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Keywords = low-frequency corrosion fatigue

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22 pages, 19807 KiB  
Article
Experimental Investigation and Modeling of Surface Roughness in BTA Deep Hole Drilling with Vibration Assisted
by Xubo Li, Chuanmiao Zhai, Canjun Wang, Ruiqin Wu, Cunqiang Zang, Shihao Zhang, Bian Guo and Yuewen Su
Materials 2025, 18(1), 56; https://doi.org/10.3390/ma18010056 - 26 Dec 2024
Cited by 1 | Viewed by 965
Abstract
The surface roughness of hole machining greatly influences the mechanical properties of parts, such as early fatigue failure and corrosion resistance. The boring and trepanning association (BTA) deep hole drilling with axial vibration assistance is a compound machining process of the tool cutting [...] Read more.
The surface roughness of hole machining greatly influences the mechanical properties of parts, such as early fatigue failure and corrosion resistance. The boring and trepanning association (BTA) deep hole drilling with axial vibration assistance is a compound machining process of the tool cutting and the guide block extrusion. At the same time, the surface of the hole wall is also ironed by the axial large amplitude and low-frequency vibration of the guide block. The surface-forming mechanism is very complicated, making it difficult to obtain an effective theoretical analytical model of the surface roughness of the hole wall through kinematic analysis. In order to achieve accurate prediction of the surface quality of the hole wall, the chip-breaking mechanism and the hole wall formation mode of BTA deep hole vibration drilling were analyzed. The influence of drilling spindle speed, feed, amplitude, and vibration frequency on the surface roughness of the hole wall during BTA deep hole vibration drilling was illustrated by a single-factor experiment. A four-factor and three-level test scheme was designed by using the Box–Behnken design (BBD) experimental design method. A surface roughness prediction model for hole wall machining was established based on the response surface methodology. The accuracy of the prediction model was analyzed through ANOVA, and the complex correlation coefficient of the model was 0.9948, indicating that the prediction model can better reflect the mapping relationship between vibration drilling parameters and surface roughness. After optimization analysis and experimental verification, the obtained vibration drilling parameters can achieve smaller surface roughness. The error between the predicted value of the model and the experimental measurement value is 8.65%. The established prediction model is reliable and can accurately predict the surface roughness of the hole wall of BTA deep hole axial vibration drilling, providing a theoretical basis for the surface quality control of the machining hole wall. It can be applied to process optimization in practical production. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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17 pages, 12801 KiB  
Article
The Study on Fatigue Crack Growth Rate of 4130X Material under Different Hydrogen Corrosion Conditions
by Shaolei Jiang, Jing Wang, Bo Zhao and Enfeng Zhang
Materials 2024, 17(1), 257; https://doi.org/10.3390/ma17010257 - 3 Jan 2024
Cited by 2 | Viewed by 1852
Abstract
In this paper, the fatigue crack growth rates of typical pressure vessel material 4130X under different corrosion conditions are investigated, and the effects of corrosion modes and loading frequency on the fatigue crack growth rate of 4130X are discussed. The results show that [...] Read more.
In this paper, the fatigue crack growth rates of typical pressure vessel material 4130X under different corrosion conditions are investigated, and the effects of corrosion modes and loading frequency on the fatigue crack growth rate of 4130X are discussed. The results show that under the same loading conditions, the pre-corroded crack propagation rate is increased by 1.26 times compared with the uncorroded specimens. The plastic deformation mechanism of the crack tip in air is dominated by phase transformation but the hydrogen introduced by pre-corrosion causes a small number of dislocations at the crack tip. The crack growth rate obtained by corrosion fatigue is four times that of the uncorroded specimen, and the fracture surface shows a strong corrosion effect. The molecular dynamics simulation shows that the hydrogen atoms accumulated at the crack tip make the plastic deformation mechanism dominated by dislocation in the crack propagation process, and the coupling interaction between low frequency and the corrosion environment aggravates the hydrogen embrittlement of the crack tip. In the air condition, the loading frequency has no obvious effect on the crack growth rate: when the frequency decreases from 100 Hz to 0.01 Hz and other conditions remain unchanged, the fatigue crack growth rate increases by 1.5 times. The parameter n in the Paris expression is mainly influenced by frequency. The molecular dynamics simulation shows that low frequency promotes crack tip propagation. Full article
(This article belongs to the Section Corrosion)
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16 pages, 4486 KiB  
Article
Low-Frequency Corrosion Fatigue Test Study of Sucker Rods under High-Salinity Well Fluids in Deep CBM Wells
by Fenna Zhang, Chuankai Jing, Jia Li, Bin Wang, Mingwei Ma, Tiantian Yi and Hao Hu
Processes 2024, 12(1), 60; https://doi.org/10.3390/pr12010060 - 27 Dec 2023
Cited by 2 | Viewed by 1533
Abstract
Corrosion fatigue test is the most direct and effective method to study the corrosion fatigue characteristics of sucker rod. At present, the commonly used test method is the high frequency fatigue test, but the working state of sucker rod is typical low-frequency and [...] Read more.
Corrosion fatigue test is the most direct and effective method to study the corrosion fatigue characteristics of sucker rod. At present, the commonly used test method is the high frequency fatigue test, but the working state of sucker rod is typical low-frequency and high-cycle corrosion fatigue, and the test with high frequency will reduce the impact of corrosion. Alloy steel 4330 is widely used in coalbed gas well high strength sucker rod, but the research on its low frequency corrosion fatigue life is relatively few. Therefore, in this paper, the corrosion fatigue test method of axial low-frequency and high-cycle was adopted to study the corrosion fatigue characteristics of 4330 steel sucker rod through the corrosion fatigue test under different typical corrosion media, temperature, and stress levels. The results show that the fatigue life of 4330 sucker rod drops sharply when the Cl concentration in high salinity well fluid exceeds the threshold value of 155 mg/L. When this threshold is exceeded, the downward trend slows down. It can be seen that the significant factor affecting the corrosion fatigue life of 4330 material is not the concentration of Cl, but the existence of Cl. The presence of HCO3 promotes a further decrease in the corrosion fatigue life of the 4330 sucker rod by Cl. The corrosion fatigue life of 4330 sucker rod decreases with the increase of temperature. When the well fluid temperature is less than 50 °C, the impact is relatively significant. When the well fluid temperature is more than 70 °C, the decline trend of corrosion fatigue life slows down. Based on the fitted S-N curve (stress-fatigue life curve), it is calculated that the fatigue limit of 4330 sucker rod at the stress ratio of 0.6 is 196 MPa in the solution of 10,000 mg/L Cl at room temperature. These could provide valuable theoretical and technical guidance for design and selection of high-strength sucker rod in high-salinity corrosion well fluid environment. Full article
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16 pages, 6918 KiB  
Article
Progress in Evaluation of Deep Artificial Defects from Sweep-Frequency Eddy-Current Testing Signals
by Milan Smetana, Daniela Gombarska and Zuzana Psenakova
Sensors 2023, 23(13), 6085; https://doi.org/10.3390/s23136085 - 1 Jul 2023
Cited by 6 | Viewed by 1974
Abstract
The article discusses the practical application of the method of electromagnetic non-destructive investigation of austenitic materials. To identify and evaluate deep artificial defects, the sweep-frequency eddy current method with harmonic excitation is used. The objects of interest are the surface electric-discharged machined notches, [...] Read more.
The article discusses the practical application of the method of electromagnetic non-destructive investigation of austenitic materials. To identify and evaluate deep artificial defects, the sweep-frequency eddy current method with harmonic excitation is used. The objects of interest are the surface electric-discharged machined notches, with a defined geometry, fabricated in a plate with a thickness of 30 mm. An innovative eddy current probe with a separate excitation and detection circuit is used for the investigation. The achieved results clearly demonstrate the robustness and potential of the method, especially for deep defects in thick material. By using the fifth probe in connection with the frequency sweeping of eddy currents, it is possible to reliably detect artificial defects up to 24 ± 0.5 mm deep by using low-frequency excitation signals. An important fact is that the measuring probe does not have to be placed directly above the examined defect. The experimental results achieved are presented and discussed in this paper. The conducted study can serve, for example, as an input database of defect signals with a defined geometry to increase the convergence of learning networks and for the prediction of the geometry of real (fatigue and stress-corrosion) defects. Full article
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16 pages, 4375 KiB  
Article
Influence of Magnetizing Conditions on Barkhausen Noise in Fe Soft Magnetic Materials after Thermo-Mechanical Treatment
by Miroslav Neslušan, Katarína Zgútová, Martin Pitoňák and Daniel Kajánek
Materials 2022, 15(20), 7239; https://doi.org/10.3390/ma15207239 - 17 Oct 2022
Cited by 4 | Viewed by 1656
Abstract
Low alloyed steels of low, medium, or high strength are frequently used for many applications in the automotive, civil (bridges), aerospace, and petrochemical industries. A variety of thermomechanical regimes, in which these steels can be produced, enable customization of their matrix with respect [...] Read more.
Low alloyed steels of low, medium, or high strength are frequently used for many applications in the automotive, civil (bridges), aerospace, and petrochemical industries. A variety of thermomechanical regimes, in which these steels can be produced, enable customization of their matrix with respect to their fatigue resistance, resistance against friction and impact wear, fracture toughness, corrosion resistance, etc. This study analyses the influence of magnetising conditions on Barkhausen noise and other extracted parameters. It was found that the increasing magnetising frequency makes Barkhausen noise weaker, especially in the high strength low alloyed steels, as a result of the decreasing magnetic field in a sample. For this reason, increasing fraction of domain walls is unpinned at the higher frequencies. Barkhausen noise for the high strength low alloyed steels at higher frequencies is remarkably attenuated. Moreover, the different behaviour with respect to direction of the sheet rolling and the transversal direction, can be found due to realignment of the domain walls. This study demonstrates that the position of Barkhausen noise envelopes and the number of Barkhausen noise pulses increase in a systematic manner at the lower magnetising frequencies. Those parameters can be employed for distinction of the low alloyed steels, investigated in this study. However, the increasing magnetising frequency makes attenuation of Barkhausen noise more remarkable for the low alloyed steels of the higher strength. Therefore, the effective value of Barkhausen noise, at the magnetising frequency 750 Hz, in the rolling direction exhibits the systematic descent along with the increasing yield strength. This parameter can be used for distinction of the low alloyed steels after their thermomechanical processing, as well. Full article
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17 pages, 3466 KiB  
Article
Life-Cycle Cost Analysis of Long-Span CFRP Cable-Stayed Bridges
by Yue Liu, Mingyang Gu, Xiaogang Liu and T. Tafsirojjaman
Polymers 2022, 14(9), 1740; https://doi.org/10.3390/polym14091740 - 25 Apr 2022
Cited by 17 | Viewed by 3343
Abstract
With the advantages of high strength, light weight, high corrosion and fatigue resistance, and low relaxation, carbon-fiber-reinforced polymer (CFRP) is an excellent cable material for cable-stayed bridges. However, the relatively high unit price of CFRP compared to that of steel may hinder the [...] Read more.
With the advantages of high strength, light weight, high corrosion and fatigue resistance, and low relaxation, carbon-fiber-reinforced polymer (CFRP) is an excellent cable material for cable-stayed bridges. However, the relatively high unit price of CFRP compared to that of steel may hinder the large-scale application of CFRP stay cables. This paper presents the economic comparison between long-span cable-stayed bridges using CFRP cables and the corresponding steel cable-stayed bridges through life-cycle cost analysis (LCCA). Three CFRP cable-stayed bridges with a main span of 600 m, 1200 m, and 1800 m, respectively, along with their steel counterparts, were designed, and their life-cycle costs (LCCs) were calculated. The comparison of LCCs was not only between the CFRP and steel cable-stayed bridges with the same span, but also between the cable-stayed bridges with different spans. Furthermore, the different unit prices of CFRP cables and different replacement frequencies of steel cables were also investigated. The results show that the initial design and construction cost of the long-span CFRP cable-stayed bridge is higher than that of the corresponding steel cable-stayed bridge, although using CFRP cables can reduce the materials used, primarily due to the higher unit price of the CFRP cable. Despite the higher initial cost, the long-span CFRP cable-stayed bridge can still achieve lower LCC than the steel cable-stayed bridge, because it has significantly lower rehabilitation cost and user cost, as well as slightly lower vulnerability cost. Furthermore, with the increase in the main span and the decrease in the unit price of CFRP cables, the LCC advantage of the long-span CFRP cable-stayed bridge becomes more obvious. Full article
(This article belongs to the Special Issue Fiber-Reinforced Polymer Composites in Construction Materials)
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18 pages, 22168 KiB  
Article
Fatigue Behavior of Metastable Austenitic Stainless Steels in LCF, HCF and VHCF Regimes at Ambient and Elevated Temperatures
by Marek Smaga, Annika Boemke, Tobias Daniel, Robert Skorupski, Andreas Sorich and Tilmann Beck
Metals 2019, 9(6), 704; https://doi.org/10.3390/met9060704 - 21 Jun 2019
Cited by 33 | Viewed by 6068
Abstract
Corrosion resistance has been the main scope of the development in high-alloyed low carbon austenitic stainless steels. However, the chemical composition influences not only the passivity but also significantly affects their metastability and, consequently, the transformation as well as the cyclic deformation behavior. [...] Read more.
Corrosion resistance has been the main scope of the development in high-alloyed low carbon austenitic stainless steels. However, the chemical composition influences not only the passivity but also significantly affects their metastability and, consequently, the transformation as well as the cyclic deformation behavior. In technical applications, the austenitic stainless steels undergo fatigue in low cycle fatigue (LCF), high cycle fatigue (HCF), and very high cycle fatigue (VHCF) regime at room and elevated temperatures. In this context, the paper focuses on fatigue and transformation behavior at ambient temperature and 300 °C of two batches of metastable austenitic stainless steel AISI 347 in the whole fatigue regime from LCF to VHCF. Fatigue tests were performed on two types of testing machines: (i) servohydraulic and (ii) ultrasonic with frequencies: at (i) 0.01 Hz (LCF), 5 and 20 Hz (HCF) and 980 Hz (VHCF); and at (ii) with 20 kHz (VHCF). The results show the significant influence of chemical composition and temperature of deformation induced α´-martensite formation and cyclic deformation behavior. Furthermore, a “true” fatigue limit of investigated metastable austenitic stainless steel AISI 347 was identified including the VHCF regime at ambient temperature and elevated temperatures. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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8 pages, 4147 KiB  
Article
Enhanced Molten Salt Resistance by Sidewall Pores Repair during Fs Laser Drilling of a Thermal Barrier-Coated Superalloy
by Zhengjie Fan, Xiaomao Sun, Xuesong Mei and Rujia Wang
Materials 2019, 12(12), 1905; https://doi.org/10.3390/ma12121905 - 13 Jun 2019
Cited by 4 | Viewed by 2810
Abstract
In this study, a novel laser-modified drilling method was used to manufacture cooling holes through thermal barrier coatings (TBCs). Due to the “cooling processing” properties during low-frequency femtosecond (LF-fs) laser drilling, the exposure of the sidewall pores, and the interlayer clearance, the inherent [...] Read more.
In this study, a novel laser-modified drilling method was used to manufacture cooling holes through thermal barrier coatings (TBCs). Due to the “cooling processing” properties during low-frequency femtosecond (LF-fs) laser drilling, the exposure of the sidewall pores, and the interlayer clearance, the inherent characteristics of plasma-sprayed coatings induced sidewall defects in the drilled holes. After drilling, a high-frequency fs (HF-fs) laser was used to repair the sidewall pores and interlayer clearance of the drilled ceramic holes. Then, the pores and microcracks were healed by local melting using the laser. Moreover, instead of obtaining laser-induced periodic surface structures (LIPSSs), refined and homogeneous grains were produced by the HF-fs laser repair treatment at high transient pressure and temperature. The results from a high-temperature corrosion test showed that healing of the open pores and microstructural improvement in the ceramic hole walls prevented the out-diffusion of Y2O3 stabilizers and the penetration of molten salt, resulting in less corrosive products and producing corresponding phase-transformation stress. Thus, reducing the stabilizer consumption can moderate corrosion fatigue and prolong the lifetime of a cooling hole and TBCs under service. Full article
(This article belongs to the Section Corrosion)
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