• 제목/요약/키워드: Welding Length

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A Study on Dynamic Characteristics of Welding voltage and Welding Current At GMAW (GMA 용접에서 전압과 전류의 동특성에 관한 연구)

  • Kim, Myun-Hee;Choi, Young-Geun;Lee, Moon-Hwan
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.2
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    • pp.207-213
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    • 2001
  • Welding variables and condition in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the chararcteristic equations of the power supply. wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

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Pulse TIG welding: Process, Automation and Control

  • Baghel, P.K.;Nagesh, D.S.
    • Journal of Welding and Joining
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    • v.35 no.1
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    • pp.43-48
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    • 2017
  • Pulse TIG (Tungsten Inert Gas) welding is often considered the most difficult of all the welding processes commonly used in industry. Because the welder must maintain a short arc length, great care and skill are required to prevent contact between the electrode and the workpiece. Pulse TIG welding is most commonly used to weld thin sections of stainless steel, non-ferrous metals such as aluminum, magnesium and copper alloys. It is significantly slower than most other welding techniques and comparatively more complex and difficult to master as it requires greater welder dexterity than MIG or stick welding. The problems associated with manual TIG welding includes undercutting, tungsten inclusions, porosity, Heat affected zone cracks and also the adverse effect on health of welding gun operator due to amount of tungsten fumes produced during the welding process. This brings the necessity of automation. Hence, In this paper an attempt has been made to build a customerized setup of Pulse TIG welding based on through review of Pulse TIG welding parameters. The cost associated for making automated TIG is found to be low as compared to SPM (Special Purpose machines) available in the market.

The Waveform Control and Blowhole Generation in the Wave Pulse MIG Welding for Galvanized Steel Sheets (아연도금강판에 대한 중첩펄스 MIG 용접에서의 파형제어와 기공 발생 특성)

  • Cho Sang-Myung;Kim Ki-Jung;Lee Byung-Woo
    • Journal of Welding and Joining
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    • v.23 no.1
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    • pp.69-76
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    • 2005
  • Recently, application of arc welding to galvanized carbon steel sheet is on the increasing Ould in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.

A Study on the Joint Properties according to the Friction Welding Area Change of Carbon Steel(SM25C) (탄소강(SM25C)의 접합면적의 변화에 따른 마찰용접의 접합특성에 관한 연구)

  • Park Keun Hyung;Min Taeg Ki;Yoon Young Joo;Park Chang Soo
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.1
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    • pp.102-107
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    • 2006
  • This study investigates the properties as the difference friction welding area on SM25C steel rod. The tensile and bending strength and of welded joints, the hardness distribution of welds, the microstructure of welds and the tensile fracture surfaces were mainly investigated through this experiment. The fixed friction welding conditions were revolution 2000rpm, friction pressure 70Mpa, friction time 1.5sec, upset pressure 100Mpa, upset time 2.0sec, upset length 2.8mm and changeable friction welding parameter was friction welding area.

Dynamic behavior of GMA considering metal transfer (금속이행을 고려한 GMA 용접 시스템의 동특성 해석)

  • 박세홍;김면희;강세령;최상균;이상룡
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.565-568
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    • 2002
  • Welding variables and conditions in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the characteristic equations of the power supply, wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated, seam tracking procedure using arc sensor was simulated with variable V-Groove geometries and weaving frequencies. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

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A study on welding structure and thermal behavior in friction welding of austenitic stainless steel (오스테나이트계 스테인레스강의 마찰압접시 압접조직과 열적거동에 관한 연구)

  • 강춘식;정태용
    • Journal of Welding and Joining
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    • v.8 no.1
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    • pp.43-53
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    • 1990
  • The transient temperature distribution in the continuous friction welding 304 stainless steel bars is investigated by experimental and analytical methods. It is calculated by F.D.M. (finite difference method). The heating pressure, the rotational speed and friction coefficient obtained from experiment are used to determine the heat input at the contacting surface. Thermal properties of the workpiece are the function of temperature. The calculated temperature is well coincided with the measured value. The grain size at weld interface is extremely small due to the severe plastic deformation at high temperature, and result of this refined zone reveals higher hardness value. Because the HAZ is very narror about 2-3 mm, welding defects do not occure.

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A Study on Seam Tracking and Weld Defects Detecting for Automated Pipe Welding by Using Double Vision Sensors (파이프 용접에서 다중 시각센서를 이용한 용접선 추적 및 용접결함 측정에 관한 연구)

  • 송형진;이승기;강윤희;나석주
    • Journal of Welding and Joining
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    • v.21 no.1
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    • pp.60-65
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    • 2003
  • At present. welding of most pipes with large diameter is carried out by the manual process. Automation of the welding process is necessary f3r the sake of consistent weld quality and improvement in productivity. In this study, two vision sensors, based on the optical triangulation, were used to obtain the information for seam tracking and detecting the weld defects. Through utilization of the vision sensors, noises were removed, images and 3D information obtained and positions of the feature points detected. The aforementioned process provided the seam and leg position data, calculated the magnitude of the gap, fillet area and leg length and judged the weld defects by ISO 5817. Noises in the images were removed by using the gradient values of the laser stripe's coordinates and various feature points were detected by using an algorithm based on the iterative polygon approximation method. Since the process time is very important, all the aforementioned processes should be conducted during welding.

A Study on Mechanical Properties of Fillet Weldment in Pipeline Repair Welding Using Sleeve (슬리브덮개를 이용한 배관 보수용접시 필릿용접부의 기계적특성에 관한 연구)

  • 김영표;김형식;김우식;홍성호
    • Journal of Welding and Joining
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    • v.14 no.5
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    • pp.49-58
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    • 1996
  • In Korea Gas Corporation, as one of the pipeline repairing methods, damaged pipelines are sometimes treated with a temporally employment of split sleeve. On conducting the repair process, circumferential fillet and longitudinal groove welding usually must be included. For the case of groove welding, a considerable amount of R&D have been carried out related to property changes, while few study on the property change in fillet welding has been conducted. In this paper, so as to confirm the specification of fillet welding in terms of safety and reliability, properties changed by fillet welding were investigated for two welding processes. Qualifying tests such as reviewing macrostructure and nick-break tests were performed according to API 1104 and ASME section IX. In addition, tensile properties and hardness were evaluated according to KS B0841 and BS 4515. The fillet weld prepared by the qualified procedure showed melting depth of 0.8∼1.3mm and heat affected zone of 2.8∼3.4mm length. No crack and lack of penetration were observed. And the results of hardness and nick-break tests satisfied code requirements. The area crossed by fillet and groove welding line was found to have minimal tensile strength.

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A Study on the Welding Amount Estimation System combined with 3D CAD Tool (3차원 CAD 통합형 용접물량 산출 시스템에 관한 연구)

  • Ruy, Won-Sun;Kim, Ho-Kyeong;Ko, Dae-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.7
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    • pp.3184-3190
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    • 2013
  • These days, the great part of design processes in the field of ship or offshore manufacturing are planed and implemented using the customized CAD system for each ship-building companies. It means that all information for design and production could be extracted and reused at the useful other area cost considerable time and efforts. The representative example is the estimation of welding length and material amount which is demanded during the construction of ship or offshore structures. The proper estimation of welding material to be used and the usage of them at the stage of schedule planning is mostly important to achieve the seamless process of production and expect the costing in advance. This study is related to the calculation of welding length and needed material amount at the stage of design complete utilizing the CAD system. The calculated amount are classified according to welding position, stage, block, bevel and welding type. Moreover it is possible to predict the working time for welding operation and could be used efficiently for the cost management using the results of this research.

A Study on Development of End Bracket for External Prestress Method (외부프리스트레스트 보강 공법에 사용되는 단부 브라켓의 개발 연구)

  • 한만엽;이재형
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.721-726
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    • 1999
  • Diverse strengthening methods for reinforced concrete are applied to real structures with a variety of materials. On the other hand, only external prestressing is used for strengthening damaged prestressed concrete girders. But the end brackets for external prestressing are hard to design and to manufacture, the magnitude of prestressing is limited when applied to real structures. The current end brackets are not clearly understood in load transmitting mechanisms and they may damage the original girder by drilling during construction. And also the designed welding area of the current bracket is insufficient to support the high load. The problems of current end bracket are solved in this study. And a new and improved end bracket is proposed and tested. The tested end bracket is similar to the end bearing bracket, but many supportting plates are addded to increase its welding length of the weakest point of the bracket. The increased welding length finally increases its load carrying capacity significantly.

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