• Title/Summary/Keyword: Welding education

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Electrochemical Evaluation of Corrosion Property of Welding Zone of 304 Stainless Steel (304 스테인리스강의 용접부위의 부식특성에 관한 전기화학적 평가)

  • Moon, Kyung-Man;Kim, Yun-Hae;Kim, Jong-Do;Lee, Myung-Hoon;Kim, Jin-Gyeong
    • Journal of Ocean Engineering and Technology
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    • v.23 no.4
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    • pp.58-63
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    • 2009
  • Two kinds of welding methods are used for austenitic 304 stainless steel: laser welding and TIG welding. The difference in the corrosion characteristics of the welded zone between these two welding methods was investigated using electrochemical methods, such as corrosion potential measurements, polarization curves, cyclic voltammograms, etc. The Vickers hardnesses of all the welded zones (WM: Weld Metal, HAZ: Heat Affected Zone, BM: Base Metal) showed relatively higher values in the case of laser welding than for TIG welding. Furthermore, the corrosion current densities of all the welding zones showed lower values compared to TIG welding. In particular, the corrosion current density of the HAZ with TIG welding had the highest value of all the welding zones, which suggests that chromium depletion due to the formation of chromium carbide appears in the HAZ, which is in the range of the sensitization temperature. Thus, it can easily be corroded with a more active anode. Consequently, we found that the corrosion resistance of all of the welding zones for austenitic 304 stainless steel could apparently be improved by using Laser welding.

A Study on Instrument Panel Welding by Ultrasonic-Waves for Automotive Interior Applied Emotional Design (감성 디자인이 적용된 자동차 인테리어 디자인을 위한 인스트루먼트 패널 초음파 용접에 관한 연구)

  • Lee, Jung-Hyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.2
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    • pp.260-266
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    • 2010
  • Today's consumers are looking for emotional design which can fulfill their own potential desire. Emotion varies according to individual circumstance, age, sex, culture, education, profession and so on. Automotive instrument panel design is the most important part of interior design, because it affects the impression of interior design and has the equipments for safety, entertainment and various information. Thus, this study was performed to apply emotional design to automotive instrument panel which is the most important part of automotive interior, and find the best bonding conditions to build instrument panel efficiently by comparing mechanical properties in thermoplastic resin of polyethylene (PE) adhesion. Satisfactory adhesion was executed in ultrasonic welding for the same materials of PE. The best welding conditions were found to be welding time of I second, welding pressure of 250 kPA for PE-PE welding. Dissimilar materials were adhered when adhesion and ultrasonic welding were performed at the same time.

Education, Examination and Qualification of Welding Engineer (용접전문기술자의 교육, 시험 및 검정)

  • 황선효
    • Proceedings of the KWS Conference
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    • v.43
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    • pp.208-210
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    • 2004
  • 국제용접학회(IIW) 및 대한용접학회(KWS)의 용접전문기술자 교육, 시험 및 검정에 대해서 기술한다. 그리고 현재까지 용접전문기술자 교육 및 검정과 관련되어 진행된 사업추진 실적에 대해서 기술하고, 이와 관련된 국내외의 환경 그리고 전망에 대해서 기술한다.

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Education, Examination and Qualification of Welding Engineer (용접전문기술자의 교육, 시험 및 검정)

  • Hwang, Seon-Hyo
    • Proceedings of the KWS Conference
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    • 2005.06a
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    • pp.121-123
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    • 2005
  • 국제용접학회(IIW) 및 대한용접학회(KWS)의 용접전문기술자 교육, 시험 및 검정에 대해서 기술한다. 그리고 현재까지 용접전문기술자 교육 및 검정과 관련되어 진행된 사업추진 실적에 대해서 기술하고, 이와 관련된 국내외의 환경 그리고 전망에 대해서 기술한다.

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A Study of Characteristics on the Dissimilar Metals (ASTM Type 316L - Carbon Steel : ASTM A516-70) Welds Made with FCA Multiple Layer Welding (스테인리스강(ASTM Type 316L)과 탄소강(ASTM A516 Gr.70) 이종금속의 FCA 다층 용접부 특성에 대한 연구)

  • Kim, Se Cheol;Hyun, Jun Hyeok;Shin, Tae Woo;Koh, Jin Hyun
    • Journal of Welding and Joining
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    • v.34 no.3
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    • pp.69-76
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    • 2016
  • Characteristics of dissimilar metal welds between ASTM Type 316L and carbon steel ASTM A516 Gr.70 made with FCAW were evaluated in terms of microstructure, ferrite content, EDS analysis, hardness, tensile strength, impact toughness and corrosion resistance. Three heat inputs of 10.4, 16.9, 23.4kJ/cm were employed to make joints of dissimilar metals with E309LMoT1-1 wire. Microstructure of dissimilar weld metals consisted of mostly vermicular type of ${\delta}$-ferrite and some lathy type of ${\delta}$-ferrite, and ${\delta}$-ferrite was transformed into globular type in reheated zone. In all conditions, weld metals were solidified on FA solidification mode. Based on the EDS analysis of weld metals, All Creq/Nieq values were in the range of FA solidification mode, and it was decreased with increasing heat inputs whereas it was increased with increasing layers. The amount of ${\delta}$-ferrite was decreased with increasing heat input due to the difference of cooling rate, and it was increased with increasing layers. Accordingly, hardness and tensile strength of dissimilar metals weld joints was decreased with increasing heat input while impact energy was increased with increasing heat input. Corrosion test of dissimilar metals weld joints showed that weight gain rate of heat input 10.4kJ/cm was the greatest, and that of three heat inputs became constant after certain time.

Evaluation of the Weldability in Spot Welding using Ultrasonic Technique

  • Hong, Min-Sung;Kim, No-Hyu
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.3
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    • pp.209-214
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    • 2005
  • Spot welding is the most widely used in automotive and aerospace industries. The quality of weld depends upon the size of nugget between the overlapped steel plates. Recently, the thickness of the steel plates is much thinner and hence, it introduces the smaller size of nugget. Therefore, it is necessary not only to develop the criterion to evaluate the quality of weld but also to obtain the optimal welding conditions for the better performance. In this paper, the steel plates, 0.5 mm through 1.5 mm thickness, have been spot welded at different welding conditions and the nugget sizes are examined by ultrasonic technique (C-scan type). The relationships between the nugget sizes and the weldability have been investigated. The result of ultrasonic technique shows the good agreement with that of the tensile test.

Effect of Transfer mode on the Overlay weldment in GMA welding (GMA용접에 용접이행모드가 오버레이 용접부에 미치는 영향)

  • Kim, Nam-Hoon;Koh, Jin-Hyun;Seo, H-H;Kim, I-J;Kim, J-K
    • Proceedings of the KAIS Fall Conference
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    • 2011.12b
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    • pp.382-384
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    • 2011
  • 최근 오일샌드, 극지유전, 심해저자원 등 극한지 자원개발이 활발해짐에 따라 수요가 증대되고 있는 극한지용 내마식 소재는 내마식성과 함께 저온 인성이 요구되고 있다. 철계 합금에서 관찰되는 변형유기 마르텐사이트 상변태는 입자의 충돌에 의한 충격을 흡수하고 소재의 표면을 가공경화시켜 내마식성 향상 및 저온 인성에 기여할 수 있을 것으로 기대되고 있지만 합금조성의 정교한 제어가 필요하기 때문에 오버레이 용접에 적용하기 위해서는 모재와의 희석률을 제어하는 방안이 필요하다. 용접플럭스 설계기술은 용접시 금속이행모드, 용융풀 거동 등과 같은 용접현상 제어를 통해 오버레이 용접재료의 용접성과 용접비드형상, 용접부 희석률을 최적화할 수 있는 기술이다. 본 연구에서는 내마식 고인성 오버레이 용접재료의 개발을 위해 다양한 용접플럭스를 첨가한 메탈코어드 와이어를 제조하고 일정 송급속도에서 GMA 용접시 용접전압과 용접전류 간의 관계를 분석하여 용접플럭스가 아크현상 및 희석률에 미치는 영향을 조사하였다.

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A Study for the Improvement of Weld Quality Through Force Control of Servo Gun in Resistance Spot Welding using Robot (저항 점 용접 로봇에서 서보건의 가압력 제어를 통한 용접 강도 향상에 대한 연구)

  • Park, Young-Whan;Lee, Jong-Gu;Rhee, Se-Hun
    • Journal of Welding and Joining
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    • v.24 no.6
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    • pp.13-20
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    • 2006
  • Resistance spot welding is widely used for joining sheet metals in the automotive manufacturing process. Recently, servo-gun is used to increase the productivity and precise control the acting force. However, force control mechanisms have not been investigated with servo-guns until now. In this paper, it is proved that servo-motor current is proportional to torque and by experiment, experimental equation between servo-motor current and electrode force was derived. Algorithm for feedback control of electrode force was suggested using current measurement. In addition, applying soft touch method to this system the impact between electrode and specimen, which is the problem of air gun, could be reduced. Indentation made the force decrease in holding time of resistance spot welding. In order to overcome this problem, force compensation using the servo gun was used and it improved weld strength in good welding current range.

Evaluation of Corrosion Property of Welding Zone of Stainless Steel by Laser Welding (Laser 용접한 스테인리스강의 용접부위의 부식특성에 관한 평가)

  • Moon, Kyung-Man;Won, Jong-Pil;Park, Dong-Hyun;Kim, Yun-Hae;Lee, Myung-Hoon;Kim, Jin-Gyeong
    • Journal of Ocean Engineering and Technology
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    • v.26 no.4
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    • pp.64-69
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    • 2012
  • Laser welding was carried out on austenitic 304 (STS 304) and 22 APU stainless steels. In this case, the differences between the corrosion characteristics of the welding zones of the two stainless steels were investigated using electrochemical methods. The Vickers hardness values of the weld metal (WM) zones in both cases, the STS 304 and 22 APU stainless steels, showed relatively higher values than those of other welding zones. The corrosion current densities of the heat affected zone (HAZ) of the 22 APU and the base metal (BM) zone of the STS 304 exhibited the highest values compared to the other welding zones. It is generally accepted that when STS 304 stainless steel is welded using a general welding method, intergranular corrosion is often observed at the grain boundary because of its chromium depletion area. However, when laser welding was performed on both the STS 304 and 22 APU stainless steels, no intergranular corrosion was observed at any of the welding zones. Consequently, it is considered that the intergranular corrosion of stainless steel can be controlled with the application of laser welding.