CHANGES IN PIPE GEOMETRY DURING SEQUENTIAL CREATION OF STRESSES ON THE INNER SURFACE UNDER EXTERNAL THERMOMECHANICAL EFFECTS

In modern high-tech industry, flexible pipe technology is widely used. Pipe benders are an integral part of pipeline systems. The most widely used are methods of pipes cold bending, which are accompanied by a number of negative phenomena – such as reduction in the crackle of the wall on outer side of the bend, ovalization of the cross section and formation of bumps. The article presents a study of influence of deformation technology of pipe billets by rolling with high tension on the structure and properties of the billet’s material. The method of pipe deformation by rolling with tension allows obtaining radial bending of the billet without its destruction and without causing obvious defects of the surface and microstructure. The tests were carried out on the samples from steel of 3sp and 12Kh18N10T grades. Research of the microstructure was performed in accordance with GOST 5639 – 82, of mechanical properties – with GOST 1397 – 84, of microhardness – with GOST 9450 – 76. The article examines the effect of changes in geometry of the pipe billet on its structure and properties. The process of pipe deformation by rolling leads to changes in the mechanical properties of the tested materials. The values of micro hardness and strength increase, while the grain points decrease. In the process of deformation, it is possible to change the microstructure of the material as a result of structural transformations (quenching). In the thermomechanical method of deformation, plastic flow of metal suggests possible change in structure of pipe walls as a result of recrystallization and heat treatment of material of the bend area. Therefore, it requires further study and more in-depth analysis of this technology.

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Effect of Modification on the Structure and Properties of QE22 and RZ5 Magnesium Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.191.109 ◽

2012 ◽

Vol 191 ◽

pp. 109-114

Author(s):

Stanisław Roskosz ◽

Bartłomiej Dybowski ◽

Janusz Paśko

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Corrosion Resistance ◽

Electron Microscope ◽

Magnesium Alloys ◽

Strength Increase ◽

Structure And Properties ◽

Metallic Inclusions ◽

Mechanical And Structural Properties ◽

Scanning Electron

Magnesium alloys are the lightest, widely used structural material. They are often used in aeronautical and automotive industries, where the weight savings are essential. Magnesium alloys present acceptable mechanical properties but their high temperature properties are unsatisfactory. This led to development of magnesium alloys with rare earth elements addition. To achieve good mechanical properties these alloys are modified with zirconium. Modification affects positively also corrosion resistance of Mg-RE alloys. It is important to study impact of modifier amount on the structure and properties of these alloys. Unmodified and modified alloys were investigated. Three variants of modification were: modification according to Magnesium-Elektron specification, 50% and 100% more modifier. Mechanical and structural properties were investigated. Fractures were observed on scanning electron microscope. Results showed that grain refinement and yield strength increase with increasing amount of modifier. Impact of modification on tensile strength is unclear, probably because of non-metallic inclusions in the material’s structure. The inclusions sources are oxygenated nappe of liquid metal and fluxes, used during smelting.

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In-depth Analysis of the Structure and Properties of Two-variety Natural Luffa Sponge Fibers

10.20944/preprints201703.0023.v1 ◽

2017 ◽

Author(s):

Yuxia Chen ◽

Na Su ◽

Kaiting Zhang ◽

Shiliu Zhu ◽

Lei Zhao ◽

...

Keyword(s):

Mechanical Properties ◽

Structural Characteristics ◽

Fiber Bundles ◽

Natural Material ◽

Test Results ◽

Structure And Properties ◽

Anatomical Characteristic ◽

Depth Analysis ◽

Luffa Sponge ◽

Scanning Electron

The advancement in science and technology has led to luffa sponge (LS) being widely used as a natural material in industrial application as its polyporous structure and light texture. In order to enhance the utility of LS fibers as the reinforcement of lightweight composite materials, this study investigate its water absorption, mechanical properties, anatomical characteristic and thermal performance. Hence, moisture regain, tensile properties of LS fiber bundles were measured in accordance with standards and the structural characteristics were investigated via microscopic observation. Scanning electron microscopy (SEM) was used to observe the surface morphology and fracture surface of fiber bundles. Test results shows that the special structure where the phloem tissues degenerate to cavities had a significant influence on the mechanical properties of LS fiber bundles. Additionally, the transverse sectional area occupied by fibers in a fiber bundle (SF), wall thickness and ratio of wall to lumen of fiber cell, and crystallinity of cellulose had an impact on the mechanical properties of LS fiber bundles. Furthermore, the fiber bundles density of LS varies range of 385.46-468.70 kg/m3, much less than that of jute (1360.40 kg/m3) and Arenga engleri (950.20 kg/m3) while LS fiber bundles has superior specific modulus.

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Structure and Properties of Biodegradable Poly (Xylitol Sebacate-Co-Butylene Sebacate) Copolyester

Molecules ◽

10.3390/molecules25071541 ◽

2020 ◽

Vol 25 (7) ◽

pp. 1541 ◽

Cited By ~ 3

Author(s):

Marta Piątek-Hnat ◽

Kuba Bomba ◽

Jakub Pęksiński

Keyword(s):

Mechanical Properties ◽

Chemical Structure ◽

Block Structure ◽

Hydrolytic Degradation ◽

Sugar Alcohol ◽

Ftir Analysis ◽

Structure And Properties ◽

Water Contact ◽

Depth Analysis ◽

Biodegradable Poly

In this work, a bio-based copolyester with good mechanical properties was synthesized and characterized in terms of structure, main properties and biodegradability Determining the chemical structure of such materials is important to understand their behavior and properties. Performing an extraction of insoluble cross-linked polymer using different solvents allowed us to analyze how the polymer behaves when subjected to different chemical environments, and to obtain soluble samples suitable for more in-depth analysis. Chemical structure of poly (xylitol sebacate-co-butylene sebacate) was determined by a 1H NMR and FTIR analysis of both prepolymer gel sample and samples obtained by extraction of cross-linked polymer using different solvents. Block structure of the copolymer was confirmed by both NMR and DSC. Gel fraction, swelling value, water contact angle, and mechanical properties were also analyzed. Biodegradability of this material was confirmed by performing enzymatic and hydrolytic degradation. Synthesizing sugar-alcohol based copolyester using three monomers leads to obtaining a material with interesting chemical structure and desirable mechanical properties comparable to conventional elastomers.

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Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-8-39-48 ◽

2020 ◽

pp. 39-48

Author(s):

B. O. Bolshakov ◽

◽

R. F. Galiakbarov ◽

A. M. Smyslov ◽

◽

...

Keyword(s):

Mechanical Properties ◽

Boron Nitride ◽

Grain Boundary ◽

Bending Strength ◽

Physical And Mechanical Properties ◽

Operating Conditions ◽

Structure And Properties ◽

Steam Turbines ◽

Friction Forces ◽

Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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Age-dependent and radial sectional differences in the dynamic viscoelastic properties of bamboo culms and their possible relationship with the lignin structures

Journal of Wood Science ◽

10.1186/s10086-020-01914-y ◽

2020 ◽

Vol 66 (1) ◽

Author(s):

Yoko Okahisa ◽

Keisuke Kojiro ◽

Hatsuki Ashiya ◽

Takeru Tomita ◽

Yuzo Furuta ◽

...

Keyword(s):

Mechanical Properties ◽

Viscoelastic Properties ◽

Structural Variation ◽

Thermal Softening ◽

Peak Temperature ◽

Outer Side ◽

Phyllostachys Pubescens ◽

Age Dependence ◽

Age Dependent ◽

S Peak

Abstract Age is an important factor that dictates bamboo’s mechanical properties. In Japan, bamboo plants aged 3–5 years are selected for use as materials because of their robustness and decorative or craft-friendly characteristics. In this study, the age-dependent and radial sectional differences in bamboo’s dynamic viscoelastic properties in relation to lignin structural variation, were evaluated. We used Phyllostachys pubescens samples at the current year and at 1.5, 3.5, 6.5, 9.5, 12.5, and 15.5 years of age. There was a clear age dependence in the peak temperature of tan δ and in the yield of thioacidolysis products derived from β-O-4 lignin structures. The highest peak temperature tan δ value was detected in 3.5-year-old bamboo, which contained the highest amount of the thioacidolysis products. Moreover, tan δ’s peak temperature was always higher on the outer side, and the ratio of S/G thioacidolysis products was always higher on the inner side of bamboo plants of all ages. These results suggest that changes in bamboo’s thermal softening properties from aging are caused by the maturation and degradation of lignin in bamboo.

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Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0312 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Mahmoud Haghighi ◽

Hossein Golestanian ◽

Farshid Aghadavoudi

Keyword(s):

Mechanical Properties ◽

Ultimate Strength ◽

Multiscale Modeling ◽

Filler Content ◽

Hybrid Nanocomposites ◽

Dynamics Simulation ◽

Strength Increase ◽

Two Phase ◽

Macro Scale ◽

Elongation To Failure

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

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Influence of Applied Bias Voltage on the Composition, Structure, and Properties of Ti:Si-Codoped a-C:H Films Prepared by Magnetron Sputtering

Journal of Nanomaterials ◽

10.1155/2014/937068 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Jinlong Jiang ◽

Qiong Wang ◽

Yubao Wang ◽

Zhang Xia ◽

Hua Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Magnetron Sputtering ◽

Bias Voltage ◽

Tribological Properties ◽

Structure And Properties ◽

Applied Bias ◽

Applied Bias Voltage ◽

Methane Mixture ◽

Composition Structure

The titanium- and silicon-codoped a-C:H films were prepared at different applied bias voltage by magnetron sputtering TiSi target in argon and methane mixture atmosphere. The influence of the applied bias voltage on the composition, surface morphology, structure, and mechanical properties of the films was investigated by XPS, AFM, Raman, FTIR spectroscopy, and nanoindenter. The tribological properties of the films were characterized on an UMT-2MT tribometer. The results demonstrated that the film became smoother and denser with increasing the applied bias voltage up to −200 V, whereas surface roughness increased due to the enhancement of ion bombardment as the applied bias voltage further increased. The sp3carbon fraction in the films monotonously decreased with increasing the applied bias voltage. The film exhibited moderate hardness and the superior tribological properties at the applied bias voltage of −100 V. The tribological behaviors are correlated to the H/E or H3/E2ratio of the films.

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Industrial economics in the context of globalization: scientific, practical foundations and development priorities

Transbaikal State University Journal ◽

10.21209/2227-9245-2021-27-5-117-125 ◽

2021 ◽

Vol 27 (5) ◽

pp. 117-125

Author(s):

I. Krasovskaya ◽

◽

T. Malysheva ◽

Keyword(s):

Russian Federation ◽

Well Being ◽

Division Of Labour ◽

Sustainable Growth ◽

High Tech ◽

Industrial Economy ◽

Industrial Economics ◽

Depth Analysis ◽

The World ◽

The Russian Federation

The relevance of the publication topic is argued by the need for an in-depth study of the globalization process, which is global financial, political and cultural integration, unification, the global division of labour, the planetary migration of capital, human and productive resources, standardization of legislation, and interference of cultures of the world community. The theoretical and practical goals of the publication are to study causal algorithms for the formation of a negative scientific and production balance of the Russian Federation and an increase in disproportions between the import and export of high-tech products, as well as a comparative description of global development as a symbiosis of contradictory trends in the subordination of the world economy to the interests of transnational capital. The theoretical and methodological basis of the publication was the scientific works of domestic and foreign scientists studying the globalization of the industrial economy due to the intensification of international scientific and technological competition and the expansion of the innovation market, deepening of specialization and division of labour, and the increase in the risks of producing high-tech products at the national and world levels. Scientific novelty lies in the authors’ interpretation of such socio-economic advantages of globalization as economies of scale, stimulation of labour productivity, rationalization of production at the interstate level and the spread of innovative technologies, cost reduction, price regression, achieving sustainable growth in the well-being of society, on the basis of which the development is confirmed global industrial economy on a research basis characterized by such attributes interdependence, asymmetry, regionalization and diversification, regression efficiency, inclusiveness, resource and raw material demarcation, a high degree of uncertainty and of the economic risk. The practical significance of the results obtained is determined by an in-depth analysis of the American (based on differentiation of labor and specialization of personnel, demarcation of labor duties, concentration of scientific and production efforts on a purely economic result) and Eurasian (characterized by mobility and compactness of production processes, saving transaction costs, adaptability to market conditions and availability of labour-tolerant staff) strategies for innovative development of industrial economics. Based on a critical rethinking of the American and Eurasian strategies, proposals and recommendations are formulated on the formation of the scientific and technical policy of the Russian Federation

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Comparative Study of Two Nanoindentation Approaches for Assessing Mechanical Properties of Ion-Irradiated Stainless Steel 316

Metals ◽

10.3390/met8090719 ◽

2018 ◽

Vol 8 (9) ◽

pp. 719 ◽

Cited By ~ 3

Author(s):

Michael Saleh ◽

Zain Zaidi ◽

Christopher Hurt ◽

Mihail Ionescu ◽

Paul Munroe ◽

...

Keyword(s):

Mechanical Properties ◽

Cross Section ◽

Ion Irradiation ◽

Thin Layers ◽

Experimental Conditions ◽

Irradiation Energy ◽

Depth Analysis ◽

Deformation Processes ◽

Stainless Steel 316 ◽

Hardness Values

Nanoindentation is a commonly used method to measure the hardness of surfaces with thin layers, and is especially useful in studying the change in mechanical properties of ion irradiated materials. This research compares two different methods of nanoindentation to study the changes in hardness resulting from ion irradiation of SS316 alloy. The samples were irradiated by He2+ ions at beam energies of 1, 2, and 3 MeV, respectively. The first method involves the indentation of the irradiated surface perpendicular to it using the continuous stiffness mode (CSM), while the second applies the indents on an oblique surface, accessing an inclined cross-section of the irradiated material. Finite element modelling has been used to further illuminate the deformation processes below the indents in the two methods. The hardness profiles obtained from the two nanoindentation methods reveal the differences in the outcomes and advantages of the respective procedures, and provide a useful guideline for their applicability to various experimental conditions. It is shown through an in depth analysis of the results that the ‘top-down’ method is preferable in the case when the ion irradiation energy, or, equivalently, the irradiated depth is small, due to its greater spatial resolution. However, the oblique cross section method is more suitable when the ion irradiation energy is >1 MeV, since it allows a more faithful measurement of hardness as a function of dose, as the plastic field is much smaller and more sensitive to local hardness values.

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