Semiconductor Property of Oxide Films on Inconel600 Formed in High Temperature Water with Zinc Addition

    Institute of Scientific and Technical Information of China (English)

    张胜寒; 檀玉; 梁可心

    2011-01-01

    Zinc addition technique is widely used in the first circuit of boiling water reactor(BWR) and pressurized water reactor(PWR) to lower the stress corrosion cracking and radioactive pollution of nickel-base alloys.An oxide film of Inconel600 with semiconductor properties was formed in high temperature water.And the semiconductor properties were changed by very little amount of zinc addition.Photoelectrochemical response and capacitance measurement were employed to investigate the oxide films formed on Inconel600 with/without zinc addition.The photocurrent of the oxide film was plotted as a function of photon energy,for separating into several parts,which can be derived from Fe2O3 with a band gap energy 2.2 eV,Cr2O3 3.5 eV,FexNi1-xCr2O4 4.1 eV besides ZnO 3.2 eV.For steady photoelectrochemical responses,the oxide film formed with zinc addition exhibited anodic photocurrent at open circle potential while the film without zinc exhibited cathodic photocurrent.Mott-Schottky plots indicates a negative movement of the flat band potential of the oxide film on Inconel600 with zinc addition to the film without zinc.At the same potential,the higher(space charge capacitance,CSC) indicated a more compact oxide film of Inconel600 with zinc addition in the high temperature water.It comes to a conclusion that the photoelectrochemical responses is a sensitive and effective method to investigate the oxide phase in the oxide film on alloy.%核电站采用Zn2+注入技术减少一回路镍基材料的应力腐蚀和辐射污染.向高温水中添加微量Zn2+制备Inconel600合金表面氧化膜,用光电化学响应技术和容抗测量技术研究Zn2+对氧化膜半导体性质的影响.光电化学响应结果表明,氧化膜中不同氧化相的特征带隙宽度分别为Fe2O3 2.2 eV,Cr2O3 3.5 eV,FexNi1-xCr2O4 4.1 eV和ZnO 3.2eV;在开路电压下,无Zn2+参与生成的氧化膜表现阴极光电流响应,有Zn2+参与生成的氧化膜表现阳极光电

  17. Viscoplastic Model Development to Account for Strength Differential: Application to Aged Inconel 718 at Elevated Temperature. Degree awarded by Pennsylvania State Univ., 2000

    Science.gov (United States)

    Iyer, Saiganesh; Lerch, Brad (Technical Monitor)

    2001-01-01

    The magnitude of yield and flow stresses in aged Inconel 718 are observed to be different in tension and compression. This phenomenon, called the Strength differential (SD), contradicts the metal plasticity axiom that the second deviatoric stress invariant alone is sufficient for representing yield and flow. Apparently, at least one of the other two stress invariants is also significant. A unified viscoplastic model was developed that is able to account for the SD effect in aged Inconel 718. Building this model involved both theory and experiments. First, a general threshold function was proposed that depends on all three stress invariants and then the flow and evolution laws were developed using a potential-based thermodynamic framework. Judiciously chosen shear and axial tests were conducted to characterize the material. Shear tests involved monotonic loading, relaxation, and creep tests with different loading rates and load levels. The axial tests were tension and compression tests that resulted in sufficiently large inelastic strains. All tests were performed at 650 C. The viscoplastic material parameters were determined by optimizing the fit to the shear tests, during which the first and the third stress invariants remained zero. The threshold surface parameters were then fit to the tension and compression test data. An experimental procedure was established to quantify the effect of each stress invariant on inelastic deformation. This requires conducting tests with nonproportional three-dimensional load paths. Validation of the model was done using biaxial tests on tubular specimens of aged Inconel 718 using proportional and nonproportional axial-torsion loading. These biaxial tests also helped to determine the most appropriate form of the threshold function; that is, how to combine the stress invariants. Of the set of trial threshold functions, the ones that incorporated the third stress invariant give the best predictions. However, inclusion of the first

  18. Effect of the Fine-Grained Structure on the Fatigue Properties of the Heat-Resistant Nickel-Iron Alloy Inconel 718

    Science.gov (United States)

    Mukhtarov, Sh. Kh.; Shakhov, R. V.

    2015-10-01

    It is well known that ultrafine-grained nickel alloys with average grain sizes d = 0.1-1 μm possess improved hot workability and can be used for superplastic forming or rolling. However, microstructure refinement can worsen some performance characteristics of the alloy, for example, heat-resistant or fatigue properties. In the present work, fatigue characteristics of the fine-grained alloy Inconel 718 are investigated. Ultrafine-grained alloys with average grain sizes d = 0.1-1 μm were manufactured by multiple forging with stage-by-stage deformation temperature decrease. During standard heat treatment of the alloy performed to obtain the desired properties, the γ-grain size was controlled by precipitations of δ-phase particles along the boundaries. Results of low-cycle fatigue tests of the fine-grained alloy at room and elevated temperatures are compared with the properties of the coarse-grained alloy.

  19. Faster methods for estimating arc centre position during VAR and results from Ti-6Al-4V and INCONEL 718 alloys

    Science.gov (United States)

    Nair, B. G.; Winter, N.; Daniel, B.; Ward, R. M.

    2016-07-01

    Direct measurement of the flow of electric current during VAR is extremely difficult due to the aggressive environment as the arc process itself controls the distribution of current. In previous studies the technique of “magnetic source tomography” was presented; this was shown to be effective but it used a computationally intensive iterative method to analyse the distribution of arc centre position. In this paper we present faster computational methods requiring less numerical optimisation to determine the centre position of a single distributed arc both numerically and experimentally. Numerical validation of the algorithms were done on models and experimental validation on measurements based on titanium and nickel alloys (Ti6Al4V and INCONEL 718). The results are used to comment on the effects of process parameters on arc behaviour during VAR.

  20. A preliminary mechanical property and stress corrosion evaluation of VIM-VAR work strengthened and direct aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1987-01-01

    This report presents a preliminary mechanical property and stress corrosion evaluation of double melted (vacuum induction melted (VIM), and vacuum arc remelted (VAR)), solution treated, work strengthened and direct aged Inconel 718 alloy bar (5.50 in. (13.97 cm) diameter). Two sets of tensile specimens, one direct single aged and the other direct double aged, were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 200 ksi (1378.96 MPa) and 168 ksi (1158.33 MPa), respectively, were realized at ambient temperature, for the direct double aged specimen. No failures occurred in the single or double edged longitudinal and transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test showed no mechanical property degradation.

  1. Effects of laser processing parameters on thermal behavior and melting/solidification mechanism during selective laser melting of TiC/Inconel 718 composites

    Science.gov (United States)

    Shi, Qimin; Gu, Dongdong; Xia, Mujian; Cao, Sainan; Rong, Ting

    2016-10-01

    A three-dimensional finite element model is proposed to study the effects of laser power and scan speed on the thermal behavior and melting/solidification mechanism during selective laser melting (SLM) of TiC/Inconel 718 powder system. The cooling time during powder delivery is taken into account to simulate the actual production process well. It shows obviously the existence of heat accumulation effect in SLM process and, the tailored set of cooling time of 10 ms during powder delivery alleviates that effectively. The maximum temperature gradient in the molten pool slightly increases from 1.30×104 °C/mm to 2.60×104 °C/mm as the laser power is increased from 75 W to 150 W. However, it is negligibly sensitive to the variation of scan speed. There is a positive corresponding relationship between the maximum rate of temperature change and processing parameters. A low laser power (75 W) or a high scan speed (300 mm/s) is more energy efficient in Z-direction of the molten pool, giving rise to a deep-narrow cross section of the pool. Whereas, a high laser power (150 W) or a low scan speed (50 mm/s) causes a shallow-wide cross section of the molten pool, meaning it is more energy efficient in the Y-direction of the melt. The combination of a laser power of 125 W and a scan speed of 100 mm/s contributes to achieve a sound metallurgical bonding between the neighbor layers and tracks, due to the proper molten pool size (width: 109.3 μm; length: 120.7 μm; depth: 67.8 μm). The SLM experiments on TiC/Inconel 718 powder system are performed to verify the reliability and accuracy of the physical model and, simulation results are proved to be correct.

  2. Assessing the kinetics of high temperature oxidation of Inconel 617 in a dedicated HTR impure helium facility coupling thermogravimetry and gas phase chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Chapovaloff, J., E-mail: chpvlff@aol.com [AREVA NP, Centre Technique, Département Corrosion-Chimie, 30 Bd de l’industrie, 71200 Le Creusot (France); Ecole Nationale Supérieure des Mines, SMS-EMSE, CNRS: UMR5146, LCG, 158 Cours Fauriel, 42023 Saint Etienne (France); Rouillard, F., E-mail: fabien.rouillard@cea.fr [CEA, DEN, DPC, SCCME, Laboratoire d’Etude de la Corrosion Non Aqueuse, 91191 Gif sur Yvette (France); Combrade, P., E-mail: pierre.combrade@orange.fr [AREVA NP, Centre Technique, Département Corrosion-Chimie, 30 Bd de l’industrie, 71200 Le Creusot (France); ACXCOR, 63, chemin de l’Arnica, 42660 Le Bessat (France); Pijolat, M., E-mail: mpijolat@emse.fr [Ecole Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR5148, LCG, 158 Cours Fauriel, 42023 Saint Etienne (France); Wolski, K., E-mail: wolski@emse.fr [Ecole Nationale Supérieure des Mines, SMS-EMSE, CNRS: UMR5146, LCG, 158 Cours Fauriel, 42023 Saint Etienne (France)

    2013-10-15

    Graphical abstract: Display Omitted -- Highlights: •New facility coupling thermogravimetry (TGA) with gas phase chromatography (GPC). •Dedicated for HT oxidation study in VHTR impure helium containing CO, H{sub 2}O and H{sub 2}. •The oxidation kinetics obeys a complete parabolic law due to a mixed kinetic regime. •CO contributes during initial stage of oxidation only for very low H{sub 2}O partial pressure. •Long-term oxidation of Inconel 617 by H{sub 2}O is diffusion controlled with constant kp. -- Abstract: A new facility coupling thermogravimetric analysis (TGA) with gas phase chromatography (GPC) has been developed. This facility is dedicated for studying high temperature oxidation of Inconel 617 in impure helium environment containing H{sub 2}O, H{sub 2} and CO at very low partial pressures (in the Pa range), which is representative of the high temperature reactor (HTR) concept developed within the Generation IV Forum. Simultaneous acquisition of mass gain and gas composition has allowed the influence of carbon monoxide and water vapour on the kinetics of oxidation to be studied. GPC measurements of gas consumption have allowed the plotting of individual mass gain curves for oxidation by H{sub 2}O and CO. During isothermal exposure at 1123 K for 20 h, the oxidation was mainly due to water vapour with a minor contribution of carbon monoxide during the first hours. The contribution of water vapour to the oxidation kinetics was extracted. It was shown to obey a complete parabolic law and to be limited by an interfacial reaction during the first few hours of oxidation and to be controlled by a mixed interfacial and diffusion process, diffusion becoming the rate-determining step for long term oxidation. There was very good agreement between GPC measurements and the experimental TGA results.

  3. Study on Selective Laser Melting Additive Manufacturing Process of INCONEL Ni-based Superalloy%INCONEL系镍基高温合金选区激光熔化增材制造工艺研究

    Institute of Scientific and Technical Information of China (English)

    张颖; 顾冬冬; 沈理达; 田宗军

    2014-01-01

    Influence of the process parameters on densification behavior ,microstructure characteristics,microhardness and wear performance of SLM-processed Inconel 718 alloy samples was studied comprehensively. The result shows that at a lower laser linear energy density (η),the balling effect caused a low densification level. At a higher value of laser energy density with reasonable process parameters,nearly full dense Inconel 718 part was obtained. Besides,as laser energy density increased,microstructures of Inconel 718 parts experienced such changes:coarsened columnar dendrites,clustered dendrites,slender and uniformly distributed columnar dendrites. Samples manufactured at optimized process parameters exhibited high microhardness of 397.8 HV0.2,low mean COF value of 0.40 and low wear rate of 4.78 ×10-4 mm3/Nm. The formation of fine microstructure and the protective tribolayer gave the sample good wear performance.%研究了激光加工工艺参数对选区激光熔化工艺成形的Inconel 718合金试样的致密化行为、显微组织特征、硬度及摩擦磨损性能的影响。结果表明:当激光线能量密度(η)较低时,球化效应的出现使试样的致密度水平较低;在较高的线能量密度与合适的加工参数下,可获得接近完全致密的Inconel 718合金试样。同时,随着激光线能量密度的增加,SLM成形Inconel 718合金试样的显微组织经历了粗大的柱状树枝晶、聚集的枝晶、细长而均匀分布的柱状枝晶等变化过程。在优化工艺参数下,成形试样的显微硬度高达397.8 HV0.2;摩擦系数和磨损率较低,分别为0.40和4.78×10-4 mm3/Nm;且试样内部显微组织均匀细小,摩擦试样的表面形成摩擦保护层,使试样的摩擦磨损性能较好。

  4. GALVANIC CORROSION OF NICKEL ALLOY INCONEL 718 COUPLED WITH VM 80 SS STEEL IN A SIMULATED FORMATION WATER%镍基合金Inconel 718与抗硫油套管钢在模拟气田地层水中的电偶腐蚀

    Institute of Scientific and Technical Information of China (English)

    魏斌; 严密林; 白真权; 冯耀荣

    2007-01-01

    采用电化学方法研究了在模拟罗家寨气田地层水中镍基合金Inconel 718和抗硫管材VM80 SS之间的电偶腐蚀特征和电偶效应.结果表明,Inconel 718和VM80 SS的自腐蚀电位分别为-260 mV和-770 mV,当阴阳极面积比S=0.25,1,4,8时,电偶电位Eg处于-760 mV~-700 mV之间,随S增大,Eg正移,Ig/Aa的初始值、稳态值和平均值均增大;而Ig/Ac的初始值降低,稳态值变化不大.根据混合电位理论计算的VM80SS的电偶腐蚀效应γ随S增大而增大,γ=1.14~4.82.

  5. 热处理对激光立体成形Inconel 718高温合金组织和力学性能的影响%Effect of Heat Treatment on Microstructure and Mechanical Properties of Laser Solid Forming Inconel 718 Superalloy

    Institute of Scientific and Technical Information of China (English)

    赵卫卫; 林鑫; 刘奋成; 赵晓明; 陈静; 黄卫东

    2009-01-01

    研究了热处理对激光立体成形(LSF)Inconel 718微观组织和力学性能的影响规律.结果表明,激光立体成形Inconel 718经直接时效(DA)处理后,与沉积态相比,组织特征变化不大,具有较强生长取向性的外延枝晶组织特征,硬度和托伸强度均明显提高,而经均匀化、固溶和舣级时效(960STA)热处理后,枝晶间Laves相颗粒完全固溶,Nb偏析降低,细针状δ相沿晶界析出,合金性能得到进一步改善,室温、高温托伸强度和塑性都达到了高强锻件的技术标准Q/3B 548-1996(高强).DA状态下合金断口形貌与沉积态相似,韧窝具有沿列状枝晶取向排布的各向异性特点,而经过960STA热处理后,各向异性现象消失.

  6. Avaliação de tensões residuais pelo método de difração de raios-X em revestimentos de inconel 625 obtidos por HVOF

    OpenAIRE

    Mariana Sgambaro de Lorenzi

    2015-01-01

    A aspersão térmica por chama hipersônica tem se destacado pelo método rápido e eficiente para aplicação de revestimentos com grandes vantagens como: tempo, custo e qualidade. Os revestimentos de Inconel 625 apresentam uma série de aplicações industriais principalmente nos segmentos industriais: químico e petroquímico. Neste contexto, o presente trabalho tem por objetivo avaliar as tensões residuais em revestimentos de Inconel 625 obtidos por aspersão térmica de chama hipersônica (HVOF) atravé...

  7. Dynamic recrystallization behavior of Inconel 690 during hot contin-uous deformation%690合金高温连续变形动态再结晶行为

    Institute of Scientific and Technical Information of China (English)

    谭化超; 董建新; 张麦仓; 姚志浩

    2013-01-01

    Continuous hot deformation testing of Inconel 690 cone samples at three different temperatures (1100, 1140 and 1180 ℃) was performed with a hydraulic press machine. Dynamic recrystallization in the alloy during con-tinuous hot deformation was studied by optical microscopy and back scattering diffraction. It is found that dynamic recrystallization in Inconel 690 happens during continuous hot compression deformation. The nucleation of dynamic recrystallization is in the order of triple junctions of grains→strain-induced boundary migration→twin boundaries→inside of grains, and the twin promotes the recrystallization process of Inconel 690.%应用液压机对690合金圆锥试样在3种不同温度下(1100、1140和1180℃)进行连续压缩变形实验,利用光学显微镜和背散射衍射技术研究690合金在热加工过程的动态再结晶行为。研究发现:在连续热压缩变形过程中动态再结晶以三叉晶界形核-原始晶界形核-孪晶形核(孪晶界和孪晶碎化)-晶内形核的顺序发展,而孪晶促进了690合金的再结晶过程。

  8. DESGASTE POR ABRASIÓN DEL ACERO API 5L X65 REVESTIDO CON NIOBIO POR ASPERSIÓN TÉRMICA A PLASMA Y CON INCONEL 625 POR SOLDADURA

    Directory of Open Access Journals (Sweden)

    JOSE MATOS

    2012-01-01

    Full Text Available El objetivo de este trabajo fue evaluar y caracterizar el comportamiento mecánico en desgaste del acero API 5L X65, revestido con niobio en comparación al desempeño del revestimiento de la aleación de inconel 625 empleados en la industria de petróleo y gas. El revestimiento de niobio fue obtenido por el proceso de aspersión térmica a plasma de arco no transferido y el revestimiento inconel 625 por soldadura con electrodo revestido. La resistencia al desgaste por abrasión fue evaluada según la norma Petrobras N-2568, en un tribómetro CTER, la rugosidad y el volumen de material desgastado se determinó a través de perfilometría y la dureza de los revestimientos por microscopia Vickers. Los revestimientos obtenidos fueron caracterizados respecto a su morfología por microscopia electrónica de barrido (MEB y microscopía óptica (MO. La mayor dureza del revestimiento con niobio obtenido puede haber contribuido a reducir la tasa de desgaste en comparación con el revestimiento de inconel 625.

  9. 氢化物发生-原子荧光光谱法测定Inconel 718合金中痕量硒%Determination of trace selenium in 718 alloy by hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    向祥蓉; 刘虹; 王佼

    2012-01-01

    本文采用氢化物发生-原子荧光光谱法测定Inconel718合金中痕量硒.对影响其测定的负高压、灯电流、载气流量、屏蔽气流量、载流酸类酸度、硼氢化钾等因素进行了较为详细的研究,优化了测定条件,考察了Inconel718合金主要组成元素和基体元素对硒测定的影响.结果表明,用氟化氨溶液络合,柠檬酸溶液作干扰抑制剂能基本消除基体元素和主要组成元素的干扰.硒浓度在0~100μg/L与荧光强度有良好的线性关系,方法的检出限为0.0083μg/L.对铁镍基高温合金标准样品和Inconel 718合金样品进行9次测定,相对标准偏差为1.6%~3.5%.%In this paper a simple and fast analytical procedure for the determination of selenium in Inconel 718 alloy by hydride generation atomic fluorescence spectrometry(HG-AFS) was developed. The in fluence of instrument parameters such as voltage of PMT, current of lamp, atomizer height, carrier gas rate,shield gas rate and concentration of HCI and KBH4 on the determination of selenium were studied, and the optimized conditions were obtained. Interference of coexistent elements and methods to eliminate the interference were investigated in detail. The results showed that ammonium fluoride and citric acid mo nohydrate were the best masking. Under the optimized conditions, the linear range of selenium is 0 ~ 100μg/L, and the detection limit is 0. 0083 μg/L. The relative standard deviation is 1. 6%~3. 5%(n=9) for the standard sample and the sample of Inconel 718 alloy.

  10. Electrochemical impedance spectrometry using Inconel 690, zircaloy 4, 316Ti steel, 17-4-PH, UR52N et URSB8. Simulation in tritiated water. Tome 1; Spectrometrie d`impedance electrochimique sur inconel 690, zircaloy 4, aciers 316Ti, 17-4-PH, UR52N, UR45N et URSB8. Simulation en eau tritiee. Tome 1

    Energy Technology Data Exchange (ETDEWEB)

    Bellanger, G.

    1994-11-01

    The redox potential of {sup 3} H{sub 2}O, as well as the corrosion potentials in this medium are found, abnormally, in the trans-passive region. This is completely different from the behavior in the chemical industry or in the water in nuclear powers. With such behavior, there will be breakdowns of the protective oxide layers, and in the presence of chloride there will be immediate pitting. Polarization and electrochemical impedance spectrometry curves are presented and discussed. These curves make it possible to ascertain the corrosion domains and to compare the kinetics of different stainless alloys. These corrosion kinetics and the corrosion potentials provide a classification of the steels studied here: Inconel 690, zircaloy 4, 316 Ti steel, 17-4-PH, UR52N et URSB8. From the results it can be concluded that URSB8 has the best corrosion resistance. (author). 279 figs., tabs.

  11. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    Science.gov (United States)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  12. Studies of Microtexture and Its Effect on Tensile and High-Cycle Fatigue Properties of Laser-Powder-Deposited INCONEL 718

    Science.gov (United States)

    Qi, Huan; Azer, Magdi; Deal, Andrew

    2012-11-01

    The current work studies the microstructure, texture, and mechanical properties of INCONEL 718 alloy (IN718) produced by laser direct metal deposition. The grain microstructure exhibits an alternative distribution of banded fine and coarse grain zones as a result of the rastering scanning pattern. The effects of the anisotropic crystallographic texture on the tensile and high-cycle fatigue (HCF) properties at room temperature are investigated. Tensile test results showed that the tensile strength of laser-deposited IN718 after direct aging or solution heat treatment is equivalent to the minimum-forged IN718 properties. The transverse direction (relative to the laser scanning direction) produces >10 pct stiffer modulus of elasticity but 3 to 6 pct less tensile strength compared to the longitudinal direction due to the preferential alignment of grains having and directions parallel to the tensile loading direction. Laser-deposited IN718 with good metallurgical integrity showed equivalent HCF properties compared to the direct-aged wrought IN718, which can be attributed to the banded grain size variation and cyclic change of inclining grain orientations resulted from alternating rastering deposition path.

  13. A Study on the Cyclic Oxidation Behavior of Detonation-Gun-Sprayed Ni-5Al Coatings on Inconel-718 at 900 °C

    Science.gov (United States)

    Saladi, Sekar; Menghani, Jyoti; Prakash, Satya

    2014-12-01

    Cyclic oxidation behavior of detonation-gun-sprayed Ni-5Al coating on Inconel-718 is discussed in the present study. Oxidation studies were carried out on both bare and coated superalloy substrates in air at 900 °C for 100 cycles. The thermogravimetric technique was used to establish kinetics of oxidation. X-ray diffraction, FESEM/EDAX, and x-ray mapping techniques were used to analyze the oxidation products of bare and coated samples. The weight gain of bare superalloy was higher than the Ni-5Al-coated superalloy. Both bare and Ni-5Al-coated superalloys followed nearly parabolic oxidation behavior. The Ni-5Al coating was able to reduce the overall weight gain by 26.2% in comparison with bare superalloy in the given environment. The better oxidation resistance of Ni-5Al coating may be due the formation of protective oxides phases such as NiO, Al2O3, and NiAl2O4 on the oxidized coating and Cr2O3 at the coating-substrate interface. The Ni-5Al coatings obtained from detonation-gun-spraying process showed very little porosity and low surface roughness values.

  14. Selective Growth of Low Stored Energy Grains During δ Sub-solvus Annealing in the Inconel 718 Nickel-Based Superalloy

    Science.gov (United States)

    Agnoli, Andrea; Bernacki, Marc; Logé, Roland; Franchet, Jean-Michel; Laigo, Johanne; Bozzolo, Nathalie

    2015-09-01

    The microstructure stability during δ sub-solvus annealing in Inconel 718 was investigated, focusing on the conditions that may lead to the development of very large grains (about 100 μm) in a recrystallized fine grained matrix (4 to 5 μm) despite the presence of second-phase particles. Microstructure evolution was analyzed by EBSD (grain size, intragranular misorientation) and SEM ( δ phase particles). Results confirm that, in the absence of stored energy, the grain structure is controlled by the δ phase particles, as predicted by the Smith-Zener equation. If the initial microstructure is strained ( ɛ < 0.1) before annealing, then low stored energy grains grow to a large extent, despite the Zener pinning forces exerted by the second-phase particles on the grain boundaries. Those selectively growing grains could be those of the initial microstructure that were the least deformed, or they could result from a nucleation process. The balance of three forces acting on boundary migration controls the growth process: if the sum of capillarity and stored energy driving forces exceeds the Zener pinning force, then selective grain growth occurs. Such phenomenon could be simulated, using a level set approach in a finite element context, by taking into account the three forces acting on boundary migration and by considering a realistic strain energy distribution (estimated from EBSD measurements).

  15. Influence of the Overlapping Factor and Welding Speed on T-Joint Welding of Ti6Al4V and Inconel 600 Using Low-Power Fiber Laser

    Directory of Open Access Journals (Sweden)

    Shamini Janasekaran

    2016-06-01

    Full Text Available Double-sided laser beam welding of skin-stringer joints is an established method for many applications. However, in certain cases with limited accessibility, single-sided laser beam joining is considered. In the present study, single-sided welding of titanium alloy Ti6Al4V and nickel-based alloy Inconel 600 in a T-joint configuration was carried out using continuous-wave (CW, low-power Ytterbium (Yb-fiber laser. The influence of the overlapping factor and welding speed of the laser beam on weld morphology and properties was investigated using scanning electron microscopy (SEM and X-ray diffraction (XRD, respectively. XRD analysis revealed the presence of intermetallic layers containing NiTi and NiTi2 at the skin-stringer joint. The strength of the joints was evaluated using pull testing, while the hardness of the joints was analyzed using Vickers hardness measurement at the base metal (BM, fusion zone (FZ and heat-affected zone (HAZ. The results showed that the highest force needed to break the samples apart was approximately 150 N at a laser welding power of 250 W, welding speed of 40 mm/s and overlapping factor of 50%. During low-power single-sided laser welding, the properties of the T-joints were affected by the overlapping factor and laser welding speed.

  16. An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Cárcel-Carrasco

    2016-11-01

    Full Text Available This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

  17. Effect of 20 % EDTA Aqueous Solution on Defective Tubes (Alloy600) in High Temperature Chemical Cleaning Environments

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyuk Chul [KHNP-CRI, Daejeon (Korea, Republic of)

    2016-04-15

    The transport and deposition of corrosion products in pressurized water nuclear reactor (PWR) steam generators have led to corrosion (SCC, denting etc.) problems. Lancing, mechanical cleaning and chemical cleaning have been used to reduce these problems. The methods of lancing and mechanical cleaning have limitations in removing corrosion products due to the structure of steam generator tubes. But high temperature chemical cleaning (HTCC) with EDTA is the most effective method to remove corrosion products regardless of the structure. However, EDTA in chemical cleaning aqueous solution and chemical cleaning environments affects the integrity of materials used in steam generators. The nuclear power plants have to perform the pre-test (also called as qualification test (QT)) that confirms the effect on the integrity of materials after HTCC. This is one of the series studies that assess the effect, and this study determines the effects of 20 % EDTA aqueous solution on defective tubes in high temperature chemical cleaning environments. The depth and magnitude of defects in steam generator (SG) tubes were measured by eddy current test (ECT) signals. Surface analysis and magnitude of defects were performed by using SEM/EDS. Corrosion rate was assessed by weight loss of specimens. The ECT signals (potential and depth %) of defective tubes increased marginally. But the lengths of defects, oxides on the surface and weights of specimens did not change. The average corrosion rate of standard corrosion specimens was negligible. But the surfaces on specimens showed traces of etching. The depth of etching showed a range on the nanometer. After comprehensive evaluation of all the results, it is concluded that 20 % EDTA aqueous solution in high temperature chemical cleaning environments does not have a negative effect on defective tubes.

  18. 涂层硬质合金刀具切削Inconel718合金的有限元分析%Finite Element Analysis of Turning Incone1718 Alloy with Coated Cemented Carbide Tools

    Institute of Scientific and Technical Information of China (English)

    张高峰; 周山麒; 陈三中; 邸江顺

    2012-01-01

    采用Third Wave AdvantEdge切削仿真软件对Inconel 718合金进行车削有限元模拟,通过2D有限元模块分析了单层/多层涂层硬质合金刀具,在不同切削速度下的切削力、进给力和切削温度,以及涂层厚度对切削性能的影响,研究结果对新刀具材料和涂层的设计具有一定指导作用.

  19. 高硬度镍基高温合金Incone1 718的切削加工%Cutting process of high hardness nickel-base heat resisting alloy Inconel 718

    Institute of Scientific and Technical Information of China (English)

    宋志伟

    2000-01-01

    @@ 1 可加工性分析 Inconel 718材料属高硬度、高强度、耐腐蚀、耐高温镍基合金,主要用于制造飞机发动机涡轮盘、飞机机匣等高强度零件,此类零件在705℃以下具有耐高蠕变和抗应力断裂性能,在980℃以下具有良好的抗氧化性能(如涡轮转子、后机匣组件等).

  20. Imaging and characterization of γ′ and γ″ nanoparticles in Inconel 718 by EDX elemental mapping and FIB–SEM tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kulawik, K., E-mail: kulawik@agh.edu.pl [AGH University of Science and Technology, International Centre of Electron Microscopy for Materials Science, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków (Poland); Buffat, P.A., E-mail: philippe.buffat@epfl.ch [AGH University of Science and Technology, International Centre of Electron Microscopy for Materials Science, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków (Poland); Ecole Polytechnique Fédérale de Lausanne, CIME, Station 12, CH-1015 Lausanne Switzerland (Switzerland); Kruk, A., E-mail: kruczek@uci.agh.edu.pl [AGH University of Science and Technology, International Centre of Electron Microscopy for Materials Science, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków (Poland); Wusatowska-Sarnek, A.M., E-mail: agnieszka.wusatowska-sarnek@pw.utc.com [Pratt & Whitney, 400 Main Street, East Hartford, CT 06108 (United States); Czyrska-Filemonowicz, A., E-mail: czyrska@agh.edu.pl [AGH University of Science and Technology, International Centre of Electron Microscopy for Materials Science, Faculty of Metals Engineering and Industrial Computer Science, Al. A. Mickiewicza 30, 30-059 Kraków (Poland)

    2015-02-15

    Microstructural characterization of Inconel 718 superalloy after three different heat treatment variants was performed by electron microscopy and electron tomography techniques, taking advantage of recent development in quantitative electron microscopy. Distribution maps of the chemical elements, collected by ChemiSTEM™ EDX system, offer a clear contrast between γ′, γ″, and the γ matrix. It was found that the γ′ phase contains mainly Ni, Al, and Ti, while the γ″ phase contains Ni, Nb, and Ti. Thus application of the Al and Nb STEM–EDX elemental maps enables identification and size measurements of γ′ and γ″ nanoparticles. 3D morphology of γ′ and γ″ precipitates was examined by electron microscopy and FIB–SEM tomography. Employed methods revealed that in all three heat treatment variants the γ′ particles are almost spheroidal while the γ″ precipitates are mainly elongated-disc shaped. However, the precipitate sizes differed for each variant contributing to differences in the yield strength. Tomographic images were used for estimation of the volume fraction of the both strengthening phases. - Highlights: • ChemiSTEM™ EDX elemental maps bring a fast mean to differentiate γ′ and γ″ particles. • Such maps enable for the explicit size measurements of γ′ and γ″ nanoparticles. • Explicit γ′ and γ″ phases total volume fraction was measured employing FIB–SEM. • γ′/γ″ co-precipitates and sandwich-like γ′/γ″/γ′ particles were present. • HRSTEM-HAADF imaging revealed atomic columns of the γ′/γ″ co-precipitates.

  1. Virtual Orthogonal Experiment Study on Needle Piercing Extrusion Process of Inconel690 Alloy Large-Diameter Thick-Walled Tube%基于虚拟正交试验的Inconel690合金大口径厚壁管挤压工艺仿真

    Institute of Scientific and Technical Information of China (English)

    张保军; 杨合; 郭良刚; 谷瑞杰; 寇永乐

    2013-01-01

    It is an important issue for the optimization design and refined control of extrusion process of large-diameter hard wrought alloy profiles to reveal the effects of forming parameters on the process and to determine the reasonable range of each forming parameter. And it's also significant for the R&D, debugging and application of the large tonnage (such as 200 MN) extrusion press. Therefore, we developed an applicable and reliable FE model for the needle piercing extrusion process for Inconel690 alloy large-diameter thick-walled tube (Φ420 mm×60 mm) under the DEFORM-2D software environment. And the effects of forming parameters (i.e. extruding ratio A, die taper angle a, sizing belt length h, billet initial temperature T and ram speed v) on the peak temperature of billet Tmax, the peak damage of billet Dmax, the uniformity of flow rate at die export Fsdv and the peak extrusion load Lmax were investigated using virtual orthogonal experiment based on the developed FE model. The results show that the order of forming parameters' significance to rmax, Dmax, Fsdv and Lmax are T>v>λ>h>a, a>v≈λ>T>h, h>v>T>α>λ, and λ>T>α>v>h, respectively. Comprehensively considering the quality of the extruded tube and the extrusion load, we pointed out that the reasonable ranges of forming parameters are as follows: λ=5.74~6.37, λ=35°~45°, h=60~120 mm, T=1080~1180 ℃, and v=150~250 mm/s.%研究挤压成形参数影响规律并确定合理的参数取值范围,是开发难变形合金大型型材挤压工艺技术和挤压过程精细化控制,以及大吨位(如2万吨)挤压机的研发、调试及应用迫切需要开展的重要内容.基于DEFORM-2D平台,以规格为Φ420 mm×60mm的难变形Inconel690合金管材穿孔针挤压为研究对象,建立了适用、可靠的无缝管材穿孔L针挤压过程的有限元仿真模型;选取挤压比λ、模角α、定径带长度h、坯料初始温度T、挤压速度v等重要成形参数为影响因素,以坯料

  2. The Study Of The Impact Of Surface Preparation Methods Of Inconel 625 And 718 Nickel-Base Alloys On Wettability By BNi-2 And BNi-3 Brazing Filler Metals

    Directory of Open Access Journals (Sweden)

    Lankiewicz K.

    2015-06-01

    Full Text Available The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240 on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

  3. The Study of the Impact of Surface Preparation Methods of Inconel 625 and 718 Nickel-Base Alloys on Wettability by BNi-2 and BNi-3 Brazing Filler Metals

    Directory of Open Access Journals (Sweden)

    Lankiewicz K.

    2015-04-01

    Full Text Available The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240 on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

  4. Estudo de Procedimentos de Soldagem MIG/MAG para Aplicação de Revestimentos de Liga de Níquel Inconel 625 em Aço Estrutural ASTM A387 Gr.11

    Directory of Open Access Journals (Sweden)

    Nathália Escóssio Cavalcante

    2016-03-01

    Full Text Available Resumo O presente trabalho objetiva o estudo de técnicas de soldagem aplicadas a reparo de componentes fabricados em aço ASTM A387 Gr.11, largamente utilizado em aplicações da indústria do petróleo e gás. Devido ao regime de trabalho e necessidade de utilização de materiais com boa resistência mecânica e à corrosão, utilizou-se como metal de adição a liga UNS N06625 (Inconel 625. O processo de soldagem utilizado foi o MIG/MAG e a técnica de soldagem aplicada foi a dupla camada. A metodologia do presente trabalho foi dividida em etapas, sendo a primeira a realização de ensaios exploratórios para definir a relevância dos fatores de controle estudados. A segunda etapa consistiu na aplicação do critério de dureza e de microestrutura para definir as melhores relações de energia para aplicação da técnica da dupla camada. A técnica da dupla camada se mostrou eficaz na melhora das propriedades da microestrutura da ZAC-GG dos revestimentos, verificou-se intenso refinamento de grão. Houve também redução nas medidas de dureza e microdureza. Para ambos os gases de proteção utilizados (Ar+25%He e Ar+4%CO2 foi possível obter relações de energia com afastamentos positivos. Em todas essas relações a energia da segunda camada foi maior que a energia da primeira camada.

  5. Probabilistic and microstructural aspects of fatigue cracks initiation in Inconel 718; Aspects probabilistes et microstructuraux de l'amorcage des fissures de fatigue dans l'alliage INCO 718

    Energy Technology Data Exchange (ETDEWEB)

    Alexandre, F

    2004-03-15

    Thermomechanical treatments have been recently developed to produce Inconel 718DA (Direct Aged). This alloy optimisation leads to an increase of the fatigue life but also the scatter. The aim of this study is on the one hand the understanding of the fatigue crack initiation mechanisms and on the other hand the modelling of the fatigue life and the scatter. An experimental study showed that the fatigue cracks were initiated from carbide particles in fine grain alloy. Interrupted tensile tests show that the particles cracking occurred at the first quarter of the fatigue cycle. Fatigue behaviour tests were also performed on various grain size 718 alloys. The last experimental part was devoted to measurements of the low cycle fatigue crack growth rates using a high focal distance microscope. For these tests, EDM micro-defects were used for the fatigue crack initiation sites. This method was also used to observe the small fatigue crack coalescence. A fatigue life model is proposed. It is based on the three fatigue crack initiation mechanisms competition: particle crack initiation on the surface, internal particle crack initiation and Stade I crack initiation. The particle fatigue crack initiation is supposed instantaneous at a critical stress level. The Tanaka and Mura model is used for analysing the Stage I crack initiation number of cycles. The fatigue crack growth rate was analysed using the Tomkins model identified on the small fatigue crack growth rate measurements. The proposed fatigue life model decomposed in three levels: a deterministic one and two probabilistic with and without crack coalescence. (author)

  6. Inconel 718 süper alaşımının farklı gerilme ve sıcaklıklarda yüksek sıcaklık sürünme davranışının incelenmesi

    Directory of Open Access Journals (Sweden)

    Ergün Subaşı

    2016-04-01

    Full Text Available Bu çalışmada, havacılıkta yaygın olarak kullanılan Inconel 718 süper alaşımının sürünme davranışına sıcaklık ve gerilmenin etkileri incelenmiştir. Deneyler; 750°C, 800°C sıcaklıklarında ve 200-350MPa gerilme aralığında gerçekleştirilmiştir. Deneysel çalışma sonuçlarından, gerilme üssü (n, sürünme hızı (έ ve aktivasyon enerjisi (Q hesaplanmıştır. Hesaplanan sonuçlara göre; sürünme hızlarının artan gerilme ile arttığı, ayrıca sıcaklığın artmasıyla birlikte sürünme hızları çok daha fazla artmaktadır. Aynı şekilde, artan gerilme ile birlikte aktivasyon enerjisi artmaktadır. Deney sonuçlarından elde edilen gerilme üssü değerlerine göre; etkin deformasyon mekanizmasının dislokasyon sürünmesi olduğu tespit edilmiştir. Inconel 718 süper alaşımının kopma sürünme ömrünü tahmin etmek için, Larson Miller grafiği çizilmiştir. Bu grafikle, Inconel 718’in yüksek sıcaklık sürünme ömürleri hesaplanabilir.

  7. Materials data handbook on Inconel Alloy 718

    Science.gov (United States)

    Muraca, R. F.; Whittick, J. S.

    1973-01-01

    Handbook is divided into twelve chapters. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures. This is supplemented with useful information in such areas as material procurement, metallurgy of alloy, corrosion, environmental effect, fabrication, and joining techniques. Design data are presented, as available.

  8. Misfit in Inconel-Type Superalloy

    Directory of Open Access Journals (Sweden)

    Pavel Strunz

    2013-01-01

    Full Text Available An important parameter for the characterization of microstructural changes in nickel base superalloys is the misfit - the relative difference between lattice parameters of γ matrix and γ′ precipitates. The misfit in IN738LC superalloy was examined at POLDI time-of-flight (TOF neutron diffractometer both at room temperature and in situ at elevated temperatures using a high-temperature furnace. A careful out-of-furnace measurement yielded the lattice parameters of both γ and γ′ phase at room temperature (aγ=3.58611(10 Å, aγ′=3.58857(17 Å as well as the misfit (equal to 6.9(6×10-4. The in situ measurement at elevated temperatures provided the temperature dependence of the lattice parameters of γ (up to 1120°C and γ′ (up to 1000°C. Using these data, the evolution of the misfit with temperature was calculated. The misfit decreases with increasing temperature until it reaches zero value at a temperature around 800°C. Above 800°C, it becomes negative.

  9. Nickel electroforming process for Inconel 600 stream generator tube repair

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Woon Suk; Lee, Dae Won; Wyi, Jung Il; Kim, Young Kuk [Inha University, Incheon (Korea); Jang, Si Sung [Jaeneung College, Seoul (Korea)

    2002-04-01

    Ni-P alloy deposits have been extensively studied owing to their high hardness and good wear resistance in both the as-plated and heat-treated conditions. Most commercial coatings have been produced by electroless deposition. But the electroless process is expensive, and the process does not readily permit control of the phosphorus content in the deposits. From the mid-1990s, the Ni-P alloy deposits extensively have been studied to improve mechanical properties by reducing grain size. In this work, the effect of phosphorus on microstructures and mechanical properties in both the as-plated and heat-treated Ni-P alloy deposits were investigated. The effect of Fe addition were also investigated. The content of P in Ni-P deposits gradually increased from 0.2 to 0.9wt.% with increasing H{sub 3}PO{sub 3} concentration from 0.007M to 0.018M in the bath. The hardness of Ni-P deposits increased with increasing P content and then reached 500VHN (Vickers hardness) at Ni-0.9wt%P while the hardness of pure Ni deposit was 150VHN. From result of XRD analysis, the grain size was linearly decreased with increasing phosphorus content and it was 15nm at 0.9wt%P while pure Ni was about 25nm. The content of Fe in the Ni-P-Fe ternary alloy deposits linearly increased with increasing ferric sulfamate concentration, and it was obtained 35wt%Fe at 0.1M. The hardness of Ni-P-Fe deposits increased with increasing Fe content and obtained maximum 660VHN at 2.2wt%Fe. 21 refs., 38 figs., 8 tabs. (Author)

  10. Arc termination cracks in Inconel 718 and Incoloy 903

    Science.gov (United States)

    Bayless, E.; Mccaig, J.; Poorman, R.

    1978-01-01

    The welding of the nickel base, heat resistant alloys that are used extensively for welded Shuttle engine components revealed solidification cracking characteristics at weld termination points. If not detected and removed, these crater cracks may cause costly component failure. To better understand this characteristic, welding termination techniques were studied and methods developed to eliminate crater cracks. It was determined that weld termination solidification cracking can be eliminated by controlled decrease of welding current, welding voltage, wire feed, and travel speed.

  11. Inhomogeneous deformation in INCONEL 718 during monotonic and cyclic loadings

    Science.gov (United States)

    Worthem, D. W.; Robertson, I. M.; Socie, D. F.; Altstetter, C. J.; Leckie, F. A.

    1990-01-01

    The paper concentrates on the relation between microstructural observations of the dislocation structures and the macroscopic deformation responses of both aged and homogenized precipitate-hardened alloys at room temperature. The deformation responses are compared to the cyclic deformation response of an aged precipitate-hardened alloy. Early in the deformation, one deformation band per grain and little evidence of work hardening are observed; with increased deformation, work hardening begins, more bands nucleate, and their spacing becomes similar to that in the aged material. It is pointed out that the degree of coarseness of inhomogeneous deformation is not a result of a softening process within the bands due to precipitate shearing, but it is a function of the amount of work hardening within the bands.

  12. Study on surface defects in milling Inconel 718 super alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Liu; Chengzu, Ren; Guofeng, Wang; Yinwei, Yang; Lu, Zhang [Tianjin University, Tianjin (China)

    2015-04-15

    Nickel-based alloys have been extensively used as critical components in aerospace industry, especially in the key section of aero engine. In general, these sections are manufactured by milling process because most of them have complex forms. However, surface defects appear frequently in milling due to periodic impact force, which leads to the deterioration of the fatigue life. We conducted milling experiments under different cutting conditions and found that four kinds of defects, i.e., tear, cavity, build up edge (BUE) and groove, commonly appear on the machined surface. Based on the observed results, the morphology and generation regime of these defects are analyzed and the carbide particle cracking is discussed to explain the appearance of the nickel alloy defects. To study the effect of the cutting parameters on the severity of these surface defects, two qualitative indicators, which are named as average number of the defects per field and average area ratio of the defects per field, are presented and the influence laws are summarized based on the results correspondingly. This study is helpful for understanding the generation mechanism of the surface defects during milling process of nickel based super alloy.

  13. The Concept Design of a Split Flow Liquid Hydrogen Turbopump

    Science.gov (United States)

    2008-03-01

    Inconel 718 unk VINCI...Ti- (Powder) Inconel 718 Inconel 718 Inconel 718 Inconel 718 Ti 6-4 Ti 6-4 ALH PWA Ti-1240 Inconel 718 Inconel 718 Waspaloy Waspaloy...unshrouded and made of titanium. The inducer, pump impellers and turbine are on a single shaft. Four cast pieces each made of Inconel 718 make up the

  14. Inhibition of sensitization in reactor pipe materials by grain boundary structure control. JAERI's nuclear research promotion program, H11-023 (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Kokawa, Hiroyuki; Shimada, Masayuki; Wang, Zhan Jie; Sato, Yutaka S. [Tohoku Univ., School of Engineering, Sendai, Miyagi (Japan); Sato, Yoshihiro [Osaka City Univ., Graduate School of Engineering, Osaka (Japan); Kiuchi, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Grain boundary structure control of type 304 austenitic stainless steel and nickel base Inconel Alloy 600 used in reactor pipe materials was studied to inhibit intergranular corrosion (IGC) due to sensitization. A transmission electron microscopic study showed that low-energy grain boundaries, such as coincidence site lattice boundaries are highly resistant to sensitization, i.e., to intergranular precipitation, chromium depletion and corrosion, compared with ordinary high-angle (random) boundaries. A thermo-mechanical treatment was tried to control grain boundary structure of type 304 austenitic stainless steel for producing a highly intergranular corrosion-resistant material. The effects of process parameters in thermo-mechanical treatment such as pre-strain, annealing temperature, time, etc., on grain boundary characteristics and IGC resistance corrosion of type 304 austenitic stainless steels were examined. The excellent IGC resistance was obtained by slight pre-strain annealing at a relatively low temperature due to the optimized grain boundary character distribution. The uniform distribution of a high frequency of coincidence site lattice boundaries and consequent discontinuity of random boundary network were observed in the material. The optimum distribution can be formed by introducing low energy segments on migrating random boundaries during twin emission and boundary-boundary reactions in the grain growth without additional generation of random boundaries. (author)

  15. Alloy 690 in PWR type reactors; Aleaciones base niquel en condiciones de primario de los reactores tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Briceno, D.; Serrano, M.

    2005-07-01

    Alloy 690, used as replacement of Alloy 600 for vessel head penetration (VHP) nozzles in PWR, coexists in the primary loop with other components of Alloy 600. Alloy 690 shows an excellent resistance to primary water stress corrosion cracking, while Alloy 600 is very susceptible to this degradation mechanisms. This article analyse comparatively the PWSCC behaviour of both Ni-based alloys and associated weld metals 52/152 and 82/182. (Author)

  16. Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Martinez, D.I., E-mail: dorairma@yahoo.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Perez, A., E-mail: betinperez@hotmail.com [Facultad de Ingenieria Mecanica y Electrica (FIME-UANL), Av. Universidad s/n. Ciudad Universitaria, C.P.66451 San Nicolas de los Garza, N.L. (Mexico); Guajardo, H., E-mail: hguajardo@frisa.com [FRISA Aerospace, S.A. de C.V., Valentin G. Rivero No. 200, Col. Los Trevino, C.P. 66150, Santa Caterina N.L. (Mexico); Garza, A., E-mail: agarza@comimsa.com [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V. (COMIMSA), Ciencia y Tecnologia No.790, Saltillo 400, C.P. 25295 Saltillo Coah. (Mexico)

    2011-12-15

    The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy, specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.

  17. Real-time monitoring of laser hot-wire cladding of Inconel 625

    Science.gov (United States)

    Liu, Shuang; Liu, Wei; Harooni, Masoud; Ma, Junjie; Kovacevic, Radovan

    2014-10-01

    Laser hot-wire cladding (LHWC), characterized by resistance heating of the wire, largely increases the productivity and saves the laser energy. However, the main issue of applying this method is the occurrence of arcing which causes spatters and affects the stability of the process. In this study, an optical spectrometer was used for real-time monitoring of the LHWC process. The corresponding plasma intensity was analyzed under various operating conditions. The electron temperature of the plasma was calculated for elements of nickel and chromium that mainly comprised the plasma plume. There was a correlation between the electron temperature and the stability of the process. The characteristics of the resulted clad were also investigated by measuring the dilution, hardness and microstructure.

  18. High Speed Cutting Inconel 718 with Coated Carbide and Ceramic Inserts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    High speed machining (HSM) technology is one of important aspects of advanced manufacturing technology. Nickel-based superalloys have been widely used in the aircraft and nuclear industry due to their exceptional thermal resistance and the ability to retain mechanical properties at elevated temperatures of service environment over 700 ℃. However, they are classified as difficult-to-cut materials due to their high shear strength, work hardening tendency, highly abrasive carbide particles in the microstructur...

  19. Étude du comportement structural de l'alliage NC 19 Fe Nb (Inconel 718)

    OpenAIRE

    Slama, C.; Cizeron, G.

    1997-01-01

    In the as-received state (following a double treatment at 720 and 620 °C), the structure of INC 718 consists of a γ matrix, intergranular β precipitates and (Nb,Ti)C carbides; moreover, γ' and $\\gamma{''}$ phases have precipitated in the matrix. Using different methods, the structural behaviour was analyzed which led to distinguish the temperature ranges in which occurs precipitation or dissolution of β, γ' and $\\gamma{''}$ phases on heating and to define the optimum conditions of homogeneiza...

  20. Application of laser ultrasonics to monitor microstructure evolution in Inconel 718 superalloy

    OpenAIRE

    Garcin Thomas; Schmitt Jean-Hubert; Militzer Matthias

    2014-01-01

    Laser ultrasonics for metallurgy is an innovative sensor dedicated to the measurement of microstructure evolution during thermomechanical processing. In this technique, broadband ultrasound pulses are generated and detected with lasers. The properties of the ultrasounds are then related to the characteristics of the microstructure. Ultrasound attenuation is primary originated by the scattering at grain boundaries and its frequency dependence can be related to the grain size. The present work ...

  1. Laser deposition of Inconel 625/tungsten carbide composite coatings by powder and wire feedstock

    OpenAIRE

    Abioye, Taiwo E.

    2014-01-01

    There is an increasing global demand to extend the life span of down-hole drilling tools in order to improve operation effectiveness and efficiency of oil and gas production. Laser cladding of tungsten carbide/Ni-based alloy metal matrix composite (MMC) coatings is currently being utilised for this purpose. However, the effect of tungsten carbide dissolution on the corrosion performance of the MMC coatings has not been completely understood. In this work, a study was carried out in which lase...

  2. Nickel super alloy INCONEL 713LC - structural characteristics after heat treatment

    Directory of Open Access Journals (Sweden)

    A. Hernas

    2007-06-01

    Full Text Available Purpose: Nickel super alloy’s products are mainly using for construction parts of jet engines, gas turbines and turbo-blowers.Design/methodology/approach: Super alloy was commercially produced and was investigated by using the light microscopy (OLYMPUS IX 71 and local chemical microanalysis and by the scanning electron microscopy (JEOL JSM 50AFindings: We found a mode of optimum heat treatment. On the basis of obtained results it is possible to recommend a following regime of heat treatment: heating and dwell at the temperature exceeding 1240 °C (min. 1260 °C, so that precipitates at the grain boundaries dissolve completely, with subsequent slow cooling down to the temperature of approx. 940-950 °C, so that there occurs intensive intra-granular precipitation of intermetallic phase γ’.Research limitations/implications: The experiment was limited by occurrence a void in cast alloys.Practical implications: Nickel super alloy’s products are mainly using for construction parts of jet engines, gas turbines and turbo-blowers.Originality/value: Mode of optimum heat treatment was proposed. On the basis of obtained results it is possible to recommend the most suitable heat treatment, which produce intensive intra-granular precipitation of inter-metallic phase γ’. It was received a new know-how in this field.

  3. Segregation behaviour and phase developments during solidification of Inconel 625; effect of iron and carbon

    DEFF Research Database (Denmark)

    Højerslev, Christian; Tiedje, Niels; Hald, John

    2004-01-01

    on representative samples of the weld overlay using a combination of X-ray diffraction and scanning electron microscopy. It was found that the concentration of niobium and molybdenum was larger in the interdendritic matrix (denoted ƒ×ID) compared to the dendrite core (ƒ×DC). In addition, both elements were found...

  4. Reduction of tritium permeation through Inconel 718 and Incoloy 800 HT by means of natural oxides

    Science.gov (United States)

    Aiello, A.; Utili, M.; Ciampichetti, A.

    2011-10-01

    Chronical releases of tritium from the helium primary coolant into the water secondary coolant is a fundamental safety issue in the design of a fusion reactor steam generator. It is well known that the steam/water circuit of a fusion reactor would be considered not relevant from a radiological point of view, while if a strong permeation of tritium will be present it will be released together with incondensable gases in the condenser. The permeation of hydrogen isotopes through candidate steam generator materials in different conditions was studied in the past. Further experiments demonstrated that nickel alloys of nuclear interest are always covered by a thin and adherent oxide layer able to reduce permeation of orders of magnitude. The major objective of this work is the evaluation of the permeated flux through nickel alloys, when exposed to pure hydrogen and to an oxidant gas stream, to verify the real permeability of these materials in conditions close to those foreseen in the helium side of the steam generator.

  5. Grinding performance evaluation of porous composite-bonded CBN wheels for Inconel 718

    Institute of Scientific and Technical Information of China (English)

    Chen Zhenzhen; Xu Jiuhua; Ding Wenfeng; Ma Changyu

    2014-01-01

    For high-efficiency grinding of difficult-to-cut materials such as titanium and nickel alloys, a high porosity is expected and also a sufficient mechanical strength to satisfy the function. However, the porosity increase is a disadvantage to the mechanical strength. As a promising pore forming agent, alumina bubbles are firstly induced into the abrasive layer to fabricate porous cubic boron nitride (CBN) wheels. When the wheel porosity reaches 45%, the bending strength is still high up to 50 MPa with modified orderly pore distribution. A porous CBN wheel was fabricated with a total porosity around 30%. The grinding performance of the porous composite-bonded CBN wheel was evaluated in terms of specific force, specific grinding energy, and grinding temper-ature, which were better than those of the vitrified one under the same grinding conditions. Com-pared to the vitrified CBN wheel, clear straight cutting grooves and less chip adhesion are observed on the ground surface and there is also no extensive loading on the wheel surface after grinding.

  6. Effect of Saline Environment on LCF Behavior of Inconel 718 at 550 °C

    Science.gov (United States)

    Mahobia, G. S.; Paulose, Neeta; Sreekanth, K.; Mannan, S. L.; Sudhakar Rao, G.; Singh, Vakil

    2015-01-01

    Low-cycle fatigue behavior of alloy IN718 was studied with NaCl salt coating at 550 °C in total strain-controlled mode. Fatigue life of the salt-coated specimens was found to be drastically reduced at the lowest total strain amplitude of ±0.40%; however, fatigue life was not affected at higher strain amplitudes. In general, there was cyclic softening in both the uncoated as well as salt-coated specimens. Variation of fatigue life with plastic strain amplitude followed Coffin-Manson relationship. Reduction in fatigue life from salt coating was found to be associated with early crack initiation from the roots of corrosion pits.

  7. Microstructural evolution in the HAZ of Inconel 718 and correlation with the hot ductility test

    Science.gov (United States)

    Thompson, R. G.; Genculu, S.

    1983-01-01

    The nickel-base alloy 718 was evaluated to study the role of preweld heat treatment in reducing or eliminating heat-affected zone hot cracking. Three heat treatments were studied using the Gleeble hot ductility test. A modified hot ductility test was also used to follow the evolution of microstructure during simulated welding thermal cycles. The microstructural evolution was correlated with the hot ductility data in order to evaluate the mechanism of hot cracking in alloy 718. The correlation of hot ductility with microstructure showed that recrystallization, grain growth, and dissolution of precipitates did not in themselves cause any loss of ductility during cooling. Ductility loss during cooling was not initiated until the constitutional liquation of NbC particles was observed in the microstructure. Laves-type phases were found precipitated in the solidified grain boundaries but were not found to correlate with any ductility loss parameter. Mechanisms are reviewed which help to explain how heat treatment controls the hot crack susceptibility of alloy 718 as measured in the hot ductility test.

  8. Grinding performance evaluation of porous composite-bonded CBN wheels for Inconel 718

    Directory of Open Access Journals (Sweden)

    Chen Zhenzhen

    2014-08-01

    Full Text Available For high-efficiency grinding of difficult-to-cut materials such as titanium and nickel alloys, a high porosity is expected and also a sufficient mechanical strength to satisfy the function. However, the porosity increase is a disadvantage to the mechanical strength. As a promising pore forming agent, alumina bubbles are firstly induced into the abrasive layer to fabricate porous cubic boron nitride (CBN wheels. When the wheel porosity reaches 45%, the bending strength is still high up to 50 MPa with modified orderly pore distribution. A porous CBN wheel was fabricated with a total porosity around 30%. The grinding performance of the porous composite-bonded CBN wheel was evaluated in terms of specific force, specific grinding energy, and grinding temperature, which were better than those of the vitrified one under the same grinding conditions. Compared to the vitrified CBN wheel, clear straight cutting grooves and less chip adhesion are observed on the ground surface and there is also no extensive loading on the wheel surface after grinding.

  9. Oxidation assisted intergranular cracking under loading at dynamic strain aging temperatures in Inconel 718 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, M.C., E-mail: monica_crezende@hotmail.com [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil); Araújo, L.S.; Gabriel, S.B. [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil); Dille, J. [Université Libre de Bruxelles, 4MAT Department, Av. F. Roosevelt 50, C.P. 194/03, Brussels (Belgium); Almeida, L.H. de [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil)

    2015-09-15

    Highlights: • Mechanical properties are controlled by DSA, precipitation hardening and OAIC. • Between 600 and 700 °C the critical strain for serrations increases with temperature. • This is related to the consumption of matrix elements (especially Nb: for γ′ and γ″). • A reduction in ductility occurs (related to the OAIC) when the DSA is no longer effective. • This reduction is accompanied by an increase in intergranular brittle fracture. - Abstract: It is well established that 718 superalloy exhibits brittle intergranular cracking when deformed under tension at temperatures above 600 °C. This embrittlement effect is related with grain boundary penetration by oxygen (Oxygen Assisted Intergranular Cracking – OAIC). Simultaneously, impacting on its mechanical properties, the precipitation of coherent γ′ and γ″ phases occur above 650 °C and Dynamic Strain Aging (DSA) occurs in the temperature range between 200 and 800 °C. Although literature indicates that OAIC is the mechanism that controls mechanical properties at high temperatures, its interactions with DSA and precipitation are still under discussion. The objective of this work is to investigate the interactions between the embrittlement phenomena (OAIC and DSA) and the hardening mechanism of γ′ and γ″ precipitation on the mechanical properties of an annealed 718 superalloy. Tensile tests were performed at a strain rate of 3.2 × 10{sup −4} s{sup −1} under secondary vacuum, in temperatures ranging from 200 to 800 °C. Fracture surfaces were observed by scanning electron microscopy (SEM) and precipitation by transmission electron microscopy (TEM). The effect of DSA and precipitation on the strength and of OAIC on the ductility was verified.

  10. Characterization of Machine Variability and Progressive Heat Treatment in Selective Laser Melting of Inconel 718

    Science.gov (United States)

    Prater, Tracie; Tilson, Will; Jones, Zack

    2015-01-01

    The absence of an economy of scale in spaceflight hardware makes additive manufacturing an immensely attractive option for propulsion components. As additive manufacturing techniques are increasingly adopted by government and industry to produce propulsion hardware in human-rated systems, significant development efforts are needed to establish these methods as reliable alternatives to conventional subtractive manufacturing. One of the critical challenges facing powder bed fusion techniques in this application is variability between machines used to perform builds. Even with implementation of robust process controls, it is possible for two machines operating at identical parameters with equivalent base materials to produce specimens with slightly different material properties. The machine variability study presented here evaluates 60 specimens of identical geometry built using the same parameters. 30 samples were produced on machine 1 (M1) and the other 30 samples were built on machine 2 (M2). Each of the 30-sample sets were further subdivided into three subsets (with 10 specimens in each subset) to assess the effect of progressive heat treatment on machine variability. The three categories for post-processing were: stress relief, stress relief followed by hot isostatic press (HIP), and stress relief followed by HIP followed by heat treatment per AMS 5664. Each specimen (a round, smooth tensile) was mechanically tested per ASTM E8. Two formal statistical techniques, hypothesis testing for equivalency of means and one-way analysis of variance (ANOVA), were applied to characterize the impact of machine variability and heat treatment on six material properties: tensile stress, yield stress, modulus of elasticity, fracture elongation, and reduction of area. This work represents the type of development effort that is critical as NASA, academia, and the industrial base work collaboratively to establish a path to certification for additively manufactured parts. For future flight programs, NASA and its commercial partners will procure parts from vendors who will use a diverse range of machines to produce parts and, as such, it is essential that the AM community develop a sound understanding of the degree to which machine variability impacts material properties.

  11. Influence of composition on precipitation behavior and stress rupture properties in INCONEL RTM740 series superalloys

    Science.gov (United States)

    Casias, Andrea M.

    Increasing demands for energy efficiency and reduction in CO2 emissions have led to the development of advanced ultra-supercritical (AUSC) boilers. These boilers operate at temperatures of 760 °C and pressures of 35 MPa, providing efficiencies close to 50 pct. However, austenitic stainless steels typically used in boiler applications do not have sufficient creep or oxidation resistance. For this reason, nickel (Ni)-based superalloys, such as IN740, have been identified as potential materials for AUSC boiler tube components. However, IN740 is susceptible to heat-affected-zone liquation cracking in the base metal of heavy section weldments. To improve weldability, IN740H was developed. However, IN740H has lower stress rupture ductility compared to IN740. For this reason, two IN740H modifications have been produced by lowering carbon content and increasing boron content. In this study, IN740, IN740H, and the two modified IN740H alloys (modified 1 and 2) were produced with equiaxed grain sizes of 90 ìm (alloys IN740, IN740H, and IN740H modified 1 alloys) and 112 µm (IN740H modified 2 alloy). An aging study was performed at 800 °C on all alloys for 1, 3, 10, and 30 hours to assess precipitation behavior. Stress rupture tests were performed at 760 °C with the goal of attaining stress levels that would yield rupture at 1000 hours. The percent reduction in area was measured after failure as a measure of creep ductility. Light optical, scanning electron, and transmission electron microscopy were used in conjunction with X-ray diffraction to examine precipitation behavior of annealed, aged, and stress rupture tested samples. The amount and type of precipitation that occurred during aging prior to stress rupture testing or in-situ during stress rupture testing influenced damage development, stress rupture life, and ductility. In terms of stress rupture life, IN740H modified 2 performed the best followed by IN740H modified 1 and IN740, which performed similarly, and IN740H. In terms of stress rupture ductility, IN740H modified 1 performed the best, followed by IN740H modified 2, IN740, and IN740H. G-phase, η, M23C 6, and MX precipitated in IN740 during stress rupture testing. IN740H and the two modified alloys displayed M23C6 precipitates that were often in lamellar form and blocky MX precipitates. However, IN740H displayed more extensive formation of lamellar precipitates along grain boundaries after both aging and during stress rupture testing, which negatively influenced stress rupture life and ductility. Grain size was also shown to influence stress rupture life and ductility; a larger grain size increased stress rupture life, but decreased ductility as shown by the IN740H modified 1 and 2 alloy results. Transmission electron microscopy analysis was performed to assess the lamellar precipitation in IN740H. These precipitates were identified to be Cr-rich M23C6 that form by discontinuous cellular precipitation (DCP). The M23C6 precipitates were found to adopt different {111} habit planes based on the conditions of DCP boundary migration. Discontinuous precipitation of lamellar M23C6 is harmful to stress rupture life and ductility.

  12. Inducement of IGA/SCC in Inconel 600 steam generator tubing during unit outages

    Energy Technology Data Exchange (ETDEWEB)

    Durance, D.; Sedman, K. [Bruce Power, Tiverton, Ontario (Canada); Roberts, J. [CANTECH Associates Ltd., Burlington, Ontario (Canada); King, P. [Babcock and Wilcox Canada, Cambridge, Ontario (Canada); Gorman, J. [Dominion Engineering, Reston, VA (United States); Allen, R. [Kinectrics, Inc., Toronto, Ontario (Canada)

    2008-07-01

    The degradation of Unit 4 SG tubing by IGA/SCC has limited both the operating period and end of life predictions for Unit 4 since restart in late 2003. The circumferential IGA/SCC has been most significant in SG4 with substantial increases in both initiation and growth rates from 2005 through the spring of 2007. A detailed review of the occurrence of circumferential OD IGA/SCC at the RTZ in the HL TTS region of Bruce 4 steam generator tubes has led a conclusion that it is probable that the IGA/SCC has been the result of attack by partially reduced sulfur species such as tetrathionates and thiosulfates during periods of low temperature exposure. It is believed that attack of this type has mostly likely occurred during startup evolutions following outages as the result the development of aggressive reduced sulfur species in the TTS region during periods when the boilers were fully drained for maintenance activities. The modification of outage practices to limit secondary side oxygen ingress in the spring of 2007 has apparently arrested the degradation and has had significant affects on the allowable operating interval and end of life predictions for the entire unit. (author)

  13. Stress Corrosion Cracking(SCC)of Inconel 690 in High Temperature Water Envi

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    3.3StressCorrosionCracking(SCC)ofInconel690inHighTemperaturewaterEnvironmentZhangPingzhu;ZhouHongyi;ThangWeiguoOperatingexper...

  14. 2500 KW Ship Service Turbine Generator Casing Welded Inconel Plug Failure and Repair Analysis

    Science.gov (United States)

    2012-06-01

    optimize the EOP start-up procedure. 3. Additional FEA using thermal test data should provide answers as to why radial cracks initiated and if radial...possible. c. The additional FEA using thermal test data may provide answers as to why radial cracks initiated and if radial cracks could reform in

  15. A Fundamental study of remedial technology development to prevent stress corrosion cracking of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, In Gyu; Lee, Chang Soon [Sunmoon University, Asan (Korea)

    1998-04-01

    Most of the PWR Steam generators with tubes in Alloy 600 alloy are affected by Stress Corrosion Cracking, such as PWSCC(Primary Water Stress Corrosion Cracking) and ODSCC(Outside Diameter Stress Corrosion Cracking). This study was undertaken to establish the background for remedial technology development to prevent SCC. in the report are included the following topics: (1) General: (i) water chemistry related factors, (ii) Pourbaix(Potential-pH) Diagram, (iii) polarization plot, (iv) corrosion mode of Alloy 600, 690, and 800, (v) IGA/SCC growth rate, (vi) material suspetibility of IGA/SCC, (vii) carbon solubility of Alloy 600 (2) Microstructures of Alloy 600 MA, Alloy 600 TT, Alloy 600 SEN Alloy 690 TT(Optical, SEM, and TEM) (3) Influencing factors for PWSCC initiation rate of Alloy 600: (i) microstructure, (ii) water chemistry(B, Li), (iii) temperature, (iv) plastic deformation, (v) stress relief annealing (4) Influencing factors for PWSCC growth rate of Alloy 600: (i) water chemistry(B, Li), (ii) Scott Model, (iii) intergranular carbide, (iv) temperature, (v) hold time (5) Laboratory conditions for ODSCC initiation rate: 1% NaOH, 316 deg C; 1% NaOH, 343 deg C; 50% NaOH, 288 deg C; 10% NaOH, 302 deg C; 10% NaOH, 316 deg C; 50% NaOH, 343 deg C (6) Sludge effects for ODSCC initiation rate: CuO, Cr{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} (7) Influencing factors for PWSCC growth rate of Alloy 600: (i) Caustic concentration effect, (ii) carbonate addition effect (8) Sulfate corrosion: (i) sulfate ratio and pH effect, (ii) wastage rate of Alloy 600 and Alloy 690 (9) Crevice corrosion: (i) experimental setup for crevice corrosion, (ii) organic effect, (iii) (Na{sub 2}SO{sub 4} + NaOH) effect (10) Remedial measures for SCC: (i) Inhibitors, (ii) ZnO effect. (author). 30 refs., 174 figs., 51 tabs.

  16. 一种改型Inconel 718合金的组织与性能的研究%Microstructures and Mechanical Properties of a Modified Inconel 718 Alloy

    Institute of Scientific and Technical Information of China (English)

    徐春梅; 谢锡善

    2009-01-01

    采用化学相分析、显微组织分析和显微硬度测试等方法,研究了一种改型镍基高温合金718A在标准热处理状态的显微组织和力学性能.试验结果表明,原型718合金和改型718A合金的主要析出相皆为γ"、γ'、δ、MC相.在标准热处理状态下,改型718A合金中强化相γ'和γ"的量较原型718合金明显增多,而对于组织稳定性不利的δ相的析出量则较718合金少.此外,改型718A合金的显微硬度与原型合金相比有了明显的提高,因此具有广阔的应用前景.

  17. Research on Control of Quality and Tool Life in Ultrasonic Vibration Cutting of Inconel 718 Alloy%Inconel 718合金超声振动切削质量与刀具寿命控制研究

    Institute of Scientific and Technical Information of China (English)

    陶若冰

    2008-01-01

    超声振动切削UVC是解决难加工材料精细加工问题的理想方法.在对Ineonel 718合金同时进行UVC和传统车削法CT加工中,研究了切削参数(切削速度、进给量、切削时间)对刀具切削性能的影响.通过对刀具磨损、切屑形态和工件表面粗糙度的研究,发现在进行低速硬态切削时,UVC在切削表面质量和刀具寿命方面均优于传统车削加工.同时随着刀具一工件表面接触率TwcR的降低,刀具磨损和切削力随之降低,而工件表面质量和刀具寿命得到提高.

  18. 固溶温度对改型Inconel 718合金组织和性能的影响%Effect of Solid Solution Temperature on Structure and Properties of Modified Inconel 718 Alloy

    Institute of Scientific and Technical Information of China (English)

    吴艳阳; 程世长; 刘正东; 李谦

    2007-01-01

    用X-射线衍射法(XRD)和扫描电镜(SEM)研究了960~1 020 ℃固溶+720℃8 h炉冷至620℃8 h空冷(二次时效)处理的改型718合金的力学性能和组织.结果表明,随固溶温度的提高,合金室温和350℃强度降低,塑性和韧性显著提高.随固溶温度升高,合金中强化相η数量减少,1 000℃时完全消失;强化相γ'+γ"随固溶温度升高而增加,达到1 000℃时最多.固溶+二次时效后,大部分γ'尺寸为10~18 nm.

  19. Experimental Study on Burrs in Micro-milling Nickel-base Superalloy Inconel718%镍基高温合金Inconel718微铣削毛刺试验研究∗

    Institute of Scientific and Technical Information of China (English)

    卢晓红; 武文毅; 王文韬; 裴兴林; 路彦君; 司立坤

    2015-01-01

    基于微小型机床的微铣削( Micro-milling )技术是加工镍基高温合金微小结构/零件的可行技术手段。文章通过镍基高温合金微铣削加工实验,利用扫描电子显微镜和能谱分析仪对刀具的磨、破损形态及局部化学成分和槽的表面形貌进行了研究分析,发现镍基高温合金微铣削毛刺形貌及成因与镍基高温合金传统切削或其他材料微铣削具有很大不同:首先,毛刺长度过长;其次,刀具磨损对鳞刺的产生有很大影响;鳞刺只出现在槽的一侧边界。在实验研究基础上,分析了毛刺的成因,为后续镍基高温合金微铣削毛刺的有效抑制研究提供参考。%Micro milling technology which is based on the micro machine tool is one of the feasible skills processing the Nickel-based superalloy micro constructions/parts. Micro-milling Nickel-based superalloy tests have been carried out and then the wear/break features and the chemical component of the testing tool as well as the surface features of the testing slots have been researched. Results show that the burrs’ features and causes in micro milling Nickel-based superalloy have great differences from the traditionally milling Nickel-based superalloy and micro milling other materials. Firstly, the length of the burrs is too long. Sec-ondly, tool wearing has great effects on the scales’ formation. Thirdly, the scales only appear on the one side of the testing slots. Based on the tests and researches, formation of the burrs has been studied to provide references for controlling the burrs in micro milling Nickel-based superalloy effectively.

  20. Multi-objective optimization of surface roughness, cutting forces, productivity and Power consumption when turning of Inconel 718

    OpenAIRE

    Hamid Tebassi; Mohamed Athmane Yallese; Riad Khettabi; Salim Belhadi; Ikhlas Meddour; Francois Girardin

    2016-01-01

    Nickel based super alloys are excellent for several applications and mainly in structural components submitted to high temperatures owing to their high strength to weight ratio, good corrosion resistance and metallurgical stability such as in cases of jet engine and gas turbine components. The current work presents the experimental investigations of the cutting parameters effects (cutting speed, depth of cut and feed rate) on the surface roughness, cutting force components, productivity and p...

  1. An empirical-statistical model for coaxial laser cladding of NiCrAlY powder on Inconel 738 superalloy

    Science.gov (United States)

    Ansari, M.; Shoja Razavi, R.; Barekat, M.

    2016-12-01

    In this study, coaxial laser cladding of NiCrAlY powder on a nickel-based superalloy is investigated from an experimental point of view so as to propose an empirical-statistical model for the process. The correlations between main processing parameters (i.e. scanning speed, powder feeding rate, and laser power) and geometrical characteristics (i.e. width, height, penetration depth, dilution and wetting angle) of single clad tracks have been predicted and are discussed using regression analysis (RA). The validity of the predictions is confirmed by providing correlation coefficient and analysis of the residuals. The correlations are established as a combined parameter (PαVβFγ) for each studied characteristic of single clad tracks. These correlations finally lead to the design of a processing map that can be practically used to select proper processing parameters for laser cladding of the particular material.

  2. Multi-objective optimization of surface roughness, cutting forces, productivity and Power consumption when turning of Inconel 718

    Directory of Open Access Journals (Sweden)

    Hamid Tebassi

    2016-01-01

    Full Text Available Nickel based super alloys are excellent for several applications and mainly in structural components submitted to high temperatures owing to their high strength to weight ratio, good corrosion resistance and metallurgical stability such as in cases of jet engine and gas turbine components. The current work presents the experimental investigations of the cutting parameters effects (cutting speed, depth of cut and feed rate on the surface roughness, cutting force components, productivity and power consumption during dry conditions in straight turning using coated carbide tool. The mathematical models for output parameters have been developed using Box-Behnken design with 15 runs and Box-Cox transformation was used for improving normality. The results of the analysis have shown that the surface finish was statistically sensitive to the feed rate and cutting speed with the contribution of 43.58% and 23.85% respectively, while depth of cut had the greatest effect on the evolution of cutting force components with the contribution of 79.87% for feed force, 66.92% for radial force and 66.26% for tangential force. Multi-objective optimization procedure allowed minimizing roughness Ra, cutting forces and power consumption and maximizing material removal rate using desirability approach.

  3. Grit Blasting for Removal of Recast Layer from EDM Process on Inconel 718 Shaft: An Evaluation of Surface Integrity

    Science.gov (United States)

    Holmberg, Jonas; Wretland, Anders; Berglund, Johan

    2016-12-01

    The heat generated during EDM melts the work material and thereby allows large amounts to be removed, but an unfavorable surface of a recast layer (RCL) will also be created. This layer has entirely different properties compared to the bulk. Hence, it is of great interest to efficiently remove this layer and to verify that it has been removed. The main objective of this work has been to study the efficiency of grit blasting for removal of RCL on an EDM aero space shaft. Additionally, x-ray fluorescence (XRF) has been evaluated as a nondestructive measurement to determine RCL presence. The results show that the grit-blasting processing parameters have strong influence on the ability to remove RCL and at the same time introduce beneficial compressive stresses even after short exposure time. Longer exposure will remove the RCL from the surface but also increase the risk that a larger amount of the blasting medium will get stuck into the surface. This investigation shows that a short exposure time in combination with a short grit-blasting nozzle distance is the most preferable process setting. It was further found that handheld XRF equipment can be used as a nondestructive measurement in order to evaluate the amount of RCL present on an EDM surface. This was realized by analyzing the residual elements from the EDM wire.

  4. Determination of Yield and Flow Surfaces for Inconel 718 Under Axial-Torsional Loading at Temperatures Up to 649 C

    Science.gov (United States)

    Gil, Christopher M.

    1998-01-01

    An experimental program to determine flow surfaces has been established and implemented for solution annealed and aged IN718. The procedure involved subjecting tubular specimens to various ratios of axial-torsional stress at temperatures between 23 and 649 C and measuring strain with a biaxial extensometer. Each stress probe corresponds to a different direction in stress space, and unloading occurs when a 30 microstrain (1 micro eplison = 10(exp -6) mm/mm) offset is detected. This technique was used to map out yield loci in axial-torsional stress space. Flow surfaces were determined by post-processing the experimental data to determine the inelastic strain rate components. Surfaces of constant inelastic strain rate (SCISRS) and surfaces of constant inelastic power (SCIPS) were mapped out in the axial-shear stress plane. The von Mises yield criterion appeared to closely fit the initial loci for solutioned IN718 at 23 C. However, the initial loci for solutioned IN718 at 371 and 454 C, and all of the initial loci for aged IN718 were offset in the compression direction. Subsequent loci showed translation, distortion, and for the case of solutioned IN718, a slight cross effect. Aged IN718 showed significantly more hardening behavior than solutioned IN718.

  5. Model of the Frictional Heating of Inconel 718 and Titanium (ti-6al-4v) in Helium

    Science.gov (United States)

    Skowlund, Christopher T.

    1991-01-01

    A computer model of the frictional heating of metals in an inert environment has been developed. The model incorporates the effects of the heat loss from the samples due to conduction, radiation, and convection to the surroundings. This model allows the measured temperatures to be used to determine the amount of heat produced at the interface during the experiment by the sliding contact of two different metallic samples. The results of the simulation for an experiment run at the NASA White Sands Test Facility (WSTF) show that for the same heat production at the interface the heat losses have a significant effect on the temperatures in the samples. But, the heat losses do not significantly affect the different calculated heat flows (or friction coefficients), at the interface, that are necessary to correlate the measured temperatures.

  6. INTRODUCTION TO INCONEL ALLOY 740: AN ALLOY DESIGNED FOR SUPERHEATER TUBING IN COAL-FIRED ULTRA SUPERCRITICAL BOILERS

    Institute of Scientific and Technical Information of China (English)

    S.J. Patel

    2005-01-01

    Chinese utilities as well as those worldwide are facingincreased demand for additional electric-ity, reduced plant emissions and greater efficiency.To meet this challenge willrequire increas-ing boiler temperature,pressure and coal ashcorrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONELRalloy 740,is described aiming at meeting this challenge. Emphasis will be on describing the alloy s mechanical properties, coal-ash and steam corrosion resistance.Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology employed to arrive at the current chemical composition.

  7. Gas-turbine HTGR materials screening test program. Quarterly progress report, July 1, 1976--September 30, 1976. [IN 100; IN 713; MM004; M21; IN 738; RENE 100; MoTZM; Hastelloy X; Inconel 617; MA 753; IN 519, Inconel 706; Inconel 718; A286; 316 SS; Incoloy 800

    Energy Technology Data Exchange (ETDEWEB)

    Rosenwasser, S.N.; Johnson, W.R.

    1976-09-30

    The duration of controlled-impurity creep-screening tests and unstressed aging tests has reached 10,000 hr. Creep and weight change data from testing up to 9,000 hr and results from post-test metallurgical evaluations of several recently returned 3,000-hr specimens, including alloys IN519 and MoTZM, are presented. Preliminary materials requirements for key GT-HTGR 850/sup 0/C (1562/sup 0/F) reactor outlet temperature reference design components are documented.

  8. Electrospark Deposition for Depot- and Field-Level Component Repair and Replacement of Hard Chromium Plating

    Science.gov (United States)

    2008-02-01

    IN625 Inconel 625 alloy IN718 Inconel 718 alloy IRR internal rate-of-return JTP joint test protocol ksi thousands of pounds per square... Inconel 718 (non-line of sight) • TF 39 shaft fabricated from Inconel 718 (chrome plate repair) • TF33 #5 bearing housing fabricated from 410 stainless...1.5.1 Process Development and Materials Testing The substrate alloy used for materials testing was Inconel 718 (IN718). Electrodes of the same

  9. Calibrating IR Cameras for In-Situ Temperature Measurement During the Electron Beam Melting Process using Inconel 718 and Ti-Al6-V4

    Energy Technology Data Exchange (ETDEWEB)

    Dinwiddie, Ralph Barton [ORNL; Lloyd, Peter D [ORNL; Dehoff, Ryan R [ORNL; Lowe, Larry E [ORNL

    2016-01-01

    The Department of Energy s (DOE) Manufacturing Demonstration Facility (MDF) at Oak Ridge National Laboratory (ORNL) provides world-leading capabilities in advanced manufacturing (AM) facilities which leverage previous, on-going government investments in materials science research and characterization. MDF contains systems for fabricating components with complex geometries using AM techniques (i.e. 3D-Printing). Various metal alloy printers, for example, use electron beam melting (EBM) systems for creating these components which are otherwise extremely difficult- if not impossible- to machine. ORNL has partnered with manufacturers on improving the final part quality of components and developing new materials for further advancing these devices. One method being used to study (AM) processes in more depth relies on the advanced imaging capabilities at ORNL. High performance mid-wave infrared (IR) cameras are used for in-situ process monitoring and temperature measurements. However, standard factory calibrations are insufficient due to very low transmissions of the leaded glass window required for X-ray absorption. Two techniques for temperature calibrations will be presented and compared. In-situ measurement of emittance will also be discussed. Ample information can be learned from in-situ IR process monitoring of the EBM process. Ultimately, these imaging systems have the potential for routine use for online quality assurance and feedback control.

  10. Calibrating IR cameras for in-situ temperature measurement during the electron beam melt processing of Inconel 718 and Ti-Al6-V4

    Science.gov (United States)

    Dinwiddie, R. B.; Kirka, M. M.; Lloyd, P. D.; Dehoff, R. R.; Lowe, L. E.; Marlow, G. S.

    2016-05-01

    High performance mid-wave infrared (IR) cameras are used for in-situ electron beam melt process monitoring and temperature measurements. Since standard factory calibrations are insufficient due to very low transmissions of the leaded glass window required for X-ray absorption, two techniques for temperature calibrations are compared. In-situ measurement of emittance will also be discussed. Ultimately, these imaging systems have the potential for routine use for online quality assurance and feedback control.

  11. Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, High-Cycle and Low-Cycle Mechanical Fatigue, Creep and Thermal Fatigue Effects

    Science.gov (United States)

    Bast, Callie C.; Boyce, Lola

    1995-01-01

    The development of methodology for a probabilistic material strength degradation is described. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing predictions of high-cycle mechanical fatigue and high temperature effects with experiments are presented. Results from this limited verification study strongly supported that material degradation can be represented by randomized multifactor interaction models.

  12. Effect of Welding Heat Input on Microstructure and Texture of Inconel 625 Weld Overlay Studied Using the Electron Backscatter Diffraction Method

    Science.gov (United States)

    Kim, Joon-Suk; Lee, Hae-Woo

    2016-12-01

    The grain size and the texture of three specimens prepared at different heat inputs were determined using optical microscopy and the electron backscatter diffraction method of scanning electron microscopy. Each specimen was equally divided into fusion line zone (FLZ), columnar dendrite zone (CDZ), and surface zone (SZ), according to the location of the weld. Fine dendrites were observed in the FLZ, coarse dendrites in the CDZ, and dendrites grew perpendicular to the FLZ and CDZ. As the heat input increased, the melted zone in the vicinity of the FLZ widened due to the higher Fe content. A lower image quality value was observed for the FLZ compared to the other zones. The results of grain size measurement in each zone showed that the grain size of the SZ became larger as the heat input increased. From the inverse pole figure (IPF) map in the normal direction (ND) and the rolling direction (RD), as the heat input increased, a specific orientation was formed. However, a dominant [001] direction was observed in the RD IPF map.

  13. AIR VEHICLE INTEGRATION AND TECHNOLOGY RESEARCH (AVIATR) Task Order 0015: Predictive Capability for Hypersonic Structural Response and Life Prediction: Phase 1-Identification of Knowledge Gaps, Volume 1: Nonproprietary Version

    Science.gov (United States)

    2010-09-01

    temperature was greater than 1000o F then Inconel 718 was used. This occurred primarily on the exterior skin surfaces. The bulkhead and keel structures which...56 Table 13. Inconel and Titanium Properties... inconel materials. The honeycomb panels consist of an upper facesheet, core, and a lower facesheet layers. Each layer can have different properties

  14. The National Shipbuilding Research Program. Impact of Recent and Anticipated Changes in Airborne Emission Exposure Limits on Shipyard Workers

    Science.gov (United States)

    1996-03-01

    thermal processing of stainless steels , high-chromium nickel alloys (eg Alloys 600 and 625), and HY80 and HY100 low- alloy steels . HY steels and...and GMAW of stainless steels , carbon steels , and low-alloy steels (including HY80 and HY100) have a high potential for Mn exposure. b There may be...SS) covers welding with High-Chromium Nickel Alloys (ie Alloys 600/625) or Stainless Steels . 4) ( HY80 /100) covers welding with E1OO or ER1OO through

  15. Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High-Entropy Alloys (Preprint)

    Science.gov (United States)

    2011-07-01

    yield stress (YS) of the studied HEAs and two high-temperature Ni-based superalloys, Inconel 718 [9] and Haynes 230 [10 Figure 3 ]. Inconel 718 is a...YS of Inconel 718 rapidly decreases to 138 MPa with a further increase in temperature to 982°C, while melting occurs at ~1210°C. Inconel 718 is...that of Haynes 230 at all studied temperatures and higher than that of Inconel 718 at temperatures above 800°C (see Figure 3). Moreover, the

  16. The French regulatory experience and views on nickel-base alloy PWSCC prevention and treatment

    Energy Technology Data Exchange (ETDEWEB)

    Turluer, G.; Cattiaux, G.; Monnot, B. [Institut de Radioprotection et de Surete Nucleaire, IRSN, 92 - Fontenay aux Roses (France); Emond, D.; Reuchet, J.; Chartier, Ph. [Direction Generale de la Surete Nucleaire et de la Radioprotection, 75 - Paris (France)

    2003-10-01

    This paper presents the experience feedback and views of the French Regulatory Authority (ASN) and of the technical support institute (IRSN) on PWSCC prevention since the initiation in 1989 of the 'Inconel Zones Review' requested by ASN to Electricite de France (EDF), the national operator of a fleet of 58 PWRs. This proactive requirement, launched before the discovery, in September 1991, of the only CRDM nozzle leak in France, on Bugey unit 3, was then triggered by the recurrence of many alloy 600 rapid degradations and leaks, world wide, and also in France in the late 1980's, particularly on steam generator tubes and on some pressurizer penetrations. Thus, the ASN requested that EDF, perform a comprehensive (generic) proactive assessment on all the nickel-base alloy components and parts of the main primary circuits, which of course included vessel head penetrations and bottom vessel head penetrations, and some other zones as a first priority. This proactive 'review' did, a minima, include the following tasks and actions: - Update and complete, by an extensive R and D program, the understanding and characterization of the Ni base alloys prone to PWSCC, - Analyze the various materials, metallurgical features, mechanical stresses, and physicochemical conditions of the parts exposed to primary water, in order to predict the occurrence of PWSCC initiation and propagation, - Provide a prioritization of the zones to be inspected, - Implement by improved NDE techniques a practical inspection program on the 58 PWRs, - Prepare and implement any needed mitigation actions as a result of the components conditions assessment. The present paper relates the main features of the French regulatory experience over more than 13 years and recalls the main principles of the assessment, which were applied by ASN. These principles, which are formalized in the current regulation rules revised in 1999, are briefly listed hereunder: - It is based on avoiding and

  17. Stress relief of transition zones

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; van Rooyen, D.

    1984-01-01

    This paper considers the problem of intergranular stress corrosion cracking, initiated on the primary side, in the expansion transition region of roller expanded Alloy 600 tubing. In general it is believed that residual stresses, arising from the expansion process, are the cause of the problem. The work reported here concentrated on the identification of an optimal, in-situ stress relief treatment.

  18. Oxide property of SG tube materials exposed to an alkaline environment as a secondary side of a PWR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongjin; Mun, Byung Hak; Kim, Hong Pyo; Hwang, Seong Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Stress corrosion cracking (SCC) is an issue that should be overcome in nuclear power plants (NPP). Recognizing that cracks initiate and propagate through unavoidable breakdowns and alterations of the surface oxide on Alloy 600, the SCC behavior is closely related to the oxide property. Corrosion resistance against SCC, in particular, was improved through a newly developed heat treatment process from LTMA (low temperature mill annealed) Alloy 600 to HTMA (high temperature mill annealed) Alloy 600, and then TT (thermally treated) Alloy 600. Intra-granular carbide widely spread in LTMA Alloy 600 dissolves, and inter-granular carbide is then formed during high-temperature mill annealing and cooling, which leads to a great SCC resistance enhancement. Inter-granular carbide is well developed, healing chromium depletion at a grain boundary, and residual stress is removed during additional thermal treatment following mill annealing, which improves the SCC resistance more. In spite of this improvement of TT Alloy 600, Seabrook and Vogtle 1 in the US, using TT Alloy 600, also showed SCC due to a non-optimum microstructure, residual stress, Pb existence, and so on over a 20-year operation of an NPP even though SCC occurs less frequently than LTMA and (or) HTMA Alloy 600s. SCC has also occurred for TT Alloy 600 tubes in Korea, whose main causes resemble US cases. The pH at high temperature in the crevice of SG tubes distributes from acidic of 4 to alkaline above 10 at high temperature depending on the impurity concentration such as chloride and hydroxide ions including other corrosive impurities such as Pb known as very detrimental species even though the bulk pH of secondary water is a mild alkaline solution. Regarding the aggressiveness of Pb, even Alloy 690 is also susceptible to SCC in a strong alkaline solution with lead. Therefore, in the present work, the oxides were investigated in a leaded alkaline solution of pH(T) 9.9 at 315 .deg. C as a function of immersion time

  19. A Foil Thrust Bearing Test Rig for Evaluation of High Temperature Performance and Durability

    Science.gov (United States)

    2008-04-01

    communication faults. Test Articles Thrust runners, shown in figures 4 and 5, are rotating disks usually constructed of Inconel 718 , a nickel-based superalloy...constructed of various corrosion-resistant steels, and bearing foils are most often constructed from Inconel X750. Commercial bearings are purchased with...coatings with increased temperature capability are required for some applications. Uncoated Inconel X750 top foils run against PS304-coatings in

  20. Revolutionary Materials for Hypersonic Flight

    Science.gov (United States)

    2011-10-01

    system consisted of an Inconel 718 case (with 3mm leading edge radius) and a nickel foam sintered to its upper and lower interior surfaces for the wick...satisfies the design requirements at minimum weight, the Nb alloy Cb752 and the Ni alloy Inconel X-750 are also viable candidates, albeit at about...vectors that enhance design options have also been determined [3]. For one of the promising candidate alloys (the Ni-based superalloy INCONEL X-750), the

  1. Performance and Thrust-to-Weight Optimization of the Dual-Expander Aerospike Nozzle Upper Stage Rocket Engine

    Science.gov (United States)

    2012-06-01

    Copper (C17000 TH04) Oxygen-Free Copper (C10100 1180 Temper) Cobalt (Forged Electrolytic) INCONEL ® 718 (Annealed & Aged) Compatible with O2 / Useable... INCONEL 718 Copper Table 9 Impact of material strength on T/W Worst Material Selection Best Material Selection Yield Strength Ultimate...Copper Hydrogen Plumbing INCOLOY 909 Oxygen Plumbing INCONEL 718 American Institute of Aeronautics and Astronautics 24 The performance values for

  2. Air Vehicle Integration and Technology Research (AVIATR). Delivery Order 0023: Predictive Capability for Hypersonic Structural Response and Life Prediction: Phase 2 - Detailed Design of Hypersonic Cruise Vehicle Hot-Structure

    Science.gov (United States)

    2012-05-01

    41 Figure 5.2.4 Minimum Skin Thickness to Prevent Flutter in 36” × 4” Inconel 718 , Simply...in 4” × 45” Inconel 718 , Simply Supported 0.049-in Thick Flat Panel at 644 keas (Corresponding to the First Panel 3 Configuration...for Panel 1 ................................. 85 Figure 6.2.17 Elastic Modulus (E) Versus Temperature for Inconel 718

  3. Effects of Contact Load on the Fretting Fatigue Behavior of IN-100 at Elevated Temperature

    Science.gov (United States)

    2009-03-01

    experimental setup which did not accurately model the turbine engine environment. Kawagoishi et al. [23] studied the nickel-based alloy Inconel 718 ...In their study with Inconel 718 [48, 49], it was found that the beneficial glaze oxide had formed and did affect the fretting fatigue life. Their...Waterhouse [52] investigated the fretting fatigue behaviors of austenitic steel type 321 and nickel-based alloy Inconel 718 at elevated temperatures. He

  4. Relation of Engine Turbine-blade Life to Stress-rupture Properties of the Alloys, Stellite 21, Hastelloy B, Cast S-816, Forged S-816, X-40, Nimonic 80, Refractaloy 26, N-155, and Inconel X

    Science.gov (United States)

    Garrett, F B; Yaker, C

    1951-01-01

    An investigation was conducted to relate the engine performance of the heat-resistant alloys, Stellite 21, Hastelloy B, cast S-816, forged S-816, X-40, Nimonic 80, Refractory 26, N-155, and Iconel X to their stress-rupture properties. The engine test consisted of the repetition of a 20-minute cycle, 15 minutes at rated speed and approximately 5 minutes at idle. The results of the investigation indicated a direct correlation between stress-rupture life and blade life for the relatively low-strength alloys. The stress-rupture life and blade life for the relatively high-strength alloys did not correlate because of the effects of the vibratory stresses and the corrosive-gas atmosphere.

  5. Materials for high-performance diesel engines. [42CrMo4; 34CrNiMo6; Inconel 713LC; TiAl6V4]. Werkstoffe im Hochleistungsdieselmotor

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R.M. (MTU Friedrichshafen, Vorentwicklung-Versuch (Germany)); Trebs, J. (MTU Friedrichshafen, Zentralabteilungen Versuch (Germany))

    1992-01-01

    In the high performance engine branch there is a trend to develop engines with increasing power density while at the same time more operational safety is demanded. The two above mentioned demands are apparently contrary. However, by using high performance materials both demands can be fulfilled. In the following a few engine components will be described to demonstrate the possibilities offered by high performance materials. (orig.).

  6. Caracterización de una aleación de níquel tipo INCONEL mediante la técnica de difracción de electrones retrodispersados EBSD

    OpenAIRE

    Cisneros Calero, Roberto Vladimir

    2015-01-01

    El campo de la Ciencia e Ingeniería de los Materiales está completamente involucrado en la manipulación de las propiedades de los materiales, con el fin de controlar las características mecánicas que éstos presentan. Con este propósito, se desarrolla la técnica de difracción de electrones retrodispersados (EBSD). Esta técnica permite analizar los aspectos cristalográficos de los materiales en estudio, siendo uno de los métodos que mayor crecimiento ha experimentado actualmente [1]. La t...

  7. 78 FR 42584 - Bureau of International Security and Nonproliferation: Report to Congress Pursuant to Section...

    Science.gov (United States)

    2013-07-16

    ..., military, or ballistic missile programs of Iran: aluminum; beryllium; boron; cobalt; copper; copper infiltrated tungsten; copper- beryllium; graphite; hastelloy; inconel; magnesium; molybdenum; nickel;...

  8. The Effect of Post-Bond Heat Treatment on Tensile Property of Diffusion Bonded Austenitic Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sunghoon; Kim, Sung Kwan; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Sah, Injin [KAERI, Daejeon (Korea, Republic of)

    2015-12-15

    Diffusion bonding is the key manufacturing process for the micro-channel type heat exchangers. In this study, austenitic alloys such as Alloy 800HT, Alloy 690, and Alloy 600, were diffusion bonded at various temperatures and the tensile properties were measured up to 650 ℃. Tensile ductility of diffusion bonded Alloy 800HT was significantly lower than that of base metal at all test temperatures. While, for Alloy 690 and Alloy 600, tensile ductility of diffusion bonded specimens was comparable to that of base metals up to 500 ℃, above which the ductility became lower. The poor ductility of diffusion bonded specimen could have caused by the incomplete grain boundary migration and precipitates along the bond-line. Application of post-bond heat treatment (PBHT) improved the ductility close to that of base metals up to 550 ℃. Changes in tensile properties were discussed in view of the microstructure in the diffusionbonded area.

  9. Steam generator tube integrity program

    Energy Technology Data Exchange (ETDEWEB)

    Dierks, D.R.; Shack, W.J. [Argonne National Laboratory, IL (United States); Muscara, J.

    1996-03-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given.

  10. Comparison of laboratory and field experience of PWSCC in Alloy 182 weld metal

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P.; Meunier, M.-C.; Steltzlen, F. [AREVA NP, Tour AREVA, Paris La Defense (France); Calonne, O.; Foucault, M. [AREVA NP, Centre Technique, Le Creusot Cedex (France); Combrade, P. [ACXCOR, Saint Etienne (France); Amzallag, C. [EDF, SEPTEN, Villeurbanne (France)

    2007-07-01

    Laboratory studies of stress corrosion cracking of the nickel base weld metal, Alloy 182, in simulated PWR primary water suggest similar resistance to crack initiation and somewhat enhanced propagation rates relative to wrought Alloy 600. By contrast, field experience of cracking in the primary circuits of PWRs shows in general much better performance for Alloy 182 relative to Alloy 600 than would be anticipated from laboratory studies. This paper endeavours to resolve this apparent conundrum. It draws on the conclusions of recent research that has focussed on the role of surface finish, particularly cold work and residual stresses resulting from different fabrication processes, on the risk of initiating IGSCC in nickel base alloys in PWR primary water. It also draws on field experience of stress corrosion cracking that highlights the important role of surface finish for crack initiation. (author)

  11. Study of the initial stages of oxidation of stainless steels in high temperature water; Etude des premiers stades d'oxydation d'alliages inoxydables dans l'eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Machet, A

    2004-06-15

    Steam Generator tubes (alloys 600, 690 and 800) are protected against corrosion by an oxide layer. The release of corrosion products into the primary water of the Pressurised Water Reactor is limited by this layer. Activation of these products increases the radioactivity. Breakdown of the passive film can lead to Stress Corrosion Cracking (SCC). The aim of this study is to understand the early stages of passivation of these alloys, in high temperature and high pressure water. A new micro-autoclave was developed to achieve short time exposures (from several seconds to 10 minutes). The surfaces were characterised by XPS, NRA, STM and SEM and a kinetic model is proposed for the alloy 600. Longer oxidation times were studied (up to 400 hours). The kinetics obtained for short time oxidations were used to fit the long oxidation time behaviour. This reveals that the initial stages of oxidation are essential in the passive films growth in such conditions. (author)

  12. Computational fluid dynamic analysis of a closure head penetration in a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, D.R.; Schwirian, R.E. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1995-09-01

    ALLOY 600 has been used typically for penetrations through the closure head in pressurized water reactors because of its thermal compatibility with carbon steel, superior resistance to chloride attack and higher strength than the austenitic stainless steels. Recent plant operating experience with this alloy has indicated that this material may be susceptible to degradation. One of the major parameters relating to degradation of the head penetrations are the operational temperatures and stress levels in the penetration.

  13. Nickel Alloy Primary Water Bulk Surface and SCC Corrosion Film Analytical Characterization and SCC Mechanistic Implications

    Energy Technology Data Exchange (ETDEWEB)

    Morton, D.; Lewis, N.; Hanson, M.; Rice, S.; Sanders, P.

    2007-04-18

    Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3 {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate

  14. Wear Test Results of Candidate Materials for the OK-542 Towed Array Handling Machine Level Winder

    Science.gov (United States)

    1994-12-29

    while extremely resistant to corrosion , is very strong mechanically and is readily available in bar form from local suppliers. Figure 32...Stainless Steel, Inconel 625, Nickel-Aluminum-Bronze, and Titanium. The specialty materials: Inconel 625, Monel, Stainless and Stellite , were clad-welded...C71500 Cu-Ni Wheel/Clad Stainless ............................................ 14 13. Clad Stellite

  15. Development of a Novel Approach for Fatigue Life Prediction of Structural Materials

    Science.gov (United States)

    2008-12-01

    11] for Inconel 718 under a similar loading condition. A kink around a fatigue life of 3xl05 cycles was noticed in the shear strain-life curve from...observed on AISI 304 stainless steel [10], Inconel 718 [11], 1045 steel [12], and an aluminum alloy [13]. However, no kink in the strain-life curves

  16. Investigation of the Use of Laser Shock Peening for Enhancing Fatigue and Stress Corrosion Cracking Resistance of Nuclear Energy Materials

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Vijay K. [Univ. of Cincinnati, OH (United States); Jackson, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Teysseyre, Sebastien [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alexandreanu, Bogdan [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Yiren [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-03-07

    The objective of this project, which includes close collaboration with scientists from INL and ANL, is to investigate and demonstrate the use of advanced mechanical surface treatments like laser shock peening (LSP) and ultrasonic nanocrystal surface modification (UNSM) and establish baseline parameters for enhancing the fatigue properties and SCC resistance of nuclear materials like nickel-based alloy 600 and 304 stainless steel. The research program includes the following key elements/tasks: 1) Procurement of Alloy 600 and 304 SS, heat treatment studies; 2) LSP and UNSM processing of base metal and welds/HAZ of alloys 600 and 304; (3) measurement and mapping of surface and sub-surface residual strains/stresses and microstructural changes as a function of process parameters using novel methods; (4) determination of thermal relaxation of residual stresses (macro and micro) and microstructure evolution with time at high temperatures typical of service conditions and modeling of the kinetics of relaxation; (5) evaluation of the effects of residual stress, near surface microstructure and temperature on SCC and fatigue resistance and associated microstructural mechanisms; and (6) studies of the effects of bulk and surface grain boundary engineering on improvements in the SCC resistance and associated microstructural and cracking mechanisms

  17. Microstructures of friction surfaced coatings. A TEM study; Gefuege durch Reibauftragschweissen aufgetragener Beschichtungen. Eine TEM-Untersuchung

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Javed; Kalvala, Prasad Rao; Misra, Mano [Utah Univ., Salt Lake City, UT (United States). Dept. of Metallurgical Engineering; Dilip, J. John Samuel [Louisville Univ., KY (United States). Dept. of Industrial Engineering; Pal, Deepankar; Stucker, Brent [Louisville Univ., KY (United States). Dept. of Industrial Engineering; 3D Sim, Park City, UT (United States)

    2016-05-15

    The microstructures of dissimilar metal welds between 9Cr-1Mo (Modified) (P91) and austenitic stainless steel (AISI 304) with Ni-based alloy interlayers (Inconel 625, Inconel 600 and Inconel 800H) are reported. These interlayers were deposited by the friction surfacing method one over the other on P91 alloy, which was finally friction welded to AISI 304. In this paper, the results of microstructural evolution in the friction surfaced coated interlayers (Inconel 625, 600, 800H) are reported. For comparative purposes, the microstructures of consumable rods (Inconel 625, 600, 800H) and dissimilar metal base metals (P91 and AISI 304) were also reported. Friction surfaced coatings exhibited dynamic recrystallization. In friction surfaced coatings, the carbide particles were found to be finer and distributed uniformly throughout the matrix, compared to their rod counterparts.

  18. Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High Entropy Alloys (Postprint)

    Science.gov (United States)

    2011-05-01

    temper ature from 548 MPa at 1000 C to 405 MPa at 1600 C (Table 2).ublic release; distribution unlimited. Table 4 Composition (in wt.%) of Inconel 718 ...values of the refractory HEAs are much higher than those of Haynes 230 at all studied temperatures and higher than those of Inconel 718 at...than twice (for the Nb25Mo25 Ta25W25 alloy) or four times (for the V20Nb20Mo20Ta20W20 alloy) higher than for Inconel 718 or Haynes 230 at 1000 C. The

  19. Functionally Graded Materials by Laser Metal Deposition (PREPRINT)

    Science.gov (United States)

    2010-03-01

    A similar work carried out by Domack et al [14] showed macroscopic cracking in powder blends containing 40-60 percent Inconel 718 on Ti6Al4V...composition of Fe-82 wt% V (powder-1) and Inconel -625 (powder-2) powders are listed in Table 1. The substrate materials used for the experiment were cold...like laser power, travel speed and powder feed rate is yet to be determined to obtain a successful FGM. Inconel -625 deposits showed macro-cracks

  20. The Effect of Hardness on Eddy Current Residual Stress Profiling in Shot-Peened Nickel Alloys

    Science.gov (United States)

    2010-06-22

    Inconel 718 alloy. Mater. Charact. 61, 49 (2010) 34. Lifshitz, I.M., Slyozov, V.V.: The kinetics of precipitation from su- persaturated solid... 718 . Mater. Sci. Eng. A 486, 117 (2008) 37. Han, Y.F., Deb, P., Chaturvedi, M.C.: Coarsening behaviour of γ ′′- and γ ′-particles in Inconel alloy 718 ...Met. Sci. 16, 555 (1982) 38. Sundaraman, M., Mukhopadhyay, P., Banerjee, S.: Some aspects of the precipitation of metastable intermetallic phases in Inconel 718 . Metall. Mater. Trans. A 23, 2015 (1992)