Effect of Structural State and Surface Finishing on Corrosion Behavior of 1.4970 Austenitic Steel at 400 and 500 °C in Flowing Pb-Bi Eutectic With Dissolved Oxygen

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Oxide Film ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Structural State ◽  
Cold Work ◽  
Surface Finishing ◽  
Polished Surface ◽  
Type Solution ◽  
Corrosion Attack ◽  
Cold Worked

The effect of structural state (solution annealed (SA) and after 40% cold work (CW)) and surface finishing (turning, grinding, and polishing) on the corrosion behavior of austenitic 1.4970 (15-15 Ti) steel in flowing (2 m/s) Pb-Bi eutectic containing 10−7 mass% dissolved oxygen at 400 °C and 10−6 mass% O at 500 °C is investigated. At 400 °C for ∼13,000 h, the corrosion losses are minor for steel in both structural states and for surfaces finished by turning and grinding—a thin Cr-based oxide film is formed. In contrast, the polished surface showed initiation of solution-based corrosion attack with the formation of iron crystallites and preferential propagation along the grain boundaries. The depth of corrosion attack does not exceed 10 μm after ∼13,000 h. At 500 °C for 2000 h, the samples in both structural states showed general slight oxidation. Cold-worked steel underwent a severe groove-type and pit-type solution-based attack of 170 μm in maximum depth, while the SA sample showed only sporadic pit-type corrosion attack to the depth of 45 μm in maximum.

scholarly journals Corrosion Behavior of a WC/C Coated 7075-T6 Aluminum Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 217-220
Author(s):  
Sergio Baragetti ◽  
M. Daurù ◽  
Riccardo Gerosa ◽  
Barbara Rivolta
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Experimental Tests ◽  
Point Of View ◽  
Surface Finishing ◽  
Polished Surface ◽  
Foreign Object ◽  
Final Thickness

In the present experimental work, a WC/C coated 7075-T6 aluminum alloy was considered from the corrosion point of view. The coating was deposited by PVD technique with a final thickness of about 2.5μm. In order to study the influence of the coating on the corrosion behavior of the aluminum alloy, the samples surfaces were partially coated and the interface among the metal and the coating was analyzed after the corrosion tests described into the ASTM G110 standard. Such experimental plan was decided in order to simulate the possible in-service local removal of the thin and hard coating. This kind of damage, due for example to a foreign object impact, can occur because of the great hardness difference between the coating and the substrate. The experimental tests were carried out on samples with different surface finishing, ranging from about 0.02μm Ra (mirror-polished surface) to about 0.8μm Ra (320 grit paper). The aim of such choice was to investigate the effect of a surface roughness different from the optimal one (mirror polished) on the coating deposition. Moreover a different corrosion resistance is expected.

Corrosion of 9% Cr Ferritic/Martensitic Steels in Flowing Pb-Bi Eutectic With 10−7 Mass% Dissolved Oxygen at 450 and 550 °C

2016 ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Incubation Time ◽  
Local Solution ◽  
Maximum Depth ◽  
Martensitic Steels ◽  
Corrosion Attack ◽  
Accelerated Oxidation ◽  
Effect Of Alloying

Corrosion behavior of 9 %Cr ferritic/martensitic (F/M) P92, E911 and EUROFER steels was investigated in flowing (2 m/s) Pb-Bi with 10−7 mass%O at 450 and 550 °C for up to 8766 and 2011 h, respectively. The steels show mixed corrosion modes simultaneously revealing protective scaling, accelerated oxidation and solution-based attack. At 450 °C, the accelerated oxidation resulted in a metal recession averaging 6 μm (± 2 μm) after ∼8766 h while local solution-based corrosion attack ranged from ∼40 to 350 μm. At 550 °C, the accelerated oxidation resulted in a metal recession of about 10 μm (± 2 μm) after ∼2011 h. Solution-based corrosion attack appears more regularly at 550 °C, with a maximum depth ranged from ∼90 to 1000 μm. Incubation time for solution based attack is 500–2000 h for 450 °C and < 300 h for 550 °C. The EUROFER steel showed more severe metal recession via both oxidation and solution-based corrosion in comparison with P92 and E911 steels. The possible effect of alloying and structure on the corrosion response of 9 %Cr F/M steels is discussed.

Corrosion Interaction of 9%Cr Ferritic/Martensitic Steels at 450 and 550 °C With Flowing Pb–Bi Eutectic Containing 10−7 Mass % Dissolved Oxygen

2019 ◽  
Vol 5 (3) ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Incubation Time ◽  
Scale Formation ◽  
Local Solution ◽  
Maximum Depth ◽  
Martensitic Steels ◽  
Corrosion Attack ◽  
Accelerated Oxidation ◽  
Protective Scale

Corrosion behavior of 9%Cr F/M P92, E911, and EUROFER steels was investigated in flowing (2 m/s) Pb–Bi with 10−7 mass % O at 450 and 550 °C for up to 8766 and 2011 h, respectively. The steels show mixed corrosion modes simultaneously revealing protective scale formation, accelerated oxidation, and solution-based attack. At 450 °C, the accelerated oxidation resulted in a metal recession averaging 6 μm (± 2 μm) after ∼ 8766 h, while local solution-based corrosion attack ranged from ∼40 to 350 μm. At 550 °C, the accelerated oxidation resulted in a metal recession of about 10 μm (± 2 μm) after ∼ 2011 h. Solution-based corrosion attack appears more regularly at 550 °C, with a maximum depth ranged from ∼90 to 1000 μm. The incubation time for the solution based attack at 450 °C is 500–2000 h and < 300 h at 550 °C.

Effect of Structural State of Austenitic 15-15 Ti Steel on Initiation and Propagation of Solution-Based Corrosion Attack in Flowing Liquid Pb-Bi Eutectic at 400 and 500 °C

2017 ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Structural State ◽  
Qualitative Information ◽  
Corrosion Attack ◽  
Flowing Liquid ◽  
Type Distribution ◽  
Initiation And Propagation ◽  
Identical Composition ◽  
Diffusion Paths ◽  
Cold Worked

Investigations of corrosion behavior of austenitic 1.4970 (15–15 Ti) steel in Pb-Bi eutectic at 400–550 °C show an effect of structural state of material with identical composition on the depth of solution-based attack. Structural boundaries play a role of active paths along which the solution-based liquid-metal attack develops preferentially. In this view it is important to have quantitative and qualitative information about grain boundary type distribution in material and state of boundaries with respect to the accumulated strains. The EBSD analysis performed on 1.4970 steel in solution-annealed and cold-worked (40% reduction) states indicates that deformation increases substantially the total length of strained boundaries. The increase in fraction of active diffusion paths results in acceleration of corrosion attack on steel via solution.

Effect of Temperature and Dissolved Oxygen on the Corrosion Behavior of Carbon Steel in High-Temperature Water

CORROSION ◽  
1991 ◽  
Vol 47 (7) ◽  
pp. 500-508 ◽  
Author(s):  
K. Mabuchi ◽  
Y. Horn ◽  
H. Takahashi ◽  
M. Nagayama
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Oxide Surface ◽  
X Ray ◽  
High Temperature Water ◽  
Temperature Water

Abstract The corrosion behavior of carbon steel in high-temperature water, and the structure and composition of the oxide film were examined as functions of dissolved oxygen concentration (DO), temperature (T), and corrosion time (t). The total amount of iron corroded (WT) was differentiated into the amounts of iron ions in the oxide (WF) and dissolved into the water (WD). The total rate of corrosion (rT), the rate of iron dissolution (rD), and the rate of accumulation of iron in the oxide (rF) were obtained by differentiating the time variations in WT, WF, and WD. The structure and composition of the oxide film were examined by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and transmission and scanning electron microscopy. In general, rT increases with increasing DO and T, rD shows T- and DO-dependent minimum, and there is serious localized corrosion at high DO above 500 ppb. Oxide films consist of magnetite except at T=60°C, DO=50 to 200 ppb where a thin layer of hydrous ferric oxide is formed. At DO=500 ppb , the outermost part of the magnetite changes into γ-Fe2O3, and above DO=1.0 ppm, appreciable amounts of α-Fe2O3 cover the magnetite oxide layer. The rT and rD values are not related to the presence of αFe2O3 or Fe3O4 in the surface structure of the oxide, but clearly decrease as the OH−/Fe mole ratio at the oxide surface increases. The mechanism determining the corrosion rate changes is discussed.

Effect of Oxygen Concentration in Static Pb-Bi Eutectic on Corrosion Mode of Aluminum-Alloyed Austenitic Steels at 550 °C for 1000 h

2021 ◽  
Vol 1024 ◽  
pp. 79-85
Author(s):  
Valentyn Tsisar ◽  
Zhang Jian Zhou ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Carsten Schroer
Keyword(s):  
Liquid Metal ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Corrosion Behavior ◽  
Austenitic Steels ◽  
Ferrite Layer ◽  
Effect Of Oxygen ◽  
Corrosion Mode ◽  
Al Oxide

Corrosion behavior of Fe-18Ni-12Cr-2.30Al and Fe-18Ni-12Cr-2.90Al-Nb-C austenitic steels was investigated in static Pb-Bi eutectic at 550 °C for 1000 h depending on the concentration of dissolved oxygen in the liquid metal. In the concentration range from 1012 to 108 mass % O, both steels underwent corrosion via dissolution resulted in the formation of spongy ferrite layer depleted in Ni and Cr and penetrated by Pb and Bi. In Pb-Bi with 106 mass % O, Fe-18Ni-12Cr-2.90Al-Nb-C steel oxidizes with formation of very thin (≤ 1 μm) Cr/Al oxide film while Fe-18Ni-12Cr-2.30Al steel shows mixed corrosion behavior represented by more intensive oxidation and dissolution. The features of corrosion response are discussed depending on the composition of steels and concentration of dissolved oxygen in the Pb-Bi eutectic.

scholarly journals Numerical Simulation of Effect of Different Initial Morphologies on Melt Hydrodynamics in Laser Polishing of Ti6Al4V

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 581
Author(s):  
Kai Li ◽  
Zhenyu Zhao ◽  
Houming Zhou ◽  
Hao Zhou ◽  
Jie Yin ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Processing Parameters ◽  
Surface Finishing ◽  
Polished Surface ◽  
Laser Polishing ◽  
Starting Position ◽  
Double Spiral ◽  
The Difference ◽  
Thermocapillary Forces ◽  
Surface Morphologies

As a surface finishing technique for rapid remelting and re-solidification, laser polishing can effectively eliminate the asperities so as to approach the feature size. Nevertheless, the polished surface quality is significantly sensitive to the processing parameters, especially with respect to melt hydrodynamics. In this paper, a transient two-dimensional model was developed to demonstrate the molten flow behavior for different surface morphologies of the Ti6Al4V alloy. It is illustrated that the complex evolution of the melt hydrodynamics involving heat conduction, thermal convection, thermal radiation, melting and solidification during laser polishing. Results show that the uniformity of the distribution of surface peaks and valleys can improve the molten flow stability and obtain better smoothing effect. The high cooling rate of the molten pool resulting in a shortening of the molten lifetime, which prevents the peaks from being removed by capillary and thermocapillary forces. It is revealed that the mechanism of secondary roughness formation on polished surface. Moreover, the double spiral nest Marangoni convection extrudes the molten to the outsides. It results in the formation of expansion and depression, corresponding to nearby the starting position and at the edges of the polished surface. It is further found that the difference between the simulation and experimental depression depths is only about 2 μm. Correspondingly, the errors are approximately 8.3%, 14.3% and 13.3%, corresponding to Models 1, 2 and 3, respectively. The aforementioned results illustrated that the predicted surface profiles agree reasonably well with the experimentally measured surface height data.

Hole Expansion by Using Al-Alloy Specimen and 0.45% Carbon Steel Specimen

2010 ◽  
Vol 452-453 ◽  
pp. 601-604
Author(s):  
Muhammed Sohel Rana ◽  
Md. Shafiul Ferdous ◽  
Chobin Makabe ◽  
Masaki Fujikawa
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Cold Work ◽  
Fatigue Crack Initiation ◽  
Steel Specimen ◽  
Expansion Method ◽  
Al Alloy ◽  
2024 Aluminum Alloy ◽  
Cold Worked

The enhancement method of fatigue life and the crack initiate and growth behavior of a holed specimen was investigated by using the 2024 Aluminum alloy and 0.45% Carbon steel. The purpose of present study is to propose a simple technical method for enhancement of fatigue life in a notched specimen. Also, the effect of local plastic deformation by cold work on fatigue crack initiation behavior was examined. This paper presents a basic experimental kinematic cold expansion method by inserting and removing a pin through the specimen hole. The shape of cross-section of pin was a circle or an ellipse. It was shown that the fatigue life of the specimen with the cold-worked hole was longer than that of the specimen with non-cold-worked hole for the case of same stress level in aluminum alloy and carbon steel. Also, the fatigue strength was higher in the case of the cold expanded hole. In this study, a methodology of lengthening of fatigue life of holed specimen is shown. Also, the improvement conditions of fatigue life were significantly affected by shape of pin, local hardening and residual stress conditions. The fatigue life improvement of the damaged component of structures was studied.

An x-ray Fourier line shape analysis in cold-worked hexagonal magnesium base alloys

1990 ◽  
Vol 5 (10) ◽  
pp. 2120-2125 ◽  
Author(s):  
S. K. Chattopadhyay ◽  
S. K. Chatterjee ◽  
S. P. Sen Gupta
Keyword(s):  
Rare Earth ◽  
Line Shape ◽  
Cold Work ◽  
Domain Size ◽  
Pure Magnesium ◽  
Nominal Composition ◽  
Al Alloy ◽  
X Ray ◽  
Microstructural Parameters ◽  
Cold Worked

Detailed Fourier line shape analyses considering x-ray diffraction profiles from fault unaffected 10.0, 00.2, 11.0, 20.0, 11.2, and 00.4 reflections and fault affected 10.1, 10.2, 10.3, 20.1, 20.2, 10.4, and 20.3 reflections have been performed on three magnesium base hexagonal alloys used extensively in the aircraft industry. The first of the three alloys (Mg–Al–Mn, Alloy I) had the nominal composition in wt.% of Al-8.3, Mn-0.35, Si-0.2, Cu-0.12, Fe-0.2, and other 0.01; the second alloy (Mg–Zn–Mn, Alloy II) had the nominal composition in wt.% of Zn-4.0, Mn-0.15, Si-0.01, Cu-0.03, Fe-0.01, Zr-0.70, and rare earth elements-1.50; and the last of the alloys (Mg–Zn–Al, Alloy III) had the nominal composition in wt.% of Zn-4.3, Al-0.15, Mn-0.01, Si-0.03, Cu-0.01, Ni-0.005, Zr-0.6, and rare earth-1.4. The microstructural parameters determined in these analyses indicated the average domain size in alloys I, II, and III as 208 Å, 314 Å, and 400 Å, respectively. The deformation fault densities, α, in these alloy systems (∼54 ⊠ 10−3, 35 ⊠ 10−3, and 28 ⊠ 10−3, respectively, in alloys I, II, and III) were found to be appreciably high compared to the earlier work on pure magnesium (0.63 ⊠ 10−3). The deformation twin fault density, β, which was found to be negligible in pure magnesium (∼0.21 ⊠ 10−3), was found to be negative here, also indicating the negligible presence of twin faults in these alloys. These results establish that on cold work the solutes introduce deformation stacking faults in an appreciable quantity in magnesium which is not normally susceptible to faulting when in pure form. Of these three alloys, however, Alloy I (Mg–Al–Mn) was found to be the most prone to deformation faulting.

Swirling Fluidized Bed Polishing: A New Non-Conventional Method of Surface Modification

2015 ◽  
Vol 813-814 ◽  
pp. 634-640
Author(s):  
N.K. Francis ◽  
K.G. Viswanadhan ◽  
M.M. Paulose
Keyword(s):  
Surface Modification ◽  
Fluidized Bed ◽  
Metal Removal ◽  
Complex Geometry ◽  
Removal Rate ◽  
Abrasive Particle ◽  
Surface Finishing ◽  
Polished Surface ◽  
Work Piece ◽  
Machining Accuracy

Swirling Fluidized Bed Polishing (SFBP) is a non–traditional alternative abrasive flow surface finishing form of Fluidized Bed Machining (FBM) in which the former has special features to overcome certain significant limitations of the latter, namely the variation of the surface roughness vertically along the component surface and the screening effect owing to the complex contours in the work piece geometry. Owing to its ability to perform machining and generate polished surface from a roughness value of Ra 1.2μ to 0.2 μ within 8 hours of processing, this new method offers greater scope in the surface modification of rough machined surfaces with complex geometry such as component with ducts and grooves. This research focus on investigating the effect of abrasive particle concentration on metal removal rate per unit area of the specimen surface. 3D surface morphology analysis investigates the quality of the polished surface and the study of circumferential uniformity and machining accuracy analysis on a complex-contoured component further investigate its scope and relevance in industrial applications.

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