Multilayer Steel Research Articles

Исследование процессов вакуумирования и нагрева многослойных стальных пакетов для получения листовых материалов ультрамелкозернистой структуры

Исследование процессов вакуумирования и нагрева многослойных стальных пакетов для получения листовых материалов ультрамелкозернистой структуры

Decoupling the contributions of constituent layers to the strength and ductility of a multi-layered steel

Multi-layered steel (MLS) consisting of alternating soft/ductile austenitic and hard/brittle martensitic stainless steel layers is a new class of hybrid material for structural application as it offers excellent combinations of strength and ductility. In this study, the contributions of each of the constituent layers to the overall strength and ductility of an MLS (having tensile strength > 1.4 GPa and ductility > 20%) were examined by recourse to nanoindentation experiments on each of them. By adapting two different indenter tip radii for the spherical nanoindentation experiments, constituent layers' stress-strain responses within the plastic regime were obtained and then compared with the macroscopic flow curve of the MLS that was obtained through tensile tests, to show that the strength contributions of the constituent steels to the global strength of MLS is as per the rule of mixtures. In order to examine the sources of tensile ductility of the MLS, sharp tip nanoindentation experiments were conducted on specimens extracted from tensile coupons that were subjected to predetermined plastic strains a priori. Results of these experiments show that the tensile failure occurs at a strain at which hardness of the austenitic layer, which is found to be dependent on the prior-plastic strain, is almost equal to the strain-independent hardness of the martensitic layer. The results are discussed in terms of martensitic transformation within austenitic layer and the role of the mechanical environment change imposed by the neighboring martensite layers on it.

Seismic behaviour of through-beam connection between square CFST columns and RC beams

This paper investigates the seismic behaviour of a new type of through-beam connection between a square concrete-filled steel tubular (CFST) column and a reinforced concrete (RC) beam. In this new connection system, the steel stub is completely interrupted in the connection zone, with longitudinal steel bars of the frame beam being continuous through this zone. The connection incorporates a strengthening joint system with a steel cage consisting of multi-layer steel meshes and radial pattern stirrups to compensate the possible decrease of strength of connection due to the interruption of the steel tube. The connection is rigid with the integrity and continuity of the columns and beams. Cyclic loading tests on five beam-column specimens are conducted to evaluate this new connection. The hysteretic response, the skeletal and load–deflection curves, the strain, ductility, strength and the stiffness degradation and energy dissipation are obtained. Experimental results demonstrate the favourable seismic performance of the connection including their superior ductility and energy dissipation capacity. A sophisticated solid finite element model is developed and verified by comparing with the experimental results, and being applied for further parametric studies. A simple fibre finite model using OpenSEES is also proposed and the efficiency and accuracy of the model are illustrated.

Screen Elements Made of Perforated Steel Tape and their Application for Shielding Electromagnetic Fields

In the present work the methods for producing flat and three-dimensional shielding screens from the perforated steel tape are proposed. The possible application variants of mentioned screens are offered and analyzed. Main attention is given for producing one-layer and multi-layer screens with cellular structure due to its relatively low weight and technological elasticity – complex three-dimensional structures could be done successfully.Examples of produced shielding screens from the perforated steel tape for protection from electromagnetic fields in different frequency range are offered and tested. The efficiency of a shielding material was determined by measuring the magnetic field before and after applying the shielding material. Distribution of the magnetic field behind the shielding screen was determined by software vector mapping. Shielding efficiency was measured for 1) a three-layer perforated steel screen; 2) an one-layer perforated steel screen - shielding screen was placed in between the magnetic field source and the measurement point forming a two dimensional screen; 3) copper composite sprayed screen. During experimental investigation it was established, that a three-layer perforated steel screen application allowed the 27% reduction in the magnetic field, while one-layer perforated steel screen gave only 12% reduction. Copper composite sprayed screen reduced magnetic field by 15%.Recommendations for producing the multi-layer perforated steel screen accordingly to shielding efficiency are elaborated and laid down. The discussed material carries also ecological significance, since the material is produced by waste products (after stumping etc.). Therefore the production of such materials comes with reduced cost both in light of capital expenditures and ecological footprint.

Crystal Plasticity Analysis of Stress Partitioning Mechanisms and Their Microstructural Dependence in Advanced Steels

Two-phase advanced steels have an optimized combination of high yield strength and large elongation strain at failure, as a result of stress partitioning between a hard phase (martensite) and a ductile phase (ferrite or austenite). Provided with strong interfaces between the constituent phases, the failure in the brittle martensite phase will be delayed by the surrounding geometric constraints, while the rule of mixture will dictate a large strength of the composite. To this end, the microstructural design of these composites is imperative especially in terms of the stress partitioning mechanisms among the constituent phases. Based on the characteristic microstructures of dual phase and multilayered steels, two polycrystalline aggregate models are constructed to simulate the microscopic lattice strain evolution of these materials during uniaxial tensile tests. By comparing the lattice strain evolution from crystal plasticity finite element simulations with advanced in situ diffraction measurements in literature, this study investigates the correlations between the material microstructure and the micromechanical interactions on the intergranular and interphase levels. It is found that although the applied stress will be ultimately accommodated by the hard phase and hard grain families, the sequence of the stress partitioning on grain and phase levels can be altered by microstructural designs. Implications of these findings on delaying localized failure are also discussed.

Dynamic Behaviors of Multi-Layered Steel Targets with Air Gaps Subjected to the Impact of EFP Simulants

Experiments and fine three-dimensional FE analyses were carried out to study the behaviors of multi-layered steel targets with air gaps subjected to normal and oblique impact of EFP (Explosively Formed Projectile) simulants. The experiments were performed using the EFP simulants with hemispherical nose that impact the targets vertically at a striking velocity of 1290m/s, while the armor shields consisted of multi 6mm-thick layers made of Q235 steel materials. The damage pattern and damage area of the targets as well as the residual velocities of EFP simulants in the experiments are presented in this paper. Systematic FE analyses on the perforation process of the experiments were conducted using the explicit finite element code LS-DYNA accompanied by the Johnson-Cook elasto-viscoplastic model. A good agreement is generally obtained between the numerical and experimental results. To further and better understand the whole process of fracture development and perforation of the layered steel targets induced by the impact of EFP simulants, the influence on obliquity angles during the impact and perforation process of EFP simulants were also investigated. The referred impact obliquity angle is varied from 5° to 40°. The result indicates that the residual velocities of EFP simulants decreased significantly with the increase of obliquity angle, and to some extent, a larger impact obliquity angle may result in the ricochet of EFP simulants.

Salmon Muscle Adherence to Polymer Coatings and Determination of Antibiotic Residues by Reversed-Phase High-Performance Liquid Chromatography Coupled to Selected Reaction Monitoring Mass Spectrometry, Atomic Force Microscopy, and Fourier Transform Infrared Spectroscopy

The persistent adhesion of salmon muscle to food container walls after treatment with urea solution was observed. This work evaluated the diffusion of antibiotics from the salmon muscle to the polyethylene terephthalate (PET) coating protecting the electrolytic chromium coated steel (ECCS) plates. New aquaculture production systems employ antibiotics such as florfenicol, florfenicol amine, oxytetracycline, and erythromycin to control diseases. The introduction of antibiotics is a matter of concern regarding the effects on human health and biodiversity. It is important to determine their impact on the adhesion of postmortem salmon muscle to can walls and the surface and structural changes affecting the functionality of multilayers. This work characterized the changes occurring in the multilayer PET polymer and steel of containers by electron microscopy, 3D atomic force microscopy (3D-AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. A robust mass spectrometry methodology was employed to determine the presence of antibiotic residues. No evidence of antibiotics was observed on the protective coating in the range between 0.001 and 2.0 ng/mL; however, the presence of proteins, cholesterol, and alpha-carotene was detected. This in-depth profiling of the matrix-level elements is relevant for the use of adequate materials in the canning export industry.

Different Types Cross Section Columns Combination of Multi-Layer Steel Frames Optimum Design Analysis

In order to study the feasibility of different types cross section columns combination of multi-layer steel frames optimum design, considering the basic cycle, the first layer shear-weight ratio, steel weight of structure and other factors to establish different types of models. Through the each model fees of different engineering cost quota, then from cost of the project perspective to analyze the optimum design of multi-layer steel frames. The analysis results: Two kinds of calculations of the project cost of each model’s main structure are different, the project cost quota of Guangxi mainly depends on steel weight of each component type, but the project cost quota of Osaka region general considering the component types and cost of material and processing fees which are determined by section types, and welding quantity is single calculated, model CM4 corresponds well. On the whole, model CM4 has the lower expenses. So Guangxi district should refining component types and section types and then determine production and installation fees.

Design of Cross-Sectional Layout of Steel Tube Umbilical

A design method is presented, which aims at the optimal cross-sectional layout of the multilayer steel tube umbilical. The merit of the method is to improve the tension stiffness and the fatigue life of umbilical. An optimization model is developed for arranging each component layer of the layout by considering the symmetry of mechanical performances of components. Finite element analysis (FEA) is carried out to check the contact force and the radial deformation of different layout types and to confirm the optimal layout design.

Response Simulation of a Micro Reinforced Concrete Target Under Ballistic Impact

The response of concrete structures subjected to impact loading has received extensive attention in both civil and military applications. Research on improving the shock resistance of concrete has led to the development of cementitious composites. Micro Reinforced Concrete (MRC), a type of cementitious composite, is a concrete matrix embedded with multilayered steel wire meshes. This paper presents 3D hydrocode simulations of MRC panels subjected to impact under a ballistic range. A finite element model based on Lagrange formulation is used to represent both a 300 mm × 300 mm × 100 mm target with 30 layers of wire mesh and a 5.56 × 45 mm projectile in simulations. Penetration depth and damage patterns of the MRC mesh cement composite panel are numerically compared with those of the field experiment. The results show a relatively good agreement.

FEM Simulations of Incremental Permeability Signals of a Multi-Layer Steel With Consideration of the Hysteretic Behavior of Each Layer

Shafts for power generation machines have to be inspected in regards to the mechanical-technological properties of the final product material. To save time and costs, the nondestructive 3MA technique, which is based on the measurement of electromagnetic properties of the inspected material, should be used for this purpose. Due to the machining process, the material shows a Multilayer structure with different residual stress levels, each characterized by its own electromagnetic properties. To simulate signals of the so-called incremental permeability mode of 3MA, the individual electromagnetic properties had to be determined first. Subsequently, FEM methods have been developed, overcoming issues with respect to multiscale geometry and time, and the local hysteretic behavior identification at every point in the material under investigation. The developed computation strategy and the modeling assumptions are validated by a comparison of the numerical simulations with measurements and shows promising results.

Development of Multilayer Steels for Improved Combinations of High Strength and High Ductility

Development of Multilayer Steels for Improved Combinations of High Strength and High Ductility

Interphase Strain Gradients in Multilayered Steel Composite from Microdiffraction

Multilayered steel composites consisting of alternating martensite and austenite layers and exhibiting a combination of high strength and ductility were successfully fabricated. To understand the microplasticity mechanisms responsible for such exceptional mechanical behavior, 3D X-ray microscopy with a submicron beam size was employed to probe the stress/strain distribution within the top two layers during incremental tensile loading. The 3D depth-dependent strain gradients were monitored in situ near the martensite/austenite interfaces as a function of the load level. It was observed that the strain gradients redistributed during loading. Specifically, large compressive strains developed in the top martensite layer transverse to the loading direction, while small tensile strains were found across the layer interface into the underneath austenite layer.

A comparative experimental study on the blast-resistant performances of single and multi-layered thin plates under close-range airblast loading

The performance of multilayered thin steel plates subjected to close-range air blasts has been experimentally studied and compared with that of monolithic plates made of the same material and having equal mass. In present experiments, multilayered plates are in-contact four-layered thin steel plates and two types of deformation/failure modes were observed for them. Comparisons concerning deformation/failure modes, strain distributions and energy absorptions between the multilayered plate and its monolithic counterpart were conducted. It is found that the multilayered plate is much superior to its monolithic counterpart in the ability to deform against blast loading. Furthermore, under intense airblast loading, the multilayered plate can not only absorb much more energy but also effectively reduce the secondary destruction ability of structural fragments in comparison with its monolithic counterpart.

Fatigue strength tests of layered steel

The work deals with original measurement of fatigue properties of formed layered steel material – damask steel. This is a material that exhibits a fine micro-structure as well as a regular composition of many material layers with complementary properties. The article experimentally verifies high-cycle fatigue properties of layered steel and evaluates them from the point of view of fatigue tests of conventional steel materials and a parallel application of a non-destructive – acoustic emission – testing. Finally, it discusses the influence of production on fatigue strength and the possibilities of using multi-layered steel materials in technological practice. A serious result of this pilot experiment is the fact documented no only by the fractographic observation, but mainly by the AE records that the fatigue service life of this material is high if it its not stressed by tension approximating the yield point Re. However, such stress is not common in practical use of tools made of damask steel and thus under common bending stress an exceptionally long service life of tools made of this type of material is demonstrable. The fact that damask steel behaves like a homogeneous material is mainly confirmed by the records of the AE signal at lower values of stress σa. When stressed by higher amplitudes of tension σa damask responds in AE records similarly to a laminate material that is stressed by bending.

Basic mechanical properties of layered steels

This article deals with identifying attributes of layered steel materials (damask steel) with the help of mechanical tests. Experimentally verify basic mechanical properties of layered steel and subsequently assessed it in comparison with the values obtained for the classic steel materials. In conclusion, there are listed the possibilities of using multilayer steel materials in technical practice, depending on the economics of production.The damask steel was prepared by forge welding from a packet consisting of 17 layers (9 layers of tool steel 19 133 (ČSN) with the thickness of 6 mm and 8 layers 80NiCr11 steel in the form of saw bands with the thickness of 1.2 mm. The packet was cut into 8 parts, folded 3 times and forged together, which provided damask steel with 136 layers. The resulting steel bars were used to make semi-finished products with the approximate dimensions of the test specimens. For evaluation of mechanical properties were applied the following tests: tensile test, Charpy impact test, hardness and microhardness measurementsThe results of tests proved that the properties of damask steel are dependent not only on the direction led impact quality forge weld layers and content iof nhomogeneities in the place of discord, but also on the quenching and tempering temperature, resp. on the choice of quenching bath, which determine the final structure of steel and the resulting hardness, respectively microhardness.

Dynamic Characteristics Analysis on The Steel Frame Structure of High-Rise Building

The paper applies pulsating method to carry out on-site test on dynamic characteristics of two houses with steel frame structure. By comparison of test results and definite element calculation result, it studies the influence of floor and in-filled wall on the dynamic characteristics of steel frame structure. According to experimental analysis and result, the vibration of pure frame house with multi-layer steel structure is shearing type; damping ratio ranges from 2% to 5%; in-filled wall obviously shortened the self-vibration cycle of the pure steel frame structure, causing the practically measured cycle smaller than the calculated. In anti-vibration calculation, one shall accordingly reduce the calculation cycle. The given cycle reduction coefficient could serve as reference to engineer designing.

Research on Rolling Force Model Based on Distributed Cooperative Control System

Three-stand mills continues produced of multi-layer composite steel plate, multiple L2 servers together computing to complete the tasks, serviced to many models in whole automated production process. In this paper, multi-embedded systems distributed and cooperative control program takes instead of multi L2 server mode, one L2 data collection and record server was remained. An example of rolling force model is used to discuss the control architecture, Sims simplified formula. The experiment and numerical results show that the control architecture is capable of reliable operation, and the accuracy of the target is no less than 94%.

強度・延性に優れた複層鋼板を実現可能にする界面制御

強度・延性に優れた複層鋼板を実現可能にする界面制御

Analytical approach to pulsed eddy current nondestructive evaluation of multilayered conductive structures

This paper proposes an analytical approach that can describe the Pulsed Eddy Current Testing (PECT) of stratified conductive structures by a single air-coil used for detecting and sizing of metal loss due to interlayer corrosion. Specifically for a single air-cored coil above a multilayered conductive structure, the coil impendance response of the cylindrical eddy-current probe is calculated based on the truncated region eigenfunction expansion (TREE) method using the generalized matrix coefficients in series form. Analytical modeling of pulsed eddy current is developed using the Fourier series for multilayered conductive structures. A simulation study is carried out for demonstrating the capability of the proposed approach for sizing the metal loss in a two-layer specimen. Furthermore, the experiment is set up to confirm the simulating results of the analytical model for multilayered steels. Good agreement between the theoretical results and measured signals is observed.