Strip Thickness Research Articles

Effect of Pulsed Current Treatment on Microstructure and Properties of 304 Stainless Steel Ultra-Thin Strip after Rolling

The annealing process is usually used to heat-treat cold-deformed 304 stainless steel to improve its microstructure and properties to a certain extent; however, it requires a high temperature and a long time. Because the thickness of the ultrathin strip reaches the micrometer level, it has only one or several layers of grains in the thickness direction, and the control of morphology and performance is complex. In this study, pulsed current loading was used to replace traditional annealing for treating ultrathin strips of cold-rolled 304 stainless steel. After loading a 25 W pulsed current treatment for 5 min on the cold-rolled sample, which had a thickness of 0.035 mm and width of 6 mm, complete recrystallization occurred, and the mechanical properties were significantly improved. At this point, the measured temperature was 540 °C. When annealing was used to treat the sample with the same temperature and for the same duration, the microstructure was still dominated by deformed crystals, and the mechanical properties were poor. When annealing was used to obtain a microstructure and properties similar to those obtained via 25 W electrical treatment, the required annealing temperature and time were 810 °C and 60 min, respectively. Pulsed current can increase the vacancy diffusion flux in the sample, accelerate the atomic movement, reduce the recrystallization activation energy, and make the cold-rolled 304 stainless steel ultrathin strip completely recrystallize at a lower temperature and in a shorter time. As the current power continued to increase, the recrystallized grains grew. When the pulsed current power was increased to 25 W, the recrystallized grains grew negligibly. Both recrystallization and grain growth have power thresholds. This study provides a novel approach for regulating the microstructure and mechanical properties of ultrathin cold-rolled 304 stainless steel strips.

Optimisation study of roll profile for controlling high-order wave defects in an ultra-wide rolling mill

This paper investigates the issue of higher-order waviness in the rolling process of wide strip steel, focusing on the different higher-order roll shape compensation curves of Baotou steel 2250 mm hot strip mill. First, three typical higher-order waviness compensation curves are fitted and quantitatively evaluated. Second, a mathematical model of the unloaded roll gap is established to analyse the shape control characteristics of the entire roll gap. Finally, a finite element model of the roll system (work roll Φ700 × 2550 mm and support roll Φ1600 × 2250 mm) is constructed to analyse the effects of changes in the position of the shifting rolls on the cross-section of the strip steel at different widths (1400, 1600, 1800 and 2000 mm) using a controlled variable method. The study finds that the fourth-order roll shape demonstrates good performance in controlling higher-order waviness while maintaining the linear control characteristics of quadratic crown. Considering the magnitude of higher-order waviness in actual rolling processes, the compensation amount for the quartic crown is determined to be 0.05 mm. Based on this, the higher-order work roll shape is optimised, resulting in industrial applications where the flatness hit rate of 1.2–2.5 mm thick strip steel increased from 70.57% to 88.7% and the hit rate for 2.51–4 mm thick strip steel increased from 89.11% to 90.8%. Further optimisation of the roll crown setting from [−0.7 mm, 0.4 mm] to [−0.55 mm, 0.55 mm] and adjustment of the shifting roll position improved the middle waviness, ultimately increasing the flatness hit rate for 1.2–2.5 mm thick strip steel to 89.2% and for 2.51–4 mm thick strip steel to 92.1%, thus validating the effectiveness of the roll shape optimisation.

Double-eigenvalue bifurcation and multistability in serpentine strips with tunable buckling behaviors

Serpentine structures, composed of straight and circular strips, have garnered significant attention as potential designs for flexible electronics due to their remarkable stretchability. When subjected to stretching, these serpentine strips buckle out of plane, and previous studies have identified two distinct buckling modes whose order of appearance may interchange in serpentine structures with a single cell. In this study, we employ anisotropic rod theory to model serpentine strips as a multi-segment boundary value problem (BVP), with continuity conditions enforced at the interface between the straight and curved strips. We solve the BVP using methods of continuation, and our results reveal that: (1) the exchange of the two buckling modes in a single-cell serpentine strip is induced by a double-eigenvalue and associated secondary bifurcations, which also alter the stability of the two buckling modes; (2) a variety of stable states with reversible symmetry can be manually obtained in tabletop models and are found to be disconnected from the planar branch in numerical continuation. Furthermore, we demonstrate that modulating the strip thickness across different cells leads to the initiation of buckling in the thinnest section, thereby allowing for the tuning of buckling modes in serpentine strips. In structures with two cells, the sequence of the two buckling modes can also be controlled by designing serpentine strips with nonuniform height. This work could enhance the mechanical design of serpentine-interconnect-based flexible structures and could have applications in multistable actuators and mechanical memory devices.

Evaluation of Reliability and Validity of Different Thicknesses of Occlusal Contact Registration Strips Vs Conventionally used Articulating Papers – An Invitro Study

Aim: To compare and evaluate the reliability and validity of different thicknesses of Occlusal Contact Registration Strips (OCRS) under simulated occlusal load.  Settings and Design: In-Vitro Comparative Study  Materials and Methods: Articulated epoxy resin dental models obtained from completely dentulous patients were interposed with occlusal contact registration strip of various thicknesses and subjected to constant axial compressive load using universal testing machine. The photographs of consistent registration marks were subjectively assessed using a computer software.  Statistical Analysis Used: Analysis of Variance (ANOVA) and post hoc mean multiple comparison using Dunnett T3 test.  Results: The thinnest occlusal registration strip used in this study registered the highest average number of markings with a borderline statistically significant difference (P=0.06). The highest average area of markings was registered by the thickest strip, which had a near marginal significance (P=0.09), whereas the lowest average area was produced by the thinnest strip which was statistically significant (P=0.03).  Conclusion: There exists a relationship between the thickness of an occlusal contact registration strip, the number and the area of the marks registered. The average number of marks registered was inversely proportional to the thickness of the occlusal indicator. Hence, the thinner the occlusal contact registration strip, the more reliable is the occlusal contact registration. The average area of occlusal contact registration mark varies proportionately to its thickness. Hence, the thickest occlusal contact registration strips were more valid for marking occlusal contacts.

Theoretical Study of Asymmetric Bending Force on Metal Deformation in Cold Rolling

A three-dimensional elastic–plastic finite element model of a six-roll cold rolling mill has been developed using the finite element software ABAQUS. The actual parameters of the rolling mill have been incorporated into the finite element model, with the working conditions applied as boundary constraints and load conditions. Subsequently, a non-symmetrical bending force is introduced to the finite element model. Through simulation calculations, this study analyzes the patterns of change in the transverse pressure of the rolling mill and roller pressure during non-symmetrical bending, as well as the variations in strip thickness, crown, edge drop, and flatness. Additionally, the regulating function of the bending force is examined. Each adjustment of 5 t in the asymmetric bending force results in an increase of approximately 0.01 mm in the thickness of the positive bending side of the strip while causing a decrease of about 0.01 mm in the thickness of the negative bending side. Therefore, the application of asymmetric bending forces proves to be effective in controlling the shape of lateral wave defects on the edges of steel strips.

Impact of Nickel Strip Configurations on Resistance and Voltage Drop in Lithium Ion Battery Packs

The impact of nickel strip designs on the resistance and voltage drop in lithium ion battery packs is examined in this study. In a series parallel battery pack configuration, the effectiveness of coated and pure nickel strips is assessed, with particular attention paid to how they influence voltage drop, internal resistance, and overall efficiency. Each of the 24 series and 3 parallel cells that make up the battery pack has an internal resistance of 6 mΩ. Two configurations are analyzed: one utilizing pure nickel strips and another with coated nickel strips. The resistivity, cross sectional area, and length of the material are used to compute the equivalent resistance of the nickel strips for each arrangement. Voltage dips at a load current of 50A are determined to compare the performance of both strip. The study also looks at the voltage drop at key locations in the battery pack, including particular bent strips. The findings show that the coated nickel design displays a larger resistance (0.237Ω) and voltage drop (11.735V) than the pure nickel configuration, which has a lower total resistance (0.048Ω) and voltage drop (2.82V). Evaluation of the voltage drop during charging is also done for charging currents of 6A and 10A, demonstrating that the pure nickel arrangement allows for more efficient charging. One of the main elements affecting battery pack performance is internal resistance, which has a direct impact on the system's voltage drop and overall energy efficiency. The thickness, width, resistivity, and number of parallel strips utilized in this nickel strip material all have a major effect on the battery pack's total resistance. Because of this, the nickel strip design can improve or worsen the pack's power delivery, particularly in high load scenarios.

Exploring the effects of finite size and indenter shape on the contact behavior of functionally graded thermoelectric materials

The performance enhancement of functionally graded thermoelectric (FGTE) devices is significantly influenced by contact studies of the FGTE materials. It is unclear how the finite thickness and the punch geometry influence the FGTE materials’ contact behaviors. This paper investigates the frictionless contact problem between three types of rigid punches (flat, triangular, and cylindrical) and the FGTE strip with finite thickness. The electric-thermo-elastic parameters of the FGTE strip vary in the thickness direction according to an exponential function. Based on the Fourier integral transform and the transformation matrix method, the problem is transformed into the numerical solution of three sets of singular integral equations. The presence of singular features on either side of the punch demands the adoption of specific collocation strategies. The distribution of the normal current density, the normal energy flux, and the normal contact stress is obtained by adjusting multiple electric-thermo-elastic parameters. The contact stresses in the case of punches with varying shapes can be effectively controlled by modulating the coefficient of thermal expansion and the strip thickness, whereas the effect of the electrical conductivity, the shear modulus, and the thermoelectric load on these stresses depends on whether they are increased or decreased.

Discretization of Thin-Walled Sections with Variable Wall Thickness

At the stage of designing thin-walled aircraft structures, to simplify calculations, their cross sections are idealized. To do this, the section with the skin and the longitudinal elements reinforcing it is replaced (when determining normal stresses) by a discrete one, consisting of concentrated areas at characteristic points. In this case, the equality of the moments of inertia of the initial and discrete sections is preserved. Such idealization is used in the calculation of thin-walled rods for normal and shear stresses (Wagner model). For sections consisting of a system of rectangular strips of constant thickness, discretization allows to set approximate values of normal and shear stresses and accurately find the locations of the singular points of the bending center (in an open contour) and the center of rigidity (in a closed one). The discrete model of a strip consists of three lumped areas: two at the edges and one in the center. The paper proposes to extend the discrete model to sections in which the skin thickness changes according to a linear law. In addition to the rectangular strip, it is possible to use elongated triangles and trapezoids, replaced by three and four concentrated areas, respectively. The possibility of using a discrete model for calculating some thin-walled sections of open and closed contours is considered. The section of an open contour is studied - the problem of transverse bending without torsion of a channel having flanges with a linearly variable thickness. Differences in the flows of tangential forces calculated from the exact and discrete models are shown. The coincidence of the results in determining the position of the bending center according to two models was established. When studying the application of a discrete model to a closed contour, its simplified option is proposed. The problem of transverse bending without torsion and finding the center of rigidity in a section with a contour line in the form of a trapezoid with front and rear walls of constant thickness and upper and lower skins and a similar section with a contour in the form of a rectangle was considered. Differences in the flows of tangential forces calculated by exact and discrete models are established. For a closed section in the form of a rectangle, the decrease in the moment of inertia for torsion due to the redistribution of material in the cross section was studied separately. It has been established that when finding the position of the center of rigidity, the discrepancy between the results of the exact and discrete models in sections with geometric parameters close to real ones was less than 1% for a rectangular contour, and 4% for a trapezoidal contour. The results indicate the possibility of extending the application of the discrete model of thin-walled cross section to the design calculations of thin-walled rods with variable skin thickness, representing practical structures.

Characteristic Times for Gap Relaxation and Heat Escape in Nanothin NbTi Superconducting Filaments: Thickness Dependence and Effect of Substrate.

We measured the temporal voltage response of NbTi superconducting filaments with varied nanoscale thicknesses to step current pulses that induce non-equilibrium superconducting states governed by a hot spot mechanism. Such detected voltage emerges after a delay time td, which is intimately connected to the gap relaxation and heat escape times. By employing time-dependent Ginzburg-Landau theory to link the delay time to the applied current, we determined that the gap relaxation time depends linearly on film thickness, aligning with the acoustic mismatch theory for phonon transmission at the superconductor-substrate interface. We thereby find a gap relaxation time of 104 ps per nm of thickness for NbTi films on polished sapphire. We further show that interfacial interaction with the substrate significantly impacts the gap relaxation time, with observed values of 9 ns on SiOx, 6.8 ns on fused silica, and 5.2 ns on sapphire for a 50 nm thick NbTi strip at T=5.75 K. These insights are valuable for optimizing superconducting sensing technologies, particularly the single-photon detectors that operate in the transient regime of nanothin superconducting bridges and filaments.

Flexural properties of moso bamboo induced by hydrothermal treatment

The superior flexural properties of bamboo make it widely used in the field of bamboo furniture. However, thick bamboo strips are more susceptible to fracture in bending due to their significant fiber gradient variation, especially the nodes. In this study, the eco-friendly hydrothermal treatment was employed to augment the flexural properties of bamboo and mitigate the fracture. The results showed that the flexural strength, flexural modulus, flexural toughness, and flexural radius of curvature increased with the increase of strip thickness. The strip thickness was positively correlated with vascular bundle content. The structure of bamboo became more uniform after hydrothermal treatment and the nodes were no longer the susceptible fracture point. The moisture content was a pivotal factor influencing the flexural properties, which increased as hydrothermal treatment time and temperature increased. Furthermore, hydrothermal treatment increased bamboo's flexibility by softening it through moisture absorption and the facilitating molecular chain movement within the fibers. The optimal moisture content for bamboo strips when manufacturing curved components was around the fiber saturation point. These findings contributed to the refinement of the green manufacturing techniques for bamboo curved furniture components, aiming to foster sustainable environmental development.

Evaluating mechanical benefit of wedge osteotomies in endoscopic surgery for sagittal synostosis using patient-specific 3D-printed models.

Endoscopically assisted sagittal strip craniotomy with subsequent cranial orthosis is a frequently used surgical approach for non-syndromic sagittal synostosis. Originally, this technique involved a wide sagittal strip craniectomy with bilateral wedge osteotomies. More recent studies suggest omitting wedge osteotomies, achieving similar outcomes. The controversy surrounding wedge osteotomies and our efforts to refine our technique led us to create models and evaluate the mechanical impact of wedge osteotomies. We conducted a 3D-print study involving preoperative CT scans of non-syndromic scaphocephaly patients undergoing minimally invasive-assisted remodelation (MEAR) surgery. The sagittal strip collected during surgery underwent thickness measurement, along with a 3-point bending test. These results were used to determine printing parameters for accurately replicating the skull model. Model testing simulated gravitational forces during the postoperative course and assessed lateral expansion under various wedge osteotomy conditions. The median sagittal strip thickness was 2.00mm (range 1.35-3.46mm) and significantly positively correlated (p = 0.037) with the median force (21.05 N) of the 3-point bending test. Model testing involving 40 models demonstrated that biparietal wedge osteotomies significantly reduced the force required for lateral bone shift, with a trend up to 5-cm-long cuts (p = 0.007). Additional cuts beyond this length or adding the occipital cut did not provide further significant advantage (p = 0.1643; p = 9.6381). Biparietal wedge osteotomies reduce the force needed for lateral expansion, provide circumstances for accelerated head shape correction, and potentially reduce the duration of cranial orthosis therapy.

Numerical solution for the interior electric displacement of the moving DBY‐PS model for semi‐permeable cracked piezoelectric material

AbstractIn this study, we analysed a moving crack at the interface of an infinitely long piezoelectric bilayer using the Dugdale–Barenblatt yield (DBY) model and the polarisation saturation (PS) model. To model the moving crack problem, a Yoffe‐type crack moves at a constant subsonic speed on the interface of an infinitely long piezoelectric bilayer. The crack faces are assumed to be semi‐permeable, and at the boundary of the bilayer, in‐plane electrical and out‐of‐plane mechanical stresses are applied. Due to the application of electro‐mechanical loads, cracks propagate, mechanical yielding zones and electric saturation zones are developed. To arrest the crack from further propagation, mechanical yield stress and saturation electric displacement are applied at the developed zones. To address this problem analytically and numerically, the mixed boundary value problem is transformed into a set of coupled Fredholm integral equations (FIEs) of the second kind using the Fourier transform and the Copson method. The closed‐form analytical expressions for the length of the electrical saturation zone (ESZ), whether longer, shorter or equal to the mechanical yielding zone (MYZ), show dependence on external electro‐mechanical loads under semi‐permeable crack conditions. The algorithm to solve the electric crack condition parameter (ECCP) has been defined using numerical discretization and the bisection method. Illustrative examples demonstrate the proposed technique's effectiveness and suitability for Yoffe‐type moving cracks. The numerical results show the convergence of the ECCP. Furthermore, the numerical results show how mechanical and electrical zone lengths and energy release rate (ERR) are affected by electrical and mechanical loads, strip thickness and crack velocity. In addition, the size of the mechanical yielding zone is consistently promoted by electrical load, while the promotion or prevention of the electrical saturation zone by mechanical load depends on the relative sizes of the nonlinear zones.

On flexural vibrations of orthotropic strips of variable thickness taken into account of transverse effects with elasticaly built in edges in the presence of axial force

Abstract The problem of bending vibrations of orthotropic strips of variable thickness is considered, taking into account transverse effects elastically built in edges in the presence of axial force. The problem was solved using the numerical collocation method. A numerical analysis of the problem was carried out. The problem of Euler stability of orthotropic plate-strips of variable thickness under plane strain conditions is considered, taking into account transverse shear and rotational inertia. The resulting equations make it possible to determine both the frequencies of natural vibrations and the critical values of the axial force at which the plate-strip loses stability. The problems are solved using a modified collocation method under various boundary conditions at the ends and values of geometric and physical parameters characterizing a plate-strip of variable thickness.

Controlling Aluminum Strip Thickness by Clustered Reinforcement Learning With Real-World Dataset

Controlling Aluminum Strip Thickness by Clustered Reinforcement Learning With Real-World Dataset

Design and Simulation of Torque Control for Hot Rolling Steel Mill

Lateral movement of a strip in the hot rolling process is an important unsolved technical problem. To minimize the strip thickness variations, the state space model formulation is usually used. It results in reducing productivity and, in the extreme case, strip tearing during tailing out at the finishing mill. This movement is caused by various asymmetric factors such as mechanical asymmetry of the mill and different temperatures along the strip width direction. Furthermore, the difference in the temperature and the thickness of steel strip resulting in deformation of the steel, which affects the bending torque of the steel strip. This study aims to understand the influences of these various factors on lateral movement. In order to reduce the lateral movement and the disturbance terms, that act on uncertain inter-connected systems, a new control approach, based on a combination of Integral Sliding Mode Control (ISMC) and Linear Matrix Inequalities (LMI) technique, is proposed. Simulation results of hot rolling system with three interconnected systems are presented to validate the new controller performance.

Study on Sustainable Lightweight Design of Airport Waiting Chair Frame Structure Based on ANSYS Workbench

The airport waiting chair frames, as an important part of the overall seating, must be designed to provide comfort, safety, and aesthetic appeal. While the airport furniture industry has made progress in terms of sustainability, more efforts are needed to improve material selection, manufacturing processes, and supply chain management to support the development of sustainable furniture. This study proposes innovative ideas for the lightweight design of the frame, based on the limitations of the existing design. Firstly, structural innovations are discussed, non-traditional mesh panels and curved rounded designs are discussed, and non-introduced mesh panels and curved designs are used to enhance the strength and stability of airport waiting chairs and enhance their overall performance. Secondly, innovations in lightweighting have focused on adjusting the thickness dimensions to enhance comfort, material utilization, and sustainability as well as to achieve a lightweight and thin appearance effect. In order to determine the optimal ranges of values for the thickness of the seat surface support strip (P5), the thickness of the backrest strip (P3), and the thickness of the seat panel (P1), nine groups of chairs with different frame sizes were tested using an orthogonal experimental method. Based on the experimental results for size and topology optimization, NX2312 software modeling will be imported into ANSYS Workbench for static analysis. Using the optimized results, the use of 2.842 kg of steel was successfully reduced by 34.8% to ensure the seat’s stability. This provides a reference and idea for the digital and standardized innovative design of airport waiting chair furniture structure in the future. Through digital design and lightweight optimization, material savings and effective use of resources can be achieved, promoting the goal of sustainable development.

Experimental study on debonding and buckling of externally bonded carbon fiber reinforced polymer sheets in compression

Although the compressive strength of Fiber Reinforced Polymer (FRP) sheets is neglected in the design of FRP-retrofitted Reinforced Concrete (RC) elements, they may be subjected to compressive stress in some load combinations. In the present study, an experimental study is conducted to investigate the behavior of externally bonded Carbon Fiber Reinforced Polymer (CFRP) sheets in compression. The experimental program is carried out in two phases. First, the behavior of CFRP strips bonded on concrete cylinders and subjected to pure compressive load is assessed. At this stage, the influence of concrete compressive strength, the dimensions of CFRP strips (thickness, width, and free length), and the type of adhesive used for bonding CFRP strips on the concrete surface, on the behavior of CFRP strips in compression are investigated. According to the test results, the FRP strips bonded with weak resin exhibit debonding failure and simultaneously buckle at a relatively low compressive strain, while CFRP strips bonded with stronger adhesive do not exhibit debonding failure in compression until concrete crushing. The behavior of CFRP strips bonded on reinforced concrete (RC) beams subjected to compressive stress due to bending moment is investigated in the second phase of this study. For this purpose, nine RC beams with the same dimensions and reinforcement detailing are fabricated and retrofitted using CFRP strips with different configurations. Four-point bending test is conducted at this stage of the experimental program. The results of the bending tests show that debonding failure and buckling of CFRP strips are observed in specimens with relatively thick CFRP sheets (3 and 4-layer) and larger free lengths.

Eccentric compression behavior of partially CFRP wrapped seawater sea-sand concrete columns reinforced with epoxy-coated rebars

The combined use of seawater sea-sand concrete (SSC), epoxy-coated rebar (ECR) and fiber-reinforced polymer (FRP) can achieve significant economic and environmental benefits in coastal infrastructure constructions. Thus, this paper first presents an experimental and analytical study on the eccentric compression behavior of partially carbon FRP (CFRP) wrapped SSC columns reinforced with ECR. The effects of load eccentricities, thickness of CFRP strips, clear spacing ratios, and slenderness ratios were comprehensively analyzed. Test results show that as the eccentricity increased from 60 mm to 120 mm, the increment of load capacity of partially CFRP wrapped columns reduced by 27.6 % to 17.1 %. Moreover, a larger lateral deflection was detected for the specimens with a relatively high slenderness ratio, which results in an obvious second-order effect and further aggravates the nonlinearity of axial load-bending curves, especially for the specimens under a small eccentricity. In addition, an eccentricity-dependent stress-strain model for concrete was developed under FRP strip-steel hoop composite confinement, and the lateral deflection formula of eccentrically loaded columns was also derived based on force equilibrium analysis. Finally, a new theoretical formula incorporating the effect of the slenderness ratio was also presented for the determination of load and moment capacity of the partially CFRP wrapped columns based on section analysis. By comparing with the test results, the developed model exhibits satisfactory accuracy.

Validity of Thin Element Approximation in diffractometry of opaque thick objects

The Thin Element Approximation (TEA) is widely used in diffraction analyses since it can be applied in efficient plane-to-plane propagation algorithms. While refinements have been developed for dielectric objects to obtain more accurate results, TEA is assumed precise for opaque objects. However, through numerical simulations presented in this work, based on Wave Propagation Method, we analyze the tendency of TEA to overestimate the dimensions of opaque objects in diffractometry. This effect was acknowledged in the case of cylinders, and we obtain similar results for the case of rectangular thick strips. On the other hand, TEA demonstrates a high level of accuracy when applied to objects with thickness concentrated at the center and thin edges, such as the isosceles triangular obstacle. Finally, we analyze objects whose shape is defined using the superellipse function, which is chosen for its versatility in generating objects of equivalent width and maximum thickness but with different shapes just changing a single parameter. Our results highlight the importance of considering the object geometry when employing this approximation in diffraction studies of opaque three-dimensional objects.

Identification of structural defects and their impact on the magnetic memory, static and cyclic strength of VNS9-SH thin sheet trip-steel

Identification of microstructure defects, which are stress concentrators (SC) during the operation of mechanical engineering products, is an important scientific and practical task relevant for manufacturing enterprises. This problem becomes especially urgent and difficult for critical helicopter parts made of sheet TRIP steel VNS9-Sh (23Kh15N5AM3-Sh) and operating under cyclic loads due to the complex microstructure of the steel and small thickness of strips and sheets. To assess the impact of structural defects on the cyclic strength of products made of the steel under study, the specimens were preliminary sorted proceeding from the results of their testing using the method of metal magnetic memory (MMM) and metallographic studies. The MMM method is a structure-sensitive procedure which provides information about the presence of structural defects that arise during the manufacture. Magnetic anomalies in the form of sharp local changes in the intrinsic stray magnetic field (SSMF) (H) and its gradient |ΔH| along the length of the controlled section Δx, were identified on the surface of sheets cut from five different batches. A conventional classification of the identified anomalies was made according to the magnitude of the magnetic field gradient. The specimens of two types were cut in zones of magnetic anomalies and outside them: type 1 — for cyclic tests and type 2 — for metallographic studies. The geometric parameters and field gradient values of magnetic anomalies on specimens of type 1 and type 2 were the same. Metallographic studies in zones of maximum magnetic field gradient on type 2 specimens revealed defects in the form of a strip at the boundary of different structures, which is a structural stress concentrator (SSC) and a source of the inhomogeneity and changes in the magnetic properties. Type 1 specimens with similar magnetic anomalies and Type 1 specimens cut from sheets outside zones of magnetic anomalies were then selected for cyclic testing. Comparative tests for cyclic strength of the specimens with and without specified SSC were carried out. It is shown that the presence of SSC zones in the specimens reduces the number of cycles to failure during cyclic tests by 1 – 2 orders of magnitude compared to the specimens free of SSC. Based on cyclic tensile tests of specimens, a limiting value of the magnetic field gradient was determined that corresponds to the acceptable level of stress concentration on structural defects. This value is recommended for use as a rejection criterion when examining a new tape by the MMM method.