Welded Pieces Research Articles

Magnetic Field Sensor Network for Pipeline Monitoring Systems

The oil pipeline industry has seen a rise in criminal activities recently. More than $133b is estimated to be lost globally as a result of the activities of cartels, organized crime members and small-time vandals to oil pipelines. To steal petroleum products from a pipeline, criminals must first drill into the pipeline, (cold or hot tapping) and subsequently weld a new weld piece or screw in an orifice to the pipeline, through which the petroleum product is diverted from the pipeline to another storage. These have crippled the ecosystem, human lives lost and a wide range of poverty in the economy which has motivated this paper to find a lasting solution to the problem at hand. This work employed a magnetic field sensor detector for early detection and petroleum monitoring which is caused by vandals and corrosion that leads to spillage, it will significantly improve productivity, safe lives, improve agricultural products and the ecosystem. The sensor network detects acts of vandalism or corrosion and triggers real-time alert message to the operators for actions to be taken, to prevent wide spread of the substance by specifying the spot location of the incidence where the corrosion or spillage took place.

Combined effects of local residual stresses, internal pores, and microstructures on the mechanical properties of laser-welded Ti-6Al-4V sheets

Laser-welded Ti-6Al-4 V is prone to severe residual stresses, microstructural variation, and structural defects which are known detrimental to the mechanical properties of weld joints. Residual stress removal is typically applied to weld joints for engineering purposes via heat treatment, in order to avoid premature failure and performance degradation. In the present work, we found that proper welding residual stresses in laser-welded Ti-6Al-4 V sheets can maintain better ductility during uniaxial tension, as opposed to the stress-relieved counterparts. A detailed experimental investigation has been performed on the deformation behaviours of Ti-6Al-4 V butt welds, including residual stress distribution characterizations by focused ion beam ring-coring coupled with digital image correlation (FIB-DIC), X-ray computerized tomography (CT) for internal voids, and in-situ DIC analysis of the subregional strain evolutions. It was found that the pores preferentially distributed near the fusion zone (FZ) boundary, where the compressive residual stress was up to -330 MPa. The removal of residual stress resulted in a changed failure initiation site from the base material to the FZ boundary, the former with ductile and the latter with brittle fracture characteristics under tensile deformation. The combined effects of residual stresses, microstructures, and internal pores on the mechanical responses are discussed in detail. This work highlights the importance of inevitable residual stress and pores in laser weld pieces, leading to key insights for post-welding treatment and service performance evaluations.

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.

Experimental study of the defects, mechanical and microstructural characteristics of friction-stir-welded Al 6061 sheets

A promising solid-state welding technique, Friction Stir Welding- FSW- and its influence on microstructure and defects formation of the Al6061 welded plates and though consequence mechanical properties have formed the central part of the present study. The current research focuses on studying the effect of 3 crucial parameters of FSW, welding and rotating speed, and pin profile (each varying in 3 levels) on grains’ modification and the occurrence of flaws after nine designed trials with the help of the Taguchi method. Vickers micro-hardness and tensile tests were conducted to determine how the grain formation and defects affected mechanical properties. It was observed that all three central regions of the welded pieces, NZ, TMAZ, and HAZ, have experienced grain modification, plastic deformation, and defect formation with different severity. The distance of the region from the weld line, welding and rotating speeds, and ratios were affecting the severity of changes. According to the obtained results, HAZ showed less strength than others since all samples’ failure occurred in this zone. Higher values of hardness and tensile strength for each pin profile resulted from higher welding speeds and lower rotational ones.

Letter to the Editor: Landsbergis et al (2019) Titled "Work Exposures and Musculoskeletal Disorders Among Railroad Maintenance-of-Way Workers".

Letter to the Editor: Landsbergis et al (2019) Titled "Work Exposures and Musculoskeletal Disorders Among Railroad Maintenance-of-Way Workers".

Deep Learning Techniques for Flaw Characterization in Weld Pieces from Ultrasonic Signals

Computer aided Interpretation of Ultrasonic signals depicting flaws in weld pieces is depicted in this work. In this work, feasibility of Long Short Term Memory (LSTM) for flaw characterization is studied. Owing to the advantage of LSTM, the first technique involves training LSTM directly with the signals as inputs and testing its ability to characterize the flaws from the input signals. Due to wide variation in the length of input sequences, which introduced sparseness in other sequences, overall accuracy is affected. Hence in the second technique, LSTM are trained with features of the signals and it is found that the overall accuracy for test data is 67.64%. These features are statistical parameters obtained from the approximation co-efficient of the input signals. The input signals are decomposed with a novel wavelet template.

Study the Properties of Two Pieces Welded After Ceramic Coating By Air Spray Coating Method

Surface coatings offer a wide range of purposes to get good properties of the components. There are more applications of surface coatings in different industries to improve the properties of substrate such as sports technology, automotive industries, chemical and petroleum, physical and electronic, decorative coating and thermal barrier coatings meter. Recently, surface coatings have been developed progressively in some specialized parts to enhance wear resistance and reduce diffusion and friction. In this study three samples were prepared by covering two welded pieces of low carbon steel with the ceramic material (mullite powder (3Al2O3.2SiO2) for the ratio of (0% as a control, 5%, 10%) and by adding varnish and thinner that were used as a binder material for reinforcement low carbon steel in welding region. Then study different properties of coating layer such as the thickness of the coating layer, contact angle, and roughness, finally examine the hardness test, wear test and Atomic Force Microscopy.

Effect of Inconel 625 on Microstructure and Mechanical Properties of Gas Tungsten Arc Welded Inconel-713LC Superalloy Joints

This study investigates how the use of Inconel filler metal 625 affects the microstructure and mechanical properties of gas tungsten arc welded joints of an IN-713LC nickel-based superalloy. Due to their difference in composition, obvious weld beads could be found by X-ray detection. In addition, it was found that the γ' strengthening phase was absent and carbide was present between the matrix and the weld bead during gas tungsten arc welding. These carbides are strongly related to the formation of cracking and weld shrinkage during solidification. The absence of the γ' strengthening phase and the presence of weld shrinkage and cracking led to a decrease in the hardness, tensile strength, and elongation of the welded pieces.

Determination of the allowable minimum thickness of protective coating for welding in carbon dioxide

Among industrial technologies, carbon dioxide welding occupies a leading position. However, this welding method is characterized by increased spattering of metal and splashing it on the welded piece of work. A protective coating layer applied to metal is effective means of preventing the consequences of this disadvantage. The paper developed the method for determining the minimum allowable thickness of the coating, sufficient to prevent the interaction of molten metal drops with the surface of the welded pieces of work.

Pre processing of ultrasonic signals austenitic stainless steel weld at high temperature

Abstract Time of flight Diffraction technique is an advanced ultrasonic NDE method, adopted in weld integrity testing. A better testing is being sought, particularly at elevated temperatures. With the suitable high temperature probes, the ultrasonic ToFD testing can be used at elevated temperatures also. The nature of weldment always plays an important role in assessment of weld integrality. High temperature ToFD testing of Austentic stainless steel weld testing yields a less Probability of Detection due to the noise added to ultrasonic signal at high temperatures. Hence, signal denoising is an essential prerequisite for the successful application of TOFD testing. In this work, one austenitic stainless steel weldment was artificially induced with slag defect. At high temperatures, the TOFD testing has been conducted on the weld piece and the resultant signals are applied over the proposed algorithms. Various combinations of wavelets, decomposition levels with different thresholding levels are applied to select an optimum denoising method. The evaluation of wavelet based denoising is achieved by calculating the SNR. Results show that the noises can be suppressed well and SNR is improved.

Discrete Wavelet Transform based Denoising of TOFD Signals of Austenitic Stainless Steel Weld at Elevated Temperature

Abstract—Time of flight Diffraction technique is an advanced ultrasonic NDE methods, adopted in weld integrity testing. During the Time of flight Diffraction (TOFD) inspection of the stainless steel welds at high temperature, grain scattering noise is developed. In Time of flight Diffraction testing, the quality of the signal plays a dominant role in characterizing the defects. Hence, signal denoising is an essential prerequisite for the successful application of Time of flight Diffraction testing. In this work, one austenitic stainless steel weldment was artificially induced with slag defect. At high temperatures, the Time of flight Diffraction testing has been conducted on the weld piece and the resultant signals are applied over the proposed algorithms. Various combinations of wavelets, decomposition levels with different thresholding levels are applied to select an optimum denoising method. The evaluation of wavelet based denoising is achieved by calculating the Signal to Noise Ratio (SNR). Results show that the noises can be suppressed well and Signal to Noise Ratio is improved.

Investigation and development of friction stir welding process for unreinforced polyphenylene sulfide and reinforced polyetheretherketone

The joining of thermoplastics through welding offers numerous advantages over mechanical joining. Most importantly, it eliminates the use of costly fasteners and has only a limited effect on the strength of the parts being joined. Since it does not require the introduction of holes, loading pins, and the associated stress concentrations, a specific form of welding, friction stir welding (FSW), was investigated for the creation of butt joints of unreinforced polyphenylene sulfide (PPS) and short carbon fiber (CF)-reinforced polyetheretherketone (PEEK) plates. Unlike metals, analytical models and experimental results show that the heat generated by the FSW tool is insufficient to produce the heat required to weld thermoplastic materials. Therefore, a second heat source is required for preheating these thermoplastics. In this research, a resistance type surface heater was placed at the bottom of two identical weld pieces to produce good quality welds. Two types of shoulder design such as rotating shoulder and stationary shoulder were developed in this study. Taguchi’s design of experiment method was utilized to develop the welding process, where heating duration, material temperature, tool rotational speed, and tool traverse speed were used as the welding parameters. One of the process parameters, tool traverse speed, had significant influence on the tensile strength of PPS samples. While PPS sample showed relatively lower tensile strength with higher traverse speed, short CF-reinforced PEEK samples had higher tensile strength with a higher traverse speed. In addition to tensile tests, fracture toughness tests were performed for both PPS and PEEK samples to observe the influence of unwelded segments in the welded parts. In this study, joint efficiency of PEEK samples was found to be higher than that of PPS samples. Micrographs of PEEK samples showed uniform homogenous mixture of part materials.

IM PROVEMENT OF MECHANICAL PROPERTIES OF ALUMINUM ALLOY 6061 –T6 WELD JOINT USING DC PULSED GAS TUNGSTEN ARC WELDING (PGTAW)

The effect of DC pulsed GTAW method factors on mechanical properties of Aluminumalloys 6061–T6 is proves. Throbbed GTAW on the sheet having dimension of (200* 100*5mm) is implemented at variable pulse current (150, 160, 170, 190) and constant frequencyto get numerous connected joints by electrode type" ER4043 (Al Si5) as a padding metallicand argon as protective gas and compared with base current GTAW welding at D C currentat 90 amps. The welded pieces are examined by X-ray radiography. The welded joints weretreated by heat, the joints heated for half an hour in the furnace to 150 C° then cooled in theair to release the residual stresses. Mechanical quality of the weld joints. Microstructuralcategorizations, Micro hardness, enduring stress are examined. Consequences exposed thata common decline of mechanical properties of TIG welded joints conveyed 34% analogieswith parent metal while the PGTAW joined offers better mechanical qualities analogy withof TIG joined in reductions conveyed 8.4% analogies with original metal this is because ofthe microstructure variations through the joining method and compressive residual stressgeneration in the weld zones. It has been found that by PGTAW improved the mechanicalproperties of welded joints which rely on current parameters.

Effects of post-weld heat treatment temperature on the microstructure and mechanical properties of welded A517-Gr.B steel by SMAW method

Welding residual stresses have consequences for the performance of welded components. The remaining stresses can be reduced by post-weld heat treatment (PWHT). In this study, A517-Gr.B steel specimens welded by shielded metal arc welding (SMAW) were subjected to PWHT at 450 °C, 500 °C, 550 °C, and 600 °C to study the effects of these temperatures on yield, tensile, bending, and impact strengths. The fracture surfaces of the specimens heat treated at different temperatures were studied using the scanning electron microscope (SEM). The results indicated that the optimum temperature for PWHT was below 500 °C. Higher PWHT temperatures increased yield strength, tensile strength, and ductility of the weld piece but greatly decreased its bending weld strength.

Analysis Of Quality In Solid State Welding (Copper-Copper) By Using NDT And DT By Altering Physical Properties At Constant Time

In this work we analyzed the diffusion welding of similar material copper-copper by keeping time as constant and by varying the physical properties such as temperature and pressure. So that the welded pieces undergone for further analysis such as mechanical properties at the welded areas. We used both destructive2 and non destructive testing methods. The bonding1 is done at different temperatures such as 700°C, 750°C and 800°C and also pressure varies 5MPa, 10MPa and 15Mpa respectively. After joint made in bonding machine the entire zone of working area where bonding was done is allowed to cooling for 6 to 8 hours. In EDM machine3 the welded joints cut as per as our requirements to perform both DT and NDT4 methods. Out of all the results obtained the bonded pieces which are bonded at 750°C, 10MPa for 90 minutes gives the optimum bonding strength.

A smart prediction tool for estimating the impact strength of welded joints prepared by vibratory welding process

Previous researches have been devoted to development of vibratory setup for inducing mechanical vibrations into the weld pool during welding process. The designed vibratory setup produces the required frequency with suitable amplitude and acceleration in terms of voltages. This helps in producing uniform and fine grain structure in the welded joints which results in an improvement in the mechanical properties of the weld pieces at heat affected zone. This paper presents the development of a smart prediction tool by implementing generalized regression neural network to establish a relation between vibration parameters such as input voltage to the vibromotor, time of vibration and impact strength of vibratory weld joints. In order to validate the feasibility of the developed prediction tool, a comparison is made with the experimental results.

Modeling and Optimization of Ultrasonic Welding Process for Low Density Polymer: A Review

The purpose of this research is to determine the effect of various weld and machine parameters on ultrasonic weld strength. In this we are going to use thermosetting material named epoxy which is one of the low density polymers. By considering three main parameters that is amplitude, pressure and weld time we are going to conduct the experiment. After doing the welding, we will check the tensile strength of the welded pieces by using UTM. (Universal testing machine).Further with the help of MINITAB software we will optimize the number of experiments.

CHARACTERIZATION AND PROCESSING OF FRICTION STIR WELDING ON COPPER WELDS

FSW(Friction Stir Welding) is a welding technology will be a part of different metals with sensible properties. During this paper, fsw attachment b/n steel, aluminum and copper plates with thicknesses of 3 millimeter was welded. Here we tend to had considered completely different completely different} materials with different combinations i.e copper and copper, copper and aluminum, aluminum & stainless steel, stainless steel & copper. Friction Stir Welding experiments were employed to get the good wieldable properties by maintaining the rpm speeds to 1120 revolutions per minute and attachment speed within the limit of 14112 mm/min and here we can adjust the pin profile of the location respect to the line butt. Micro struc analysis can be done for examine the parent and the welded material. Cutting and sectioning of the welded pieces for metallographic analysis of the planes which are perpendicular for the attachment and the travelling direction & which is parallel to the friction welding was done. Here the mechanical properties of welding which was were determined by employing the same standard micro hardness and also tensile hardness testing and finding the maximum elongation of the metals to the properties of fsw. From experimental fsw process it can be found the pin profile and also the rotational speed, feed is an important in manufacturing of free welds in fsw of aluminum, copper and steel.

Aspects Regarding the Achievement of Vertical Welding Joints

The vertical MAG welding procedure is a difficult position to be executed because the trend of the molten bath flowing. This article aims to present the achievement of vertical welding joints with a linear device with a radial oscillation system that should achieve automatic vertical welds and the correlation of the welding parameters with the movement of the welding torch in order to obtain these, using the MAG procedure, protective gas M 21 (82% argon + 18% CO2), welding wire SG2, the material of the welded pieces S 355 JR. Samples will be cut from the welded steel plates and they will be characterized from the mechanical point of view (hardness, microstructure and macrostructure).

Flexural Strength Improvement of Welded Joints Prepared by Vibratory Welding Process

Vibration techniques have been used in welding for improving the mechanical properties of metals in the last few decades. In the present work, vibratory setup has been used for inducing mechanical vibrations into the weld pool during welding. The designed vibratory setup produces the required frequency with the amplitude and acceleration in terms of voltages. An increase in the flexural strength of the weld pieces in to the heat affected zone (HAZ) has been observed. The increase in mechanical properties is attributed to, as the weld pool solidifies, grains are not only limited in size but also dendrites are broken before they grow large in size. Refined microstructure has been observed. The above mechanism is responsible for the improvement in flexural strength of weld pieces welded with vibratory setup compared to without vibration during welding.