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1

Analysis of the process of qualifying the welding technology of S355JR structural steel using the submerged arc welding method

Wieczorska A., Labuda W.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 118, nr 1

18--27

EN

Purpose This paper presents the issue of welding technology qualification using the example of structural steel S355JR with a plate thickness of 25 mm and 100 mm, bevelling ½V. The main objective of this work was to attempt to perform a full qualification of the submerged arc welding process in accordance with the requirements of PN EN ISO 15614. Particular attention was paid to the issue of the qualification of welding technology. The samples were subjected to non-destructive testing, i.e. visual and penetrant testing, as well as ultrasonic testing and heat treatment. This was followed by destructive testing, including macroscopic testing and hardness testing. According to the proposed procedure for the recognition of submerged arc welding technology, once the necessary tests had been carried out and the protocols with positive results had been obtained. The documentation had been completed, the analysis needed to obtain certificates of conformity for factory production control and welding quality was carried out. Design/methodology/approach Submerged arc welding is often used for highly responsible butt joints, particularly when joining thick components. This has been achieved through the proper design of the preparation of the parts to be welded and the development of a welding technology that practically eliminates the pre-phase that occurs in traditional technology, thereby eliminating the risk of it affecting the quality of the welded joint. Findings During the implementation of submerged arc welding, a number of technological problems were encountered. The first test joints contained many defects, i.e. sticking and slag inclusions inside the welds. In addition, obtaining welds with the correct profile and removing the slag from the weld groove was difficult. These obstacles were eliminated experimentally by carrying out successive tests using different parameters and welding groove geometries. Practical implications The correct implementation of any welding process depends on its input parameters. These parameters include welding current, welding speed, welding current, wire diameter, welding voltage and many others. Submerged arc welding (SAW) is widely used in the industry for manufacturing as it is more reliable, provides deep penetration in the work, ensures a smooth finish on objects, and results in high productivity. Originality/value The technology was developed for a company that manufactures control discs for steam turbines.

2

A study on welding quality for the automatic vertical-position welding process based on Mahalanobis Distance method

Jin B.-J., Park M.-H., Yun T.-J., Shim J.-Y., Kang B.-Y., Kim I.-S.

Archives of Materials Science and Engineering

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2018

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Vol. 91, nr 1

31--40

EN

Purpose: The welding quality and reducing production cost could be achieved by developing the automatic on-line welding quality monitoring system. However, investigation of welding fault to quantify the welding quality on the horizontal-position welding has been concentrated. Therefore, MD (Mahalanobis Distance) method on the vertical-position welding process by analysing the transform arc voltage and welding current gained from the on-line monitoring system has been applied. Design/methodology/approach: The transformed welding current and arc voltage data were taken from the experiment whereby the data number was 2500 data/s. The prediction of Contact Tip to Work Distance (CTWD) to gain best welding quality using the waveform variations were then taken from the experimental results. MD was employed to quantify the welding quality by analysing the transformed arc voltage and welding current. Finally, the optimal CTWD setting has verified the developed algorithms through additional experiments. Two kinds of experiments has been carried out by changing welding parameters artificially to verify the sensitivity and feasibility of WQ (Welding Quality) based on the concepts of MD and normal distribution. Findings: The results represented that WQ was fully capable of quantifying and qualifying the welding faults for automatic vertical-position welding process. Research limitations/implications: The arc welding process on the vertical-position compared to a horizontal-position welding is much more difficult because the metal transfer is influenced by the gravity force. To solve the problem, a new algorithm to monitor and control the welding fault during the arc welding process has been developed. Furthermore, optimization of welding parameters for the vertical-position welding process was really difficult to use the developed algorithms because they are only useful in selecting stored data and not for evaluating the effect of the variation of welding parameters on the weld ability. Practical implications: The developed algorithm could be achieved the highest welding quality at 15mm CTWD setting which the welding quality is 99.50% for the start section and 99.68% at the middle section. Originality/value: This paper proposed a new algorithm which employed the concepts of MD (Mahalanobis Distance) and normal distribution to describe a good quality welding.

3

A study on on-line mathematical model to control of bead width for arc welding process

Son J. S., Lee J. P., Park M. H., Kim D. H., Jin B. J., Ki K. S., Kim C. G., Kim I. S.

Archives of Materials Science and Engineering

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2015

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Vol. 72, nr 2

78--85

EN

Purpose: Recently, not only robotic welders have replaced human welders in many welding applications, but also reasonable seam tracking systems are commercially available. However, fully adequate control systems have not been developed due to a lack of reliable sensors and mathematical models that correlate welding parameters to the bead geometry for the automated welding process. Design /meth o d o lo g y/ap p ro ach : In this paper, two on-line empirical models using multiple regression analysis are proposed in order to be applicable for the prediction of bead width. For development of the proposed models, an attempt has been made to apply for a several methods. For the more accurate prediction, the prediction variables are first used to the surface temperatures measured using infrared thermometers with the welding parameters (welding current, arc voltage) because the surface temperature are strongly related to the formation of the bead geometry. The developed models are applied to monitor and control the bead width as welding quality. Findings: The developed two on-line empirical models are able to predict the optimal welding parameters required to achieve desired bead width and weld criteria, help the development of automatic control system and expert system and establish guidelines and criteria for the most effective joint design. Research lim ita tio n s /im p lic a tio n s : This research was concentrated to develop on the on-line empirical models that can predict bead width in robotic GMA welding process. The developed empirical models can only be employed to control the bead width for butt welding. O rig in ality /va lu e : It has been realized that with the use of the developed algorithms, the prediction of bead width becomes much simpler to even a novice user who has no prior knowledge of the robotic GMA welding process and optimization techniques.

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Development of the intelligent algorithm to control on-line bead height for robotic welding process

Son J. S., Kim I. S., Lee J. H., Park M.H., Jeon G.S.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 58, nr 2

87--93

EN

Purpose: The demand to increase productivity and quality, the shortage of skilled labour and strict health and safety requirements finally led to the development of the robotic welding process to deal with many problems of the welded fabrication. Many techniques were developed to control process parameters to get the optimal bead geometry during welding process by minimizes their magnitude in the affected area. Design/methodology/approach: The development of thermo mechanical mechanism in some techniques is not fully understood. To solve this problem, we have carried out the sequential experiment based on a Taguchi method and identified the various problems that result from the robotic GMA welding process. Findings: To characterize the GMA welding process and establish guidelines for the most effective joint design. Also using multiple regression analysis with the help of a standard statistical package program, SPSS, on an IBM-compatible PC, a quadratic model has been developed for on-line control which studies the influence of process parameters on bead height and compares their influences on the bead height to see which one of process parameters is most affecting. Originality/value: This model developed has been employed the prediction of optimal process parameters and assisted in the generation of process control algorithms.

5

Awaria pewnego przekrycia strukturalnego w świetle wymagań dotyczących jakości spawania

Szefiner Z., Janik T.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2012

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R. 56, nr 1

41-45

PL

Przedstawiono analizę spawalniczych przyczyn awarii dachu pawilonu meblowego w Szczecinie. Dach w formie stalowego przekrycia strukturalnego wykonany był w wytwórni i zmontowany na placu budowy przez dużą firmę budowlaną w latach 60. ubiegłego stulecia. Stan techniczny konstrukcji skonfrontowano z wymogami jakości dotyczącymi spawania według zawartymi w aktualnych normach PN-EN 1090-2, PN-EN ISO 3834 i PN-EN ISO 14731.

EN

Welding reasons of the failure of the roof on a furniture pavilion in Stettin have been analyzed. The roof in the form of the steel structural cover was made in a factory and then assembled on building site by a large building company in the sixties of the last century. The technical state of the structure was compared with quality requirements relating to welding area specified in the valid standards: PN-EN 1090-2, PN-EN ISO 3834 and PN-EN ISO 14731.

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Problemy oceny jakości złączy spawanych różnymi metodami oraz wykonanych z różnych materiałów konstrukcyjnych : (dokończenie)

Czuchryj J., Sikora S., Staniszewski K.

Dozór Techniczny

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2011

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z. 3

67--72

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Problemy oceny jakości złączy spawanych różnymi metodami oraz wykonanych z różnych materiałów konstrukcyjnych

Czuchryj J., Sikora S., Staniszewski K.

Dozór Techniczny

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2011

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z. 2

41--48

8

Problemy oceny jakości złączy spawanych różnymi metodami oraz wykonanych z różnych materiałów konstrukcyjnych : (dokończenie)

Czuchryj J., Sikora S., Staniszewski K.

Dozór Techniczny

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2011

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z. 4

89--91

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Analiza porównawcza oceny złączy spawanych na podstawie norm

Katolik G.

Dozór Techniczny

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2011

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z. 5

107--113

10

Control of welding process for BV-AH 32 steel

Kim H. H., Kim I. S., Kim I. J., Kang B. Y.

Archives of Materials Science and Engineering

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2008

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Vol. 33, nr 1

45-48

EN

Purpose: The GMA welding process involves large number of interdependent variables, which may affect product quality, productivity and cost effectiveness. With the combination of sensors and mathematical models, increased effectiveness in control of the automatic welding process was achieved. In this study, it focuses on development of mathematical models for the selection of process parameters using BV-AH32 steel for shipbuilding industry. Design/methodology/approach: The base material used for this study was the BV-AH32 steel with 12 mm in thickness for multi-pass butt welding. A curvilinear regression analysis was performed with the predictors that were found to be statistically significant against bead geometry based on the results from the above factorial design. The adequacy of the models and the significance of coefficients were tested by applying the analysis of variance technique and T-test respectively. Findings: From the above resultant equation for estimation of bead geometry, the sensitivity equations are obtained by differentiation with respect to process parameters of interest such as arc current, welding voltage and welding speed that are explored. Practical implications: Sensitivity analysis has been investigated to represent the effectiveness of the processing parameters on these empirical equations and showed that the change of process parameters affects the bead width and bead height more strongly than penetration relatively. Originality/value: These models are extended to shielding gas composition, weld joint position, polarity and many other parameters which are not included in this research in order to establish a closed loop feedback control system to minimize possible errors from uncontrolled variations.

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ISO 3834:2005 : nowe narzędzie zapewnienia jakości w spawaniu wyrobów metalowych

Wojtal K.

Spajanie Metali i Tworzyw w Praktyce

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2006

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nr 2(13)

42-45

PL

Specyficzną cechą procesów spawalniczych jest ich wynik, który zwykle nie może być sprawdzony w sposób łatwy lub ekonomiczny. Dlatego też, zgodnie z terminologią stosowaną w normach z zakresu zarządzania jakością, zalicza się je do grupy procesów specjalnych, wymagających specyficznego traktowania. W produkcji wielu wyrobów, procesy spawania metali są stosowane w szerokim zakresie, a w niejednej firmie zajmują dominującą pozycję.