• 제목/요약/키워드: Humping Bead

검색결과 22건 처리시간 0.033초

하이브리드 용접방식을 이용한 박판 및 후판용접공정 (Hybrid Welding Process for Sheet Metal and Narrow Gap Fill Pass)

  • 최해운;신현명;임문혁
    • 대한기계학회논문집A
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    • 제32권11호
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    • pp.978-983
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    • 2008
  • An application of innovative laser+GMA hybrid welding process is presented for reducing bead humping defects in high speed welding and increasing side wall fusion in narrow groove welding without torch or wire oscillation. In this hybrid process, the laser heat input is applied adjacent to the weld pool at a relatively low power density to produce a wider, flatter weld bead. In bead on plate in sheet metal gauges, the hybrid process was able to produce hump-free welds from 70ipm (${\sim}1780mm/min$) to over 150ipm (${\sim}3810mm/min$) of the travel speed compared to the un-assisted GMAW process. A square-butt joint in 15mm A572 Gr50 steel welds was investigated. A square butt joint with a gap of 3.2mm was filled with 6 passes. Liquid Nitrogen calorimetry and innovative $CO_2$ laser reflective optics were also developed to demonstrate the concept of hybrid welding.

티타늄 판재의 파이버 레이저 용접시 공정변수에 따른 용접특성 (II) - 입열량 제어에 따른 영향 - (Weldability with Process Parameters During Fiber Laser Welding of a Titanium Plate (II) - The Effect of Control of Heat Input on Weldability -)

  • 김종도;김지성
    • 대한기계학회논문집A
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    • 제40권12호
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    • pp.1055-1060
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    • 2016
  • 레이저 용접은 고밀도 용접법 중에 하나로 기존 용접방법에 비해 적은 입열로 깊은 용입과 빠른 용접속도를 얻을 수 있다. 연속 출력 파형 레이저 용접 시 입열량은 레이저 출력 및 용접속도에 의해 결정된다. 본 연구에서는 파이버 레이저를 사용하여 두께 0.5 mm의 순 티타늄 박판에 비드 및 겹치기 용접을 실시하였으며 레이저 출력 및 용접속도에 따른 용접성을 평가하였다. 레이저 출력 및 용접속도에 따른 용입깊이, 비드폭, 접합길이, 비드형상을 관찰하고 인장전단시험을 통해 기계적인 특성을 파악하였다. 실험결과, 겹치기 용접은 $P_L=0.5kW$, ${\nu}=2.5m/min$$P_L=1.5kW$, ${\nu}=6m/min$ 조건에서 양호한 접합길이를 가진 용접부를 얻을 수 있었으며, 용접부는 고출력보다 저출력 조건일 때 더 우수한 연성을 나타냈다.

Narrow Gap 맞대기 TIG 용접에서 생산성 향상을 위한 연구 (A Study on Productivity Improvement in Narrow Gap TIG Welding)

  • 전재호;김성률;조상명
    • Journal of Welding and Joining
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    • 제34권1호
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    • pp.68-74
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    • 2016
  • Adoption of narrow gap welding shall be increased for the butt joint of thick plate, because the deformation and welding cost is reduced by decrease of cross-sectional area. However, sometimes narrow gap causes defects such as lack of fusion since it has small groove angle and narrow groove width. Therefore, GMAW, GTAW and SAW process shall be adopted to narrow gap welding with small bead hight and low deposition rate. In this study, Super-TIG welding using C-type strip was applied to semi-narrow gap butt joint in order to increase the welding productivity. High deposition rate 10kg/hr was obtained by high current 600A without undercut, humping bead and other welding defects. Measuring the mean and standard deviation of the melting depth to evaluate the developed processes, the fusion line type was determined by measuring the difference between maximum and minium melting depth. Furthermore, a model on arch fusion line and linear fusion line was suggested in order to prevent LF on groove wall in narrow gap butt welding.

AlSi12 분말의 직접 레이저 용융 적층 시 공정 조건에 따른 적층 특성에 관한 연구 (Study on Effects of Direct Laser Melting Process Parameters on Deposition Characteristics of AlSi12 powders)

  • 서자예;윤희석;이기용;심도식
    • 소성∙가공
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    • 제27권5호
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    • pp.314-322
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    • 2018
  • AlSi12 is a heat-resistant aluminum alloy that is lightweight, corrosion-resistant, machinable and attracting attention as a functional material in aerospace and automotive industries. For that reason, AlSi12 powder has been used for high performance parts through 3D printing technology. The purpose of this study is to observe deposition characteristics of AlSi12 powder in a direct energy deposition (DED) process (one of the metal 3D printing technologies). In this study, deposition characteristics were investigated according to various process parameters such as laser power, powder feed rate, scan speed, and slicing layer thickness. In the single track deposition experiment, an irregular bead shape and balling or humping of molten metal were formed below a laser power of 1,000 W, and the good-shaped bead was obtained at 1.0 g/min powder feed rate. Similar results were observed in multi-layer deposition. Observation of deposited height after multi-layer deposition revealed that over-deposition occurred at all conditions. To prevent over-deposition, slicing layer thickness was experimentally determined at given conditions. From these results, this study presented practical conditions for good surface quality and accurate geometry of deposits.

API강재의 파이버레이저 용접시 유기되는 플라즈마의 방사특성 (II) -용접조건과 방사신호의 관련성- (Characteristics of Plasma Emission Signals in Fiber Laser Welding of API Steel (II) -The Relationship between Welding Conditions and Emission Signals-)

  • 이창제;김종도;김유찬
    • Journal of Welding and Joining
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    • 제30권4호
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    • pp.24-30
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    • 2012
  • Laser welding by fiber laser accompanied by a lot of spatter and humping bead. This is because the deep and narrow keyhole usually form due to high beam quality. So the weld bead is formed defects, because the plasma jet with a high vapor pressure make the molten pool on keyhole wall scattered. For such a reason, unstable behavior of keyhole is difficult to monitor laser welding by using the laser induced plasma. Mostly, fiber laser welding of thick plates most be influenced by this effect. Therefore, fiber laser welding has been difficult to apply the sole. Thus, laser welding monitoring based on plasma measurements have much difficulty in measurements and analysis of signal. In this study, influence of the plasma emission signal according to welding speed and laser power in fiber laser welding analysed by using RMS and FFT analysis. We can verify that RMS value of the plasma emission signal changes with welding parameters in fiber laser welding, and aspect ratio greater than 1, the peak of FFT frequency had been moved in accordance with welding parameter.

소결밀도에 따른 분말 소결금속과 탄소강의 이종금속 레이저 용접성 고찰 (The Study of Laser Weldability of two different Metal, Carbon Steel and Sintered Materials, Depends on the Sintered Density)

  • 김용;양현석;박기영;이경돈
    • 한국레이저가공학회지
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    • 제11권2호
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    • pp.8-14
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    • 2008
  • Sintered specimen which used for a blade of diamond tool was manufactured in order to verify $CO_2$ laser weldability depend on sintered temperature. Five kind of specimen were prepared and the range of temperature is from $600^{\circ}C$ to $1000^{\circ}C$ at intervals of $100^{\circ}C$. As a result of the sintered density test, the porosity rate appeared in the range of $2.1%{\sim}21.4%$. After welding, the most segments had exceeds the minimum fracture stress (600MPa, The Standard Safety of Europe) at the welding strength test except on the sintered at $600^{\circ}C$. In case of the sintered at $700^{\circ}C$, even satisfied the safety allowable stress but cannot get the good quality for bead appearance because of humping defect. In the conclusion, we could know that it showed not only relatively soundness bead but also enough welding strength when the sintered blade of diamond tool is included less than 4% of porosity rate.

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LPG 재응축기용 순티타늄 박판의 Nd:YAG 레이저 용접성(I) - 순티타늄의 물성과 용접변수 - (Weldability of Pure Titanium Thin plate for LPG Re-Condenser by Nd:YAG Laser - Physical Constant and Welding Parameter -)

  • 김종도;곽명섭;이창제;김창수
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2007년 추계학술발표대회 개요집
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    • pp.363-365
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    • 2007
  • Titanium and its alloys have excellent corrosion resistance, high strength to weight ratios and high temperature creep properties, which make them using many various fields of application. Responding to these needs, welding processes for titanium are also being used including TIG, MIG, resistance welding, plasma arc welding, diffusion welding, electron beam welding and laser welding. In this study, It is possible to get sound beads without humping bead and spatter with the decrease of peak power according to increase of pulse width and change of welding speed for heat input control at pulsed Nd:YAG laser welding of titanium plates for Lap welding.

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$6mm^t$조선용 프라이머 코팅강판의 $CO_2$레이저 용접성( I ) - 프라이머 코팅조건과 갭 간극의 영향 - (The Weldability of $6mm^t$ Primer-coated Steel for Shipbuilding by $CO_2$ Laser( I ) - Effects of Primer Coating Condition and Gap Clearance -)

  • 김종도;박현준
    • Journal of Welding and Joining
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    • 제23권3호
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    • pp.76-82
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    • 2005
  • Recently the application of laser welding technology has been considered to shipbuilding structure. However, when this technology is applied to primer coated steel, good quality weld beads are not easily obtained. Because the primer-coated layer caused the spatter, humping bead and porosity which are main part of the welding defect attributed to the powerful vaporizing pressure of zinc. So we performed experiment with objectives of understanding spatter and porosity formation mechanism and producing sound weld beads in 6mmt primer coated steels by a $CO_2$ CW laser. The effects of welding parameters; defocused distance, welding speed, coated thickness and coated position; were investigated in the bead shape and penetration depth on bead and lap welding. Alternative idea was suggested to suspend the welding defect by giving a reasonable gap clearance for primer coated thickness. The zinc of primer has a boiling point that is lower than melting point of steel. Zinc vapor builds up at the interface between the two sheets and this tends to deteriorate the quality of the weld by ejecting weld material from lap position or leaving porosity. Significant effects of primer coated position was lap side rather than surface. Therefore introducing a small gap clearance in the lap position, the zinc vapor could escape through it and sound weld beads can be acquired. In conclusion, formation and suspension mechanism of the welding defects was suggested by controling the factors.

Al 5052 합금의 저입열 Pulse MIG 최적 현장 용접조건 산정에 관한 실험적 연구 (Study on the Optimization Field Welding Conditions of Low Heat-Input Pluse MIG Welding Process for 5052 Aluminum Alloy Sheets)

  • 김재성;이영기;안주선;이보영
    • Journal of Welding and Joining
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    • 제29권1호
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    • pp.80-84
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    • 2011
  • The weight reduction of the transportations has become an important technical subject Al and Al alloys, especially Al 5052 alloys have been being applied as door materials for automobile. One of the most widely known car weight-reduction methods is to use light and corrosion-resistant aluminum alloys. However, because of high electrical and thermal conductivity and a low melting point, it is difficult to obtain good weld quality when working with the aluminum alloys. Also, Pulse MIG welding is the typical aluminum welding process, but it is difficult to apply to the thin plate, because of melt-through and humping-bead. In order to enhance weld quality, welding parameters should be considered in optimizing the welding process. In this experiment, Al 5052 sheets were used as specimens, and these materials were welded by adopting new Cold Metal Transfer (CMT) pulse process. The proper welding conditions such as welding current, welding speed, torch angle $50^{\circ}$ and gap 0~1mm are determined by tensile test and bead shape. Through this study, range of welding current are confirmed from 100A to 120A. And, the range of welding speed is confirmed from 1.2m/min to 1.5m/min.

조선용 Primer코팅강판의 $CO_2$레이저 용접성 (The Weldability of Primer-coated Steel for Shipbuilding by $CO_2$ Laser)

  • 박현준;김종도;김영식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.316-321
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    • 2003
  • The spatter and porosity could be occurred during $CO_2$ CW laser welding of Primer-coated Steel for Shipbuilding. This study has suggested an alternative idea by examining of weld-defect formation mechanism. The primer-coated plate has caused the spatter, humping bead and porosity and these are main part of the welding defect, attributed to the powerful vaporizing pressure of primer attached on the base metal. The zinc of primer has a boiling point that is the lower temperature than melting point of steel. Zinc va}X)f will build up at the interface between the two sheets and this tends to deteriorate the quality of the weld by ejecting weld material from lap position or leaving porosity. Therefore introducing a small gap clearance in the lap position, the zinc vapor could escape through it and sound weld beads can be acquired. In conclusion, we suggested the occurred and prevented mechanism of weld defects with searching the factor.

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