• 제목/요약/키워드: Ultrasonic metal welding

검색결과 55건 처리시간 0.026초

원자로 입출구 노즐 Alloy 82/182 이종금속 용접부 Weld Inlay 적용 후 초음파나노표면개질이 잔류응력 완화에 미치는 영향 (The effect of ultrasonic nano crystal surface modification for mitigation of the residual stress after weld inlay on the alloy 82/182 dissimilar metal welds of reactor vessel in/outlet nozzles)

  • 조홍석;박익근;정광운
    • Journal of Welding and Joining
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    • 제33권2호
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    • pp.40-46
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    • 2015
  • This study was performed to investigate the effect of ultrasonic nano crystal surface modification (UNSM) on residual stress mitigation after Weld Inlay repair for butt dissimilar metal weld with Alloy 82/182 in reactor vessel In/Outlet nozzle. As-welded and Weld Inlay specimens were made in accordance with design standard of ASME Code Case N-766, and two planes of their weld specimens were peened by the optimum UNSM process condition. Peening characteristics for weld specimens after UNSM treatment were evaluated by surface roughness and Vickers hardness test. And, residual stress for weld specimens developed from before and after UNSM treatment was measured and evaluated by instrumented indentation technique. Consequently, it was revealed that the mitigation of residual stress in weld metal after Weld Inlay repair of reactor vessel In/Outlet nozzle could be possible through UNSM treatment.

플라스틱과 금속재료를 이용한 3 차원 박벽 제품의 쾌속 제작 (Rapid Manufacturing of 3D Thin-walled Products using Plastics and Metals)

  • 신보성;강보식;박재현;노치현
    • 한국정밀공학회지
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    • 제23권8호
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    • pp.195-202
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    • 2006
  • High-speed machining (HSM) with excellent quality and dimensional accuracy has been widely used to create 3D structures of metal and plastics. However, the high-speed machining process is not suitable for the rapid realization of 3D thin-walled product because it consumes considerably long time in fixturing process of a work piece. In this paper, an effective rapid manufacturing process is proposed to fabricate 3D thin-walled products directly using HSM, phase change filling and ultrasonic welding. The filling process is useful to hold the thin-walled product during the machining step. The ultrasonic welding process is introduced to make one piece product from two piece parts that are machined by HSM and filling process. The proposed rapid manufacturing (RM) process has been shown that the RM process enables to fabricate the 3D thin-walled products using ABS plastics and aluminum metals from 3D CAD data to functional parts.

Analysis on the cascade high power piezoelectric ultrasonic transducers

  • Lin, Shuyu;Xu, Jie
    • Smart Structures and Systems
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    • 제21권2호
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    • pp.151-161
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    • 2018
  • A new type of cascade sandwiched piezoelectric ultrasonic transducer is presented and studied. The cascade transducer is composed of two traditional longitudinally sandwiched piezoelectric transducers, which are connected together in series mechanically and in parallel electrically. Based on the analytical method, the electromechanical equivalent circuit of the cascade transducer is derived and the resonance/anti-resonance frequency equations are obtained. The impedance characteristics and the vibrational modes of the transducer are analyzed. By means of numerical method, the dependency of the resonance/anti-resonance frequency and the effective electromechanical coupling coefficient on the geometrical dimensions of the cascade transducer are studied and some interesting conclusions are obtained. Two prototypes of the cascade transducers are designed and made; the resonance/anti-resonance frequency is measured. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the experimental results. It is expected that this kind of cascade transducer can be used in large power and high intensity ultrasonic applications, such as ultrasonic liquid processing, ultrasonic metal machining and ultrasonic welding and soldering.

불규칙 표면 시편을 이용한 Flexible 위상배열초음파기술 적용 연구 (Feasibility Study of Flexible Phased Array Ultrasonic Technology Using Irregular Surface Specimen)

  • 이승표;문용식;정남두
    • 비파괴검사학회지
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    • 제35권1호
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    • pp.52-60
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    • 2015
  • 원자력발전소에는 탄소강과 스테인리스강 용접을 위해 alloy600 용접재를 적용한 이종금속용접부가 다수 존재하며, 전 세계적으로 이종금속용접부에서 결함 발생 보고가 지속되고 있다. 주기적인 건전성 평가를 위해 이종금속용접부 초음파검사 일반절차서 (KPD-UT-10)를 적용하여 검사를 수행하고 있으며, 검사절차서에서는 탐촉자와 검사체 표면 사이의 간격을 최대 1/32"(0.8mm) 이내로 제한하고 있다. 국내의 일부 이종금속용접부는 테이퍼진 형상과 불규칙한 표면 형상을 가지고 있어, 가변형 위상배열초음파기술을 적용하여 검사 신뢰성을 높이고자 본 연구를 수행하였다. 연구 결과, 검사체 표면이 불규칙한 시편 내부의 인공결함에 대한 검출이 양호하였고, 이를 통해, 가변형 위상배열초음파기술의 현장 적용 가능성을 확인하였다.

피로강도 향상을 위한 표면마찰교반법의 가공조건 및 비드형상 (Bead Shape and Conditions of Friction Stir Processing to Improve Fatigue Strength)

  • 박정웅;안규백;김흥주;조병철
    • Journal of Welding and Joining
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    • 제31권4호
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    • pp.73-79
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    • 2013
  • Burr grinding, Tungsten Inert Gas (TIG) dressing, ultrasonic impact treatment, and peening are used to improve fatigue life in steel structures. These methods improve the fatigue life of weld joints by hardening the weld toe, by improving the bead shape, and by creating the compressive residual stress. In this study, a new post-weld treatment method improving the weld bead shape and metal structure at the welding zone using Friction Stir Processing (FSP), a welding process, is proposed to enhance fatigue life. For that, a pin-shaped tool and processing condition employing Friction Stir Processing (FSP) is established through experiments. Experimental results revealed that fatigue life is improved by around 50% compared to as-welded fatigue specimens by reducing the stress concentration at the weld toe and by generating a metal structure finer than that of flux-cored arc welding (FCAW).

금속(Au)범프의 횡초음파 접합 조건 연구 (Study of Metal(Au) Bump for Transverse Ultrasonic Bonding)

  • 지명구;송춘삼;김주현;김종형
    • Journal of Welding and Joining
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    • 제29권1호
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    • pp.52-58
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    • 2011
  • In this paper, the direct bonding process between FPCB and HPCB was studied. By using an ultrasonic horn which is mounted on the ultrasonic bonding machine, it is alternatively possible to bond the gold pads attached on the FPCB and HPCB at room temperature without an adhesive like ACA or NCA. The process condition for obtaining more bonding strength than 0.6 Kgf, which is commercially required, was carried out as 40 kHz of frequency, 0.6 MPa of bonding pressure and 2 second of bonding time. The peel off test was performed for evaluating bonding strength which results in more than 0.8 Kgf.

Alloy718 마찰접합조건의 최적화와 비파괴 평가 (Optimization of Friction Welded Joint Conditions in Alloy718 and the Nondestructive Evaluation)

  • 권상우;공유식;김선진
    • 한국해양공학회지
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    • 제22권1호
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    • pp.53-57
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    • 2008
  • Friction welding was performed to investigate mechanical properties for Ni-base superalloy with 15 mm diameter solid bar. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, impact energy test, Vickers hardness surveys of the bond of area and heat affected zone. And then, the nondestructive technique to evaluate the weld quality was carried out by acoustic emission(AE) and ultrasonic attenuation coefficient. The tensile strength of the friction welded joint was shown up to 90 % of the Alloy718 base metal under the condition of the heating time over 5 sec. The optimal welding conditions were n=2,000 rpm, $P_1=200$ MPa, $P_2=200$ MPa, $t_1=8$ sec and $t_2=5$ sec when the total upset length was 4.4 mm.

유도 가열 접합 시스템을 이용한 대용량 이차전지 전극의 접합 방법 및 특성 (Electrode bonding method and characteristic of high density rechargeable battery using induction heating system)

  • 김은민;김신효;홍원희;조대권
    • Journal of Advanced Marine Engineering and Technology
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    • 제38권6호
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    • pp.688-697
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    • 2014
  • 본 연구에서는 최근, 전기자동차 및 소형 레저용 선박을 중심으로 연구가 진행 중인, 대용량 이차전지의 용량 증대를 위하여 필요한 내부 전극 접합 기술에 관하여 연구하였다. 종래의 초음파 용접으로 적층할 수 있는 적층 량의 한계를 극복하기 위한 방안으로 전극 소재에 직접 가열을 통한 용접 방법이 아닌 용가재 금속을 적용하여 전극을 접합시켜, 통전성과 인장강도를 증대시킴과 동시에 열적요인으로 인한 전극표면에 화학적 활성물질의 변성을 최소화 할 수 있는 저온 접합 방법에 대하여 연구하였다. 부연하여 현재 일반적으로 적용되고 있는 초음파 용접 및 저항 용접은 전극을 다량 적층 접합 시켰을 경우 일정한 전기 전도성과 접합 강도를 구현하기 힘들다. 용접을 위하여 무리하게 출력을 상승시킬 경우 용접열의 영향으로 전극의 변형 및 활성물질의 변성을 야기함과 동시에 최종 페키징(packaging) 이후 출력저하, 발열 등, 배터리의 안정성을 저하시키는 요인으로 작용한다. 따라서 본 연구에서는 고주파 유도가열을 통한 유도 가열 방식의 접합 방법과 용융 도금을 통한 용가재 금속의 전처리를 통한 종래와는 차별화된 전극접합 방법을 소개한다.

이종마찰용접 강봉재의 기계적특성과 비파괴 평가 (The Mechanical Properties and the Nondestructive Evaluation of Dissimilar Friction Welded Steel Bars)

  • 정원택;공유식;김선진
    • 동력기계공학회지
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    • 제10권1호
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    • pp.77-82
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    • 2006
  • In this study, dissimilar friction welding were produced using 15mm diameter solid bar in chrome molybedenum steel(SCM440) to carbon steel(S45C) to investigate their mechanical properties and the relationship between the weld parameters and the nondestructive coefficients, such as AE counts and ultrasonic attenuation coefficient. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, Vickers hardness surveys of the bond of area and heat affected zone. The specimens were tested as-welded and post weld heat treated(PWHT). The tensile strength of the friction welded steel bars was increased up to 100% of the S45C base metal under the condition of all heating time. The ductility of PWHT specimens is higher than as-welded.

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자동차 이차전지 제조를 위한 알루미늄과 무산소동의 레이저 용접특성 (Laser Welding Characteristics of Aluminum and Copper Sheets for Lithium-ion Batteries)

  • 강민정;박태순;김철희;김정한
    • Journal of Welding and Joining
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    • 제31권6호
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    • pp.58-64
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    • 2013
  • Several joining methods involving resistance welding, laser welding, ultrasonic welding and mechanical joining are currently applied in manufacturing lithium-ion batteries. Cu and Al alloys are used for tab and bus bar materials, and laser welding characteristics for these alloys were investigated with similar and dissimilar material combinations in this study. The base materials used were Al 1050 and oxygen-free Cu 1020P alloys, and a disk laser was used with a continuous wave mode. In bead-on-plate welding of both alloys, the joint strength was higher than the strength of O tempered base material. In overlap welding, the effect of welding parameters on the tensile shear strength and bead shape was evaluated. Tensile shear strength of overlap welded joint was affected by interfacial bead width and weld defect formation. The tensile-shear specimen was fractured at the heat affected zone by selecting proper laser welding parameters.