Mild Steel Plates Research Articles

EFFECT OF WELDING ELECTRODES AND POST-WELD HEAT TREATMENT ON SOME MECHANICAL PROPERTIES AND MICROSTRUCTURAL TRANSFORMATIONS OF MILD STEEL WELDMENT USING SMAW PROCESS

The current study investigates the effect of some welding electrodes and post-weld heat treatment (PWHT) on tensile strength, hardness, impact energy, and microstructural transformations of mild steel weldments, using the shielded metal arc welding (SMAW) technique. Four different electrode specifications were used in this study, these includes cast iron (AG4700), mild steel (E6014), stainless steel (E308L-16), and mild steel (E6013) electrodes. Eight (8) samples of mild steel plate of length 100mm and 5mm thickness were first sectioned and welded across the width using the four electrodes (2 samples per each). After welding, four of the welded plates with each of the four different electrode materials were then subjected to the post-weld heat treatment (Normalizing) at a temperature of 8000C, soaked for 50 mins, and then allowed to cool naturally in an open-air. Both the heat-treated and the as-welded samples were then subjected to various mechanical tests. The result obtained showed that the welds with mild steel electrodes (E6013 and E6014) possess higher tensile strength for both the heat-treated and untreated welds, while the AG4700 electrode gave the highest impact energy after thermal treatment as compared to other welds. The hardness values with all the four electrode materials were generally found to decrease after post-weld heat treatment. The microstructural results revealed the breaking of the original fine grain structures in the as-welded condition to more coarser structures after heat treatment for all the weldments, which appears to account for the lower hardness obtained in the post-treated steel welds. Based on the results obtained, it can be concluded that some electrode materials impart adequate mechanical properties in the as-welded condition, while some, depending on the type of mechanical properties to be improved, require post-weld heat treatment on the weldment.

Parameters optimization in plasma arc cutting of AISI 1020 mild steel plate using hybrid genetic algorithm and artificial neural network

The aim of this study was to optimize the cutting parameters such as cutting speed, standoff distance, cutting current and gas pressure of the CNC plasma arc cutting process that affected the material removal rate, surface roughness and nozzle diameter change after cutting performed on AISI 1020 mild steel plate. Three levels of variation were taken to the four cutting parameters that were chosen. Twenty-seven trial experiments were carried out using L27 orthogonal array of Taguchi design. In this experimental investigation, the highest material removal rate (MRR) of 8.96 g/s, Ra surface roughness (SR) of 15.734 µm and nozzle orifice diameter (ND) of 1.4637 mm were achieved, whereas the lowest obtained values of MRR, SR and ND were 2.324 g/s, 5.98 µm and 1.2114 mm, respectively. For modeling the plasma arc cutting process experimental input parameters and responses' results, a hybrid ANN-GA model was constructed. This model was used to forecast and optimize MRR, SR and ND, as well as the control factors that go with it. The results indicated that the ANN-GA model could predict the output responses with a mean square error of 1.06885e–1. During optimization, a 4-9-3 network trained with neural network of back propagation by Levenberg-Marquardt algorithm was used to have the greatest prediction capability, with optimum values of MRR, SR and ND of 7.0032 g/s, 4.2062 µm and 1.3142 mm, respectively. From the confirmation tests, the average results of 6.9247 g/s of MRR, 4.3429 µm of SR and 1.3703 mm of ND were obtained. The percentage of errors between the ANN-GA predicted optimal responses' results and the confirmatory experimental results were found 1.121%, 3.250% and 4.269% for MRR, SR and ND, respectively.

Structural Behavior of Short Thin-Walled Steel Columns Filled with High Strength Concrete Made of Recycled Aggregate

This paper introduces an experimental work to study the behavior of 12 recycled aggregate concrete-filled steel tubular (RACFST) short columns with high-strength concrete grade subjected to axial compression loading. These columns formed from six different cross-sections involving triangle, elliptical, and hexagon, whereas the other three sections included traditional forms for control purposes, involving square, rectangular, and circular. All RACFST columns used are made of mild steel plates. These columns were divided into two groups. The steel tube thickness was the only parameter modified to study its effect properly. In addition, the study included the search for the best effective section concerning the properties of stability and confinement, so these columns were designed so that the cross-sectional areas of steel tubes were approximately equal. Also, composite action and level of ductility for these columns were studied. The ultimate failure axial load, the reduction in the axial column length, the failure pattern of cross-section shape, and lateral displacement were recorded during the test. Regarding the two groups of columns with (1 and 2) mm thick steel plates, testing data obtained from RACFST columns with elliptical and circular cross-sections respectively showed better stability and confinement of concrete and the ability to withstand a higher ultimate failure stress. Moreover, columns with polygonal sections showed when the number of ribs for the steel plates of the model or increased the angle between the two sides is (90°) or more, column cross-sections can achieve more stability and confinement, respectively. In general , increasing the thickness of the steel tubes increases. Finally, for all columns, the higher values of the concrete contribution ratio (C.C.R) led to an increase in the strength index (S.I.) values. An increase in values of final failure stresses accompanied this increase.

Continuous Wave Fibre Laser Welding of AISI Stainless Steel SS 410 and Mild Steel

The main aim of this paper is to study laser welding of AISI stainless steel (SS) 410 and mild steel (MS) at different values of welding power, welding speed and frequency. The welding of dissimilar metals is most useful in structural, automobiles, furniture and decorative applications. But there is a difficulty in welding of mild steel and stainless steel due to the loss of carbon from mild steel and precipitation of chromium in stainless steel. Laser welding is best suitable process which is used to control the problems occurred during welding on base metals joints. A 2 kW continuous wave fibre laser welding machine was used to weld 2 mm thick stainless steel (SS) and mild steel (MS) plates. The photos of the welded joints were assessed and then tested to investigate the mechanical properties of the welded joints.

A methodological approach to design a coil for localised high-frequency induction heating of flat plate

High-frequency induction heating (HFIH) is a quick heating technology, mostly used for localised surface treatment. The HFIH process has a portable RLC tank circuit consisting of a fixed size capacitor bank, load-matching transformer and a small size inductor coil. However, the work feasibility of small size inductor coil involves complexity in matching the resonant frequency between the RLC tank circuit and the high-frequency induction power source. Because the resonant frequency of the RLC tank circuit depends on the shape, size and configuration of the considered inductor coil. To address the issue, a numerical model-based approach is proposed herein to do the frequency matching for any coil configurations. Three different coil configurations such as co-direction, single-direction and opposite-direction current coils are considered in the simulation study to optimise their geometry and estimation of resonant frequencies. Based on the derived resonant frequency of the inductor coils, another coupled electromagnetic-thermal model is developed to get the thermal characteristics for a planar heating process of an 8 mm thick mild steel plate. After finding the optimal geometry of all coil configurations, the coils are fabricated and used in experimentation to verify the results of numerical models. It is found that the coil geometry has a significant effect on the resonant frequency and the heating characteristics. In addition, the current work emphasises a systematic approach to address the temperature non-uniformity that arises at the inlet and outlet positions of the workpiece in movable induction heating.

Experimental investigation of damping characteristics of sandwiched engine isolators using two-way isolator excitation method (TWIEM) and performance evaluation

Dynamic properties of engine isolators are of significant importance in determining the performance of the isolator and precise prediction of the dynamic behavior at the design stage. Unfortunately, the damping property can not be deduced deterministically from other structural properties because it is highly dependent on dynamic shear properties such as frequency and temperature of material under application. Generally damping properties are determined from experiments conducted on the desired setup. Many times, designers use the damping property data available in literature. Such data may not be recommended for development of predictive models for dynamic behavior. This paper presents a novel method of determination of damping property of the engine isolator. The method is called two-way isolator excitation method (TWIEM). The damping property is determined by excitation of the isolator for active and passive transmissibility. The purpose of this paper is to analyze the vibration isolation by checking the transmissibility ratio for various engine isolators. Sandwiched engine isolators are designed to blend the good properties of different isolation materials to make it more efficient. The experimentation was carried out using three different isolator designs and compared the performance of the isolator on the basis of isolation percentage. Mild steel plates, polymer foam sheets and natural rubber materials are used as Isolator materials. The results show that low damping ratio isolating material is more effective in isolating the vibration source.

Numerical and thermal analysis of mechanical properties degradations and distortions in steel weld joint

To quantify the degradation of mechanical properties and material distortion associated with steel weld. Twin mild steel plates each of dimension 20 mm × 100 mm × 6 mm were joined in butt configuration using the arc welding method. Thermal and mechanical analyses of the system were carried out using a numerical method and the associated heat transfer/stress distribution problems were formulated based on FEM. The thermal analysis involves numerical evaluation of the transient temperature distribution in the specimen. The effects of some operational parameters including welding speed and welding power on the temperature profile were studied independently. The results suggest that a good combination of these operational variables guarantees stable welding operation which in turn assists in achieving a quality welded joint. The numerical results were validated using experimental data and further applied to solve the prevailing mechanical problem. The maximum residual stress of 200 N/mm2 was recorded along the weld line while a maximum distortion of 15 mm was recorded numerically at the free end of the steel segment at the prevailing stress condition. Therefore it is recommended that maintaining low but sufficient high welding power helps to minimize excessive temperature rise in the base metal and improves stress distribution along the welding line, which in turn mitigates degradation of tensile strength and other mechanical properties.

Effect of quenching media on mechanical properties of welded mild steel plate

Quenching is a swift way of returning metal back to ambient temperature in order to acquire a certain property. Although it is often used to enhance the hardness of metals and their micro-structure, it equally causes a serious variation in the mechanical and physical properties of the metals. This research focuses on quenching media's effect on the microstructure and mechanical properties of a 150mm x 80mm x 8mm welded mild steel plate through microscopic examination, metallography mounting, surface grinding, and surface polishing. Microstructural analysis with hardness and impact test was carried out on the steel plate using water, air, and oil as the quenching media. The results of the test show the Vickers Pyramid Number (HV) for water, oil, and air to be 284.2, 270.9, and 262.2 HV for the base metal, heat affected zone (HAZ), and weld metal (WM), respectively. The amount of energy absorbed by the three specimens during fracture is 23.12, 25.27, and 26.83 J, respectively. The test further indicates that the water-quenched media exhibited mostly martensitic structures and held back austenite with many structures of cementite while the oil and air media exhibited martensite phase and refined grains structures individually. It is therefore concluded that air is more suitable to cool the weld metal for damping applications in engineering.

Al2O3 and CuO nano particulate-based paints for marine applications

The present study focuses on the Preparation of Aluminum Oxide, and Copper oxide antifouling coatings to prevent or reduce corrosion and fouling in ships and marine vehicles. Al2O3 and CuO nanoparticles were prepared using the ball milling process. The nano paints were prepared using these nanoparticles as pigment and linseed alkyd resin as a binder. Mild-steel specimens coated with nano paint were immersed in seawater for 120 days and the properties were studied using Scanning electron microscopy, SEM—EDAX, X-ray Diffraction, and Fourier transform-infra red spectroscopy. It found an improvement in anti-fouling exhibited by Al2O3 mild steel plates and also an improvement using CuO when compared to bare paint. Contact angle measurement showed a marked increase for base paint which indicates its hydrophobic nature.

Experimental Evaluation of Wöhler Curve for Mild Steel Plates Manufactured In Nepal

This research work was carried out to explore the fatigue behavior of Mild Steel Plates manufactured in Nepal and determine the Wöhler Curve of the plates by preparing test specimens and conducting fatigue experiment of the specimens in the rotating cantilever bending fatigue test machine. The laboratory data thus obtained were plotted to generate the Wöhler Curve of the material. Along with the curve the Basquin’s Coefficients and Endurance limitup to 106 cycles were determined. Specimen was designed in accordance to ASME E 466-15 and the machining was done in accordance to IS 1075-1985 and then was subjected to various different loads. Exploratory tensile test of the material was also done in order to find out the proportion of the applied load with respect to the ultimate strength of the material. Surface crack was also inspected.Micro void coalescence and Micro cleavage formations were noticed in the fractured section.

Performance of predictive models to determine weld bead shape parameters for shielded gas metal arc welded T-joints

Assessing weld bead shape is essential for the quality control of a welded joint. This work presents an attempt to predict the weld bead shape parameters of shielded Gas Metal Arc Welded (GMAW) fillet joints through the application of statistical design techniques and artificial neural network. Extensive tests were performed on low carbon mild steel plates ranging in thickness from 3 mm to 10 mm. Welding voltage, welding current, and moving heat source speed were considered as the welding parameters. To develop empirical equation for defining bead geometry parameters of GMAW, multiple linear regression model (MLR) was formulated. Also, an artificial neural network (ANN) model was developed and individual feature importance was studied using SHapley Additive exPlanations (SHAP). The results show that the ANN-based approach performs better in predictability and error assessment. The predictive model has been used to study the temperature profile of a joint numerically, and an excellent match has been noticed when compared with experimental measurement. This study shows the usefulness of the predictive tools to aid numerical analysis of welding.

Experimental Study of Hybrid Flat-Plate Solar Collector/Nocturnal Radiator for Water Heating and Cooling in Owerri, Nigeria

The quest for new, alternative energy sources and technologies have risen due to myriads of crises associated with fossil fuel dominated energy mix in Nigeria, in terms of supply and its adverse effect on the environment.
 Experimental study of hybrid flat-plate solar collector/nocturnal radiator for water heating and cooling in Owerri, Nigeria, is presented. The experimental rig consists of a single flat surface (absorber plate) made of a mild steel plate, film-coated with an acrylic resin which made the surface spectrally selective. Underneath, were arrays of copper tube risers. A sample test on acrylic resin’s coating, on a metallic substrate showed that it has high clear spectral absorptivity (low emissivity) in the solar radiation band (0.2-0.3µm) as well as low absorptivity (high emissivity) in the atmospheric window band (3-8µm). A water reservoir 2m above was connected to the system inlet header to supply water. Experimental data were harvested for days/nights through a read-out basic language programmed data logger. The experimentation were conducted under the metrological condition of Federal Polytechnic Nekede Owerri (5.49oN, 7.02oE), South-East Nigeria. The results obtained under solar heating phase showed a peak water temperature of 60⁰C at a plate temperature of about 80⁰C and a heat collection efficiency of 31%. The peak insolation was about 900W/m2 and the ambient temperature was between 27⁰C and 32⁰C throughout the diurnal phase. Also, under the nocturnal radiation phase, a cooling power of 41w/m2 was achieved during cooling on clear night and about 20w/m2 on a cloudy night. Water temperature in the range of 19⁰C to 20⁰C was recorded at temperature depression of about 5⁰C. The night sky temperature of the location was obtained in the range 10⁰C to 16⁰C for the period under study. The result shows that the system can provide substantial energy savings when incorporated into building structure, to providing hot and cold water for domestic/process use, space heating and cooling applications.

GAN-Based Image Dehazing for Intelligent Weld Shape Classification and Tracing Using Deep Learning

Weld seam identification with industrial robots is a difficult task since it requires manual edge recognition and traditional image processing approaches, which take time. Furthermore, noises such as arc light, weld fumes, and different backgrounds have a significant impact on traditional weld seam identification. To solve these issues, deep learning-based object detection is used to distinguish distinct weld seam shapes in the presence of weld fumes, simulating real-world industrial welding settings. Genetic algorithm-based state-of-the-art object detection models such as Scaled YOLOv4 (You Only Look Once), YOLO DarkNet, and YOLOv5 are used in this work. To support actual welding, the aforementioned architecture is trained with 2286 real weld pieces made of mild steel and aluminum plates. To improve weld detection, the welding fumes are denoised using the generative adversarial network (GAN) and compared with dark channel prior (DCP) approach. Then, to discover the distinct weld seams, a contour detection method was applied, and an artificial neural network (ANN) was used to convert the pixel values into robot coordinates. Finally, distinct weld shape coordinates are provided to the TAL BRABO manipulator for tracing the shapes recognized using an eye-to-hand robotic camera setup. Peak signal-to-noise ratio, the structural similarity index, mean square error, and the naturalness image quality evaluator score are the dehazing metrics utilized for evaluation. For each test scenario, detection parameters such as precision, recall, mean average precision (mAP), loss, and inference speed values are compared. Weld shapes are recognized with 95% accuracy using YOLOv5 in both normal and post-fume removal settings. It was observed that the robot is able to trace the weld seam more precisely.

Design and Fabrication of Portable Motor Driven Concrete Mixing Machine: A Review

Abstract: The aim of our paper is design and fabrication of portable concrete mixture machine. Mixer widely used to make a concrete mixture which used to building construction and other industrial application such as concrete block, pipe, sheets, etc. As for all materials, the performance of concrete is determined by its microstructure. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site. the concrete mixture machines which are currently available in the market is heavy and having big capacity of concrete mixing. Continuously and easy handling, we have fabricated this concrete mixture machine. The construction and building industries are expanding on a daily basis as a result of increase in human population and continually demand for shelter. Concrete which comprises mainly of sand, cement and gravel is an important component required for construction of houses and roads. However, most operation of mixing concrete in Nigeria is done manually as a result of lack of insufficient machinery and high importation cost. In this research, I carried out the design of a low-cost concrete mixing machine. The materials used in this research work are as follow; sand, gravel, water, mild steel, hopper, electric motor, shaft, bearing, V-belt, angle bar, mild steel plate, bolts and nuts, etc. In other to achieve a good design, feasibility studies, and preliminary tests were carried out. The materials selected for this design were justified. Keywords: portable mixer, design model, mixing volume, power, torque, belt tension

A Study on Micropiles in Foundation

Micropiles are piles of smaller diameter used around footings capable of reducing settlement and improves the bearing capacity of soil. Studies were conducted on locally available clayey soil. Mild steel micropiles of length 10D, 20D and 30D and spacing of the micropiles were varied as 5D, 4D and 3D were D is the diameter of micropiles. Mild steel plate of dimension 150x150x10 mm were taken as the model square footing. Plate load test were carried out in a model tank of dimensions 800x800x500mm with and without micropiles and corresponding settlements were taken. It is studied that the settlement can be reduced considerably by increasing the length and reducing the spacing of micropiles

Repeated uniform blast loading on welded mild steel rectangular plates

The present research paper deals with a combined experimental and numerical assessment of the deformation mode and failure mechanism of welded rectangular plates exposed to three successive uniform blast loading. To perform the experimental study, three different categories of 0 W (a plate without any weld seam), 1 W (a plate with a single weld seam), and 2 W (a plate with double weld seams) were conducted and mounted onto the ballistic pendulum apparatus. The effect of the number of blasts, the number of weld seams, and the explosive charge mass was investigated on the structural dynamic response. Unlike 0 W plates, plates with double weld seams experienced large plastic deformation along with small thinning happening at the long side clamped boundary. Therefore, despite increasing the deformation resistance, the welding lines tended to mitigate the damage tolerance of the tested mild steel plates. To gain more insight into the influence of two other key parameters like the position of the weld seam and its orientation on the dynamic response and energy absorption capacity, numerical simulations were also performed using the ABAQUS/Explicit finite element solver in conjunction with the inbuilt ConWep blast function code. For modeling the amplified blast wave produced by the detonation of the explosive charge, the scaling factor of 4.1 was adopted. Due to the welding process on the tested plates, the material degradation at the Heat-Affected Zone (HAZ) was also incorporated into the simulation by obtaining the knockdown factor from quasi-static tensile tests on unwelded and welded specimens. An excellent agreement between experiments and simulation results was achieved in terms of the impulse of the applied load and central permanent deflection. Furthermore, the present paper provides the primary experimental data and numerical simulation support for the blast resistance design of metallic structures using welded specimens.

In situ Raman Spectroscopy Monitors the Corrosion of Mild Steel in a Salt Fog Chamber

The global cost of corrosion imposes a significant burden on society, with safety and environmental consequences in addition to its direct impact. One challenge to its management is that the process of corrosion is complex, and common experimental techniques provide only limited information. The neutral salt spray test, a standardized test used for the evaluation of the corrosion resistance of steels and coatings, creates an aggressive environment not suitable for many analytical methods. Here, we report the first use of in situ Raman spectroscopy to detect the formation, growth, and evolution of corrosion products on metal surfaces, monitoring a mild steel plate in alternating salt fog and dry atmospheric conditions over a period of eight days to identify and track key corrosion products. Assisted by multivariate curve resolution alternating least squares (MCR-ALS) analysis and online weighing of the sample, we found the chemical conversion of iron hydroxides to oxides takes much longer than the physical drying of the corroded surface. Together, these results pave the way for real-time online observation of corrosion inside a salt fog chamber to obtain chemically relevant information with a single, compact apparatus.

Tunnel-magnetoresistive-based Pulsed Eddy Current Probe for Inspection of Corrosion under Insulation

The problem of corrosion in the industrial oil and gas pipes has been one of the major contributors in catastrophic structural failures. Among the various types of corrosion, corrosion under insulation (CUI) has been known to cause serious problems. Pulsed eddy current (PEC) non-destructive testing has shown its effectiveness in detecting hidden CUI. Most PEC systems have been developed by using an inductive coil as their sensing device, while some use a magnetic sensor which potentially offers better resolution. A new probe design based on a solid-state Tunnel magnetoresistance (TMR) is presented. TMR sensors offer higher sensitivities compared to other commercially available sensors. The performance of the probe is evaluated by using ferromagnetic mild steel plates that have thicknesses in the range of 8mm to 12mm at different stand-offs with a thin aluminium sheet under the probe. The different thicknesses represent different corrosion levels, while the stand-offs and thin aluminium sheet are to mimic the insulation of different thicknesses and the cladding in the real pipeline structure. The results show an overall mean absolute error (MAE) of 0.19 mm, which is better than our existing Hall-device-based PEC probe.

Turmeric as eco-friendly corrosion inhibitor for electron beam-curable steel coating in 3.5% sodium chloride solution

Purpose This study aims is to evaluate the environmentally friendly turmeric as a corrosion inhibitor for mild steel in a simulated seawater corrosion medium such as a 3.5% NaCl solution. To accomplish this, different proportions of turmeric (0.3, 0.6, 0.9 and 1.5%) were added to solvent-free epoxy-acrylate resin-based coating formulations. Then, all the formulations were sonicated and coated as thin films on different substrates; these coated films were then polymerized under a dose of 10 kGy of electron beam (EB) radiation. Design/methodology/approach Various properties of all cured coating films such as Fourier transform infrared spectroscopy, water contact angle, thermogravimetric analysis and scanning electron microscopy were studied, in addition to their physical, chemical and mechanical properties. Turmeric was then evaluated in these formulations as an anticorrosion agent for mild steel in 3.5% NaCl. The different corrosion-resistant properties of all EB-cured coating films were evaluated by open circuit potential measurements, rust degree, blistering, adhesion loss at X-cut and weight loss measurements. Findings The results showed that most of the formulations are homogeneous, especially at low concentrations of turmeric, and their films have high-performance properties. Originality/value It was also found that the formulation containing 0.6% of turmeric per 100 g of coating was considered the best formulation as it gave the highest protection to the mild steel plates with no negative effects on the chemical and physical properties of their films.

Detection of mode frequencies for spherical cavity embedded within a mild steel plate

The modern era of structures has observed a vast increase in non-destructive evaluation techniques in order to detect unwanted damages or porosities within the structure. Detection of defect frequencies will play a vital role in local defect resonance–based defect imaging in the future. In this paper, a technique for porosity and cavity detection in metals is discussed. A numerical investigation is carried out first on a square mild steel plate with a spherical cavity and a square mild steel block with multiple cavities. Different resonance frequencies and corresponding mode shapes in the case of the single cavity are calculated using steady state dynamic analysis. Six fundamental mode shapes are identified as Rocking (R), Torsional (T), Bouncing (B), 4-noded (4 N), 6-noded (6 N) and 8-noded (8 N) modes. Moreover, an explicit dynamic analysis is performed by exciting the model with a chirp signal for both cases of single and multiple cavities. The numerical study is supported by experimental results, performed on a mild steel plate embedded with a single spherical cavity and previously published literature. It is observed that the analytical, numerical as well as the experimental results obtained for all the modes are in close agreement with each other. The bouncing mode is found to be the promising one for pore imaging due to its uniform displacement across all the directions.