• Title/Summary/Keyword: fillet welds

Search Result 53, Processing Time 0.041 seconds

The Effects of Welding Parameters on Quality in Lap Joint Fillet Welds of Thin Plate by Plasma Welding (Plasma 용접에 의한 박판 겹치기 이음 필릿 용접부의 품질에 미치는 용접 변수의 영향)

  • Park, Kun-Gi;Yang, Jong-Soo;Cho, Sang-Myung;Yoon, Hun-Sung
    • Special Issue of the Society of Naval Architects of Korea
    • /
    • 2006.09a
    • /
    • pp.122-127
    • /
    • 2006
  • In case of lap joint fillet welds of thin plate, the example which is applicable to Plasma Welding increases substituting for the exiting TIG Welding but the quality of Plasma arc welding has a special feature influenced sensitively by the condition of welding caused by controlling the various parts of welding torch. This research is purposed to improve lap joint fillet welds of thin plate in high quality and attain the high productivity and it is examined that how the change of electrode tip angle and Setback has an effect on the quality of welding and it is investigated how the change of Setback and Standoff has an effect on Melting efficiency using Response Surface Analysis.

  • PDF

Proposal of Estimation Equation for Nominal Strength of Longitudinal Fillet Welds with Different Types of Steel (강종에 따른 종방향 필릿용접부 공칭강도 계산식의 제안)

  • Jo, Jae-Byung;Lee, Hye-Youn
    • Journal of Korean Society of Steel Construction
    • /
    • v.24 no.5
    • /
    • pp.503-510
    • /
    • 2012
  • High performance, high strength steels were developed and used in steel structures recently. Since the newly developed high strength steels posses different toughness, weldability, yield strength ratio, etc. in compare with conventional structural steels, it is requred to investigate the applicability of the design strength of fillet weld specified in the existing design codes. The comparison of the design strengths of various codes from domestic and overseas shows quite a difference. Test results for fillet weld strengths were collected and statistically analysed. Each of yield strength, tensile strength of parent material and tensile strength of weld metal was selected as a main parameter for each estimation equation respectively. All the estimation equations yield almost same values for each type of steel regardless the type of main parameter selected. Considering the behaviour of fillet welded joints and for practical purposes, it is proposed that the equation with tensile strength of parent material is to be used in design codes. The comparison with the proposed nominal strengths of fillet welds shows that the existing design codes could lead to an uneconomical result for low strength steels and lie on an unsafe side for high strength steels.

CO₂ Weldability of Zn Coated Steel Sheet(3);Effect of Process Condition on the Generation of Weld Defects (아연도금강판의 CO₂ 용접특성(3);용접결함의 발생에 미치는 시공조건의 영향)

  • Lee, Jong Bong;An, Yeong Ho;Park, Hwa Sun
    • Journal of Welding and Joining
    • /
    • v.18 no.2
    • /
    • pp.196-196
    • /
    • 2000
  • Formation of the weld defect, such as a blowhole and a pit in lap-jointed fillet arc welds has been a serious problem in arc welding of Zn-coated steel sheet. In this study, the relationship among welding conditions, welding materials and defect formation was investigated in order to minimize these defects in the CO₂ welds. In addition, the arc stability of the commercial welding wires was evaluated for revealing their effects on defect formation. Main conclusions obtained are as follows:1) There was no difference between shear tensile strength of the sound welds and that of the welds with blowholes whose diameters are less than 0.5mm. However, the welds with blowholes whose diameters are equal or larger than 0.5mm and pits exhibited tensile strength 10~20% and 30~40% lower than that of the sound welds respectively.2) The optimum welding condition to effectively prevent or reduce the weld defects formation are as follows:- The welding variables of 220A-23V-100cm/min and 120A-190V-30cm/min were recommended for minimizing the weld defects.- The gap between the two sheets at the lap-joint should be controlled to more than 0.2mm- Solid wire was less susceptible to the formation of the weld defects than the flux-cored wire.- The low welding current condition produced less weld defects than the hihg welding current condition.3) One of the reason why the amount of the defect was reduced at the low welding current was the gas discharging by the active agitation of the molten pool, due to an increasing in the number of the short circuit. (Received September 27, 1999)

$CO_2$ Weldability of Zn Coated Steel Sheet(3) - Effects of Process Condition on the Generation of Weld Defects - (아연도금강판의 $CO_2$ 용접특성(3) - 용접결함의 발생에 미치는 시공조건의 영향 -)

  • 이종봉;안영호;박화순
    • Journal of Welding and Joining
    • /
    • v.18 no.2
    • /
    • pp.69-76
    • /
    • 2000
  • Formation of the weld defect, such as a blowhole and a pit in lap-jointed fillet arc welds has been a serious problem in arc welding Zn-coated steel sheet. In this study, the relationship among welding conditions, welding materials and defect formation was investigated in order to minimize these defects in the CO₂welds. In addition, the arc stability of the commercial welding wires was evaluated for revealing their effects on defect formation. Main conclusions obtained are as follows: 1) There was no difference between shear tensile strength of the sound welds and that of the welds with blowholes whose diameters are less than 0.5mm. However, the welds with blowholes whose diameters are equal or large than 0.5mm and pits exhibited tensile strength 10∼ 20% and 30∼40% lower than that of the sound welds respectively. 2) The optimum welding condition to effectively prevent or reduce the weld defects formation are as follows: -The welding variables of 220A-23V-100cm/min and 120A-19V-30cm/min were recommended for minimizing the weld defects. -The gap between the two sheets at the lap-joint should be controlled to more than 0.2mm. -Solid wire was less susceptible to the formation of the weld defects than the flux-cored wire. -The low welding current condition produced less weld defects than the high welding current condition. 3) One of the reason why the amount of the defect was reduced at the low welding current was the gas discharging by the active agitation of the molten pool, due to an increasing in the number of the short circuit.

  • PDF

A Study on Design of Fillet Weld Size for Stiffener in the Hull Bottom of Crude Oil Tanker (Crude Oil Tanker 선저부 보강재 필렛 용접부 각장 설계에 관한 연구)

  • Kang, Bong-Gook;Shin, Sang-Beom;Park, Dong-Hwan
    • Journal of Welding and Joining
    • /
    • v.32 no.1
    • /
    • pp.79-86
    • /
    • 2014
  • The purpose of this study is to determine the proper fillet weld size for the stiffeners on hull bottom plate of crude oil tanker. To achieve it, the effective notch stress and hot spot stress of the fillet weld with leg length specified in the rule were evaluated by using comprehensive FE analyses. Based on the results, the fatigue damages at each location of weld were calculated. Meanwhile the transitional behavior of initial welding distortion in the hull bottom plate under the design conditions was investigated by using a non-linear FEA. Welding distortion and residual stress introduced during fabrication process were considered as initial imperfections. According to FE analysis results, if the fillet leg length satisfies the design criteria of the classification society, the concern on the root failure at the fillet welds in the bottom hull plate during the design life can be negligible. In addition, considering the transitional behavior of the distortion during the service life, the fillet leg length should be minimized.

Characteristics of Residual Stress in welds Composed of Similar or Dissimilar Steels (동종강재 및 이종강재 용접접합부의 잔류응력 특징)

  • Chang, kyong Ho;Lee, Chin Hyung;Lee, Sang Hyong;Lee, Eun Taik
    • Journal of Korean Society of Steel Construction
    • /
    • v.15 no.3
    • /
    • pp.241-250
    • /
    • 2003
  • This study, investigated the characteristics of residual stress in weldis composed of similar or dissimilar steels, are investigated byusing 3three-dimensional thermal elasto-plastic FEM analysis. The results showed that for the groove welding of the similar steels, increasedthetensile strength of the steels (POSTEN60

A Study on the Behavior of Welded Connections (용접 연결부의 거동에 관한 연구)

  • 안주옥;윤영만
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1994.10a
    • /
    • pp.145-151
    • /
    • 1994
  • Welded connections have been designed on basis of allowable stresses, wherein the response to loading is assumed to be totally elastic. This is the vector analysis method, which resolves the stresses determined from the direct stress formula and the torsion formula into a vector combination to obtain a solution. It has been known that this method gives conservative answers and typically a very high factor of safety. An analytical method based on the Instantaneous Center of Rotation has been developed which predicts the ultimate strength of an eccentically loaded fillet welded connection. The method of Instantaneous Center of Rotation results in weld resistance capacities greater than the vector analysis method, by recognizing the variation in fillet weld strength with respect to the direction of the applied loading and actual load-deformation response of elemental fillet welds. The procedure of numerical analysis is iterative and complex. The relations between vector analysis method and the method of Instantaneous Center of Rotation on eccentrical distance subjected to variation of load direction are presented in this paper. Considering of the effects on configuration of weld groups, the method of Instantaneous Center of Rotation are provided a more exact results of the numerical analysis.

  • PDF