Steel Sheets Research Articles

Numerical simulation and ANN algorithm-based predictive modeling in self-piercing riveting of aluminum and high-strength steel sheets

Numerical simulation and ANN algorithm-based predictive modeling in self-piercing riveting of aluminum and high-strength steel sheets

The Influence of Different Hot-Dip Zinc Coating Types on the Gas Metal Arc Welding of Galvanized Steel Sheets

Abstract The work was focused on evaluating the influence of the structure of the protective Zn coating on steel sheets on arc welding. Two types of galvanized steel sheets were used in the experiments, HX340LAD + ZF (GA type) and HX300LAD + Z (GI type), with a thickness of 2 mm. First, the analysis of the structure of the Zn protective layer was carried out on the selected materials. After that, test welds were made using the gas metal arc (GMA) welding in the short-circuit metal transfer. The influence of the type of protective Zn coating on the occurrence of defects, the geometry of the weld, and the stability of the welding process was evaluated. From the achieved results, it can be concluded that the protective Zn layer on the HX340LAD + ZF sheet was formed by intermetallic phases FexZny-Fe concentration ranged from 19.0 wt.% (at the steel plate coating interface) up to 9.5 wt.% (on the coating surface). An Fe-Al inhibitor layer was observed at the steel sheet-coating interface of the HX300LAD + Z material, while the Fe content in the Zn coating decreased from 8.2 to 0.8 wt.% towards the surface. Better weld evaluation results were achieved on samples made on HX340LAD + ZF galvanized sheet. The welds were without porosity, and the stability parameter (electric arc stability criterion) was almost two times smaller than the stability parameter in the evaluation of the HX300LAD + Z sheet metal welding process.

Design and Development of a Semi-Automatic Coconut Broom Stick Machine

This paper focuses on the design and development of a semi-automatic machine to separate individual dry coconut leaves into their stick (stem) and leaf portions, aimed at streamlining broomstick production. The machine is powered by a 1/4 HP direct-drive motor, which drives two rubber rollers via a shaft supported by Unit Cast Pedestal (UCP) bearings. As the coconut leaf is fed into the machine, the rollers pull it through, while a precisely positioned blade mechanism efficiently detaches the stick from the leaf. The structure of the machine is constructed using durable mild steel (MS) sheet metal, ensuring robustness and longevity while securely housing all components. Key design considerations include motor configuration, blade placement, and material selection for strength and weight optimization. The design process employs CAD modelling for precision and visualization, while testing and iterative refinements ensure optimal machine performance. This semi-automatic solution aims to enhance productivity, minimize manual labour, and improve efficiency in the broomstick manufacturing process. The paper serves as a significant step towards mechanizing traditional tasks in rural industries, offering a cost-effective and reliable alternative to manual leaf separation methods. Keywords Coconut Broom Stick, Semi-Automatic Machine, Leaf Stick Separation, Mechanization, Agricultural Equipment

The Optimization of Rotary Bending Die Process: Criteria for the Metal Sheet Angles and Springback Effects

Rotary die bending enables the precise fabrication of sheet metal components across various bending angles, offering high dimensional accuracy, structural stability, and reduced springback. This study employs explicit and implicit numerical simulations using the Abaqus software to analyze the rotary die bending process and springback behavior of SUS304 stainless steel sheets. Five key criteria are investigated: desired angle post-springback (asi), springback factor (ksi), forming stress (Von Mises) at the required bending angle (Sr), residual stress (Von Mises) after springback (Sb), and equivalent plastic strain (PEEQ). These criteria enable accurate predictions of material behavior during rotary die bending, including elastic-plastic deformation and stress distribution. The insights gained support a more flexible design process, enhance the precision of sheet metal bending, and ensure that the final product meets the specified requirements. This research serves as a valuable reference for professionals working with sheet metal components made from various metals and bimetal sheets. Additionally, it informs strategies to mitigate or eliminate residual stress in bent parts, improving reliability and manufacturability.

Effect of process parameters and hybrid voltage-wind field on nanosecond laser spiral layer hole-cutting performance for thin stainless steel sheets

Effect of process parameters and hybrid voltage-wind field on nanosecond laser spiral layer hole-cutting performance for thin stainless steel sheets

Structural Performance of Concrete-Filled Funnel-Shaped Profiled Steel Sheet Composite Shear Walls Subjected to Lateral Cyclic Loading

Structural Performance of Concrete-Filled Funnel-Shaped Profiled Steel Sheet Composite Shear Walls Subjected to Lateral Cyclic Loading

Anisotropic Hardening of HC420 Steel Sheet: Experiments and Analytical Modeling

Choosing the appropriate yield function is essential to precisely predicting the anisotropic hardening behavior of steel metals considering general loading directions. This research investigates the anisotropic hardening behavior of HC420 steel sheet by combining experimental and analytical modeling. Experiments are conducted for uniaxial tensile tests according to the three different directions and bulging tests to obtain hardening data. The experimental findings show that the loading direction affects the anisotropic behavior of HC420 steel’s strength and plastic deformation. The Chen-coupled quadratic and non-quadratic (Chen-CQN) approach is used to ensure the convexity of the HC420 steel. By comparing the Chen-CQN approach with the Yld2000-2d and Stoughton-Yoon’2009 yield functions, the Chen-CQN approach shows superiority in predicting the hardening behavior of the HC420 sheet, exhibiting a more straightforward numerical implementation and enhanced accuracy in yield stress predictions under different loading directions. Results from experimental hardening tests reveal that the Chen-CQN function precisely and flexibly characterizes the yield surface of HC420 steel, with a constant variation of within 2% from its predictions.

Research on the stress concentration effects and fracture mechanisms of DC04 sheet steel with holes

DC04 sheet steel is widely used in automotive engineering because of its light weight and high ductility. The sheet steel with holes will emerge stress concentration under loading, then the peripore crack appeared around holes until the fracture occurred. The conventional analysis started around the macroscopic experiment and theoretical analysis, but the study on the evolution law and fracture mechanism of peripore cracks caused by stress concentration effect was not systematic. So, the hole stress of DC04 sheet steel with circular, oval, rectangular and diamond holes were firstly analyzed in this paper. At the same time, 15 groups of tensile tests were verified the influence of cavity shape on stress concentration. Then, taking the sheet steel with circular hole and oval hole as the research object, the evolution of aperture and stress change law were analyzed, and the corresponding empirical formula of stress concentration coefficient about net section was obtained. Finally, the microscopic crack development was observed by electron microscopy, and the crack evolution law and the fracture mechanism caused by stress concentration around the hole were analyzed. These studies will provide theoretical support for the practical engineering design.

Design and Analysis of Double‐Sided U‐Shaped Linear Primary Permanent Magnet Vernier Motor

This paper introduces a new double‐sided U‐shaped linear primary permanent magnet Vernier (U‐LPPMV) motor, whose most important feature is a U‐shaped Halbach structure in which the magnetization direction of five permanent magnets is concentrated at the center point, which provides more than twice the thrust density compared with existing single‐sided motors. The secondary stage adopts a convex pole structure consisting of laminated silicon steel sheets, which has the advantages of a simple structure and low cost. The no‐load counter‐electromotive force and magnetic chain are made more sinusoidal by changing the side end structure at both ends of the primary. Next, the air‐gap magnetic density of the motor is analyzed analytically by establishing the magnetomotive force potential‐magnetic conductance model, and the accuracy is verified by simulation analysis. In addition, a global optimization of the motor is performed to increase the average thrust and improve the electromagnetic performance based on the optimized structural parameters. Finally, the accuracy of the theory is demonstrated by prototype design and fabrication as well as by building a test platform, and the motor is more suitable for long‐stroke, high‐load, and high‐precision application scenarios. © 2025 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Microstructure and mechanical properties of dissimilar resistance spot welds of TBF and HSLA300 steel sheets

Abstract The welding behavior of the resistance spot welded dissimilar TBF–HSLA300 steel joints under different welding parameters was investigated. TBF steels were used as galvanized or ungalvanized. Microstructural characterization and mechanical tests were performed. Higher heat input resulted in the higher possibility of shrinkage cavities at the weld nugget and also increased the risk of liquid metal embrittlement (LEM) crack in the heat affected zone (HAZ) on galvanized TBF steel sheets. A partial melting zone was observed on HSLA300 side. The welds with ungalvanized TBF sheets had the higher nugget size and indentation. The highest hardness values (over 500 HV0.1) were observed in HAZ on TBF side. The lowest hardness values (below 300 HV0.1) on TBF side were observed in a very narrow softening zone between tempered zone and base metal. The fractures of all spot welds in the tensile shear test occurred on the TBF steel side with the thinner thickness. Low-strength steel sheet have to be sufficiently thicker in order to achieve higher welding strength. Higher welding time led to higher weld strength in the ungalvanized TBF combination. In the galvanized TBF combination, higher heat input led to the drastic decrease in weld strength due to LEM cracks.

Microstructure Evolution of Cold-Rolled Carbide-Free Bainite Steel Sheets During Continuous Annealing Process

A modified carbide-free bainite (CFB) steel has been developed, building on existing alloys for compatibility with commercial continuous annealing lines (CALs), featuring a low austenitization temperature and short overaging time. The microstructural features of such candidate CFB sheets are compared with those of conventional CFB steel sheets that require higher reheating temperatures and longer overaging times. The effects of annealing parameters such as reheating temperatures and overaging temperatures on phase transformation kinetics and microstructure evolution are presented. The annealing process was simulated in a Gleeble thermomechanical processing simulator, and the microstructural characterization was carried out using XRD, SEM, and EBSD. Reconstruction of parent austenite grains from EBSD data did not reveal any variant selection, regardless of changes in the austenitization temperature, overaging temperature, or carbon content. It was observed that the V1–V2 variant pairing is the most common at the lower overaging temperature for reheating at 950 °C; however, this pairing decreases as the isothermal overaging temperature increases, with variant pairings involving low misorientation boundaries—such as V1–V4 and V1–V8—becoming more frequent. Steels with higher carbon content exhibit no significant changes in their variant pairing, regardless of variations in the austenitizing or isothermal temperatures. The XRD results show that the retained austenite fraction is reduced by increasing the isothermal transformation temperature.

Numerical Modeling and Analysis of Steel Sheet Pile Cofferdams, Considering the Construction Sequence

The construction of steel sheet pile cofferdams is a systematic project. Simplified construction sequences are widely used to facilitate the numerical modeling of cofferdams, while the mechanical behaviors of cofferdams with different construction sequences have yet to be understood. In the present study, finite element models of steel sheet pile cofferdams with different construction sequences were established, based on the temporary cofferdam of the Shenzhen–Zhongshan Link. The mechanisms of simplified construction sequences on bending moment were revealed by analyzing the displacements and contact press of steel sheet piles. The distribution of bending moment with elevation demonstrates the importance of the layered backfill process in numerical modeling. In addition, a finite element model of the cofferdam considering steady-state seepage was also established. The comparison of the hydrostatic pressure results and the bending moment results obtained by engineering experience and seepage analysis were discussed. The analysis results showed that the empirical method overestimated the maximum bending moment of the inner side of piles, which led to a more conservative design of the cofferdam. This work can serve as a reference for numerical modeling of steel sheet pile cofferdams and contribute to risk assessment in related engineering projects.

Carbon Footprint Analysis of Distribution Network Transformers Based on Life Cycle Assessment

Transformers in the distribution network must have their carbon emissions analyzed in order to meet the “double carbon” goal. Using an oil-immersed distribution transformer as the research object, this paper develops a “cradle-to-grave” carbon accounting model. A life cycle assessment (LCA)-based methodology is proposed to account for carbon emissions and total energy demand over the full life cycle and further analyze the carbon emissions within each stage. A case study is presented using data from a 200 kVA transformer manufactured by a transformer plant in Xinjiang. According to the data, there are 112.18 t of carbon emissions and 798.21 GJ of total energy consumed. Distribution network transformers have carbon emissions of 282 kg, 782 kg, 122.96 kg, 11,079.64 kg, and −88.6 kg throughout the manufacture and manufacturing stage, transportation stage, construction and installation stage, operation stage, and waste recycling stage, respectively. There are 4.12 GJ, 9.06 GJ, 1.34 GJ, 785.97 GJ, and −0.28 GJ in total energy requirements. According to the study, which covered 99.03% of the entire life cycle, the operation stage had the largest percentage of carbon emissions. In addition to streamlining the production process and using more energy-efficient equipment, the waste recovery stage successfully decreased the environmental impact of carbon emissions. Sensitivity analysis shows that the silicon steel sheet and transformer oil has a significant impact on the carbon emissions of distribution network transformers during the life cycle, and the higher the grade of silicon steel sheet, the lower the carbon emissions, and the synthetic ester transformer oil has the most comprehensive performance and the lowest carbon emissions.

Calculation of Stray-Field Loss of TEAM P21 Model Under Complex Excitations Based on the Improved Energetic Hysteresis Model

An efficient numerical calculation method of stray-field loss is investigated for typical magnetic load components (grain-oriented silicon steel sheets (GO), magnetic steel plate, and combined components of both materials) under non-sinusoidal excitations (NSE) containing symmetrical harmonic and DC to avoid the local overheating caused by high stray-field loss density. The paper investigates the stray-field loss with different types of load components and working conditions based on the leakage flux complementary-based measurement method, derives an analytical formulation calculating the energetic hysteresis model parameters under different magnetic flux densities to reduce the dependence on measurement data, establishes a loss calculation method considering the influence of non-sinusoidal magnetization on magnetic loss, and discusses the advantages and limitations of existing numerical approaches of additional loss to establish an effective computational strategy of stray-field loss. Finally, the effectiveness of the proposed method is verified by simulations and experiments.

Investigation on multiple bending using laser forming of mild steel plate and its bend angle prediction

In manufacturing industries like shipbuilding, automotive, microelectronics, and aerospace, laser forming is a potential new technology. Laser forming is an intricate thermo-mechanical process in which the process mechanisms are determined by the temperature profile across the sheet thickness, which is influenced by laser power, scan speed, number of passes, laser beam diameter, and workpiece geometry. During the process, the material deforms because of compressive stress generated in the underneath region due to the thermal expansion of the irradiated region. This study focuses on the multiple bending and the effect of different process parameters on the laser bending of the sheet. Experiments were performed on 4 mm and 8 mm thick sheets of mild steel sheet of grade IS 2062 E250 using a 2-kW fiber laser with various influencing parameters such as power, scan speed, and laser spot diameter. Hardness and grain size measurements of laser-formed surfaces at different combinations of influencing parameters were performed and the features formed due to laser irradiation were analyzed. An artificial neural network (ANN) model is proposed to predict the bend angle value.

Defect attention-based lightweight real-time adaptable surface defect analysis

Surface defect diagnosis for steel sheets is essential to maintain the quality of the product. However, it is challenging to do such a task due to the high manufacturing speed of 100–140 m/min, making it impossible to observe defects visually. However, developing a lightweight and real-time adaptable intelligent approach can both overcome this issue and satisfy the requirements of the concept of Industry 4.0. Based on that motivation, this study aimed to satisfy such a demand by introducing an attention-based surface defect identification approach called MobileNetV2-AGCA and UNET-AGCA for defect localisation. The effectiveness of the proposed techniques was evaluated by considering steel strip surface defect images of the NEU-CLS and NEU-DET surface defect dataset where six different defects are included. The Adaptive Graph Channel Attention (AGCA) Module was implemented in an edited version of MobileNetV2 and UNET architecture to improve segmentation accuracy while maintaining or improving the execution speed. According to the experimental results, MobileNetV2-AGCA successfully identified the surface defects with an average accuracy of 99.72%. Regarding defect localisation, UNET-AGCA reached an F1 score of 0.795. It is concluded that the proposed methods provided promising results to be applied to a real-time problem related to surface defect identification and localisation.

Study of Atmospheric Corrosion of Galvanized Steel Sheet in Addis Ababa Region Using Atmospheric Corrosion Models

The present study deals with the investigation of the long term atmospheric corrosion phenomena for galvanized steel sheet in the region of Addis Ababa in Ethiopia using various atmospheric corrosion models. Addis Ababa have transforming atmosphere type of urban/industrial atmosphere, and these changes are going to affect the atmospheric corrosion phenomena for galvanized steel sheet used in this region, which is investigated through atmospheric corrosion models using atmospheric data collected from National Meteorology Agency, Ethiopia for 21 years from 2000 to 2020. Atmospheric corrosivity category for Addis Ababa is determined, and it is found that with little deviation in atmospheric pollutant these categories can shift between C2 and C3 corrosivity category for galvanized steel sheet atmospheric corrosion. Further to study the atmospheric corrosion of galvanized steel sheet, standard atmospheric corrosion models were employed namely Feliu et al. model and Kucera et al. model. These studies corroborate the findings of atmospheric corrosion of galvanized steel sheet and cross verified with the similar region atmospheric corrosion experimental studies performed earlier on the same material. All the atmospheric corrosion models confirmed the trend of the atmospheric corrosion of galvanized steel sheet in the region of urban/industrial atmosphere type. And based on the comparative analysis of all models predictions with experimental results in literature, it is confirmed that the atmospheric corrosion model results are reliable for the study of short and long period of atmospheric corrosion of galvanized steel sheet in Addis Ababa region.

An Experimental Study on Dissimilar Welding of Mild Steel and Stainless-Steel Sheets by Resistance Spot Welding Process

An Experimental Study on Dissimilar Welding of Mild Steel and Stainless-Steel Sheets by Resistance Spot Welding Process

Synthesis and properties of a new environmentally friendly bicyclic imidazoline quaternary ammonium salt as a corrosion inhibitor of carbon steel

Abstract A new corrosion inhibitor, environment-friendly bicyclic imidazoline quaternary ammonium salt (DL-IM), was synthesized using DL-aspartic acid, hydroxyethyl ethylenediamine, and benzyl chloride as the main raw materials. The amidation, cyclization, and quaternization reactions were carried out at 140 °C for 4 h, 220 °C for 3 h, and 70 °C for 3 h, respectively. The structure of DL-IM was characterized by infrared spectroscopy and nuclear magnetic hydrogen spectroscopy. The corrosion experiments of carbon steel sheets (American Petroleum Institute, API 5CT N80, primarily used in well drilling operations to protect the wellbore), protected with or without DL-IM, demonstrated that DL-IM had a good anti-corrosion performance (with the inhibition efficiency and corrosion rate of 97.13% and 0.6528 mm/a, respectively) in the 1 M HCl solution at 60 °C. DL-IM was a kind of cathodic protection-type corrosion inhibitor confirmed by Tafel curves. The analysis of adsorption kinetics by quantum chemical simulations demonstrated that the imidazoline ring in the DL-IM molecule can form covalent bonds with the empty d-orbitals of Fe through charge sharing. Moreover, the dipole moment of DL-IM is 1.3931 D (1 D = 3.34×10-30 C·m), suggesting a good hydrophobicity of DL-IM. Therefore, the adsorption film formed by DL-IM on the surface of N80 can effectively isolate the corrosive medium from N80. Thus, successful synthesis of DL-IM provides a new insight into the design and synthesis of the environment-friendly corrosion inhibitor with stronger corrosion inhibition effect.

Tribo-Electrochemical Mechanism of Material Removal Examined for Chemical Mechanical Planarization of Stainless-Steel Using Citrate Buffer as a Complexing Agent.

Chemical mechanical planarization (CMP) is a technique used to efficiently prepare defect-free, flat surfaces of stainless steel (SS) foils and sheets that are implemented in various modern devices. CMP uses (electro)chemical reactions to structurally weaken the surface layers of a workpiece for easy removal by low-pressure mechanical abrasion. Using a model CMP system of 316/316L stainless steel (SS) in an acidic (pH = 3.63) slurry with alumina abrasives, citrate buffer (CB), and H2O2, we examine the tribo-electrochemical mechanisms of SS CMP that dictate the designs of functionally efficient and cost-effective CMP slurries. The use of CB as a pH-controlled complexing agent prevents defect-causing dissolution of SS and eliminates the need for using separate (often toxic) corrosion inhibitors in the slurry. A material removal rate of 8.6 nm min-1 is obtained at a moderate down pressure of 0.014 MPa with a platen rotation speed of 95 RPM. Electrochemical techniques are strategically combined with mechanical abrasion of SS test samples to probe complex CMP mechanisms that are not readily accessible with electrochemical experiments alone. Corrosion-like reactions of salt-film formation at the SS surface act to enable the CMP process, where corrosion-induced wear plays a major role in material removal.