Welding inspection

Berdasarkan hasil observasi mengenai proses pengerjaan pembuatan pintu air penulis mengamati bahwa pengait pintu yang ada. Pengait pintu Karangnongko memiliki peran penting dalam menjaga keamanan dan kestabilan pintu pada fasilitas industri. Namun, dalam prosess pembuatan, pengait ini mengalami cacat pada saat proses pembuatan dan kerusakan akibat pembentukan design menggunakan alat potong blender las potong manual.
Untuk mengatasi permasalahan ini, teknik pengelasan SMAW (Shielded Metal Arc Welding) digunakan sebagai metode perbaikan yang efektif. Pengelasan SMAW digunakan untuk suatu pekerjaan yang paling sering digunakan dalam dunia konstruksi dan industri saat ini. Pengelasan sering digunakan untuk perbaikan maupun pemeliharaan alat yang berbahan logam, baik sebagai penambalan, penyambungan, maupun pemotongan logam (Imam Ibnu Pamungkas, Nani Mulyaningsih, 2019). karena memiliki keunggulan dalam kemudahan aplikasi, fleksibilitas dalam berbagai kondisi lingkungan, serta kekuatan hasil las yang cukup baik untuk komponen berbahan logam seperti pengait pintu. Proses perbaikan ini melibatkan tahapan persiapan, pemilihan elektroda yang sesuai, serta prosedur pengelasan yang tepat agar hasil perbaikan dapat memperpanjang umur pakai komponen tersebut.

A critical variable in Gas Metal Arc Welding (GMAW) is the Mode of Metal Transfer. The mode of metal transfer required for a specific application can vary based on many factors, including base metal thickness and position. The mode of metal transfer is also affected by the shielding gas and the welding parameters used in the welding procedure. There are four modes of metal transfer: 1. Short Circuit Transfer 2. Globular Transfer 3. Spray Transfer 4. Pulsed-Spray Transfer The stability of the welding arc and the metallurgical changes in the electrode wire are dependent on the mode of transfer. Welding procedures are categorized according to the mode of transfer.

The paper deals with the development of a system for automatic weld recognition using new information technologies based on cloud computing and single-board computer in the context of Industry 4.0. The proposed system is based on a visual system for weld recognition, and a neural network based on cloud computing for real-time weld evaluation, both implemented on a single-board low-cost computer. The proposed system was successfully verified on welding samples which correspond to a real welding process in the car production process. The system considerably contributes to the welds diagnostics in industrial processes of small-and medium-sized enterprises. HE quality of manufacturing process is one of the most important aspect of production. Welding processes are used in many manufacturing processes and automotive industry. This makes prerequisites for researching and developing new modern methods and system for welding quality evaluation. Visual inspection of the weld is one of the weld quality diagnostic methods for weld quality diagnostic. This method enables to check weld joint and its various parameters. Visual inspection does not destruct the weld so it is notdestructive methods for weld joints and materials. This examination is done as the first examination and it detects various defects. There is no need to use another method after detecting a defect with this method, so it is cost and timesaving. This work deals with application for evaluation algorithm and weld recognition. It is based on the single-board computer using the visual system. This method is based on the method for visual quality evaluation and modern computer vision and image processing methods. Industry production, as well as mobile robotics, will find the usage of these methods.

Shielded Metal Arc Welding (SMAW) is the most widely used welding technique in engineering industries. Compared to other arc welding techniques like TIG, SMAW is less heat-concentrating. However, welding thick jobs using SMAW can result in serious issues such as structural distortion due to non-uniform input heat distribution. High thermal stresses and distortions can degrade mechanical properties, similar to high input heat. Fast heat removal may prevent such defects, and different quenching media like sand, water, and oil were used to investigate variations in mechanical properties. High-strength low-alloy steel was selected due to its good weldability and easy availability, which makes it suitable for many industrial applications, such as in the space and defense industries. The tensile testing results showed that oil quenching was superior to other quenching techniques because oil-cooled joints had the highest tensile strength and ductility. However, water-cooled joints showed the highest yield strength, but oil-quenched joints had the highest welding efficiency. The hardness of water-cooled joints in the heat-affected zone and weld zone was greater due to rapid cooling in water. The impact energy of oil-cooled joints in the heat-affected zone was superior to that of other joints. Overall, the mechanical properties of oil-cooled joints were superior and showed better geometric configuration, such as minimal distortions.

Although the formation of defects in continuous casting has been studied for several decades, a deeper understanding and improved quality prediction concepts are needed to correlate the defects with the actual steel compositions, machine data and casting parameters. The aim of this work was to derive new quality criteria based on steel composition and cooling pattern for continuous casting and for the subsequent cooling and reheating processes. The criteria were devised based on the outputs of multiphysics simulation tools for online casting applications. The developed criteria were found to be good predictors of whether a steel grade combined with a given cooling pattern is prone to a specific defect. The criteria useful in providing a theoretical justification as to why certain defects form or would form, and can be used for devising practical solutions to avoid them. In practice, the final determination of whether a defect will form depends on the cumulative impact of various single quality criteria combined with the models/data describing the mechanical and thermal stresses forming. The criteria proposed are applicable as part of online quality prediction systems in casting machines. In this paper, new quality criteria were proposed for different kind of cracking-related and gas defects along with case examples. In further work, the criteria will be used to develop rule-based online control systems, in which cumulative effects of individual quality criteria are combined with data from mechanical and thermal stress calculations.

Polyethylene (PE) pipes are widely used in oil and gas industry. Their joints are prone to various flaws e.g., lack of fusion and cold fusion, and are the most problematic part of the pipeline. So, the infrastructure industry requires effective techniques to evaluate the pipes and joints. Butt-fusion (BF) is the most common method of joining PE pipes. Ultrasonic inspections are usually carried out using pulses of finite bandwidth with different frequency components. PE is viscoelastic and its mechanical response at high frequency differs significantly from that of the low frequency. Therefore, when a broadband ultrasound pulse passes through PE pipe, the waveform of the pulse changes as result of attenuation and dispersion of PE. Previously, attenuation was primarily thought of in terms of the reduction of signal amplitude, ultimately limiting the penetration of ultrasound. Actually, one of the major effects of acoustic absorption through PE is wave form distortion. In the present study, with the aim of investigating the possibility of using ultrasonic waves to evaluate HDPE materials and butt fusion of polyethylene pipes, the characteristics and behavior of ultrasonic waves in HDPE materials are studied and researched. For this purpose, the finite element method is used to simulate the propagation of ultrasonic waves in HDPE butt fusion joints. Changes in the wave velocity, and amplitude of the received waves are measured in order to identify the dispersive behavior and attenuation of the waves in HPDE within the effective ultrasonic frequency range of 1-5MHz. Also, by modeling the lack of fusion (LOF) defects embedded in the BF joint with different lengths, the inspection sensitivity, using a 4MHz transducer, for evaluating the LOF defects is evaluated. The numerical results show that the dispersive behavior of longitudinal wave is decreased, as the frequency of transducer increases. Therefore, higher frequency transducers, in the range of 4-5 MHz, can be used for ultrasonic inspection of HDPE butt fusion joints to increase the inspection sensitivity.

The possibility to use fillet welds instead of complete joint penetration welds (CJP ) in directly- welded flange FR (fully restrained) connections is the main aim of this study. An experimental comparison has been made between these two types of welds. Fifteen specimens have been configured by welding plates to form butt, Tee and lap joint connections; three specimens with butt-joint, six with lap-joint, and six specimens were with T-joint. Fillet and CJP groove welds separately have been used to make these connections. After testing of all these specimens, the results indicated that the appropriately sized fillet weld is a good alternative to CJP groove weld when it is used for fully restrained FR moment connections.

Under the Direction of the A WS Technical Activities Committee Approved by the A WS Board of Directors This code covers the welding requirements for any type of welded st:mcture made from the commonly used carbon and low-alloy constmctional steels. Clauses 1 through 11 constitute a body of mies for the regulation of welding in steel constmction. There are eight normative and eleven infonnative annexes in this code. A Commentary of the code is included with the document.

The determination of quality parameters of resistance spot weld in real time is of great importance in today's industry. Acoustic waves can solve this problem in the sense of measuring certain features directly related to the weld quality -degree of heating of the weld zone, moment of beginning of melting and some others. The ultrasonic transducer incorporated into an electrode sends short acoustic pulses into the weld area and receives the signals reflected from different interfaces in heat affected zone during welding process. The specific image and signal processing algorithms applied to the received signals enable us to localize weak reflections from internal interfaces, recognize their nature and use this information to characterize the weld quality. Introduction: The inspection of resistance spot weld quality in real time is quite a challenging and at the same time promising field of NDT. It enables one to monitor the dynamics of the spot weld properties right at the moment of the weld manufacturing. It is extremely important on the industrial floor as it gives the operator information about the quality of the product and thus enables him to correct the mistake before it is too late. Quality inspection of "hot" welds is relatively new field of NDT studies which is potentially capable of providing 100% quality output of the production line. It becomes especially important as long as implementation of the in-line quality inspection techniques will help save a lot of time by elimination or, at least, reduction of costs of after-production inspection and fixing bad parts. Our approach to the above mentioned problem is using the acoustic waves which pass through the spot weld structure during welding. On their way through the setup the waves are modified by the media and thus carry some information about the processes taking place inside the system. The setup consists of a set of one or two ultrasonic transducers incorporated into the electrodes of the spot welder. The ultrasonic transducers are driven by pulser-receiver; the last is controlled by the computer. The schematic view of the setup is presented in Figure .

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La detección y la medición de las radiaciones nucleares se han convertido en un importantísimo renglón en la aplicación de los detectores nucleares y específicamente los Geiger-Muller. Los tubos Geiger con una alta sensibilidad de detección, su robusta construcción y un simple circuito adjunto continúan siendo uno de los detectores más usados en todas las áreas de aplicación en la física e investigaciones nucleares. Se presenta un nuevo diseño de instrumento para medir la tasa de dosis externa ambiental de radiación gamma desde 0,05 µSv/h hasta 10 mSv/h. Consta de tres elementos fundamentales: el detector Geiger-Muller, una tarjeta electrónica de adquisición y control y el software de aplicación. El instrumento se comunica a través de una interfase USB con la computadora solo para variar y ajustar los parámetros de la calibración. El software se desarrolló en lenguaje C utilizando el compilador PICC4.08.

In some austenitic stainless steel welds grains orientation cause deviation and splitting of the ultrasonic beam. It is especially true in the case of multipass welds when the remelting process after each pass causes complex solidification process. With these orientations we define a precise description of the heterogeneous and anisotropic material. Non destructive testing (NDT) is commonly used industrial method to evaluate the integrity of individual components. In service induced cracks such as fatigue and stress corrosion cracks can, if they are detected, be sized and monitored in order to postpone repairs or replacements.

Penelitian ini bertujuan untuk menguji penerapan teknik Double Wall Double Viewing (DWDV) pada pipa carbon steel menggunakan film AGFA D7 sebagai metode uji tak merusak (Non-Destructive Testing). Teknik ini digunakan untuk mendeteksi cacat pada material tanpa merusak struktur aslinya. Dalam pengujian ini, lima parameter utama dianalisis sesuai dengan persyaratan ASME V Artikel 2, yaitu sistem identifikasi, marker lokasi, artifact pada film, citra huruf B, dan sensitivitas Image Quality Indicator (IKB). Hasil pengujian menunjukkan bahwa seluruh parameter memenuhi standar yang ditetapkan. Teknik DWDV ini terbukti sensitif dalam mendeteksi cacat pada detail kecil, seperti kawat IKB nomor 6 dan lubang 2T. Dengan demikian, metode ini dapat diandalkan untuk inspeksi material secara non-destruktif dan cocok untuk diterapkan di berbagai sektor industri.

Penelitian ini bertujuan untuk menguji penerapan teknik Double Wall Double Viewing (DWDV) pada pipa carbon steel menggunakan film AGFA D7 sebagai metode uji tak merusak (Non-Destructive Testing). Teknik ini digunakan untuk mendeteksi cacat pada material tanpa merusak struktur aslinya. Dalam pengujian ini, lima parameter utama dianalisis sesuai dengan persyaratan ASME V Artikel 2, yaitu sistem identifikasi, marker lokasi, artifact pada film, citra huruf B, dan sensitivitas Image Quality Indicator (IKB). Hasil pengujian menunjukkan bahwa seluruh parameter memenuhi standar yang ditetapkan. Teknik DWDV ini terbukti sensitif dalam mendeteksi cacat pada detail kecil, seperti kawat IKB nomor 6 dan lubang 2T. Dengan demikian, metode ini dapat diandalkan untuk inspeksi material secara non-destruktif dan cocok untuk diterapkan di berbagai sektor industri.

COMPARATIVE ANALYSIS OF MAGNETIC PARTICLE INSPECTION ON DEFECT SURFACE SPECIMENS USING DIRECT CURRENT AND ALTERNATING CURRENT. This study evaluates the effectiveness of alternating current (AC) and direct current (DC) in Magnetic Particle Inspection (MPI) for detecting defects in metal specimens with calibrated artificial defects. The primary objective is to compare the capabilities of each current type in detecting surface. The results reveal that AC is highly effective in detecting surface defects, with an average defect length of 24 mm, an error rate of 4%, and an accuracy of 96%, due to the skin effect that concentrates the magnetic field at the surface layer. Conversely, DC, with an average defect length of 26.97 mm, an error rate of 7.87%, and an accuracy of 92.13%, excels in detecting subsurface defects because its magnetic field penetrates deeper. These findings underscore the importance of selecting the appropriate current type based on the location of the defects. Therefore, MPI using AC is rec ommended for surface defect detection, while DC is more effective for subsurface defects, providing practical guidance for optimal testing methods in industrial applications.

Objective: This study investigates the effects of heat treatment on the properties of 5083
aluminum alloy, focusing on impact testing.
Theoretical Framework: The process involves forming and cutting the aluminum material,
followed by heating in a furnace. The samples are then cooled using different media: seawater,
oil, and air.
Method: Natural cooling treatments with seawater, lubricating oil, and air were employed in
this research.
Results and Discussion: The optimal conditions yielded the highest tensile strength and strain
values, with results of 196.48 N/mm² and 6.91%, respectively, for samples cooled in seawater
compared to oil. For impact strength, the greatest value was achieved using seawater as the
cooling medium, measuring 0.42 J/mm². The highest flexural strength, recorded at 69.77
N/mm², was observed in samples cooled with oil.
Research Implications: The findings indicate that natural cooling treatments significantly
influence mechanical properties, with seawater providing superior impact strength, while oil
cooling results in enhanced flexural strength.
Originality/Value: This study reveals that the lowest values for impact and flexural strength
occur in welding materials subjected to natural cooling. Conversely, the tensile strength and
strain improve in welding materials subjected to controlled cooling, indicating increased
hardness.

One of the businesses that are mushrooming in the community in the city and Pekalongan district is the welding workshop business. The market segment for the welding workshop business is the same, namely products used in the housing sector, such as fences, door trellises, stairs and others. Welding in this welding workshop business group mostly uses SMAW welding. SMAW welding is a metal joining process that uses heat energy to melt the workpiece and electrode (filler material). Heat energy in the SMAW welding process is generated due to the jump of ions (cathode and anode) of electricity that occurs at the tip of the electrode and the
surface of the material. In the SMAW welding process, the type of rotection used is a flux membrane found on the electrode. The flux on the SMAW electrode functions to protect the melted weld metal during the welding process. This flux will become slag when it is solid. The
parent metal in this welding experiences melting due to heating from the electric arc that occurs between the tip of the electrode and the surface of the workpiece which results in poor welding results or product defects. The purpose of this community service is to help UMKM welding
workshops to improve the quality of welding products by introducing and providing education related to the use of MIG and MAG welding tools. This MIG-MAG welding tool has several advantages compared to SMAW welding, including: the flow of argon gas or CO2 gas in GMAW welding makes the welds not oxidized by outside air, the welds are stronger due to deep weld penetration and higher corrosion resistance, the heat center is very small to minimize the occurrence of burn through defects or perforated welds. The output target produced from this solution is to introduce another welding method, namely MIG-MAG welding, by conducting training on the use of MIG-MAG welding and providing assistance for monitoring the skills of welding workers

Controlling the moisture content of the electrode-covering is crucial in the production of defect-free, high-quality welds during shielded metal arc welding of steels. The welding industry has long faced the challenge of the high susceptibility of basic electrodes (e.g., E7018) to moisture absorption. In this paper, we demonstrate that applying a nanosilica coating to the surface of the E7018 electrodecovering using a dip-coating technique can effectively reduce the moisture absorption capability of the electrode-covering. The moisture measurement results before and after exposure to a moist environment of 80% humidity and a temperature of 27 °C for 9 h indicate that the moisture absorption values of conventional and nano-treated E7018 electrodes during exposure are 0.67 wt% and 0.03 wt%, respectively. While reducing the size of the pores on the surface of the electrodecovering can to some extent enhance the resistance to moisture absorption, it has been identified that turning the wetting behavior of the electrode-covering surface from hydrophilic to hydrophobic by the nanosilica coating is the most effective mechanism that contributes to the enhanced moisture absorption resistance of the nanosilica-treated electrode-covering. The results indicate that this approach does not have any deleterious effects on the chemical analysis and tensile properties of the weld metal. This simple modification to the electrode-covering can be generally applied to a wide range of electrode-covering types to produce hydrophobic, moisture-resistant electrodes.

Suatu peralatan kilang minyak mempunyai umur dan batas waktu. Jika dalam perawatan peralatan tidak baik dapat mengakibatkan kerusakan seperti kebocoran pada peralatan kilang. Untuk memenuhi reliability pada peralatan kilang, maka perlu dilakukan perawatan terhadap sistem peralatan tersebut secara bertahap dan berkesinambungan. Pada tugas akhir ini dilakukan penilaian resiko terhadap tingkat kerawanan korosi pada unit CDU IV dan HVU II dengan menggunakan pemetaaan korosi. Pemetaan korosi (Corrosion Mapping) adalah suatu pemetaan kecenderungan peralatan dalam instalasi pengolahan minyak tersebut terhadap resiko korosi. Peta korosi yang dituangkan dalam bentuk pewarnaan pada Process Flow Diagram (PFD) dapat digunakan sebagai suatu instrumen untuk memperkirakan tingkat resiko kegagalan peralatan selama beroperasi dalam keadaan normal. Peta korosi peralatan pada unit CDU IV dan HVU II tersebut akan digunakan sebagai masukan dalam pelaksanaan Risk Base Inspection (RBI). Analisa laju koros...

The work investigates the microstructure and mechanical properties of quenched heat-affected zones of mild steel weldment. Here, fifteen samples of mild steel with weldment from metal arc welding process was used and five of the samples were each quenched in palm oil, water, and air respectively. Then the microstructure of the heat-affected zone of the samples were observed. Again, the tensile strength and hardness developed for each of the samples were also studied. For water quenched samples, high hardness, fine grain structure and high cooling rate was observed. This is because water has high specific gravity. Oil quenched sample revealed less hardness and coarse grain structure. While Air cooled sample has hardness and fine microstructure close to that of water quenched. Considering the tensile strength, water quenched samples has highest ultimate tensile strength followed by air cooled sample and oil quenched sample has the least. Again, it was observed that air cool is more ductile than water quenched and oil quenched samples. Finally, oil quenched samples has highest engineering fracture stress followed by water quenched and air cooled samples.

In this study, the optimization of welding parameters for dissimilar joints of SAE 1020 and SS 303 using the Manual Metal Arc Welding (MMAW) process is investigated. The research aims to enhance the ultimate tensile strength (UTS) by employing the Taguchi method and Analysis of Variance (ANOVA) to analyze and optimize critical welding parameters: welding current, welding speed, root gap, and joint angle. Experiments were conducted following an L9 orthogonal array using Minitab 19 software, and a regression model was developed to predict UTS based on these parameters. The findings indicate that welding speed is the most significant factor influencing UTS, followed by root gap and welding current. Optimal parameter settings were identified, resulting in a maximum UTS value closely matching the predicted outcome with a minimal error margin of 2.59%. This study demonstrates the efficacy of statistical methods in optimizing welding conditions for achieving enhanced mechanical properties in dissimilar metal welding applications.

The material of the inlet wall of the sleeve is steel casting GS-20Mn5, WNo: 1.1120, according to the standard DIN 17182. The rough cast microstructure of the casting is subject to the appearance of porosity, which, together with coarse non-metallic inclusions and dynamic loading during exploitation, and an improperly performed welding procedure, can adversely affect lifetime of the inlet wall and lead to cracking of the material.

9Cr steels have great importance in the development of thermoelectric generation industry due to their high creep strength. The weldability of these alloys is critical as they are used in welded construction equipment. The mechanical properties are achieved after post weld heat treatments (PWHTs), then the variation of the parameters used are important for the best performance in service. This work studied the influence of solubilizing PWHT on the mechanical properties at high temperatures of 9Cr welds, using an experimental tubular wire by FCAW-G (Ar-20% CO2). An all weld metal coupon (AWM) was welded according to ANSI/AWS A5.29/A5.29M: 2010 standard; the chemical composition was determined. Two PWHT's were applied: a) tempering at 760°C for 2 hours and b) solubilizing at 1050°C for 1 hour followed by tempering at 720°C for 2 hours. Flat tensile specimens were machined for Hot Tensile Test (HTT) at constant crosshead speed of 5; 1; 0.1 and 0.02 mm/min at constant temperatures of 625 and 650°C. The microstructure resulting from the application of PWHTs was studied by in-situ XRD during HTT. The results were extrapolated using the Larson-Miller parameter. It was found that the application of a solubilizing treatment before tempering increased the resistance of the weld metal at high temperatures.

Existen dos tipos de turbinas hidráulicas: de acclón 2 y de reacción, generalmente son máquinas motoras, es decir, el agua proporciona la energía necesaria para que éstas giren; la parte importante de las turbinas es su rodete, al cual van sujetos los aditamentos necesarios para captar el flujo de agua. Las turbinas hidráulicas son turbomáquinas que permiten la transferencia de energía del agua a un rotor provisto de álabes, mientras el flujo pasa a través de éstos. Cuando el paso del agua por el rotor se efectúa en dirección radial 3 , las máquinas se llaman radiales, de las cuales, el tipo más representativo es la turbina Francis. Cuando el paso por entre los álabes se hace en la dirección del eje de la máquina, se dice que ésta es de tipo axial, de las que son ejemplos la turbina Kaplan y la turbina Pelton, aunque a esta última se le clasifica también como turbina tangencial, por la forma particular de ataque del agua al rotor. Las tres turbinas citadas, Francis, Kaplan y Pelton, son conocidas como las tres grandes, por ser las principales turbinas hidráulicas empleadas en la actualidad. Recientemente se están introduciendo las turbinas tubulares, de bulbo y de pozo para cargas muy reducidas (hasta de poco más de un metro) y grandes caudales. La figura 1 representa esquemáticamente las 4 turbinas citadas y las curvas de rendimiento, operando cada una dentro de las condiciones de carga y caudal propias de Datos del espécimen: Longitud máxima: 350 mm. Diámetro máximo: 300 mm. Peso máximo: 25 kilogramos. Datos de la máquina: Fuente de alimentación: 400 Volts. Corriente trifásica. Corriente máxima por fase: 43 Amperes. Consumo máximo de energía: 17.2 kVA Factor de operacionalidad: 40°/o Sistema de control: Circuito Lógico Programable (PLC) SIEMENS. Presión de aire: de 4 a •e bar. Consumo de aire por ciclo: 0.5 NI Abrazadera: 8 mm. Dimensiones: largo de 1.92 metros, altura de 1. 75 metros y profundidad de 0.83 m. Peso total aproximado: 550 kilogramos. El panel de control y la base de la máquina constituyen una sola pieza. Contenedor de agentes de prueba de 40 litros con bomba incluida.

Existen dos tipos de turbinas hidráulicas: de acclón 2 y de reacción, generalmente son máquinas motoras, es decir, el agua proporciona la energía necesaria para que éstas giren; la parte importante de las turbinas es su rodete, al cual van sujetos los aditamentos necesarios para captar el flujo de agua. Las turbinas hidráulicas son turbomáquinas que permiten la transferencia de energía del agua a un rotor provisto de álabes, mientras el flujo pasa a través de éstos. Cuando el paso del agua por el rotor se efectúa en dirección radial 3 , las máquinas se llaman radiales, de las cuales, el tipo más representativo es la turbina Francis. Cuando el paso por entre los álabes se hace en la dirección del eje de la máquina, se dice que ésta es de tipo axial, de las que son ejemplos la turbina Kaplan y la turbina Pelton, aunque a esta última se le clasifica también como turbina tangencial, por la forma particular de ataque del agua al rotor. Las tres turbinas citadas, Francis, Kaplan y Pelton, son conocidas como las tres grandes, por ser las principales turbinas hidráulicas empleadas en la actualidad. Recientemente se están introduciendo las turbinas tubulares, de bulbo y de pozo para cargas muy reducidas (hasta de poco más de un metro) y grandes caudales. La figura 1 representa esquemáticamente las 4 turbinas citadas y las curvas de rendimiento, operando cada una dentro de las condiciones de carga y caudal propias de Datos del espécimen: Longitud máxima: 350 mm. Diámetro máximo: 300 mm. Peso máximo: 25 kilogramos. Datos de la máquina: Fuente de alimentación: 400 Volts. Corriente trifásica. Corriente máxima por fase: 43 Amperes. Consumo máximo de energía: 17.2 kVA Factor de operacionalidad: 40°/o Sistema de control: Circuito Lógico Programable (PLC) SIEMENS. Presión de aire: de 4 a •e bar. Consumo de aire por ciclo: 0.5 NI Abrazadera: 8 mm. Dimensiones: largo de 1.92 metros, altura de 1. 75 metros y profundidad de 0.83 m. Peso total aproximado: 550 kilogramos. El panel de control y la base de la máquina constituyen una sola pieza. Contenedor de agentes de prueba de 40 litros con bomba incluida.

During the production of pharmaceutical glass tubes, a machine-vision based inspection system can be utilized to perform the high-quality check required by the process. The necessity to improve detection accuracy, and increase production speed determines the need for fast solutions for defects detection. Solutions proposed in literature cannot be efficiently exploited due to specific factors that characterize the production process. In this work, we have derived an algorithm that does not change the detection quality compared to state-of-the-art proposals, but does determine a drastic reduction in the processing time. The algorithm utilizes an adaptive threshold based on the Sigma Rule to detect blobs, and applies a threshold to the variation of luminous intensity along a row to detect air lines. These solutions limit the detection effects due to the tube’s curvature, and rotation and vibration of the tube, which characterize glass tube production. The algorithm has been compared wi...

Remotely controlled subsea welding is often required for pipeline repair and hot tapping where pipelines are installed in water depths beyond acceptable diving depths. The present investigation concerns the development of hyperbaric gas metal arc welding of X65 steel. Welding was carried out at 12-35 bar with low alloyed steel and Inconel 625 wires. All welds gave overmatch situation with respect to strength. Toughness requirements at-30 °C were also satisfactory met, although the Charpy values tend to be close to the minimum required individual values of 40J due to high oxygen and fairly high nitrogen contents. The Inconel 625 weld metal toughness was very high. This was also the case for the fusion line toughness for both wires.

Remotely controlled subsea welding is often required for pipeline repair and hot tapping where pipelines are installed in water depths beyond acceptable diving depths. The present investigation concerns the development of hyperbaric gas metal arc welding of X65 steel. Welding was carried out at 12-35 bar with low alloyed steel and Inconel 625 wires. All welds gave overmatch situation with respect to strength. Toughness requirements at -30 °C were also satisfactory met, although the Charpy values tend to be close to the minimum required individual values of 40J due to high oxygen and fairly high nitrogen contents. The Inconel 625 weld metal toughness was very high. This was also the case for the fusion line toughness for both wires.

The influence of the thermal condition of the steel on the transformation temperatures of two chromium hot-work tool steels was investigated. The steels studied were in two different thermal states: the soft-annealed state and the hardened-and-tempered state. The soft-annealed condition, i.e., the fully annealed condition, is a thermal state of steels in which the matrix is ferritic, and the carbon is chemically bonded in spherical carbides. The hardened-and-tempered condition, on the other hand, means a fully hardened-and-tempered martensitic matrix with uniformly distributed (primary and secondary) carbides. The samples were analysed in a simultaneous thermal analyser (STA) using the differential scanning calorimetry (DSC) method to determine the transformation temperatures. We also performed calculations based on the CALPHAD method to obtain the equilibrium temperatures of the transformations. The aim of the study was to determine the influence of different thermal conditions of chromium hot-work tool steels on the transformation temperatures such as solidus/liquidus temperatures, eutectoid transformation temperatures (A1 and A3), austenite solidification temperature and martensite transformation start temperatures. Since DSC analysis also measures thermal influence, we were able to determine the energies absorbed during eutectoid transformation and melting (endothermic processes) and the energies released during the solidification of d-ferrite and austenite (exothermic processes), as well as the energies released during martensite transformation. It was found that hardening and tempering reduce both eutectoid transformation temperatures and that the solidification intervals are closer to those calculated. From an energetic point of view, hardening and tempering reduce the energies absorbed during melting.

In practice, in the design stage of revitalization, renovation or reinforcement, there is often a need to determine the strength of steel as well as its weldability. The strength of steel can be determined in two ways: directly through destructive testing or indirectly - by the Brinell hardness test. In the case of weldability, this turns out to be much more difficult, because there are three groups of factors which determine this property, i.e.: local weldability, operative weldability, and overall weldability. This paper presents the results of the verification of the relationship between the hardness and strength of three grades of steel from the early twentieth century. The evaluation of the overall weldability of structural steels is discussed in an analytical approach preceding costly weldability tests. An assessment based on selected indicators of weldability can only lead to confusion.

The history of welding has a rich history dating back thousands of years. It originated as a technique to join metals such as gold-copper alloys and bronze, with evidence of its use dating back over 3,000 years before the Common Era. Initially, heat was provided by wood or charcoal, but the advent of electricity revolutionized welding methods.

Welding of steel plates is accompanied by residual stresses that increase as the constraint provided by the welded components becomes greater. Consequently, crack initiation has been reported after welding thick plates due to the high residual stresses developed by the welding procedure. This is further exacerbated by the higher likelihood of imperfections present in thick steel plates due to the rolling and cooling process. The research described herein aims to develop improved submerged arc welding (SAW) procedures to reduce the residual stresses for steel plates of thickness greater than 50mm. Acceptance criteria are developed for discontinuities present in the steel plates prior to welding, to limit the probability of crack initiation. A parametric study of SAW procedure parameters was conducted utilizing a validated finite element model. Two welding procedures were recommended for thick steel plates. Discontinuity acceptance limits were also recommended for each welding procedure using a fracture toughness database and an expression developed to calculate the probability of a crack to initiate.

Welding is considered today as the standard joining operation in steel construction. Its purpose is to ensure the continuity of the material to be assembled, the quality of which depends on the proper functioning of the welding technique. Penetrant testing is a non-destructive test that consists of implementing investigative techniques to judge "without destruction" the state of the weld joint. The final objective of this work is to develop an opinion on the suitability of the welding joint of different thicknesses. Thus, metal specimens of different thicknesses were inspected. The results obtained show that, for small thicknesses, the defects are minimal and increase considerably, proportionally with an increase in the thickness of the welded parts. This analysis can be a way to facilitate the location of surface defects in order to reduce defects during welding operations.

During the production of pharmaceutical glass tubes, a machine-vision based inspection system can be utilized to perform the high-quality check required by the process. The necessity to improve detection accuracy, and increase production speed determines the need for fast solutions for defects detection. Solutions proposed in literature cannot be efficiently exploited due to specific factors that characterize the production process. In this work, we have derived an algorithm that does not change the detection quality compared to state-of-the-art proposals, but does determine a drastic reduction in the processing time. The algorithm utilizes an adaptive threshold based on the Sigma Rule to detect blobs, and applies a threshold to the variation of luminous intensity along a row to detect air lines. These solutions limit the detection effects due to the tube’s curvature, and rotation and vibration of the tube, which characterize glass tube production. The algorithm has been compared with state-of-the-art solutions. The results demonstrate that, with the algorithm proposed, the processing time of the detection phase is reduced by 86%, with an increase in throughput of 268%, achieving greater accuracy in detection. Performance is further improved by adopting Region of Interest reduction techniques. Moreover, we have developed a tuning procedure to determine the algorithm’s parameters in the production batch change. We assessed the performance of the algorithm in a real environment using the “certification” functionality of the machine. Furthermore, we observed that out of 1000 discarded tubes, nine should not have been discarded and a further seven should have been discarded.