Welding Production Research Articles

Insights on Weld Quality using Unsupervised Learning: Clustering of MIG/MAG Process Signals

Abstract With the increasing complexity of gas metal arc welding (GMAW) processes, data-driven approaches for monitoring and understanding automated GMAW production lines are gaining increased prominence. In this work, welding process data recorded in a production environment is analysed using unsupervised learning methods. We describe a data processing pipeline for feature engineering and apply a state-of-the-art clustering method to gain more insights into the welding production process. The clustering results are compared with the results from the application of dimensional reduction techniques and discussed based on human-interpretable characteristics of the welding process.

Working conditions and health status in workers in boiler and welding production in power engineering

Introduction. Preserving the health of qualified workers of older age groups is especially important under conditions of exposure to occupational hazards. The purpose of the study was to assess the influence of occupational hazards on the development of occupational and somatic diseases among workers of various age groups in the main occupations of mechanical engineering. Materials and methods. The study tested the results of hygienic research at workplaces of an enterprise in the power engineering industry in the manufacture of welded metal structures. We assessed the health status in workers based on the results of an in-depth medical examination and ultrasound examination of the vessels of the upper extremities with assessment of blood flow indices. Using a survey method, data were obtained on assessing the influence of production factors on the health status in workers. Results. The working conditions in the main occupational workers groups were assessed as harmful grades 1–3, the priority occupational hazards were: increased noise, and at the workplaces of electric gas workers there were also fibrogenic aerosols, chemical substances, and heavy physical work. Electric and gas welders and boilermakers work in the most unfavourable conditions, about 30% of whom continue to work after reaching retirement age. We have established a significant gain in the incidence of arterial hypertension and sensorineural hearing loss among workers over 40 years of age and an increase in the prevalence of all chronic diseases in the age group over 60 years. Limitations. The study is limited by the number of workers examined and the lack of ability to assess the health status of the studied contingent of workers over time. Conclusion. In conditions of exposure to elevated noise and other occupational hazards, there is an enhancement in the prevalence of work-related and somatic diseases in workers over 40 years of age. With advancing age, the rise in the vascular resistance index is observed, however, the first signs of peripheral blood flow disturbance are often recorded at a young age. In this regard, it is necessary to introduce methods of early diagnosis and prevention of occupational and work-related pathology.

Online welding status monitoring method of T-joint double-sided double arc welding based on multi-source information fusion

In modern manufacturing, double-sided double arc (DSDA) welding brings advantages in properties and efficiency for T-shaped joints. However, the double-side forming makes it difficult to detect the imperfections and ensure weld joint quality, which few studies have covered. Most existing methods deal with single-arc welding with limited sensing sources. To fill the gap, an online welding status monitoring method for DSDA welding is proposed based on the fusion of welding current, arc voltage, arc sound, and weld pool images. In pre-processing, the automatic weld pool region of interest (ROI) detection method based on the lightweight YOLO-L model and the waveform denoising algorithm are designed. In feature engineering, waveform signals are analyzed in both the time and frequency domain. A weld pool feature extractor based on a convolutional neural network (CNN) is proposed with good effectiveness and interpretability. The output feature combination is refined by Fisher-based selection and evaluation. In model building, an ensemble learning model based on three high-fit basic learners is proposed, with an accuracy of 98.538 %. The proposed model shows significant advantages over the single basic classifier and other ensemble methods. Experiments verify high precision and robustness, laying a foundation for accurate real-time monitoring of DSDA welding production.

Method for complex increase of welding production control efficiency based on swarm intelligence algorithms and evolutionary modeling

Method for complex increase of welding production control efficiency based on swarm intelligence algorithms and evolutionary modeling

PROGRAM AND ANALYTICAL COMPLEX OF THE INDUSTRIAL SAFETY AND HEALTH ANALYSIS SYSTEM

Aim. To investigate the quantitative characteristics of magnetic fields created during electric contact welding by various methods: contact point, arc-contact, capacitor point, contact-contact continuous and pulsating reflow. The problem being solved is the lack of necessary information on the electromagnetic safety of the specified welding methods. Methodology. A description of the proposed methodical approaches to determining the levels of magnetic fields, means of measuring them, and methods of assessing their impact on the welder's body is provided. Based on the analysis and processing of the received oscillograms and spectrograms of magnetic fields, measurements of their quantitative characteristics were performed. To determine the general level of the multifrequency magnetic field that occurs during contact welding, the proposed generalized indicator of the level of the magnetic field was used. Implications of research. It was established that during contact spot welding with a stationary machine, the magnetic field level exceeds the maximum permissible value at the workplace in the range of 50-1000 Hz at a distance of 0.3 m from the welding electrodes. During manual welding by this method, the level of the magnetic field exceeds the permissible level in the frequency ranges of 5-50, 50-1000 Hz directly near the electric cable. Condenser spot welding with direct current is characterized by exceeding the maximum allowable MP at the workplace in the high-frequency range of 1000–10000 Hz. During arc-joint welding at the workplace, exceeding the maximum allowable levels of the magnetic field was not detected. Practical implications. It is shown that the spectral composition and magnitude of the magnetic field signal is determined by the welding method itself and the initial parameters of the power sources. The obtained results can be used in the field of welding production and labor protection for the improvement of contact welding technologies and the development of measures to protect welders from the magnetic field.

Mathematical model of in-line manufacturing of sections in a flexible shipyard production system

The assembly and welding production of the shipyard is a complex production system. Studying the functioning of its individual elements, the interrelationships between them, and responses to the disturbing effects of external and internal factors in real conditions is difficult, expensive, and time-consuming. For this purpose, it is appropriate to use all possible modeling methods, especially when it comes to modeling systems with streaming processes. The application of this practice will allow, without significant expenditure of various kinds of resources, in a short time to find the optimal planning solution for the composition and performance of equipment, the placement of personnel, etc. Most modeling methods are based on a pre-developed mathematical model. The purpose of its development in the context of this article is reduced to the search for rational solutions related to increasing the flexibility of existing production processes and their management.

Multi-model feature aggregation for classification of laser welding images with vision transformer

The laser welding technique is quite common in various manufacturing lines, including those for lithium-ion power batteries, due to its remarkable productivity, effectiveness, and flexibility. However, it has been observed that the consistency of the welding quality is not always optimal. This study investigates the adoption of laser welding in the manufacturing of lithium-ion batteries, such as their anode, cathode and safety vent, where consistent weld quality is crucial for battery performance and safety. Therefore, evaluating the laser-welding product is indispensable for industrial production and the public domain. Several techniques have been utilized for laser welding evaluation, both destructive and non-destructive. However, these methods are ineffective and too cumbersome to be adopted in mass manufacturing. In contrast, a machine vision strategy has recently been adopted to distinguish between successful and unsuccessful laser welding items. This opened new perspectives for evaluating the quality of the laser welding product using digital image techniques. However, these methods cannot deliver outstanding performance across multiple laser-welding products and achieve optimal classification accuracy. Deep learning has evolved remarkably in recent years and gained popularity in detecting welding defects. This paper presents the observation of a Hybrid Vision Transformer (HViT) to classify the laser welding images corresponding to their feature patch images based on multi-model feature aggregation. The VGG-16 and MobileNet, which were pre-trained on ImageNet, were utilized as the core models to extract the rich features of the laser welding image. To integrate these features, the squeeze excitation module (SE) was utilized, and a multi-layer perception (MLP) approach with a label smoothing optimizer was used for classification. To determine the effectiveness of the proposed strategy, a comparative analysis was conducted with a multitude of alternative machine learning and deep learning approaches. The results indicate that the proposed strategy surpasses all other methods in terms of classification accuracy and evaluation metrics on the test dataset.

Comparative Life Cycle Assessment of a centrifugal compressor impeller: Hybrid technology production versus welding production

Sustainable development is one of the main objectives in the turbomachinery sector to achieve the climate neutrality targets set by 2050 protocols. The manufacturing industry consumes an average of 23% of global energy, significantly contributing to the generation of greenhouse gases and other pollutants. Therefore, it is crucial to research technological solutions aimed at reducing consumption for the benefit of the environmental sustainability of the products manufactured. This study presents a comparative environmental impact assessment using the Life Cycle Assessment (LCA) methodology to evaluate the sustainability of two technological alternatives used to produce centrifugal impellers in the industrial sector. The first process analyzed deals with making an impeller by welding the shroud to the impeller body. The second process involves producing the component from a semi-finished product, machined through milling and Electrical Discharge Machining (hybrid solution). The study has been conducted at Nuovo Pignone company. It is based on primary inventory data collected through specific measurement campaigns and modeled using the environmental database Ecoinvent v3.9. The results were produced using the ILCD Midpoint method, and four different impact categories were investigated: Climate Change, Human Toxicity, Cancer Effects, and Freshwater Ecotoxicity. The results demonstrate that the solution produced through hybrid manufacturing is generally less impactful compared to the welded one. The insight implemented in the work is functional in drafting suggestions for manufacturers and customers to reduce the environmental burdens of the examined product.

Electric-thermal-mechanics modeling for in-process phenomena during micro resistance spot welding spark plug of Pt and Inconel600

The spark plug is one of the important components in the gasoline engine's combustion chamber. To reduce vehicle emissions, the platinum spark plug is selected due to its good performance. Due to the high productivity of resistance spot welding (RSW), a micro-scale RSW process is employed to assemble the platinum tip to Inconel600 part in the production of spark plugs. In order to understand the electric-thermal-mechanics phenomena during micro resistance spot welding spark plug for controlling the welding quality and saving electric energy, a three-dimensional simulation model and the in-house finite element program JWRIAN-RSW3D were developed. The potential history and upper electrode displacement results were verified with experiments. Numerical case studies were made to investigate the influence magnitude of welding current on the electric-thermal-mechanics phenomena. The developed model reveals inside phenomena to clearly understand the welding mechanism for potential, current density, temperature, electrode displacement and their distribution/history as well as the molten zone. The comprehensive phenomena of maximum temperature distribution on both base metals and Inconel600 were clarified using a top perspective, revealing differences in distribution on the contact surface between horizontal and vertical sections. To achieve a complete welding joint, the molten zone on the contact area is required carefully in order to facilitate the bonding of both base metals. Based on simulation results for three welding conditions, the alternating current at the magnitude of 1.2 kA with the welding time of 0.1 s is recommended to obtain the welded joint with minimized energy consumption in production.

Effect of Exothermic Additions in Core Filler on Arc Stability and Microstructure during Self-Shielded, Flux-Cored Arc Welding

In the conditions of an energy crisis, an important issue is the increase in energy efficiency and productivity of welding and hardfacing processes. The article substantiates the perspective of using exothermic additives introduced into core filler for flux-cored wire arc welding processes as a relatively cheap additional heat source, reducing energy consumption when melting filler materials, and increasing the deposition rate. The mixture design (MD) was selected as the design method to optimize the average values of current and voltage, as well as arc stability parameters depending on core filler composition. This article studies the influence of the introduction of exothermic addition (EA), as well as the ratios CuO/C and CuO/Al on arc stability for the FCAW S process. Parameters characterizing arc stability were determined using an oscillograph, and from the obtained oscillograms, an analysis was conducted on arc voltage and welding current signals during flux-cored arc welding. It was determined that various methods can be used to evaluate arc stability, which can be divided into two groups: graphical (current and voltage cyclograms, box plots with frequency histograms, ellipse parameters plotted on current, and voltage cyclograms) and statistical (standard variation and coefficients of variation for welding current and arc voltage). In this paper, a comprehensive evaluation of arc stability depending on the composition of the cored wire filler was carried out. It was determined that the most stable current parameters were observed for the flux-cored wire electrode with an average exothermic addition content at the level of EA = 26.5–28.58 wt.% and a high carbon content (low values of CuO/C = 3.75). Conversely, the lowest values of arc stability (CV(U) and Std(U)) were observed during hardfacing with a flux-cored wire electrode with a high CuO/Al ratio ≥ 4.5 and a content of exothermic addition in the core filler below the average EA < 29 wt.%. Mathematical models of mean values, standard deviation, coefficient of variation for welding current, and arc voltage were developed. The results indicated that the response surface prediction models had good accuracy and prediction ability. The developed mathematical models showed that the ratio of oxidizing agent to reducing agent in the composition of exothermic addition (CuO/Al) had the greatest influence on the welding current and arc voltage characteristics under investigation. The percentage of exothermic mixture in the core filler (EA) only affected the average welding current (Iaw) and the average arc voltage (Uaw). The graphite content expressed through the CuO/C ratio had a significant impact on welding current parameters as well as the coefficient of variation of arc voltage (CV(U)). Two welding parameters were selected for optimization: the mean welding current (Iaw) and the standard deviation of arc voltage (Std(U)). The best arc stability when using exothermic addition CuO-Al in the core filler was observed at CuO/Al = 3.6–3.9, CuO/C = 3.5–4.26, and at an average EA content of 29–38 wt.%. The significant influence of the CuO/Al and CuO/C ratios on arc voltage parameters can also be explained by their impact on the elemental composition of the welding arc (copper, cupric oxide (CuO), and Al2O3). The more complete this reaction, the higher the amount of easily vaporized copper (Cu) in the arc plasma, enhancing arc stability. The influence of core filler composition on the microstructure of deposited metal of the Fe-Cr-Cu-Ti alloy system was investigated.

RS/AS and nugget zone SEM analysis and mathematical equations for parameter optimization on friction stir welding tool

In order to find the ideal process parameters, the friction stir welding (FSW) production process is combined with mathematical optimisation techniques in the current thesis. In terms of optimisation, the goals (or objectives) are process- related in that they define or represent how the process behaves. The Welding Institute (TWI),UK introduced the FSW process, which has been enhanced in this study, as a relatively new welding technology in 1991. In conclusion, because the process is solid-state and does not involve melting, many of the problems of conventional fusing welding techniques may be avoided. In the FSW process, two work pieces are submerged in a spinning tool. As a result of friction and plastic dissipation, the temperature rises to the point where the material is sufficiently softened to be mixed together, forming a weld. Involving solid material ow, heat transmission, thermal softening, recrystallization, and the production of residual stresses, the process is multiphysics in nature.

Experimental and Computational Study of Microhardness Evolution in the HAZ for Al–Cu–Li Alloys

The Laser Beam Welding (LBW) of aluminum alloys has attracted significant interest from industrial sectors, including the shipbuilding, automotive and aeronautics industries, as it expects to contribute to significant cost reduction associated with the production of high-quality welds. To comprehend the behavior of welded structures in regard to their damage tolerance, the application of fracture mechanics serves as the instrumental tool. However, the methods employed overlook the changes in the microstructure within the Heat-Affected Zone (HAZ), which leads to the degradation of the mechanical properties of the material. The purpose of this study is to simulate microhardness evolution in the HAZ of AA2198-T351 LBW. The material represents the latest generation of Al-Cu-Li alloys, which exhibit improved mechanical properties, enhanced damage tolerance behavior, lower density and better corrosion and fatigue crack growth resistance than conventional Al-Cu alloys. In this work, the microhardness profile of LBW AA2198 was measured, and subsequently, through isothermal heat treatments on samples, the microhardness values of the HAZ were replicated. The conditions of the heat treatments (T, t) were selected in line with the thermal cycles that each area of the HAZ experienced during welding. ThermoCalc and DICTRA were employed in order to identify the strengthening precipitates and their evolution (dissolution and coarsening) during the weld thermal cycle. The microstructure of the heat-treated samples was studied employing LOM and TEM, and the strengthening precipitates and their characteristics (volume fraction and size) were defined and correlated to the calculations and the experimental conditions employed during welding. The main conclusion of this study is that it is feasible to imitate the microstructure evolution within the HAZ through the implementation of isothermal heat treatments. This implies that it is possible to fabricate samples for fatigue crack growth tests, enabling the experimental examination of the damage tolerance behavior in welded structures.

Tungsten Inert Gas Welding of 6061-T6 Aluminum Alloy Frame: Finite Element Simulation and Experiment.

In order to address the irregularity of the welding path in aluminum alloy frame joints, this study conducted a numerical simulation of free-path welding. It focuses on the application of the TIG (tungsten inert gas) welding process in aluminum alloy welding, specifically at the intersecting line nodes of welded bicycle frames. The welding simulation was performed on a 6061-T6 aluminum alloy frame. Using a custom heat source subroutine written in Fortran language and integrated into the ABAQUS environment, a detailed numerical simulation study was conducted. The distribution of key fields during the welding process, such as temperature, equivalent stress, and post-weld deformation, were carefully analyzed. Building upon this analysis, the thin-walled TIG welding process was optimized using the response surface method, resulting in the identification of the best welding parameters: a welding current of 240 A, a welding voltage of 20 V, and a welding speed of 11 mm/s. These optimal parameters were successfully implemented in actual welding production, yielding excellent welding results in terms of forming quality. Through experimentation, it was confirmed that the welded parts were completely formed under the optimized process parameters and met the required product standards. Consequently, this research provides valuable theoretical and technical guidance for aluminum alloy bicycle frame welding.

Review on the Application of the Attention Mechanism in Sensing Information Processing for Dynamic Welding Processes

Arc welding is the common method used in traditional welding, which constitutes the majority of total welding production. The traditional manual and manual teaching welding method has problems with high labor costs and limited efficiency when faced with mass production. With the advancement in technology, intelligent welding technology is expected to become a solution to this problem in the future. To achieve the intelligent welding process, modern sensing technology can be employed to effectively simulate the welder’s sensory perception and cognitive abilities. Recent studies have advanced the application of sensing technologies, leading to the advancement in intelligent welding process. The review is divided into two aspects. First, the theory and applications of various sensing technologies (visual, sound, arc, spectral signal, etc.) are summarized. Then, combined with the generalization of neural networks and attention mechanisms, the development trends in welding sensing information processing and modeling technology are discussed. Based on the existing research results, the feasibility, advantages, and development direction of attention mechanisms in the welding field are analyzed. In the end, a brief conclusion and remarks are presented.

Advancements in energy-efficient welding production techniques: Innovative models and methods for combined workpiece fabrication

This article highlights notable advances in energy-efficient welding manufacturing techniques, with particular emphasis on new models and methodologies for combined welding machines. High energy density welding processes such as laser beam and electron beam welding are being investigated for their potential to optimize energy use in various industrial applications. Furthermore, the examination extends to energy- efficient high-density welding procedures, notably encompassing electric arc, gas welding, and autogenous welding, while also taking into account factors tied to corrosion processing. Technological advances in machining, cutting techniques, and specialized connectors are also explored in detail, and their contribution to reducing energy consumption and improving overall equipment efficiency is examined. This thorough investigation would not be complete without considering the implications for the energy sector, where the use of energy-efficient welding techniques is critical in reducing costs and refining manufacturing processes.

Numerical Simulation and Experimental Analysis on Seam Feature Size and Deformation for T-Joint Laser-GMAW Hybrid Welding.

As an innovative technique, laser-GMAW hybrid welding manifests significant superiority in enhancing welding productivity and quality, albeit the optimization of process parameters poses a challenge for practical application. The present manuscript elucidates the influence of process parameters on the dimensional characteristics of the welding seam and the distortion of 8 mm T-joints in the context of laser-GMAW hybrid welding, and channels both simulation and experimentation. The outcomes denote that the dual conical model serves as an efficacious aid for the numerical simulation of T-joint laser-GMAW hybrid welding. Furthermore, the repercussions of process parameters on welding seam dimensional characteristics remain consistently similar in both the simulation and experimental results. From the simulation outcomes, it becomes apparent that the distortion of the base material can be efficiently managed by implementing anti-distortion measures. This inquiry offers both a theoretical and experimental foundation for optimizing process parameters of T-joint laser-GMAW hybrid welding, presenting certain engineering applicability.

Fusion of dies with economy-layed secondaryhard-ducted steel

Problem. The purpose of the work is to increase the wear resistance and heat resistance of secondary hardening surfacing steels by improving the composition of alloying powder wires due to the optimization of the content of titanium, molybdenum and chromium. It was found that increasing the heat resistance of iron-based Cr-Mn-Ti alloys contributes to an increase in the content of the carbide phase [TiC]; the introduction of [Mo] stabilizes the value of hardness at elevated temperatures, increases heat resistance and hardness during dispersion hardening. High indicators of heat resistance and wear resistance of steel 18X4G10M5T3S are achieved due to additional diffusion formation of the carbide phase during aging, increased contact strength, a significant amount and uniform distribution in the volume of the deposited metal of the carbide phase. Goal. Іncreasing the wear resistance and heat resistance of secondary hardening surfacing steels by improving the composition of alloying powder wires due to the optimization of the content of titanium, molybdenum and chromium. Methodology. For automatic arc surfacing under the flux, attachment devices were designed and manufactured for feeding the de-energized flux-cored wire into the welding bath. The use of these devices on the A-1401 and TS-17M welding machines made it possible to study the influence of the de-sintering additive on the deposition parameters, chemical and phase composition of the deposited metal. The surfacing was carried out on samples made of steel 20 and 50 KhNM according to the "slide" scheme. The powder wire was produced at the laboratory facility of the Department of Welding Production of UIPA. The crack resistance of the alloys was studied at the LTP 1-6 installation. Results. On the basis of experimental studies, it was established that automatic surfacing with a de-energized additive increases the technical and economic indicators of melting - the surfacing coefficient is up to 30 g/Ag, the share of the base metal in the surfacing decreases to 11...14%, reduces the specific fuel costs and energy costs - increases the specific energy for the formation of a seam above the conventional limit of fusion and thermal efficiency. by 60...70% and 40...50%, reduces the coefficients of the relative mass of slag by 24...28%, increases the absorption coefficients of alloying elements by 70...80% in contrast to single-electrode melting. Originality It was found that increasing the heat resistance of iron-based Cr-Mn-Ti alloys contributes to an increase in the content of the carbide phase [TiC]; the introduction of [Mo] stabilizes the value of hardness at elevated temperatures, increases heat resistance and hardness during dispersion hardening. Practical value. On the basis of the conducted research, economically alloyed wear-resistant alloys and the technology of their application were developed to restore the grooves of the matrices of hot metal stamping dies. The use of these alloys and the technology of their application ensures a reduction in energy and resource costs and an increase in the durability of the stamping tool.

A guidance system for robotic welding based on an improved YOLOv5 algorithm with a RealSense depth camera

Vision-based automatic welding guidance technology plays an essential role in robotic welding. A laser vision sensor (LVS) relies on manual intervention to guide the robot when near the workpiece, which reduces the autonomy of the welding robot and productivity. To solve this problem, a robot welding guidance system based on an improved YOLOv5 algorithm with a RealSense Depth Camera was proposed. A coordinate attention (CA) module was embedded in the original YOLOv5 algorithm to improve the accuracy of weld groove detection. The center of the predicted frame of the weld groove in the pixel plane was combined with the depth information acquired by a RealSense depth camera to calculate the actual position of the weld groove. Subsequently, the robot was guided to approach and move over the workpiece. Then, the LVS was used to guide the welding torch installed at the end of the robot to move along the centerline of the weld groove and complete welding tasks. The feasibility of the proposed method was verified by experiments. The maximum error was 2.9 mm in guiding experiments conducted with a distance of 300 mm between the depth camera and the workpiece. The percentage error was within 2% in guidance experiments conducted with distances from 0.3 to 2 m. The system combines the advantages of the depth camera for accurate positioning within a large field and the LVS for high accuracy. Once the position of the weld groove of the workpiece to be welded has been determined, the LVS combined with the robot can easily track the weld groove and realize the welding operation without manual intervention.

Application of Hybrid Laser Arc Welding for Construction of LNG Tanks Made of Thick Cryogenic 9% Ni Steel Plates

AbstractHybrid laser-arc welding (HLAW) was applied for butt welding of 14.5 mm thick plates of ferritic cryogenic steel X8Ni9 containing 9% Ni, which is used for manufacturing storage and transport facilities of liquefied natural gas (LNG). The weld seam formation and the achievable metallurgical and mechanical properties of the hybrid welds were investigated experimentally for two types of filler wire, an austenitic wire dissimilar to the base metal (BM) and an experimentally produced matching ferritic wire. Safe penetration and uniform distribution of the austenitic filler metal in the narrow hybrid weld could only be achieved in the upper, arc-dominated part of the weld. The pronounced heterogeneous distribution of the austenitic filler metal in the middle part and in the root area of the weld could not ensure sufficient notched impact toughness of the weld metal (WM). As a result, a decrease in the impact energy down to 17 ± 3 J was observed, which is below the acceptance level of ≥ 34 J for cryogenic applications. In contrast, the use of a matching ferritic filler wire resulted in satisfactory impact energy of the hybrid welds of up to 134 ± 52 J at the concerned cryogenic temperature of -196 °C. The obtained results contribute to an important and remarkable conversion in automated manufacturing of LNG facilities. In other words, the results will help to develop a new laser-based welding technology, where both quality and productivity are considered.The efficiency of the developed welding process has been demonstrated by manufacturing a prototype where a segment of the inner wall of large size LNG storage tank was constructed. In this concern, hybrid laser arc welding was conducted in both horizontal (2G) and vertical (3G) positions as a simulation to the actual onsite manufacturing. The prototype was fabricated twice where its quality was confirmed based on non-destructive and destructive examinations.

Rancang Bangun Sistem Pemantauan dan Pengendali Kualitas Udara Pada Aplikasi Welding Habitat Proses Welding Pipeline Sistem Dengan Data Logger

Abstract
 Air Quality Monitoring and Control System is a method of monitoring and controlling air quality in an area or place where air contamination may occur in an activity or work. In this case, the Air Quality Monitoring and Control System is applied to the welding habitat or the welding house in the system pipe welding process. At this time, the welding habitat in the welding pipe pipeline system with the shielding gas process has not been monitored and controlled for air quality during the welding process, this condition causes the welder in the welding habitat to become uncomfortable which can affect the quality of the welding and endanger the welder's health. For this reason, an air quality monitoring and control system is needed that can unite and control the air quality in the welding habitat during the welding process. The purpose of the design of this Air Quality Monitoring and Control System is to make the welding process in the welding habitat of the system pipe welding process more comfortable and safer for the welder's health. So that the welder can concentrate fully on the welding process and produce good and quality welding production. With the application of this system, it can provide a level of weld repair that can reduce welding repair costs incurred by the Company.
 Keywords: Air Quality; Data Logger; ESP32; ISPU (Air Pollution Standards Index); Sensors