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Liu, Jinxin, i Kexin Li. "Intelligent Metal Welding Defect Detection Model on Improved FAST-PNN". Coatings 12, nr 10 (11.10.2022): 1523. http://dx.doi.org/10.3390/coatings12101523.
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In order to solve the problem of accurate and efficient detection of welding defects in the process of batch welding of metal parts, an improved Probabilistic Neural Network (PNN) algorithm was proposed to build an automatic identification model of welding defects. Combined with the characteristics of the PNN model, the structure and algorithm flow of the FAST-PNN algorithm model are proposed. Extraction of welding defect image texture features of metal welded parts by a Gray Level Co-occurrence Matrix (GLCM) screens out the characteristic indicators that can effectively characterize welding defects. Weld defect texture features are used as input to build a defect classification model with FAST-PNN, for accurate and efficient classification of welding defects. The results show that the improved FAST-PNN model can effectively identify the types of welding defects such as burn-through, pores and cracks, etc. The classification recognition accuracy and recognition efficiency have been significantly improved. The proposed defect welding identification method can accurately and effectively identify the damage types of welding defects based on a small number of defect sample images. Welding defects can be quickly identified and classified by simply collecting weld images, which helps to solve the problem of intelligent, high-precision, fast real-time online detection of welding defects in modern metal structures; it provides corresponding evidence for formulating response strategies, with a certain theoretical basis and numerical reference.
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Widyawati, Fauzi, i Lino Marano. "IDENTIFIKASI CACAT LASAN FCAW PADA FONDASI MESIN KAPAL MENGGUNAKAN METODE ULTRASONIC TESTING". Jurnal TAMBORA 5, nr 2 (21.07.2021): 53–58. http://dx.doi.org/10.36761/jt.v5i2.1124.
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Ultrasonic testing is one of the non-destructive inspection methods for welding results. The ultrasonic testing method has several advantages, namely it can be used to analyze the position of the defect in the object, both the depth of the defect and the dimensions of the defect, and it is an environmentally friendly method. Physical defects that are in solid objects of course cannot be known from direct vision so it is necessary to carry out an inspection of an object to see whether or not there are defects that occur in solid objects. Ultrasonic testing of the results of FCAW welding on the foundation of the ship's engine. FCAW welding is applied to the foundation with two types of welding positions, namely the overhead position coded P1 and the horizontal position coded P2. The test was carried out using a wave frequency of 4 MHz and using a 0° probe for analysis of defects in the area around the weld metal and a 70° probe for analysis of the weld metal. The tests were carried out using the ASME section V and ASTM E164 standards as the standard for determining defects. The test results at the P1 welding position found two types of defects, namely incomplete fusion defects with five welding points with the longest defect length of 40mm and porosity defects with two points with the longest defect length of 30mm. While the results of ultrasonic testing at the P2 welding position found two types of defects, namely slag inclusion defects with a defect length of 35mm and incomplete penetration defects with a defect length of 20 mm. The conclusion of ultrasonic testing is that the difference in welding positions is that the welding position greatly affects the quality of the welding results. The defects resulting from the welding position also vary.
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Zai, Le, i Xin Tong. "FusionWelding of High-Strength Low-Alloy Steel: A Mini- Review". SOJ Materials Science & Engineering 7, nr 1 (26.03.2019): 1–4. http://dx.doi.org/10.15226/sojmse.2019.00157.
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High-Strength Low-Alloy (HSLA) steel exhibits excellent tensile strength and ductility, and it also possesses good welding performance due to its low carbon equivalent. However, welding defects always inevitably appear during the fusion weldingof HSLA steel. In this paper, the previous investigations on the microstructure of the joined HSLA steel by different fusion welding processes arereviewed, and the mechanical properties of the fabricated joint are analyzed. Also, the practicability of different fusion welding processes on HSLA steel has been systematically analyzed. Finally, the prospect of the welding of HSLA steel is expected according to the research status. Keywords: High-Strength Low-Alloy Steel; Fusion Welding; Welding Defect; Microstructure; Mechanical Properties
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Rizvi, Saadat Ali, i Wajahat Alib. "Welding defects, Causes and their Remedies: A Review". Teknomekanik 2, nr 2 (15.12.2019): 39–47. http://dx.doi.org/10.24036/tm.v2i2.3272.
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This review paper looks at the causes of welding defects and their remedies which occur during the welding process. Welding industries in developing countries bearing poor quality and productivity due to the involvement of a number of the process parameter. Even in a completely controlled process, defects in the welding are observed and hence welding process is also known as the process of uncertainty which challenges explanation about the cause of welding defects. In order to identify the welding defect and problem-related to welding, the study is aimed at the research work. This will be beneficial in enhancing the yield of welding. Beside this, standardization (optimization) of process parameter for the entire cycle of manufacturing of the critical part is intended in the proposed work .This review paper also provides the accurate guideline to the quality control department to find welding defects and will help them to analyze defects which are not desired. In this review paper, an attempt has been made to categorise the various welding defects and their root causes of happening.
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Et.al, Christopher Paulraj. "An intelligent Model for Defect Prediction in Spot Welding". Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, nr 3 (11.04.2021): 3991–4002. http://dx.doi.org/10.17762/turcomat.v12i3.1689.
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There are more than 30% defect in the spot welding of cars and randomly chosen cars are performed ultrasound or destructive testing. This makes the process very vulnerable and unpredictable. This results in huge reworks, productivity, monetary loss and negative impact on brand name.
This research paper presents the prediction of defect using machine learning models and as well forecasting models in spot welding through optimized methodology. This defect prediction model is useful in determining the defects that are likely to occur during spot welding. The forecasting model for process parameters data pattern, trends, etc. helps to identify the link between predicted defects. This model can evolve and improve over time by considering data from previous phases and history data of the spot welding cycle. Predicting the defects before testing begins improves the quality of the product being delivered and helps in planning and decision making for future spot welding.
The optimized defect prediction methodology in spot welding reduces the defects and predicted sample for testing which reduces the rework and increase the productivity, monetary value and brand name.
The experimental result shows that the spot-welding methodology has shown improvement over existing spot-welding method. Please see the six-sigma (Fig:13) chart for before and after improvement curve and value.
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Li, Qiang, Qi Lu, Yingchun Chen, Junwei Su i Jie Yang. "Effect of the ultrasonic phased array on defect detection of HDPE electro-fusion joint". Journal of Physics: Conference Series 2419, nr 1 (1.01.2023): 012070. http://dx.doi.org/10.1088/1742-6596/2419/1/012070.
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Abstract As a common welding method for polyethylene natural gas pipelines, electro-fusion welding has been widely used. However, defects are easy to occur in the fusion area during the welding. In this paper, high-density polyethylene (HDPE) pipes with different types of electric welding joint defects are processed, and the detection effect of the ultrasonic phased array on joint defects is explored. The results show that: Ultrasonic phased array detection technology is easy to operate and reliable. It can detect three common defects: inadequate socket, cold welding, and scratch of oxide scale. In addition, according to the inspection result chart, the defect type can be accurately judged.
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Zhu, Caixia, Haitao Yuan i Guohong Ma. "An active visual monitoring method for GMAW weld surface defects based on random forest model". Materials Research Express 9, nr 3 (1.03.2022): 036503. http://dx.doi.org/10.1088/2053-1591/ac5a38.
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Abstract In the automatic manufacturing of robotic welding, real-time monitoring of weld quality is a difficult problem. Meanwhile, due to volatilization of zinc vapor in galvanized steel and complexity of welding process, the existence of welding defects greatly affects industrial production process. And real-time detection of welding defects is a key step in development of intelligent welding. To realize real-time monitoring of weld surface defects, an active visual monitoring method for weld surface defects is proposed. Firstly, after applying Gabor filter to remove interference signals such as arc and noise, obtain weld centerline image; then employ the slope analysis method to extract peak valley coefficient of weld defects, extract five feature points of weld surface quality by Douglas-Puke algorithm, and analyse geometric and spatial distribution features of different types of defects in weld laser stripe images. Finally, using eight feature vectors extracted from weld features, design a weld defect recognition random forest model based on decision tree. After optimizing the decision tree depth and number of model evaluators, compared with the traditional decision tree ID3 and CART algorithm model, this model has better performance than traditional machine learning algorithms on five weld surface defect data sets. The experimental results show that accuracy of weld defect identification in the training set is 99.26%, accuracy of weld defect recognition in the test set is 96%, and processing time of a single image is only 5.3 ms, which overcomes difficulty of real-time weld defect detection in intelligent welding and ensures real-time and accuracy.
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Hua, Liang, Peng Xue, Jin Ping Tang, Hui Jin i Qi Zhang. "Welding Defects Classification Based on Multi-Weights Neural Network". Advanced Materials Research 820 (wrzesień 2013): 130–33. http://dx.doi.org/10.4028/www.scientific.net/amr.820.130.
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Incomplete fusion and incomplete penetration are two types of damage serious welding defects. These two kinds of defects have the similarity in the features in X-ray imaging. Identifying the two kinds of defects automatically and accurately can improve the welding technology and improve the quality of welding effectively. The causes of defects and features of X-ray images are described in the paper. The welding defects calssification method based on multi-weights neural network is put forward in the paper. The multi-weights neural network based on graphic geometry theory is introduced, which uses the geometrical shape in high dimensional space to cover the same class defect samples via constructing multi-weights neural network. The experimental results proved the effectiveness of the algorithm.
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Song, Seung-Hyon, Chang-Soon Lee, Tae-Hwan Lim, Auezhan Amanov i In-Sik Cho. "Fatigue Life Improvement of Weld Beads with Overlap Defects Using Ultrasonic Peening". Materials 16, nr 1 (3.01.2023): 463. http://dx.doi.org/10.3390/ma16010463.
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Welding defects are common during the production of large welded structures. However, few studies have explored methods of compensating for clear welding defects without resorting to re-welding. Here, an ultrasonic peening method to compensate for the deteriorated mechanical properties of overlap weld defects without repair welding was studied. We experimentally investigated changes in the mechanical properties of defective welds before and after ultrasonic peening. The weld specimen with an overlap defect contained a large cavity-type defect inside the weld bead, which significantly reduced the fatigue life. When the surface of the defective test piece was peened, the fatigue life of the weld plate was restored, resulting in an equivalent or higher number of cycles to failure, compared to a specimen with a normal weld. The recovery of mechanical properties was attributed to the effect of surface work hardening by ultrasonic peening and the change in stress distribution. Thus, ultrasonic peening could compensate for the deterioration of mechanical properties such as tensile strength, fatigue life, and elongation due to overlap defects, without resorting to repair welding.
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Junianto, Teguh, Imam Bayhaqi i Erna Rahayu. "Pengendalian Kualitas Pengelasan Pada Proyek Pipeline Sabar#2". Jurnal Inovator 3, nr 2 (21.12.2020): 1–8. http://dx.doi.org/10.37338/ji.v3i2.133.
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PT. ICG is a company that handles the pipeline welding process at PetroChina Jabung Ltd. The welding process carried out is cutting, rolling, pressing and painting. The problem that occurs is that 243 defects are found from the output of 457 welding points. The types of defects after the welding process included 106 points of Root Cancellation defects, 99 points of Incomplete fusion, 29 points of Porosity, 8 points of Slug Inclusion, and 1 point of Tungsten Inclusion. This study aims to control quality by looking at the sigma value of the pipeline production process and analyzing the improvements that should be made to reduce the defects that occur. The results of the calculation of Defect Per Million Opportunities (DPMO) show that the number of welding defects that arise every one million opportunities is 174,10. The quality of the welding process in the pipeline Sabar # 2 project is at a sigma value of 2,43 with a DPMO value of 174,10. From the results of the sigma value obtained, this value is still far from the expectations of Petrochina's management to achieve a minimum sigma value of 4,0. The potential causes of weld defects include welding machines, work errors, work methods and work environment.
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Lai, Huansheng, Dengshuai Fan i Kanglin Liu. "The Effect of Welding Defects on the Long-Term Performance of HDPE Pipes". Polymers 14, nr 19 (21.09.2022): 3936. http://dx.doi.org/10.3390/polym14193936.
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High-density polyethylene (HDPE) pipes are the preferred pipes of water systems in nuclear power plants because they are durable, corrosion-free, easy to install, and not subject to fouling. However, their long-term performance can be affected by welding defects. In this paper, the effect of welding defects on the long-term performance of HDPE pipe butt fusion joints was studied using a creep test. A welding defect with a hole or inclusion in the joint was simulated by artificially inserting a copper ball during butt fusion welding. The test results showed that the creep life of the joint decreased with increased defect size. An expression describing the creep life and the defect ratio was obtained according to the test results. In addition, the test results showed that the creep life of the joint without a welding bead was about 50% of that in a joint with a welding bead.
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Muhamad Leon Habibi i Muhamad Zainal Fanani. "Studi Pengaruh Derajat Kemiringan Tool Head Terhadap Hasil Pengelasan Friction Stir Welding (FSW)". Teknobiz : Jurnal Ilmiah Program Studi Magister Teknik Mesin 10, nr 3 (10.11.2020): 9–13. http://dx.doi.org/10.35814/teknobiz.v10i3.1757.
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Aluminum and its alloys are non-ferrous metals which are widely used in the shipping industry because aluminum is a lightweight metal, has a relatively high tensile strength and good corrosion resistance. Friction-stir Welding (FSW) is a welding that is widely used on thin aluminum plates. The heat input of the FSW welding is affected by the degree of tilt of the head tool to the material. This study aims to determine the optimal degree of slope in FSW welding. The parameters used in this study are 1500 rpm rotational speed, 1.33 mm / s welding speed with the same material thickness of 4mm and the type of connection used by lap joint refers to the AWS standard. In this study, the tool head tilt variation is 0o, 1o, 2o and 3o and the effect on the welding results. The results of the study show that welding with a slope angle of 0 ° and 1 shows visible defects or undercut defects caused by overheating when welding. The results of welding with a degree of slope 2 show the results of welding is good at the beginning of welding, but in the middle of welding visible defect undercut. Tilt angle welding shows the best results with no visible defects due to welding. The results showed that visually the results of welding with a slope angle 3 degree had the best results. This was due to the heat input on the welding with the head tool tilt not excessive so there was no visual defect.
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Aboali, Abdalla, Mohamed El-Shaib, Ashraf Sharara i Mohamed Shehadeh. "Screening for Welding Defects Using Acoustic Emission Technique". Advanced Materials Research 1025-1026 (wrzesień 2014): 7–12. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.7.
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– Welding defects can create a major threat in industrial equipments and pressure vessels can during operation. Detecting and identifying of existing welding defects has a great role in the assessment of the probability of failure in different situations. Acoustic emission (AE) is only a nondestructive technique that can be used as in-service testing and used on large structures. This paper examines the changes in the properties of AE source generated from Pencil Lead Break (PLB). AE is recorded across different seam welds with pre-identified welding defects. Series of experiments are carried out on three certified standard Carbon Steel plates. Each plate has different pre-identified defect such as lack of fusion, porosity and slag. Different AE parameters such Energy, Amplitude and number of counts have been used to identify quantitatively the type of defects. The results are showing that AE technique is capable to identifying the different defects types which can be upgraded for higher productivity and accuracy for welding inspection.
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Meshram, Suresh, i Madhusudhan Reddy. "Influence of Tool Tilt Angle on Material Flow and Defect Generation in Friction Stir Welding of AA2219". Defence Science Journal 68, nr 5 (12.09.2018): 512–18. http://dx.doi.org/10.14429/dsj.68.12027.
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Heat treatable aluminium alloy AA2219 is widely used for aerospace applications, welded through gas tungsten and gas metal arc welding processes. Welds of AA2219 fabricated using a fusion welding process suffers from poor joint properties or welding defects due to melting and re-solidification. Friction stir welding (FSW) is a solid-state welding process and hence free from any solidification related defects. However, FSW also results in defects which are not related to solidification but due to improper process parameter selection. One of the important process parameters, i.e., tool tilt angle plays a critical role in material flow during FSW, controlling the size and location of the defects. Effect of tool tilt angle on material flow and defects in FSW is ambiguous. A study is therefore taken to understand the role of tool tilt angle on FSW defects. Variation in temperature, forces, and torque generated during FSW as a result of different tool tilt angles was found to be responsible for material flow in the weld, controlling the weld defects. An intermediate tool tilt angle (1o-2o) gives weld without microscopic defect in 7 mm thick AA2219 for a given set of other process parameters. At this tool tilt angle, x-force, and Z- force is balanced with viscosity and the material flow strain rate sufficient for the material to flow and fill internal voids or surface defects in the weld.
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Totino, Benito, Fanny Spagnolo i Stefania Perri. "RIAWELC: A Novel Dataset of Radiographic Images for Automatic Weld Defects Classification". International Journal of Electrical and Computer Engineering Research 3, nr 1 (15.03.2023): 13–17. http://dx.doi.org/10.53375/ijecer.2023.320.
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In the last few years, extracting, analyzing and classifying welding defects in radiographic images received a great deal of attention in several industry manufacturing. Nowadays, computer vision affords considerable accuracy in many practical applications, but making automatic processes approachable also in this field is still a challenge. As an example, Convolutional Neural Networks (CNNs) are widely recognized as efficient and accurate classification structures, but, due to the limited availability of specific datasets, training a CNN to classify welding defects is not trivial. This paper presents a new dataset collecting 24,407 radiographic images related to several classes of welding defects: lack of penetration, cracks, porosity and no defect. The proposed dataset of welding defects in radiographic images is released freely to the research community. As an example of application, the dataset has been used to train a customized version of the SqueezeNet CNN obtaining a test accuracy higher than 93%.
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Hunt, Johnathon B., Brian A. Mazzeo, Carl D. Sorensen i Yuri Hovanski. "A Generalized Method for In-Process Defect Detection in Friction Stir Welding". Journal of Manufacturing and Materials Processing 6, nr 4 (31.07.2022): 80. http://dx.doi.org/10.3390/jmmp6040080.
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Friction stir welding (FSW) is an advantageous solid-state joining process that is suitable for many materials in multiple industries. In an industrial setting, manufacturers are actively seeking faster welding speeds to increase throughput. Increasing welding speed limits the size of defect-free parameter windows, which may increase the frequency of defects. The push for faster welding speeds emphasizes the need for economical non-destructive evaluation (NDE) for FSW, like any other type of welding. This work introduces a generalized defect detection method that recognizes the stochastic nature of the FSW process, and that can be generally applied to FSW of a material across a dynamic range of process parameters and welding conditions. When applied to aluminum friction stir-welded blanks at speeds ranging from 1500 to 3000 mm/min with varying ranges of tool tilts, the methodology proved 100% effective at positive detection when defects were present with zero scrap rate. Furthermore, additional development demonstrated the proposed stochastic approach can be used to detect the spatial location of a defect within a weld with 94% detection accuracy and a 4.2% scrap rate.
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Tao, Sun, Wu Siyu, Yifu Shen, Jin Jiayi, Lu Jiazhu i Qin Tianxiang. "Effect of Traverse Speed on the Defect Characteristic, Microstructure, and Mechanical Property of Friction Stir Welded T-Joints of Dissimilar Mg/Al Alloy". Advances in Materials Science and Engineering 2020 (20.11.2020): 1–15. http://dx.doi.org/10.1155/2020/4515079.
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The AZ31 B/2024-T4 T-lap-joint was successfully fabricated by friction stir welding (FSW) with different welding parameters. The defect characteristics and metallurgical structure were observed and analyzed using optical microscope (OM) and scanning electron microscopy (SEM). Besides, the effects of defects and welding parameters on mechanical properties were investigated. The results show that an effective metallurgical reaction zone can be formed between Mg and Al (Mg-Al MRZ) and the island structures and lamellar structures appeared in the Mg-Al MRZ. The T-joints without tunnel defects can be obtained and the excellent mechanical properties of the T-joint were achieved using the welding speed of 50 mm/min. The tensile strength along the skin and the stringer was mainly affected by the kiss bonding defects.
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Yun, Gwang-ho, Sang-jin Oh i Sung-chul Shin. "Image Preprocessing Method in Radiographic Inspection for Automatic Detection of Ship Welding Defects". Applied Sciences 12, nr 1 (23.12.2021): 123. http://dx.doi.org/10.3390/app12010123.
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Welding defects must be inspected to verify that the welds meet the requirements of ship welded joints, and in welding defect inspection, among nondestructive inspections, radiographic inspection is widely applied during the production process. To perform nondestructive inspection, the completed weldment must be transported to the nondestructive inspection station, which is expensive; consequently, automation of welding defect detection is required. Recently, at several processing sites of companies, continuous attempts are being made to combine deep learning to detect defects more accurately. Preprocessing for welding defects in radiographic inspection images should be prioritized to automatically detect welding defects using deep learning during radiographic nondestructive inspection. In this study, by analyzing the pixel values, we developed an image preprocessing method that can integrate the defect features. After maximizing the contrast between the defect and background in radiographic through CLAHE (contrast-limited adaptive histogram equalization), denoising (noise removal), thresholding (threshold processing), and concatenation were sequentially performed. The improvement in detection performance due to preprocessing was verified by comparing the results of the application of the algorithm on raw images, typical preprocessed images, and preprocessed images. The mAP for the training data and test data was 84.9% and 51.2% for the preprocessed image learning model, whereas 82.0% and 43.5% for the typical preprocessed image learning model and 78.0%, 40.8% for the raw image learning model. Object detection algorithm technology is developed every year, and the mAP is improving by approximately 3% to 10%. This study achieved a comparable performance improvement by only preprocessing with data.
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Aljufri, Aljufri, i Indra Mawardi. "Analysis of Defects in SMAW Welding Joint Using E 7016 Electrode Due to the Direct Cooling Process". Journal of Welding Technology 4, nr 2 (grudzień 2022): 48–54. http://dx.doi.org/10.30811/jowt.v4i2.3304.
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Welding defects in a construction if repairs are not immediately carried out, then in the weld defect area can cause cracks that are aggravated by wider cracking and corrosion so that it can cause brittle fractures to the detriment. The problem with brittle fracture is a big problem in steel that has been welded, especially in welded joints, this brittle fracture becomes more important due to the factors of voltage concentration, inappropriate structure and defects in the weld, the purpose of this study: to find out how to use suitable electrodes for ST 37 material in the welding process, whose cooling process directly uses Oil and water (Direct Colling Process), and to obtain optimal welding results after going through the results of welding defect examination using the Penetrant Test method, and the Maghnetic Particle Test. From the results of the examination research conducted by the Welding Inspection team of PT. Superintending Company of Indonesia (SUCOFINDO) to 15 ST 37 specimens that have undergone welding does not show any welding defects, in the sense that they are still within the acceptable limit criteria (Acceptance Standard Ansi B 31.3), from the results of tensile testing On the use of different electrodes in the welding process of ST 37 material, shows that the ST 37 material whose welding process uses electrode E7016 welded results and tensile strength is better than the ST 37 material which in the welding process uses electrodeS E 7018 with the cooling process using Oil and water
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Atroshchenko, V. V., A. S. Selivanov, V. S. Lobachev, Yu V. Logachev i A. R. Sadrislamov. "The study of the effect of parameters of the mode of copper friction stir welding on the mechanical properties and electrical conductivity of welded joints". Frontier materials & technologies, nr 3 (2022): 50–60. http://dx.doi.org/10.18323/2782-4039-2022-3-1-50-60.
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Copper is widely used when producing current-conducting parts, basically the electrotechnical power equipment buses. Traditional ways of welding copper become complicated because of high thermal conductivity, fluidity, significant oxidation at fusing temperature, and susceptibility. The application of the solid-phase welding methods, a prominent representative of which is friction stir welding (FSW), is one of the ways to solve problems when welding copper. The paper presents the experimental study of the influence of a tool working part shape and the welding mode parameters: welding rate, tool rotation frequency, and tool dip angle – on the possibility of the appearance of defects in welded joints of M1 copper plates of 5 mm in thickness produced by FSW. The paper contains the results of mechanical tests on static tension and bending of welded joints with a tunnel defect and without it. Welded joints with a tunnel defect showed a decrease in mechanical properties level: the value of ultimate tensile strength at stretching is lower by 33 %, and the specific elongation is lower by 8 % than ones of a joint without defects. The authors specify some factors influencing the appearance of defects at FSW: the welding rate, tool rotation frequency, tool working part construction, tool dip angle, strength and depth of immersion, pin displacement, blank thickness, and grip conditions. The study identified that the application of a tool with a concave surface taper shoulder allows producing welded joints without external and internal defects. Based on data obtained during the experimental research, the authors determined the welding modes, which makes it possible to produce welded joints with the electrical resistance value at the level of a parent metal: tool rotation frequency is 1250 rpm, welding rate is 25 mm/min, and tool immersion depth is no less than 0.41 mm.
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Bachinskyi, V., O. Kondratenko, V. Kondratenko, T. Zharun i O. Sokolovskyi. "FIELD WELDING QUALITY CONTROL". Collection of scientific works of Odesa Military Academy 1, nr 14 (25.01.2021): 62–68. http://dx.doi.org/10.37129/2313-7509.2020.14.1.62-68.
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Fast and high-quality repair of weapons in the field will be crucial in modern combat. Thus, quality control of welding of weapons in the field will be the main criterion in determining the degree of readiness of weapons for their intended use, after repairs in the field. Defects of welded joints have the greatest danger for the technical condition of weapons samples. The purpose of the article is to assess the main defects of welding in the field and analyze ways to detect them through quality control of welding. Defects lead to a decrease in the strength of the weld, to a violation of the tightness of the connection and to a decrease in the operational reliability of the sample of weapons. The conducted researches allowed revealing the main reasons of defects of welding. 2-3 methods of control of welded joints are usually used to determine the quality of welding in the field. These methods are selected from a variety of existing ones, taking into account the numerous initial data. Therefore, the main methods in the field, in our opinion, will be – visual quality control and ultrasonic quality control. These methods of control are considered the most accessible and efficient. At the same time, studies have shown that the main disadvantage of visual quality control is the human factor, which affects 100% of the results; low reliability of the obtained results, subjectivity; use only to search for large defects (not less than 0.1-0.2 mm); limited research only by visible part of the structure. Studies have shown that the main disadvantages of the ultrasonic quality control include: limited information about the defect; some difficulties when working with metals with coarse-grained structure, which arise due to scattering and attenuation of waves; the need for preliminary preparation of the seam surface. The problems arising at quality control of welding in field conditions are revealed. Indicators of quality of welding of details, the main defects of welding and the reasons of their occurrence are shown. The comparative analysis of methods of visual control and ultrasonic control of quality of welding in field conditions is carried out. The problems and peculiarities of control of welding of products in field conditions revealed in the article should be taken into account in the process of development of operational, normative and technical documentation and personnel training. Keywords: quality of welded joints, defects, quality control.
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Sandu, Liliana, Sorin Porojan i Florin Topală. "Marginal Adaptation of Cast Metallic Dental Crowns Using Microplasma Welding Procedures". Advanced Materials Research 383-390 (listopad 2011): 4051–57. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.4051.
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Modern welding proceedings can be a beneficial method for repairing marginal adaptation defects in fixed prostheses technology. The aim of the study was to conduct experimental investigations to determine the optimal microplasma welding parameters according to the defect type. Different Ni-Cr alloy cast metal restorations with marginal defects were selected and divided depending on the repair possibility. A microplasma welding device, Welder, was used and as filling material a specific Ni-Cr wire was chosen. The process parameters were determined for each case. Introducing the practice of welding in dental technology requires prior experiments to determine the process parameters for the individual processes and their reproducibility.
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Bęczkowski, R. "Repair Welding of the Massive Cast". Archives of Foundry Engineering 17, nr 2 (27.06.2017): 5–8. http://dx.doi.org/10.1515/afe-2017-0041.
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Abstract The rebuilding technologies are used to develop surface of ladle. Among many welding methods currently used to obtain surface layer without defects one of the most effective way of rebuilding is using metal arc welding. This additional material gives more possibilities to make expected quality of rebuild surface. Chemical composition, property and economic factors allow to use metal wire. Because of these reasons, solid wire gives opportunity to be wildly used as material to rebuild or repair the surface in different sectors of industry. The paper shows a few ways to rebuild the surface in the massive cast with the use of metal active gas welding for repair. The work presents studies of defect in the massive cast. It contains the pictures of microstructures and defects. The method of removing defects and the results of checking by visual and penetrant testing methods are shown. The paper describes the methodology of repair the ladle with metal active gas welding, preheating process and standards nondestructive testing method.
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Bilici, Mustafa Kemal. "Investigation of the effects of welding variables on the welding defects of the friction stir welded high density polyethylene sheets". Journal of Elastomers & Plastics 54, nr 3 (7.12.2021): 457–76. http://dx.doi.org/10.1177/00952443211058845.
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Modern thermoplastic materials are used in an expanding range of engineering applications, such as in the automotive industry, due to their enhanced stress-to-weight ratios, toughness, a very short time of solidification, and a low thermal conductivity. Recently, friction stir welding has started to be used in joining processes in these areas. There are many factors that affect weld performance and weld quality in friction stir welding (FSW). These factors must be compatible with each other. Due to the large number of welding variables in friction stir welding processes, it is very difficult to achieve high strength FSW joints, high welding performance, and control the welding process. Welding variables that form the basis of friction stir welding; machine parameters, tool variables, and material properties are divided into three main groups. Each welding variable has different effects on the weld joint. In this study, friction stir welds were made on high density polyethylene (HDPE) sheets with factors selected from machine parameters and welding tool variables. Although the welding performance, quality, and strength gave good results in some conditions, successful joints could not be realized in some conditions. In particular, welding defects occurring in the combination of HDPE material with FSW were investigated. Welding quality, defects, and performances were examined with macrostructure. In addition, the tensile strength values of some the joints were determined. The main purpose of this study is to determine the welding defects that occur at the joints. The causes of welding defects, prevention methods, and which weld variables caused were investigated. Welding parameters and welding defects caused by welding tools were examined in detail. In addition, the factors causing welding defects were changed in a wide range and the changes in the defects were observed.
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Grigoriev, V. V., V. I. Muravyev i P. V. Bakhmatov. "A Study of the Influence of Electron Beam Welding Defects on Fracture Processes in Titanium Alloys". Proceedings of Higher Educational Institutions. Маchine Building, nr 03 (720) (marzec 2020): 23–34. http://dx.doi.org/10.18698/0536-1044-2020-3-23-34.
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The appearance of pores when welding titanium has been extensively studied by domestic and foreign researchers, but there has been no consensus on the causes and conditions of pore formation to date. An overview of advances in the studies of pore formation showed that the problem of formation of the macropores, reaching 0.1 mm was investigated by A.A. Erokhin, V.V. Frolov, G.D. Nikiforov, S.M. Gurevich, V.N. Locks, V.I. Muravyev, B.I. Dolotov, P.V. Bakhmatov et al. The advent of modern x-ray machines in the technological control of permanent joints made by electron beam welding has enabled researchers to detect a specific defect — the so-called dark bands, which make it difficult to assess the quality of permanent connections due to the absence of this defect in the normative and technical documentation. Determining the causes of specific defects and their effect on the properties of titanium alloy structures made by electron beam welding is an important task. This paper presents the results of studies investigating the effect of specific defects of electron beam welding of titanium alloys VT20, VT23 on the nature of destruction under static and dynamic loads and changes in the mechanical properties of the welded joints. It is established that specific defects occurred during electron beam welding have a significant impact on the strength properties of welded joints, as well as on the stages of their destruction. It is determined that the presence of such welding defects as lack of penetration, residual stresses and pores in the fusion zone, expulsion without bonding, etc. contribute to the formation of sub-micropores that lead to brittle destruction of welded joints. The presence of specific defects in permanent joints made by electron beam welding leads to decreased strength properties and to nearly complete absence of such characteristics as elongation and contraction. It is established that heat treatment improves the quality of welded joints.
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Shiwa, M., A. Yamaguchi, M. Sato, S. Murao i M. Nagai. "Acoustic Emission Waveform Analysis From Weld Defects in Steel Ring Samples". Journal of Pressure Vessel Technology 121, nr 1 (1.02.1999): 77–83. http://dx.doi.org/10.1115/1.2883671.
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Acoustic emission (AE) signals from weld defects, incomplete penetration (IP), slag inclusion (SI), and porosity (PR), in longitudinal seam welding of UOE steel pipes were evaluated by using an envelope analysis system and waveform analysis system. In test results, the location accuracy of the envelope and the waveform systems during the loading tests were a few 10 mm and a few mm, respectively. AE activity and intensity and waveform type could identify the welding defect types. Three types of AE spherical radiation patterns (AERPs), a monopole mode, a tensile fracture of dipole mode, and a tensile and shear mixed of dipole mode, were observed during the test. Information from cross section observation of the IP by SEM and AERP suggested that activity and intensity of AE signals from welding defects could depend on both stress concentration of the defect and brittleness of the microstructure around the defect.
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Li, Qiang, Weihan Li, Yanfeng Li i Jie Yang. "Study on X-ray testing of buried polyethylene pipeline thermal fusion welding". Journal of Physics: Conference Series 2419, nr 1 (1.01.2023): 012020. http://dx.doi.org/10.1088/1742-6596/2419/1/012020.
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Abstract Thermal fusion welding is a common method for high-density polyethylene (HDPE) pipelines. However, defects are easy to occur at the joints in the welding process, causing hidden danger. In this study, HDPE pipes with thermal fusion welding defects were made and the X-ray technology was used for detection. The results show that the testing effects of different defects are quite different. The X-ray cannot detect cold-welding defects. The weld seam of the over-welding in the negative is narrowed. Besides, the unfilled holes collapse during welding, resulting in poor detection results. The filled holes can be detected.
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Sumardani, Nur Ichsan, Ngainun Ibnu Setiawan, Bebeh Wahid Nuryadin i Dadan Sumardani. "The Defect Analysis of Carbonsteel Pipe Welding Connections Using Non-Destructive Testing with the Penetrant Test Method". Risenologi : Jurnal Sains, Teknologi, Sosial, Pendidikan, dan Bahasa 5, nr 1 (28.04.2020): 38–47. http://dx.doi.org/10.47028/j.risenologi.2020.51.72.
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In a welding process carried out on metallic materials is sometimes found defects in the material being tested, it is caused by many factors, such as the lack of good materials used and the lack of perfection of the welding process. At testing, it aims to know the surface defects in carbonsteel pipes to know the defects arising after welding. This test is performed with non-destructive tests (NDT) using Dye Penetrant testing method. This test uses 3 types of liquids, including; Cleaner, Penetrant, and developer. The results of these tests will then be observed whether defects occur after welding and what factors affect it. From the test, results there are known 10 locations defects on the surface of the carbonsteel pipe welding with a type of rounded indication of defects that are then followed up by re-welding on indications of such defects.
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Li, Qiang, Yingchun Chen, Yu Tang i Hongyan Liu. "Ultrasonic phased array detection method for butt fusion welding defects of HDPE pipes". Journal of Physics: Conference Series 2419, nr 1 (1.01.2023): 012071. http://dx.doi.org/10.1088/1742-6596/2419/1/012071.
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Abstract The welding joint is the weak link of the high-density polyethylene pipeline. The continuous development of ultrasonic phased array technology is expected to replace traditional non-destructive testing methods. In this paper, ultrasonic phased array technology is used to detect the defects of butt fusion welding. The results show that the ultrasonic phased array can distinguish between metallic and non-metallic inclusions, and the inclusion size can be displayed. Besides, insufficient fusion defects have no obvious defect features in the sector scan results. The types of insufficient fusion defects can be judged from the end-face line scan results.
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Khedr, Mahmoud, Atef Hamada, Antti Järvenpää, Sally Elkatatny i Walaa Abd-Elaziem. "Review on the Solid-State Welding of Steels: Diffusion Bonding and Friction Stir Welding Processes". Metals 13, nr 1 (25.12.2022): 54. http://dx.doi.org/10.3390/met13010054.
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Solid-state welding (SSW) is a relatively new technique, and ongoing research is being performed to fulfill new design demands, deal with contemporary material advancements, and overcome welding defects associated with traditional welding techniques. This work provides an in-depth examination of the advancements in the solid-state welding of steels through diffusion bonding (DB) and friction stir welding (FSW). Considerable attention was given to DB of steel, which overcame the difficulties of segregation, cracking, and distortion stresses that are usually formed in liquid-phase welding techniques. The defects that affected DB included two types: two-dimensional defects of a metallic lattice, i.e., phases and grain boundaries, and three-dimensional defects, i.e., precipitation. FSW, on the other hand, was distinguishable by the use of relatively low heat input when compared to fusion welding processes such as tungsten inert gas (TIG), resulting in the formation of a limited heat-affected zone. Moreover, fine grain structures were formed in the FSW interface because of the stirring tool’s severe plastic deformation, which positively affected the strength, ductility, and toughness of the FSW joints. For instance, higher strength and ductility were reported in joints produced by FSW than in those produced by TIG. Nevertheless, the HAZ width of the specimens welded by FSW was approximately half the value of the HAZ width of the specimens welded by TIG. Some defects associated with FSW related to the diffusion of elements, such as C/Cr atoms, through the weld zone, which affected the local chemical composition due to the formation of rich/depleted regions of the diffused atoms. Moreover, the lack-of-fill defect may exist when inappropriate welding conditions are implemented. On the other hand, the stirring tool was subjected to extensive wear because of the high hardness values, which negatively affected the economical usage of the FSW process. A summary of the results is presented, along with recommendations for future studies aimed at addressing existing difficulties and advancing the solid-state technology for steel.
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Ferenza, Oktovalen, Tuparjono Tuparjono i Sugiyarto Sugiyarto. "Pengaruh Variasi Arus pada Pengelasan Baja ST37 Menggunakan Las Shield Metal Arc Welding (SMAW) dengan Posisi Pengelasan 3F". Syntax Idea 3, nr 8 (19.08.2021): 1967. http://dx.doi.org/10.36418/syntax-idea.v6i8.1432.
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Welding is a very important part in the development and growth of the industry because it has a role in engineering, repair and construction. Shielded metal arc welding (SMAW) is the process of joining two or more materials using a wrapped electrode as heat energy to melt the material. The purpose of this study was to determine the effect and welding defects that arise with current variations so that the optimal welding results obtained from 3 amperes were tested using E6013 electrode diameter 3,2 at the 3F welding position fillet joint. This study uses an experimental method with the material used is St 37 steel with a current variation of 90A, 100A, and 110A. From the research conducted, it was not found optimal welding results where from each ampere tested there was still a weld defect. The defects that occur in the three amperes are caused by the arc, electrode angle, and arc length that exceed the normal limit and are also influenced by the welding speed. From the three variations of the amperage used, the dominant welding results did not occur, namely the 90 amperage, while the 100 amperage welding leg showed good results.
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Ferenza, Oktovalen, Tuparjono Tuparjono i Sugiyarto Sugiyarto. "Pengaruh Variasi Arus pada Pengelasan Baja ST37 Menggunakan Las Shield Metal Arc Welding (SMAW) dengan Posisi Pengelasan 3F". Syntax Idea 3, nr 8 (19.08.2021): 1967–78. http://dx.doi.org/10.46799/syntax-idea.v3i8.1432.
Pełny tekst źródłaStreszczenie:
Welding is a very important part in the development and growth of the industry because it has a role in engineering, repair and construction. Shielded metal arc welding (SMAW) is the process of joining two or more materials using a wrapped electrode as heat energy to melt the material. The purpose of this study was to determine the effect and welding defects that arise with current variations so that the optimal welding results obtained from 3 amperes were tested using E6013 electrode diameter 3,2 at the 3F welding position fillet joint. This study uses an experimental method with the material used is St 37 steel with a current variation of 90A, 100A, and 110A. From the research conducted, it was not found optimal welding results where from each ampere tested there was still a weld defect. The defects that occur in the three amperes are caused by the arc, electrode angle, and arc length that exceed the normal limit and are also influenced by the welding speed. From the three variations of the amperage used, the dominant welding results did not occur, namely the 90 amperage, while the 100 amperage welding leg showed good results.
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Li, Qiang, Weihan Li, Qi Lu, Yanfeng Li i Tao Yang. "Study on the detection method of HDPE electro-fusion welding defect based on X-ray technology". Journal of Physics: Conference Series 2419, nr 1 (1.01.2023): 012069. http://dx.doi.org/10.1088/1742-6596/2419/1/012069.
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Abstract Electro-fusion welding is a common method for high-density polyethylene (HDPE) pipes. It has a high degree of automation and mature technology. However, during the welding process, various buried defects are easily generated. In this paper, HDPE pipes with welding defects were processed, and X-ray technology was used to detect the defects. The results show that: The X-ray detection technology is sensitive to the defects of sockets and ultralight clay-filled holes. But it is difficult to distinguish the size of the holes. Unfilled holes are partially fused during the welding process, which makes them difficult to detect. In addition, the defects of cold-welding and unscratched oxide skin cannot be detected.
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Qi, AiLing, i JiaSen Wang. "Welding defect signal extraction technology based on GAMP-SBL algorithm". Journal of Physics: Conference Series 2221, nr 1 (1.05.2022): 012042. http://dx.doi.org/10.1088/1742-6596/2221/1/012042.
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Abstract Flip chip technology has been rapidly developed and widely used in the field of microelectronic packaging, and defect detection has also received more and more attention. Aiming at the problem that noise affects the location and extraction of signal defects in ultrasonic testing, the sparse Bayesian learning based on generalized approximate message passing (GAMP-SBL) algorithm is used to extract signal defects, and the over-complete Gabor dictionary is used to reconstruct signal defects to effectively improve Sparse decomposition algorithm. The precision experiment tested the defect simulation signal and the actual ultrasonic signal respectively, and compared with the greedy algorithm. The experimental results show that the GAMP-SBL algorithm can more effectively extract the defect signal under the noise background.
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Yang, Xue Ming, i Dong Ci Chen. "Molecular Dynamics Study on Formation of Carbon Nanotube X-Shaped Junction by Heat Welding". Advanced Materials Research 538-541 (czerwiec 2012): 1460–63. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1460.
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Molecular dynamics simulations are used to investigate the junction formation of two crossed single-walled carbon nanotubes (SWCNTs) with or without preexisting structural defects by heat welding. The junction formation of the chiral SWCNTs by heat welding is discussed. Furthermore, both the single vacancy defects and double vacancy defects are introduced in SWCNTs to explore the effect on junction formation by heat welding. We found the single vacancy defects and double vacancy defects pairs distributed on both crossed SWCNTs will accelerate the heat welding process and make the junction easier, and the required temperature for junction formation will be significantly reduced.
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Kountchev, Roumen K., Stuart H. Rubin, Vladimir T. Todorov i Roumiana A. Kountcheva. "Automatic detection of welding defects". International Journal of Reasoning-based Intelligent Systems 3, nr 1 (2011): 34. http://dx.doi.org/10.1504/ijris.2011.037739.
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Liu, Yang, Kun Yuan, Tian Li, Sha Li i Yonggong Ren. "NDT Method for Line Laser Welding Based on Deep Learning and One-Dimensional Time-Series Data". Applied Sciences 12, nr 15 (4.08.2022): 7837. http://dx.doi.org/10.3390/app12157837.
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Welding testing is particularly important in industrial systems, but there are still some deficiencies in terms of testing performance, anti-noise capability and defect identification in current mainstream welding non-destructive testing technologies. With the development of structured-light non-destructive testing technology, deep learning technology, signal processing technology and other fields, various possibilities have emerged that make it possible to propose new ideas for welding non-destructive testing. This study used a laser sensor to propose a non-destructive method for testing welding defects in seam contours. In order to solve the problems of low sampling rates and poor recognition accuracy in traditional methods of welding defect detection, the proposed method introduces image coding into laser sensors and applies deep-learning algorithms to the classification and detection of weld defect images. By preprocessing the weld seam by encoding one-dimensional data as two-dimensional images, this method develops a framework for the detection and classification of pre-coded laser weld seam images. After taking the original extracted weld image center trajectory data as one-dimensional sequence data, we utilized the method of encoding one-dimensional time series data as two-dimensional time-series images. In doing so, the one-dimensional laser data can be encoded into the corresponding two-dimensional images and, with the application of a deep neural network, welding defect classification and detection can be realized. Experimentation was used to verify that the proposed method is of higher accuracy than traditional methods for classifying and detecting defects directly from two-dimensional welding images.
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Zhang, Sujie, Ming Deng i Xiaoyuan Xie. "Real-time recognition of weld defects based on visible spectral image and machine learning". MATEC Web of Conferences 355 (2022): 03014. http://dx.doi.org/10.1051/matecconf/202235503014.
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The quality of Tungsten Inert Gas welding is dependent on human supervision, which can’t suitable for automation. This study designed a model for assessing the tungsten inert gas welding quality with the potential of application in real-time. The model used the K-Nearest Neighborhood (KNN) algorithm, paired with images in the visible spectrum formed by high dynamic range camera. Firstly, projecting the image of weld defects in the training set into a two-dimensional space using multidimensional scaling (MDS), so similar weld defects was aggregated into blocks and distributed in hash, and among different weld defects has overlap. Secondly, establishing models including the KNN, CNN, SVM, CART and NB classification, to classify and recognize the weld defect images. The results show that the KNN model is the best, which has the recognition accuracy of 98%, and the average time of recognizing a single image of 33ms, and suitable for common hardware devices. It can be applied to the image recognition system of automatic welding robot to improve the intelligent level of welding robot.
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Nguyen, Huu Loc, Anh Van Nguyen, Han Le Duy, Thanh-Hai Nguyen, Shinichi Tashiro i Manabu Tanaka. "Relationship among Welding Defects with Convection and Material Flow Dynamic Considering Principal Forces in Plasma Arc Welding". Metals 11, nr 9 (13.09.2021): 1444. http://dx.doi.org/10.3390/met11091444.
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The material flow dynamic and velocity distribution on the melted domain surface play a crucial role on the joint quality and formation of welding defects. In this study, authors investigated the effects of the low and high currents of plasma arc welding on the material flow and thermodynamics of molten pool and its relationship to the welding defects. The high-speed video camera (HSVC) was used to observe the convection of the melted domain and welded-joint appearance. Furthermore, to consider the Marangoni force activation, the temperature on the melted domain was measured by a thermal HSVC. The results revealed that the velocity distribution on the weld pool surface was higher than that inside the molten weld pool. Moreover, in the case of 80 A welding current, the convection speed of molten was faster than that in other cases (120 A and 160 A). The serious undercut and humping could be seen on the top surface (upper side) and unstable weld bead was visualized on the back side (bottom surface). In the case of 160 A welding current, the convection on the weld pool surface was much more complex in comparison with 80 A and 120 A cases. The excessive convex defect at the bottom side and the concave defect at the top surface were observed. In the case of 120 A welding current, two convection patterns with the main flow in the backward direction were seen. Almost no welding defect could be found. The interaction between the shear force and Marangoni force played a solid state on the convection and heat transportation processes in the plasma arc welding process.
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Zhang, Tian Hui, Wen Min Liu, Ren Ping Xu i Bin Xu. "Effect of Welding Method on Weld Defects of ADB610 Steel". Advanced Materials Research 97-101 (marzec 2010): 818–21. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.818.
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Statistical analysis was carried on weld defects of low carbon bainite ADB610 steel using shielded metal arc welding (SMAW) and mixed active-gas arc welding (MAG). By Pareto diagram analysis, although the ratio of porosity air hole using SMAW is slightly higher than the one using MAG, there is no qualitative difference in ADB610 steel weld defect types between two welding methods. And the crack occurs seldom, which indicates ADB610 steel has lower crack-sensitivity using SMAW and MAG. By histogram analysis and rank test, it can be concluded that there is distinctive difference in defect size between SMAW and MAG, and the average size using SMAW is bigger than the one using MAG. So if possible, MAG is recommended for low carbon bainite ADB610 steel.
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Woźny, Piotr, i Józef Błachnio. "Managing the influence of microstructure defects on the strength of EN AW 5754 aluminium alloy welded joints executed with the TIG method". MATEC Web of Conferences 182 (2018): 02025. http://dx.doi.org/10.1051/matecconf/201718202025.
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The paper concerns the issue of the impact of welding defects on the strength of EN AW 5754 aluminium alloy welded joints, executed with the TIG welding method (tungsten inert gas, i.e., a method of welding with a non-consumable tungsten electrode shielded with inert gases). The article presents examples of operating damage to welded joints and discusses the factors impacting the weld quality. The strength test results of welding samples taken under different process parameters were presented. The impact of welding defects and non-conformities identified with a CAT test on the weld joint impact was analysed. The studies showed a strong relation between the presence of welding defects, welding process parameters and weld strength.
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Sen, Murat, i Mustafa Kurt. "Laser and TIG welding of additive manufactured Ti-6Al-4V parts". Materials Testing 64, nr 5 (1.05.2022): 656–66. http://dx.doi.org/10.1515/mt-2021-2165.
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Abstract Electron beam melting (EBM) is a powder bed additive manufacturing (AM) technology for small and medium-sized Ti-6Al-4V components. In this study, EBM-built Ti-6Al-4V tensile specimens were joined using tungsten inert gas (TIG) welding and laser beam welding (LBW) to form large-scale components. Weld morphology, defects, mechanical properties, and microstructure of joints made by LBW and TIG welding were compared. It was found that the pore sensitivity of EBMed Ti-6Al-4V is extremely high. In EBM, the most common defect is pores, but this has been ignored as parts are broken at welding zone. Large pores are distributed along the edge of the weld in TIG welding, whereas in laser welding they are distributed at top of the weld. LBW has a much smaller grain size in the weld center than TIG welding. The TIG welded sample has more heat at the weld boundary. Mechanical properties of TIG welded parts were superior to laser welded parts. The main reason for this is that the weld cross section is larger than the center. In addition, in the microstructure examination of TIG welding, it was observed that the weld had fewer defects than laser welding. Also, the elongation of all specimens is very low.
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Zhu, Xin Wei, Jin Ping Pan i Lian Jiang Tan. "Microwave Scan Inspection of HDPE Piping Thermal Fusion Welds for Lack of Fusion Defect". Applied Mechanics and Materials 333-335 (lipiec 2013): 1523–28. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1523.
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In this paper, microwave scan inspection was employed to detect the lack of fusion defect existing in the thermal fusion welds of high-density polyethylene (HDPE) piping. The thermal fusion welds without defects were firstly inspected by microwave scan technique. The obtained microwave interference pattern and the scan image produced were taken as the evaluation standard. Then the thermal fusion welds containing lack of fusion defects obtained under different welding conditions were inspected, and the corresponding scan images were recorded. The problems occurring in the welding processes that lead to lack of fusion defects in thermal fusion welds can be distinguished by analyzing the scan images. Mechanical tests were performed to confirm the effectiveness and reliability of the microwave scan method in detecting the lack of fusion defects in thermal fusion welds of HDPE piping.
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Aldanondo, Egoitz, Javier Vivas, Pedro Álvarez i Iñaki Hurtado. "Effect of Tool Geometry and Welding Parameters on Friction Stir Welded Lap Joint Formation with AA2099-T83 and AA2060-T8E30 Aluminium Alloys". Metals 10, nr 7 (1.07.2020): 872. http://dx.doi.org/10.3390/met10070872.
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In this paper the effect of tool geometry and welding parameters on friction stir welded lap joints with AA2099-T83 and AA2060-T8E30 aluminium alloys has been investigated through the study of the material flow and weld formation along with the reaction forces during friction stir welding (FSW) for various sets of welding parameters and two FSW tools with different geometrical features. The results showed that welding parameters and tool probe geometry strongly affect the characteristics of the typical defect features (hook and cold lap defects) of the friction stir welded lap joints. From the relationship established between the welding parameters, tool probe geometry and the hook and cold lap defect formation, some guidelines are concluded with the objective of guaranteeing appropriate FSW lap joint properties.
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Zhang, Peng Lin, Zhi Qiang Zhao, Yuan Sang i Ya Xing Xu. "Study on the Method of Typical Defects in Butt Welding of 20 Steel". Applied Mechanics and Materials 456 (październik 2013): 421–24. http://dx.doi.org/10.4028/www.scientific.net/amm.456.421.
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Nondestructive test in the power, petroleum, chemical industry, aviation, aerospace, marine, etc have been widely used in the field, that can more accurately detect magnetic products and the workpiece surface and internal defects, can effectively reduce the risk of accidents from happening. Methods for magnetic particle testing beginners the defects on the surface and nearsurface defects of the learning and understanding of needs, effectively grasp of crack defects identification and quantification methods, articles to the typical method of crack defect detection were studied, produced can be used for comparison of magnetic particle inspection of training and engineering, defect rate of 80%.
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Gao, Xiangdong, Xinxin Dai, Xiaohu Zhou, Yanfeng Li, Deyong You, Yanxi Zhang i Nanfeng Zhang. "Elucidation of magnetic flux leakage for welding defect detection at different magnetic field directions through alternating magnetic field measurement". Insight - Non-Destructive Testing and Condition Monitoring 61, nr 12 (1.12.2019): 720–28. http://dx.doi.org/10.1784/insi.2019.61.12.720.
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Alternating current field measurement (ACFM) is a technology for detecting magnetic flux leakage (MFL) using a magnetic sensor and is often used to detect welding defects. An alternating magnetic field was generated under the excitation of an alternating electric field. The magnetic field direction of an alternating magnetic field changes with time and the size and direction of the leakage magnetic field on the weldment also change periodically. In order to verify this rule, the distribution of the leakage magnetic field in different magnetisation directions was analysed through simulation and experiment. The simulation results show that when sinusoidal excitation is applied to the coil, the direction of magnetisation changes with time and the magnetic field density (B) gradually changes periodically on the weldment. This was verified through related experiments. When the surface of the weldment had welding defects, the dynamic magneto-optical image was captured in different magnetisation directions. Welding defects have different magneto-optical images in different frames, which can present more information for the same defect. In addition, in the experiment, the correlation between the grey-level co-occurrence matrix (GLCM) of magneto-optical images in different magnetisation directions and that of the leakage magnetic field in the corresponding direction was analysed. Simulations and experiments were performed on different types of welding defect. It was found that the trend of characteristics for the leakage magnetic fields was similar to that of the characteristics for the grey-level co-occurrence matrix of the magneto-optical images. The results show that the characteristics of the leakage magnetic field can reflect the texture features of the welding defect.
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Wang, Bin, Xiao Xu Li i Weng Ming Zhang. "Design on the Detection System of Stud Welding Dynamic Parameters". Advanced Materials Research 983 (czerwiec 2014): 404–7. http://dx.doi.org/10.4028/www.scientific.net/amr.983.404.
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Stud welding plays an important role in fixing stud on car bodies. The quality of stud welding is seriously affect automotive security. During the stud welding process,stud welding machine by monitor welding current,welding voltage and welding time to determine the welding quality is good or bad,and uses the average parameter monitoring system,but there are many defects of welding quality relate to these instantaneous value of the parameter.Based on the above issues, designed a dynamic parameter detection system.through the real-time monitoring of dynamic parameter,it can more accurately detect the defects of welding quality.
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Kocurek, Robert, i Janusz Adamiec. "The Repair Welding Technology of Casts Magnesium Alloy QE22". Solid State Phenomena 212 (grudzień 2013): 81–86. http://dx.doi.org/10.4028/www.scientific.net/ssp.212.81.
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Alloys from group Mg-Ag-RE-Zr are characterized by creep resistance up to 200°C, good casting and mechanical properties. Defects of magnesium alloys are propensity to cracks and deformations during heat treatment, low corrosion resistance. Welding technologies are most often use to repair of casts, mainly nonconsumable electrode welding in inert gas cover. About possibility repair or regeneration of magnesium alloy castings by welding depends on their weldability. Weldability of most magnesium alloys is good however, welding and surfacing cast elements create many problems. The purpose of this research work was develop a repair welding technology of casts magnesium alloy. Research project consisted of weldings and padding trials, microstructure and mechanical properties tests. Presented research results in this paper support conclusion that casts alloy QE22 reveal susceptibility to stable connection.
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Liu, Jinping, Baoping Xu, Yingchao Feng, Peng Chen, Cancan Yan, Zhuyuan Li, Kaisong Yang, Kun She i Yiming Huang. "Study on Porosity Defect Detection in Narrow Gap Laser Welding Based on Spectral Diagnosis". Materials 16, nr 14 (13.07.2023): 4989. http://dx.doi.org/10.3390/ma16144989.
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As an advanced connection technology for large thick-walled components, narrow gap laser welding has the advantages of small heat input and high efficiency and quality. However, porosity defects are prone to occur inside the weld due to the complex welding environment. In this study, the influence of the process parameters and pollutants such as water and oil on the porosity defect were explored. The action mechanism of water on the electron temperature and spectral intensity of the laser-induced plasma was analyzed. The results showed that the spectral intensity during narrow gap laser welding was weaker than that of flat plate butt welding. Under the optimal welding process conditions, the electron temperature during narrow gap laser self-fusion welding was calculated as 7413.3 K by the Boltzmann plot method. The electron density was 5.6714 × 1015 cm−3, conforming to the thermodynamic equilibrium state. With six groups of self-fusion welding parameters, only sporadic porosity defects were observed according to the X-ray detection. When there was water on the base metal surface, a large number of dense pores were observed on the weld surface and in the weld through X-ray inspection. Compared with the spectral data obtained under the normal process, the relative light intensity of the spectrometer in the whole band was reduced. The electron temperature decreased to the range of 6900 to 7200 K, while the electron density increased. The spectrum variation during narrow gap laser wire filling welding was basically the same as that of laser self-fusion welding. The porosity defects caused by water and oil pollutants in the laser welding could be effectively identified based on the intensity of the Fe I spectral lines.
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Shaloo, Masoud, Martin Schnall, Thomas Klein, Norbert Huber i Bernhard Reitinger. "A Review of Non-Destructive Testing (NDT) Techniques for Defect Detection: Application to Fusion Welding and Future Wire Arc Additive Manufacturing Processes". Materials 15, nr 10 (21.05.2022): 3697. http://dx.doi.org/10.3390/ma15103697.
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In Wire and Arc Additive Manufacturing (WAAM) and fusion welding, various defects such as porosity, cracks, deformation and lack of fusion can occur during the fabrication process. These have a strong impact on the mechanical properties and can also lead to failure of the manufactured parts during service. These defects can be recognized using non-destructive testing (NDT) methods so that the examined workpiece is not harmed. This paper provides a comprehensive overview of various NDT techniques for WAAM and fusion welding, including laser-ultrasonic, acoustic emission with an airborne optical microphone, optical emission spectroscopy, laser-induced breakdown spectroscopy, laser opto-ultrasonic dual detection, thermography and also in-process defect detection via weld current monitoring with an oscilloscope. In addition, the novel research conducted, its operating principle and the equipment required to perform these techniques are presented. The minimum defect size that can be identified via NDT methods has been obtained from previous academic research or from tests carried out by companies. The use of these techniques in WAAM and fusion welding applications makes it possible to detect defects and to take a step towards the production of high-quality final components.