Small Steel Research Articles

An Experimental Study on the Effectiveness of Particle Tuned Mass Dampers

The effectiveness of a particle-tuned mass damper was investigated experimentally using a small single story steel structure. Two cases were examined. First, the damper was suspended from the structure with a fixed weight inside the container and in the second case the fixed weight was replaced by particles of equal mass filling two unequal size compartments. In both cases, the frequency of the damper was close to the natural frequency of the structure. The dynamic behavior of the structure with the damper was examined under random excitation. It was found that while the root mean square (RMS) of the response acceleration was reduced in both cases, the substitution of the fixed weight with the particles increased the attenuation of the motion. Reduction of the RMS of the relative displacement was observed after the first few seconds of the excitation. The excitation level has a minimal effect on the effectiveness of the particle-tuned mass damper with the two unequal size compartments.

Experiments on Gas-Metal-Arc Welding (MAG) with Combined Spin-Arc and Weaving Facilities, for Interdisciplinary Applications

The article presents experiments for the development of the welding technology for plates of the steel S355JR, according to EN 10025-2:2004, for ship building and harbor structures.Marine steel plate grades for ship hull, according to ABS, American Bureau of Shipping, are presented, compared with the S355JR steel.For applications on board ships, the standard EN ISO 5778:1998 is also mentioned. It specifies the materials and quality levels for small weathertight steel hatches.The filler metal is the copper-coated, manganese-silicon-alloyed solid wire, type SG-3, according to EN ISO 14341:2020. The shielding gas is the gas mixture CORGON 18/82, according to EN ISO 14175:2008, type M21.As a welding travel unit, the modular drive system MDS-1, made by the company BUG-O Systems, of USA was used. It has the following main components: 1- rack-based track; 2- carriage; 3- master drive unit; 4- clutch; 5- weaver control module; 6- linear weaver unit; 7- linear weaver cross arm; 8- gun mounting group; 9- welding gun.The welding source is the Inverter MIG 300 A type, manufactured by Mahe GmbH, Germany.The sizes of the two plates for the welding test piece are: length 700 mm; width 200 mm; thickness 15 mm, I groove with 8 mm gap.The welding parameters used for all the layers (root, fill #1 - fill #4) are presented in a common table, for comparison.The parameter ranges are as follows: welding current 177-251 A; welding voltage 21.9-23.1 V; wire advance speed 6.5-7.2 m/min; shielding gas flow rate 20.8-21.8 liters/min; welding speed 20-45 cm/min. A special spin-arc welding method was applied on all weld layers. The execution of the welding test piece is described with specific details and photos.Upon visual inspection after the execution of each layer, the appearance is adequate. No defects or imperfections are observed.On ultrasonic examination, the results are adequate.Metallographic examination, tensile, bending and Charpy V impact tests are presented with appropriate results.The conclusions mention the adequate results obtained, regarding the ranges of the welding parameters and the use of the innovative spin-arc technology. Possible applications of the S355JR steel are recommended.The references present titles related to ship building steels, filler metal, shielding gas, welding equipment and some specific technologies.

Mechanical behavior of GFRP-recycled concrete-steel multitube concrete columns under axial compression

This paper proposed a novel GFRP-recycled concrete-steel multitube concrete column (RA-MTCC), which consisted of an external circular GFRP tube, a group of small internal steel tubes in a circular array, and recycled aggregate concrete filling for all the space inside of these tubes. The mechanical behavior of eleven specimens were investigated under uniaxial compressive test considering parameters of the GFRP tube thickness, the configurations of internal steel tubes, the strength and the replacement ratio of recycled coarse aggregates (RCAs). Test results indicated that: (1) the replacement ratio of RCAs had no significant impact on the failure mode and ultimate load bearing capacity but noticeable adverse effect on the stiffness of RA-MTCCs; (2) the small internal steel tube could significantly increase the ultimate load bearing capacity and stiffness of RA-MTCCs, with a maximum enhancement of 82% and 114%, respectively; (3) specimens with GFRP outside exhibited excellent ductility behavior due to the effective confinement provided by GFRP jacket and steel tubes. An analytical model considering the replacement ratio of RCAs was proposed and verified with the present test results. The predicted results showed that the proposed model could accurately predict the full range stress–strain response of RA-MTCCs. Finally, based on the proposed analytical model, a simplified calculation formula for the ultimate bearing capacity of RA-MTCC was proposed.

Thermodynamic investigations of steel deoxidation process with calcium and barium

The use of alloys with alkaline earth metals (AEM) it possible to optimize the processes of deoxidation and refining of steel from non-metallic inclusions. The technologies of ladle treatment of the melt with the use of AEM complexes to obtain high-quality metal products even if it is impossible to use expensive equipment (vacuumers, tribe apparatus, etc.), which is often typical for small steel foundries. At the same time, a number of issues related to the mechanisms implemented during the refining of liquid steel with calcium and barium require further study. In the course of this work, the authors constructed state diagrams of double (CaO–BaO) and ternary (FeO–CaO–BaO) oxide systems and carried out thermodynamic modeling of equilibria in the Fe–Ca–Ba–C–O system. It is noted that in this system there is an extensive equilibrium region of the oxide melt with solid solutions of CaO-based oxides. The solubility surfaces of components for the temperatures of steel ladle treatment (1550–1600 °С) and for different carbon contents (0; 0,1; 0,4 % С) are constructed for the studied system. A comparative analysis of the constructed diagrams suggests that a change in the carbon content within the indicated limits does not significantly affect the type of the diagrams. It follows that the revealed patterns will be maintained in the production of a wide range of economically alloyed low-carbon steels. It is shown that during the deoxidation of steel without aluminum, and with a calcium content typical for real production processes (about 30 ppm), the expected active oxygen content is about 30 ppm (log[O] = –2.5), which does not meet modern requirements for purity become. At the same time, a change of the barium content has practically no effect on the degree of deoxidation of the metal. Thus, it is shown that the main role of calcium and, especially, barium in the processing of liquid steel is modification and removal of non-metallic inclusions from the melt

A method for sensitivity analysis of deviation factor for geometric correction of cone-beam CT system

To propose a sensitivity test method for geometric correction position deviation of cone-beam CT systems. We proposed the definition of center deviation and its derivation. We analyzed the influence of the variation of the three-dimensional spatial center of the steel ball point, the projection center and the size of the steel ball point on the deviation of geometric parameters and the reconstructed image results by calculating the geometric correction parameters based on the Noo analytical method using the FDK reconstruction algorithm for image reconstruction. The radius of the steel ball point was within 3 mm. The deviation of the center of the calibration parameter was within the order of magnitude and negligible. A 10% Gaussian perturbation of a single pixel in the 3D spatial coordinates of the steel ball point produced a deviation of about 3 pixel sizes, while the same Gaussian perturbation of the 2D projection coordinates of the steel ball point produced a deviation of about 2 pixel sizes. The geometric correction is more sensitive to the deviation generated by the three-dimensional spatial coordinates of the steel ball point with limited sensitivity to the deviation generated by the two-dimensional projection coordinates of the steel ball point. The deviation sensitivity of a small diameter steel ball point can be ignored.

Evaluation of Multi-Compartment Particle Dampers for the Attenuation of Dynamic Vibrations

An experimental study was performed examining the effectiveness of a multi-compartment damper in attenuating the response of structures under random and earthquake excitations. The damper consisted of four compartments of unequal size; it was mounted on a small one-story steel structure. The same number of steel spherical particles were placed inside each compartment, resulting in filling area ratios (the total area of the squares around the projected particles divided by the area of the compartment) from 40% to 70%. The damper was effective in reducing the response displacement and acceleration of the structure considerably. The use of different filling area ratios enabled the damper to be effective for a wide range of excitation levels.

Morphology transformation of stainless steel 316L powder from spheres to flakes using high-energy ball milling and the investigation of transformation behaviour

ABSTRACT Today, microfiltration plays the most significant role in removing fine particulate impurities in gas streams used in high-tech industries. However, the current SS316L gas filter has a limitation in enhancing performance due to the trade-off relationship between filterability and permeability. This limitation can be overcome by the geometrical effect of the gas filter that maximises inertial impaction and diffusion interception due to complex flow channels using small flake particles. However, since the smaller the particle size, the yield strength higher, there are few reports of preparing the small flake particles by plastic deformation. This study used a high-energy ball milling process to demonstrate the preparation method for small stainless steel 316L flake particles. Furthermore, the process parameters are systematically optimised to fully transform the spherical particles into thin platelets without fracture and cold welding, and the transformation behaviour is discussed in detail.

A study on the evolution mechanism of small diameter thin-walled stainless steel bellows during a bending process

In order to accurately construct the evolution mechanism of the matrix during the bending process, this paper combines finite element simulation and material characterization methods to study the evolution process of the matrix in detail. Firstly, a repeated bending model of the bellows was constructed by ABAQUS finite element software. The deformation hardening, geometry evolution, stress and strain evolution of the matrix were analyzed in depth. At the same time, by characterizing the microstructure of the trough under different bending times, the evolution of the microstructure during the fracture process was obtained. Combined with the fracture characteristics, it can be seen that the deformation hardening of the trough is significant and the stress is large, so it is most likely to become the failure zone. The waveform distortion increases the deformation inhomogeneity of the trough at different positions, resulting in local large strain accumulation and further aggravating the fracture failure of the trough. During the bending process, a large number of martensite tissue appears in the central area of the bellow wall thickness, and the dislocation gradually moves from the inner and outer surfaces to the center. The crack initiates first at the bellow outer surface and propagates along the circumference and wall thickness direction. Bending four times is the key node of crack propagation. Moreover, the crack propagation models of the trough in the wall thickness and circumferential direction are established, and the fracture failure mechanism of the trough during repeated bending is revealed.

Differential eddy current method for full circumferential defect detection of small diameter steel pipe: Numerical analysis and experimental study

Duplex stainless steel (DSS) coiled tubing (CT) is widely used in offshore and onshore operations because of its high plasticity, high toughness, and high corrosion resistance. However, the online detection technology of DSS CT has not yet been achieved. In this paper, we propose an eddy current testing method using a differential curved surface probe designed for CT inspection. The probe parameters are optimized using numerical simulation. The array probe is placed alternately on the surface of CT, enabling 360° fully covered detection of coiled tubing with a diameter of less than 50.8 mm. The method detects longitudinal and axial defects and overcomes the limitation of magnetic flux leakage (MFL) detection, which can only detect unidirectional defects in carbon steel. Finally, we processed and tested a sample tube, demonstrating that the device meets the testing standard of coiled tubing.

Influence of High-Frequency Welding Production Parameters on Microstructure and Cold Resistance of Small and Medium Diameter Steel Pipe Welded Joints

Influence of High-Frequency Welding Production Parameters on Microstructure and Cold Resistance of Small and Medium Diameter Steel Pipe Welded Joints

Assessment of Small Diameter Steel Pile as a Stabilizing Element for Transmission Tower Slope Stability

Background: Stabilization of unstable slopes with relatively large reinforced concrete piles has been widely adopted over the past several decades. Small diameter steel piles have several advantages as a slope reinforcement technique for an unstable transmission tower slope where space and access restrictions that typically occur render alternate approaches unfeasible. Methods: In this study, a numerical performance assessment of small diameter steel pile as a stabilizing element for transmission tower slope stability was carried out using an uncoupled analysis, in which the pile response and slope stability are considered separately. Numerical evaluations are presented and the influencing parameters that could affect the behavior of reinforcing piles to increase transmission tower slope stability are investigated. Results: The numerical analysis results indicate that the soil properties, slope geometry, pile location, pile diameter, pile length and number of pile rows have a combined effect on the performance of small diameter steel piles to stabilize transmission tower slopes. Conclusion: The numerical assessment can satisfactorily capture some fundamental response of transmission tower slope reinforced with multi-row small diameter steel piles.

Failure of urban subway segments in coastal area and reinforcement effect of bonded steel plate: a case study in China

The construction of metro in coastal areas is prone to safety accidents when it encounters unfavourable geology. Serious water inrush and sand gushing occurred during the construction of the shield tunnel connection channel of Shenzhen Metro Line 20, resulting in extensive deformation and even cracking of the shield segment. With the event as the background, it is conducted in this article with a further analysis of the causes of sand gushing in the connecting channel. Using convergence displacement and crack width as indicators, the shield segments are classified as strong influence zone, moderate influence zone, weak influence zone and no influence zone. Furthermore, by combining numerical simulation and field investigation, the innovative method of epoxy bonded steel plate reinforcement is proposed. In particular, it should be noted that the steel plate needs to be opened at the connection channel, so four small right-angle steel plates are designed to reduce the concentrated stress of the split ring. According to finite element analysis and on-site measurement, it can be known that after the steel plate is reinforced, the internal force of the segment is greatly reduced, and the deformation is stable, which can ensure the safe service of the tunnel. This research provides a new idea for the damaged reinforcement of urban subway segments in coastal areas in the future.

Non-Destructive Eggshell Strength Assessment Using Hertz Contact Theory—Part II: Implementation and Validation

Eggshell strength is a critical quality factor for consumption eggs as it affects the probability of breakage in practice. In this study, a fast and low-cost methodology for the non-destructive determination of eggshell strength is presented. The method utilized a small steel ball to impact the egg and a microphone to analyse the impact characteristics. Hertz contact theory was applied to relate the measured impact characteristics to the local stiffness of the eggshell. Therefore, a total of 150 eggs were studied on which eight consecutive measurements per egg were taken around the equator at equidistant places. The results showed a strong correlation of 0.93 between the traditional static stiffness measured during quasi-static compression tests and the average stiffness obtained from the new methodology. This paves the way towards fast, low-cost and non-destructive in-line shell strength measurements to reduce the number of cracked eggs reaching the consumer.

Non-Destructive Eggshell Strength Assessment Using Hertz Contact Theory Part I: Theory and Applicability

In the egg industry, fast and highly reliable quality measurements are crucial. This study presents a novel method based on Hertz contact theory that allows for non-destructive determination of eggshell strength. The goal of the study was to evaluate the material strength (Young's Modulus) and structural strength (stiffness) of eggshells. To this end, an experimental setup was constructed to measure the collision of an eggshell with a small steel ball, which was recorded using a laser vibrometer. The study analyzed a sample of 120 eggs and found a correlation of 0.85 between the traditional static stiffness measured during quasi-static compression tests and the stiffness obtained from the Hertz contact theory. The results show that Hertz contact theory is valid for small steel spheres impacting eggshells, while a sensitivity analysis indicated that the most important factor in determining the strength of the eggshell is the contact duration between the egg and the impactor. These results open up the possibility of grading eggs based on their shell strength in a non-destructive manner.

Introduction and Investigation into Oil Well Logging Operations (Review)

ole in all sta Oil well logging, also known as wireline logging, is a method of collecting data from the well environment to determine subterranean physical properties and reservoir parameters. Measurements are collected against depth along the well's length, and many types of wire cabling tools depend on the physical property of interest. Well probes generally has a dynamic respon to changes in rock layers and fluid composition. These probes or well logs are legal documents that record the history of a well during the drilling stages until its completion. Well probes record the physical properties of the well, which must then be interpreted in petrographic terms to obtain the characteristics of the rocks and fluids associated with the well. Many bases on which well probes are depend on obtaining information, and preventing the rocks from responding to stimuli sent by special devices, whether those stimuli are electrical, radioactive, or acoustic. In addition, there are electrically controlled mechanical bases used to measure the diameter of the well, its flow, pressure, perforation, and taking samples. Wireline refers to the technique of using the cable to deliver special equipment to the bottom of the well to repair, evaluation, or equipment recovery. A simple wireline consists of a shiny metal wire (called a slickline) that is very durable for tensile and wear operations. It is of (0.108" or 0.125") diameter. The equipment is installed at the end of the wire. Still, sometimes a braided cable is used from many small steel wires (Braided line), which makes it stronger and heavier than the first type. The information obtained from the logs is considered to assess geological areas based on porosity, permeability, hydrocarbon fluids, and shale ratio. Well logging uses logs that are much cheaper than core operations and also cheaper than the information obtained from drilling mud. This review aims to pinpoint on the most important logging processes used in oil wells, as well logs have an effective role in all stages of the oil industry.

Determination and Application of Similar Materials in a Subway Excavation and Support Model Test

In order to study the mechanical response of strata during the construction of a subway, it is crucial to develop similar materials suitable for indoor model tests. Therefore, based on the similarity theory, combined with the uniaxial compressive test results of similar materials, the similar materials and their ratios of advanced small pipes, shotcrete and steel frames were determined. Then, they were applied to the model test of a subway excavation and support. The variation laws of surface displacement, stress distribution around the tunnel and internal force of the steel frame during tunnel excavation and support were obtained to verify the reliability of similar materials. The results show that the aluminum arch frame with width of 4.87 mm and thickness of 5.00 mm can be used to simulate the grid steel frame. Nine fine steel wires in a ring are taken to simulate the advanced small pipes, and gypsum with elastic modulus of about 1.12 GPa are prepared to simulate the initial shotcrete. They are proven to accurately simulate the physical characteristics of supporting materials in practical engineering, and the variation is similar to that obtained from the field test, which improves the authenticity of the model test results.

Numerical analysis of the possibility of noxious gases infiltration into a shelter located in a gas-bearing coal-rock mass

Shelters in coal mines are used to protect miners during accidents associated with gassing of roadways, fires, explosions of methane-air mixture. Supporting of the shelter must provide the necessary level of tightness to prevent the penetration of noxious gases from the mine atmosphere or gas-bearing rocks. The purpose of this work is to study the possibility of noxious gases penetration into a shelter in case of its sealing failure for the early detection of weak constructional elements and to ensure safe conditions for people in the shelter during accidents. To achieve the goal, methods of numerical simulation of time-dependent processes of elastic-plastic deformation and gas filtration were used. A coal-rock mass with a roadway and an adjacent shelter with typical supporting elements were considered at a depth of 400 m and 1000 m. The study of the stress state of the shelter support showed that under the considered conditions, in the case of a relatively small depth, hard steel and concrete constructional elements withstand the load without loss of their stability. With an increase in the depth of the shelter location, inelastic deformation of the concrete barrier between the shelter and the roadway occurs on a small area. The probable destruction of this zone will not lead to a violation of the entire barrier integrity, which makes it impossible to start mass exchange processes between clean air in the shelter and harmful combustion products in the roadway. The roof and walls of the shelter, covered with reinforced concrete and sealed, remain practically impermeable from the next day after their construction in both the first and second cases. But later, in the lower left corner of the shelter at a depth of 1000 m, methane from the coal seam begins infiltrating through the unsupported and unsealed floor. The developed numerical model can be used with other basic data on mining and geological conditions to identify constructional elements of a shelter, which lose stability during operation and threaten the shelter's tightness. Timely strengthening of such weak elements will prevent the danger of noxious gases infiltrating into the shelter. Keywords: time-dependent rock deformation, shelter, sealing failure, gas filtration, numerical simulation.

Supplier evaluation using AHP for a small scale iron and steel plant in eastern India

The paper presents a multi-criteria decision-making model for evaluation of suppliers using the analytic hierarchy process (AHP) for a small-scale sponge iron and steel plant in eastern India. A systematic research framework has been proposed for the same. The process uses a pair-wise comparison of the criterion importance based on decision-makers' opinions to find their relative weights. The main criteria are identified based on literature review and experts' opinions. The criteria are cost, delivery, quality, location, communication, management, performance history and reputation. The next stage involves a pair-wise comparison of the suppliers based on each criterion to find their relative importance. Overall sensitivity analysis has been conducted using MS Excel to inspect the flexibility of the model for evaluating suppliers, i.e., how the change in the ranking of the suppliers occurs when there is a change in relative weightage of criteria.

Improvement of functional and technological solutions for modernization of steel heating in the tundish of continuous casting machine

The using of the system of plasma heating of metal directly in the tundish is quite promising in terms of improving the technology of continuous casting of steel. At the same time, the efficiency of this technology is significantly influenced by the design of the tundish, the location of the plasmatron, the direction of movement of the circulation flows and their speed, the presence of forced mixing of the liquid metal bath, etc. In terms of design, the main technical solutions proposed for plasma heating of steel in a ladle are based on the creation of two-chamber tundish. Moreover, steel is heated in a special receiving chamber. Such heating devices are compact enough to be built into tundish without any significant modifications. Moreover, such heating devices practically do not reduce the useful volume of the tundish. The widespread use of the technology of plasma heating of metal in the tundish of the continuous casting machine (CCM) at a few metallurgical plants in the world is due to the need to increase the stability of the parameters of the casting process and improve the quality of the workpiece while simultaneously reducing specific energy costs. At the same time, additional prerequisites are created for the transformation of the tundish into a multifunctional unit for adjusting the steel temperature and the possibility of its refining. The using of plasma heating in the tundish is especially relevant in the conditions of mini-mills operating technological units of small capacity, for which the implementation of traditional highly efficient solutions for out-of-furnace processing, as well as processing on tundish-furnace units, is not always possible due to the complexity of organizing the heating process, large heat losses and high specific costs of refractories. In addition, such tundish can be quite effective when pouring high-quality grades of steel into billets of small cross-sections, which are produced, as a rule, in relatively small mixer-batches, which makes it difficult to prove them in small steel pouring ladles.

Influence of anisotropy on the deformation behaviour in microtensile 316L steel specimens fabricated by laser powder bed fusion (PBF-LB/M)

Laser powder bed fusion of metals (PBF LB/M) allows fabrication of intricate structures without any need of tools and moulds. In this process the building orientation becomes a significant issue for the complex structures. Here we fabricated small size 316L steel tensile specimens aligned with their loading axis perpendicular and parallel to the building direction by PBF LB/M. Microstructure and mechanical properties were characterized by colour etching, in-situ tensile testing in a scanning electron microscope, nanoindentation and digital image correlation. The orientation of the melt pools has a significant impact on the deformation behaviour of the PBF LB/M specimens. In parallel specimens (polar angle = 90o) the semi-circular melt pools are aligned perpendicular to the loading axis resulting in an accommodation of larger amount of plasticity as compared to the perpendicular specimens (polar angle = 0o). While strain is localized in the case of perpendicular specimens because primary slip lines are aligned perpendicular to the loading axis, strain is homogenously distributed along the longitudinal axis of the parallel specimens because primary slip lines are aligned parallel to the loading axis. Twin-induced-plasticity and transformation induced plasticity are the deformation mechanisms observed on the fractured specimens. Strain hardening rate in stage IV extended to a higher stress value for the perpendicular specimens as compared to parallel specimens because cross slip is confined in the fusion boundaries. The building direction has shown significant influence on the deformation mechanisms of the PBF LB/M steels which may be a significant issue to overcome for the complex shape specimens.