STS304L 캡슐의 펄스형 GTA 용접에서 용접변수들이 용접부 형상에 미치는 영향

이형근,한현수,손광재,Lee, Hyoung-Keun,Han, Hyon-Soo,Son, Kwang-Jae 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.5

The aim of this paper is to investigate the effects of welding parameters on the weld shape in seal-welding of STS304L capsule for manufacturing a radioisotope source which is widely used in nondestructive testing of metal structures using gamma ray. Pulsed gas tungsten arc (Pulsed GTA) welding is performed for thin cross sectional area of the capsule. Seven welding parameters including current waveform parameters and arc length etc. are selected as main process parameters using design of experiment. The weld shape such as bead width, penetration depth, weld area, aspect ratio and area rate is investigated to assess the effects of welding parameters. As results, the combination of pulse duty/welding speed largely affects on bead width, penetration depth, area and aspect ratio. Finally, it is concluded that the key parameters are the combination of pulse duty/welding speed, base current and arc length, and their optimal conditions are 50%/1.77mm/s, 6.4A and 1 mm.

A Review on Optimizations of Welding Parameters in GMA Welding Process

Ill-Soo Kim,Min-Ho Park 대한용접·접합학회 2018 대한용접·접합학회지 Vol.36 No.1

With the increase of automatic welding system employed in the manufacturing industries, the selection of optimal welding parameters must be more specific to ensure that quality is obtained. Furthermore, it is necessary to have a suitable model that establishes the interrelationship between welding parameters and bead geometry to get the desired weld ability as quality since it is a complicated process, which involves interactions of thermal, mechanical, electrical and metallurgical phenomenon. Many researchers have reported theoretical, numerical, empirical and AI models to give the optimal welding conditions for GMA(Gas Metal Arc) welding process. In addition, controlling the welding parameters plays an important role in ensuring the quality of the weld. However, there is a need to comprehensively review the GMA welding process in terms of different independent and dependent welding parameters for the purpose of modeling and optimization of GMA process. In this paper, several experimental design and optimization methodologies are reviewed and discussed with current literature on experimental design, multiple regressions analysis, the neural network, fuzzy logic, and genetic algorithm to improve the quality of weldments. This review underlines the need of development of appropriate nature inspired algorithm for the optimization of such advanced manufacturing process.

Welding parameters prediction for arbitrary layer height in robotic wire and arc additive manufacturing

Zeqi Hu,Xunpeng Qin,Yifeng Li,Mao Ni 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

In wire and arc additive manufacturing, the weld bead geometry determined the slicing layer height, which was decided by the welding parameters. Generally, the determination of the welding parameters relied on empirical and experimental data through the trial-and-error methods that incur considerable time and cost. To obtain the proper welding process parameters according to the desired single bead geometry and layer height, a full factorial experimental design matrix was applied to collect the original data of welding parameters and bead geometrical variables. A forward artificial neural network (FANN) was built to predict the bead geometry form the welding parameters. Then, a closed-loop iteration method combined a genetic algorithm (GA) and the FANN model (FANN-GA) was developed to search for the most optimal welding process parameters in accordance with the selected bead geometrical variables. The results confirmed that the FANN-GA model has a good performance on the backward prediction of the welding process parameters compared with the direct backward artificial neural network (BANN). Several groups of single layer multi-bead and multi-layer multi-bead experiment were performed to testify the proposed method, and the relative error between the desired and actual layer height was small. The proposed method makes it possible to fabricate the component with an arbitrary desired layer height, and could be used in the adaptive slicing additive manufacturing or surface coating.

용접 각 변형량 해석해를 이용한 용접 공정변수 최적화에 관한 연구

이세환 대한용접접합학회 2003 대한용접·접합학회지 Vol.21 No.7

Welding distortion is a current issue in many industrial parts, especially for heavy industry such as shipbuilding, plant industry. The welding process has many processing parameters influencing welding angular distortion such as heat input power, welding speed, gas flow rate, plate thickness and the welded material properties, etc. In this work, the conventional local minimization concept was applied to find a set of optimum welding process parameters, consisted of welding speed, plate thickness and heat input, for a minimum angular distortion. An analytic solution for welding angular distortion, which is based on laminated plate theory, was also applied to investigate and optimize the welding process parameters. The optimized process parameters and the angular distortion for various parametric conditions could be easily found by using the local minimum concept.

Ir-192 방사선원의 밀봉 용접부 품질에 미치는 저항용접 공정변수의 영향

한인수,손광재,이영호,이유황,이준식,장경덕,박울재,박춘득,Han, In-Su,Son, Kwang-Jae,Lee, Young-Ho,Lee, You-Hwang,Lee, Jun-Sig,Jang, Kyung-Duk,Park, Ul-Jae,Park, Chun-Deuk 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.1

Ir-192 radiation sealed sources are widely employed to the therapeutic applications as well as the non-destructive testing. Production of Ir-192 sources requires a delicate but robust welding technique because it is employed in a high radioactive working environment. A GTA(Gas Tungsten Arc) welding technique is currently well established for this purpose. However, this welding method requires a frequent replacement of the electrode, which results in the delay of the production to take a preparatory action such as to isolate the radiation sources from the working place before getting access to the welding machine. Hence, a resistance welding technique is considered as an alternative method of the GTA welding technique. The advantages of resistance welding are high welding speed and high-rate production. Also it has very long life of electrode comparing to GTA welding. In this study, the resistance welding system and proper welding conditions were established for sealing Ir-192 source capsule. As a results of various experiments, it showed that electrode displacement can be employed as a indicator to predict welding quality. We proposed two mathematical models(linear and curvilinear) to estimate electrode displacement with process parameters such as applied force, welding current and welding time by using regression analysis method. Predicting results of both linear and curvilinear model were relatively good agreement with experiment.

아연도금강관의 가스메탈아크용접에서 용접인자가 기공형성에 미치는 영향

임영민,장복수,고진현,Lim, Young-Min,Jang, Bok-Su,Koh, Jin-Hyun 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.5

This study was carried out to investigate the effect of welding parameters such as shielding gas compositions welding voltage and welding current on the pore formation in the weld beads of galvanized steel pipes produced with gas metal arc welding. The porosity was evaluated and rated by metallography and radiographic test in terms of weight percentage, number and distribution of pores in weld beads. The porosity increased with increasing welding voltage and current, in which Ar gas produced the most porosity while $Ar+5%O_2$ generated the least porosity. It was found that the porosity could be reduced by selection of the proper gas mixture composition such as $Ar+5%O_2$ and $Ar+10%CO_2$ and by using current (130~150A) and voltage(16~20V).

Predicting the combined effect of TiO2 nano-particles and welding input parameters on the hardness of melted zone in submerged arc welding by fuzzy logic

Masood Aghakhani,Mohammad Reza Ghaderi,Maziar Mahdipour Jalilian,Ali Ashraf Derakhshan 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.7

Submerged arc welding (SAW) is a high-quality arc welding process used in heavy industries for welding thick plates. In this process,selecting appropriate values for the input parameters is required for high productivity and cost effectiveness. A very important weld quality characteristic affected by welding input parameters is the hardness of melted zone (HMZ). This paper reports the applicability of fuzzy logic (FL) to predict HMZ in the SAW process which is affected by the combined effect of TiO2 nano-particles and welding input parameters. The arc voltage, welding current, welding speed, contact tip-to-plate distance, and TiO2 nano-particles were used as input parameters and HMZ as the response to develop FL model. A five-level five-factor central composite rotatable design (CCRD) was used in the experiments to generate experimental data. Experiments were performed, and HMZs were measured. The predicted results from FL were compared with the experimental data. The correlation factor value obtained was 99.99% between the measured and predicted values of HMZ. The results showed that FL is an accurate and reliable technique for predicting HMZ because of its low error rate.

STS 304L의 Nd:YAG 레이저 용접에서 용접조건이 용접부 형상에 미치는 영향

이형근,석한길,한현수,박울재,홍순복 대한용접접합학회 2004 대한용접·접합학회지 Vol.22 No.1

The control of the weld bead shape is important in laser welding of the small parts. The effects of laser welding parameters on the weld bead shape in the pulsed Nd:YAG laser welding of STS 304L material were investigated. Shielding gas type, flow rate, pumping voltage, pulse frequency, pulse width, focal position and overlap distance were selected as laser welding parameters. Experiments were designed and conducted using the Taguchi method which was a statistical experimental method. The weld bead width, penetration, area and aspect ratio were measured and analysed as the weld bead shape properties and the welding parameters were optimized to maximize the weld aspect ratio. Weld aspect ratio were greatly affected by the pulse width, pumping voltage and pulse frequency, and somewhat by the overlap distance, and little by the shielding gas type, flow rate and focal position. A confirmation experiment were conducted using the optimized welding parameters.

Effect of Welding Parameters on Fracture Resistance Characteristics of Nuclear Piping

Shin, In-Hwan,Park, Sang-Kyu,Kim, Sang-Young,Seok, Chang-Sung,Koo, Jae-Mean Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.1

To guarantee the safety of nuclear power plants during operation and maintain coolant pipe integrity during life time, the evaluation of the coolant pipe integrity is necessary. The welded part is the most vulnerable place for the crack initiation and subsequent growth. Moreover, the weld width and the crack location also affected the deformation and fracture behavior of the welded part. Therefore, the evaluation of the welded part integrity in the coolant pipe while considering the residual stresses and welding defects is very important. In recent years, FE analysis about the welded parts in a pipe has been performed to evaluate the fracture toughness characteristics for the welded parts with various welding parameters. However, test method has not been proposed to evaluate the fracture toughness properties of the welded parts in a pipe. In this study, piping materials which are equivalent to those in safety injection pipes of nuclear power plants were welded to form a butt welding part. Then, fracture toughness tests for base metal, the similar and the dissimilar welded parts were performed to evaluate the effect of welding parameters.

FCA 필릿 파이프 용접에서 다중 비선형 회귀 모형과 구간적 3차 에르미트 보간법을 통한 비드 형상 예측

조대원,나석주,이목영,Cho, Dae-Won,Na, Suck-Joo,Lee, Mok-Young 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.5

Pipe welding is used in various ranges such as civil engineering and ship building engineering. Until now, many technicians work for pipe welding manually under harmful, dangerous and difficult conditions. So it is necessary to install automation process. For automation pipe welding, relation between welding parameters & bead shape should be considered. Using this relation, bead shape could be expected from welding parameters. FCAW was used in this study. Instead of pipe workpiece, fillet joint plate is used, which were inclined 0,45,90,135,180 degree. By analyzing between welding parameters (current, welding speed, voltage) and bead shape parameters with non-linear multiple regression, bead shape parameters could be expected. Piecewise Cubic Hermite Interpolation was used to expect smooth curved bead shape with bead shape parameters. From these processes, bead shape could be expected from welding parameters.