S235JR Steel Research Articles

Microstructure and Wear Behavior of MMC Coatings Deposited by Plasma Transferred Arc Welding and Thermal Flame Spraying Processes

In this study, two erosion protection MMC coatings with WC particles were deposited by the plasma transferred arc (PTA) welding. One of the coatings with tungsten carbide WC in the NiBSi matrix (WC/NiBSi), and the second coating WC in NiCrBSi matrix (WC/NiCrBSi) was deposited by the flame spray process on the same substrate material S235JR steel. Experiments were performed using a gas blast sand erosion test facility with high-velocity erodent particles impact (approximately 100 m/s) at different particle impact angles (20°–45°), with an objective to study erosion wear characteristics and mass loss of two MMC coatings. Microstructural characterization of MMC coatings was done by scanning electron microscope equipped with energy-dispersive X-ray spectroscopy, whereas X-ray diffraction analysis was used for identification of present phases. The hardness of coatings was determined by Vickers hardness measurements. WC/NiBSi obtained by the PTA process shows superior hardness and erosion properties.

Effect of Ti addition on microstructure and corrosion properties of laser cladded WC-Co/NiCrBSi(Ti) coatings

In order to improve mechanical properties and corrosion resistance of low carbon steel, various composite coatings are usually deposited on its surface using different methods. Laser cladding is used nowadays very often due to its industrial advantages. Laser cladding forms dense and protective coatings with higher bond strength and increased deposition efficiency then those prepared by other coatings technologies. The present research aims to study the influence of the pulse laser power and Ti addition on WC-Co/NiCrBSi cladded coatings obtained by preplacing the feedstock material on a S235JR steel substrate. The properties of the coatings in terms of microstructure and corrosion resistance were investigated. The microstructure characterization was done by scanning electron microscopy (SEM) and EDS analysis; the phases identification was performed by XRD technique. In order to evaluate the properties of the WC-Co/NiCrBSi coatings with and without the addition of Ti, hardness measurements and the electrochemical corrosion tests in NaCl 3.5% solution were carried out.

Foot intrinsic muscle forces impact on internal stresses and strain on diabetic foot subjects

This paper presents the analysis of the statistical size effect in steel structural elements using the stochastic finite element (FE) method. The three-dimensional random field theory is applied to simulate the uncertainty of a nonlinear material. The proposed approach, which combines the discrete random field describing the randomness of the material properties via Monte Carlo simulations, is used for computing the bearing capacity variability of the steel structures. In addition, the mapping interpolation method makes it possible to separate the random field mesh and FE model mesh. The three-dimensional random field for the material properties is established according to the yield strength with a lognormal distribution based on reasonable assumptions, and the corresponding random field parameters are studied. Finally, the results of experimental investigation and simulations are compared based on the tensile and bending tests, and they indicate that the statistical size effect cannot be overlooked in S235JR steel structural elements and that the use of stochastic FE in the analysis of the statistical size effect has tremendous potential.

Experimental and numerical investigations of statistical size effect in S235JR steel structural elements

Abstract This paper presents the analysis of the statistical size effect in steel structural elements using the stochastic finite element (FE) method. The three-dimensional random field theory is applied to simulate the uncertainty of a nonlinear material. The proposed approach, which combines the discrete random field describing the randomness of the material properties via Monte Carlo simulations, is used for computing the bearing capacity variability of the steel structures. In addition, the mapping interpolation method makes it possible to separate the random field mesh and FE model mesh. The three-dimensional random field for the material properties is established according to the yield strength with a lognormal distribution based on reasonable assumptions, and the corresponding random field parameters are studied. Finally, the results of experimental investigation and simulations are compared based on the tensile and bending tests, and they indicate that the statistical size effect cannot be overlooked in S235JR steel structural elements and that the use of stochastic FE in the analysis of the statistical size effect has tremendous potential.

Research of maximum stresses zones in circular perforated plates made of S235JR steel loaded with concentrated force

Research of maximum stresses zones in circular perforated plates made of S235JR steel loaded with concentrated force

RBF surrogate model and EN1317 collision safety-based optimization of two guardrails

The purpose of using roadside safety equipment is to protect vehicle occupants during an accident by reducing the severity of impact. Using poorly designed safety equipment can have serious consequences. While roadside safety elements are designed primarily for safety, cost-effectiveness cannot be overlooked. This study is aimed to optimize H1W4 and H2W4 performance level guardrails manufactured from S235JR, S275JR, and S355JR grade steel materials in terms of safety and economy. For this purpose, surrogate model-based optimization is utilized. In this context, the design variables are selected as post width (x1) and cross-sectional thickness of rail (x2), while objective functions are selected as working width (w) and vehicle exit angle (α). The design variables (x1, x2) are derived by full factorial design (FFD) method and crash test simulations are utilized to construct objective and constraint functions. Consequently, radial basis function (RBF)-based metamodels are created with the help of the obtained data and later the accuracy of the models is validated. Finally, the RBF metamodels are optimized using the multi-objective genetic algorithm (MOGA). As a result of the simulation-based design optimization (SBDO), the optimum designs of H1W4 and H2W4 guardrail systems for different steel material grades are achieved. It is concluded that the final guardrail designs meet the safety criteria as well as provide an economic advantage of up to 23% compared to existing guardrail designs.

The Analysis of Fiber and CO2 Laser Cutting Accuracy

The aim of the conducted research was to compare the functional properties and the cutting accuracy of items produced using Fiber lasers in comparison with CO2 lasers. The object of 6 mm thick sheet plates made of S235JR steel cut with the two different laser types were analyzed. The tests covered dimensional accuracy (in accordance with the PN EN 22768-fH standard) and the surface after cutting (in accordance with the PN-EN ISO 9013: 2017-04). The results of the analysis have demonstrated that for the same welding linear energy, more accurate cutting surface is obtained using Fiber laser cutting.

Gray Box Approach for Prediction of Air Bending

Analytical predictions and black box approaches are well-known strategies for the prediction of forming processes. Each of them has its own advantages and weaknesses. Analytical predictions lack flexibility, but usually have a strong theoretical foundation. Black box approach means models based purely on empirical data, these models provides tailored solutions, but do not have any valid physical background. In this paper, we propose to merge these two concepts into a single procedure: a gray box approach. The gray box approach combines the best features from both prediction strategies: on the one hand, it provides a theoretical ground for the considered manufacturing process; on the other hand, it can be tailored for a given task. Prediction of the springback for the air bending process was taken as an example to test the concept. In the experimental investigation stage, construction steel S235JR sheets of various thicknesses have been used, which resulted in 174 bending tests. The obtained results have been used both to train and to test the gray box model. Validation tests revealed that the gray box approach is a suitable option for springback prediction, as it provides more accurate and consistent results than the analytical and black box approaches.

Analysis of the impact of slot geometry on the stresses distribution in a plate of S235JR steel subjected at biaxial load

Analysis of the impact of slot geometry on the stresses distribution in a plate of S235JR steel subjected at biaxial load

Characterisation of porosity, density, and microstructure of directed energy deposited stainless steel AISI 316L

Directed Energy Deposition (DED) was used to form a Stainless Steel AISI 316 L steel block component on a Mild Steel S235JR substrate. Porosity, density, and defect were characterised at 4 localities within the DED component by microscopy and x-ray tomography. Three-dimensional (3D) reconstruction of the x-ray tomographic image sequences focused at select porosities is presented. The element composition and Vickers microhardness measurements were taken at the fusion lines and track body locations to characterise the differences in materials and mechanical properties at the 2 locations. Lastly, an element mapping analysis was conducted to determine the solidification mode for the DED component. Sources for defects were proposed based on the characteristics of the porosity analysis and conclusions were made about the solidification behaviour of the DED component.

Numerical and Experimental Investigations of Trajectory Effects into Temperature Distribution and Distortion in the Slot Welding of Steel S235JR

One of the significant factors that impresses on welded parts’ performance is welding trajectory. Slotted samples with loop and parallel trajectories welded by two steel plates by S235JR and GMAW process. Temperature distributions were registered by the four K type thermocouples. Heat affected zone dimensions were measured on polished and etched cross-sections of each sample. Induced distortions by dial indicators were gauged along welding process and cooling. To evaluate temperature field and distortion in the welding process, three-dimensional FE models were performed. There was good agreement between the FE model predictions and experimental measurements. The most temperatures, distortions and induced longitudinal and transverse residual stresses by welding in the loop trajectory were more than the parallel.

Analysis of Favorable Process Conditions for the Manufacturing of Thin-Wall Pieces of Mild Steel Obtained by Wire and Arc Additive Manufacturing (WAAM)

One of the challenges in additive manufacturing (AM) of metallic materials is to obtain workpieces free of defects with excellent physical, mechanical, and metallurgical properties. In wire and arc additive manufacturing (WAAM) the influences of process conditions on thermal history, microstructure and resultant mechanical and surface properties of parts must be analyzed. In this work, 3D metallic parts of mild steel wire (American Welding Society-AWS ER70S-6) are built with a WAAM process by depositing layers of material on a substrate of a S235 JR steel sheet of 3 mm thickness under different process conditions, using as welding process the gas metal arc welding (GMAW) with cold metal transfer (CMT) technology, combined with a positioning system such as a computer numerical controlled (CNC) milling machine. Considering the hardness profiles, the estimated ultimate tensile strengths (UTS) derived from the hardness measurements and the microstructure findings, it can be concluded that the most favorable process conditions are the ones provided by CMT, with homogeneous hardness profiles, good mechanical strengths in accordance to conditions defined by standard, and without formation of a decohesionated external layer; CMT Continuous is the optimal option as the mechanical properties are better than single CMT.

The quality of water jet cutting of selected construction materials

The article presents examinations of the quality of water jet cutting process four different construction materials. The study was conducted on selected materials: aluminium alloy (AlCu4MgSi), brass (CuZn37), stainless steel (X5CrNi18-10) and non-alloy steel (S235JR). All these materials had the same thickness of 10mm. Sample geometry has been designed to be able to obtain five different surfaces and slit. During the water jet cutting process parameters were being changed to obtain five surfaces and to compare parameters. The water jet cutting process for this tests was carried out on one-head waterjet machine produced by PTV, designed for 2D and 3D cutting. Quality of all surfaces of samples was then evaluated including: surface roughness, deviation perpendicularity, bevel angle, the width of the cut and the bore. Because there are no standard describing quality tests of water jet cut surfaces, during this study standard ISO 9013:2017 for thermal cutting process was used. Basing on this standard tests of surface roughness and perpendicular deviation or slanting of cut edges were made. The other parameters were tested for information only. In this article results of this test were presented. Quality of surfaces, possibility of using this cutting method for tested construction materials were analysed. The test results have shown usability of water jet cutting process for 10mm thick aluminum alloy AlCu4MgSi, brass CuZn37, stainless steel X5CrNi18-10 and non-alloy steel S235JR. The surface quality obtained after cutting compared to construction materials is sufficient and profitable in Q3 average quality. For the better quality, of course better results, but the cost of cutting increases significantly. Therefore, the details can be cut at a lower quality, and then subjected to further mechanical processing, which is less expensive.

Experimental and theoretical study ofMatricaria recutitachamomile extract as corrosion inhibitor for steel in neutral chloride media

PurposeThis study aims to investigate the inhibition performance of an aqueous extract ofMatricaria recutitachamomile on the corrosion of S235JR steel in 0.5 M NaCl by using electrochemical impedance spectroscopy (EIS) and polarization measurements.Design/methodology/approachThe inhibition performance was investigated using EIS and polarization measurements. Surface analysis demonstrates the presence of a protective layer on the steel surface in the presence of the extract. Quantum chemical parameters calculated for the molecules contained in the aqueous extract are interpreted to predict the corrosion inhibition efficiency of the considered extract.FindingsThe inhibition efficiency of chamomile aqueous extract for S235JR steel increases with increasing amounts of plant concentration and with an increase in the immersion time. The optimal inhibition efficiency of chamomile extract, 98.90 per cent, was achieved for S235JR steel when immersed in 15 per cent v/v of extract concentration for 2 h. The surface analysis in the absence and presence of the chamomile extract confirmed the formation of a protective layer on steel surface. The quantum chemical calculations allowed to explain the great inhibition efficiency values by interpreting the calculated quantum parameters.Originality/valueThis is the first study carrying out an experimental and theoretical investigation onM. recutitachamomile as a green corrosion inhibitor, with interesting potential industrial applications.

Analysis of the Void Volume Fraction for S235JR Steel at Failure for Low Initial Stress Triaxiality

Abstract This paper deals with problems of failure mechanisms of S235JR structural steel. One of the fundamental parameters of the Gurson-Tvergaard-Needleman damage mechanics-based material model is considered in order to describe the behaviour of the material at the plastic range. The analysis was performed on the void volume fraction fF determined at failure of S235JR steel. The case of low initial stress triaxiality η = 1/3 was taken into consideration. Different from the most popular methods such as curve-fitting, the experimental method based on the digital image analysis of the fracture surface of S235JR steel is proposed in order to determine the critical parameter fF.

The properties of zinc coatings electrodeposited on S235JR steel in choline chloride / urea deep eutectic solvent containing ZnCl2

The properties of zinc coatings electrodeposited on S235JR steel in choline chloride / urea deep eutectic solvent containing ZnCl2

Comparison of resistance to damage of unalloyed carbon steels under the influence of hydrogen

One of the most commonly used construction material in industry is unalloyed steel S235 and S355. These types of steel are used for construction of ships, bridges, coastal construction, welded tanks, and in buildings. Due to the operating conditions, these types of steel may undergo hydrogen degradation in the process of manufacturing of welded structures or when operating the structures. This paper presents the results of study into resistance of selected types of non-alloy structural steels to hydrogen degradation. Tests were carried out to determine changes in mechanical properties in the static trials of stretching without hydrogen, and after saturation with hydrogen. Parallel fractographic and electrochemical studies were carried out. Hydrogen saturation was carried out at the time from 3. up to 24. hours in a solution of 0.1N H2SO4 with the addition of 2 mg/dm3 arsenic oxide (III) at an electric current density of 20 mA/cm2. The results of the tests have shown that the impact of hydrogen on the tested steels S235JR and S355J2 leads to a significant deterioration in their mechanical and electrochemical properties. At comparable concentrations of hydrogen, steel S235JR is less susceptible to hydrogen degradation and has greater corrosive resistance measured in 3% NaCl solution, in comparison with steel S355J2.

Multiaxial fatigue study on steel transversal attachments under constant amplitude proportional and non-proportional loadings

In this study, the multiaxial fatigue strength of full-scale transversal attachment is assessed and compared to original experimental results and others found in the literature. Mild strength S235JR steel is used and an exploratory investigation on the use of high strength S690QL steel and the effect of non-proportional loading is presented. The study focuses on non-load carrying fillet welds as commonly used in bridge design and more generally between main girders and struts. The experimental program includes 33 uniaxial and multiaxial fatigue tests and was partially carried out on a new multiaxial setup that allows proportional and non-proportional tests in a typical welded detail. The fatigue life is then compared with estimations obtained from local approaches with the help of 3D finite element models. The multiaxial fatigue life assessment with some of the well-known local approaches is shown to be suited to the analysis under multiaxial stress states. The accuracy of each models and approaches is compared to the experimental values considering all the previously cited parameters.

Influence of plastic deformation of S235JR steel rods on their mechanical properties and corrosion behavior in NaCl solution

Studies show that although commonly used steels are standardized, some of their mechanical properties (such as tensile strength) vary widely and knowledge of their corrosion behavior is insufficient. Additional treatments, such as plastic deformation, alter the structure of carbon steels and affect their properties. This article explores one of the most widely used materials in mechanical and civil engineering - steel S235. Two types of rods, 6 mm in diameter, from hot-rolled non-alloy structural steel (S235JR, BDS EN 10025-2: 2005) and bright cold drawn steel (S235JRC, BDS EN 10277-2: 2008) have been tested. Tensile tests have been carried out, stress-strain curves are constructed and compared, the main mechanical properties such as yield strength, tensile strength and modulus of elasticity are determined. The typical consequences of plastic deformation such as increased yield strength have been identified. The assessment of corrosion behavior was done by means of the weight loss method in a 3,5% NaCl water solution for 5 weeks. It was found out that in the studied period the two types of rod exhibit close corrosion resistance, with the tendency for the cold drawn steel to have a higher uniform corrosion rate over a longer period.

Characterization of a coating 316L applied by plasma transferred arc

Parts of industrial machines and structures are often exposed to the action of aggressive environments, which in a short period of time can provoke the loss of their integrity. It is well known that for extending the service life against erosion and corrosion, protection of the exposed structure zone by coating is frequently used. Various application methods of protective coatings are applied, and the most common are welding and thermal spraying processes. The aim of this study was characterization of coatings made of stainless steel 316L, widely used in chemical and petrochemical industries. The coating was applied on a structural steel S235JR by plasma transferred arc using powder as a filler material. Due to a number of advantages, the plasma transferred arc (PTA) surfacing process has found significant usages in the field of surface protection. This paper presents results of hardness measurements in characteristic zones of the coating and the base material, as well as microstructural characterization of coatings using optical and scanning electron microscopy. Results of EDS analysis of the coating and hardness measurements indicated that a relatively high dilution (26.1 %) of the base material (BM) and the filler material (FM) occurred in a very narrow zone above the fusion line, and thus did not significantly affect the chemical composition of the rest of the coating. Also, erosion resistance tests of coatings were performed by changing the basic functional parameters that is the impact angle and the speed of erodent particles. It was observed that the erosion resistance of the coating material decreases approximately linearly with the increase of the particle speed. Also, with the increase of the impact angle of the erodent (up to 45 ?), the mass loss of the coating material is increased.