가압력 변화에 따른 STS304 박판의 점용접성 평가

조상명 釜慶大學校 1998 釜慶大學校 論文集 Vol.3 No.2

Precision resistance spot welding was applied to two kinds of thin stainless steel (STS304) strips to be soft and hard. The hard STS304 was produced by cold working. and the soft STS304 was obtained by solid solution treatment in the present experiment. Thickness of the specimens was 0.2mm. The welding load was varied by 1∼ 18kgf,the range of wdlding current was 500∼1500A. In the welding process, the splash from weldment was ovserved carefully. The welded specimen with lap joint was tested by the tensile shear test. And the nugget of the weldment was investigated by macro-section macro-section ovservation and micro-vickers hardness test. When the welding load was low, the good condition with stable quality and no splash could not be obtained. Therefore, to suppress the splash from the weldment, sufficient welding load and adequate currentwas needed. This approach method was developed for the hard and soft thin STS304 strips. The nugget and heat affected zone in the weldment by the hard STS304 was softened remarkably �� 새 rapid heating and cooling by the welding process. However for the soft STS304, the hardness of the weldment was not changed, but almost uniform. Because of this mechanism, the weldment by the hard STS304 was failed by the plug fracture mostly when welding current had been adative or high. But for the weldment by the soft STS304, the tear fracture was appeared mainly in the same range of current.

아연도금강판에 대한 중첩펄스 MIG 용접에서의 파형제어와 기공 발생 특성

조상명,김기정,이병우,Cho Sang-Myung,Kim Ki-Jung,Lee Byung-Woo 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.1

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.

펄스 TIG용접에서 필러 와이어 송급속도에 따른 아크압력 변동이 용입에 미치는 영향

조상명,김진우 대한용접접합학회 2004 대한용접·접합학회지 Vol.22 No.1

In the standpoint of the arc pressure, the effects of the filler wire feed rate on the penetration was investigated in this study. The pure Ar gas was used as a shield gas and the parameters investigated were the welding current and the filler wire feed rate. By making the experiment on the arc pressure, we could know that the arc pressure was fluctuated as the depth-into-arc of the tungsten rod. Instead of the filler wire, the tungsten rod was supplied into the molten pool to make this experiment. Because the filler wire melted in arc and then we couldn't measure the arc pressure. So, the tungsten rod - the highest melting point - was used. According to the depth-into-arc of the tungsten rod, the arc pressure could be measured by using the manometer. It was proved that the arc pressure got higher as the wire feed rate was slow. It is reported the arc pressure is proportion to welding voltage and the square of welding current. But, in the filler wire TIG welding, we could blow that arc pressure was fluctuated as the depth-into-arc of filler wire was changed. We could measure the arc pressure by the variation of the filler wire feed rate and could verify that it affected bead shape and penetration.

LNG연료탱크용 9%Ni강의 용접재료 종류에 따른 품질 특성

조상명,Murali Mohan Cheepu,조재일,백효진 대한용접·접합학회 2020 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2020 No.11

왜 용접 솔루션의 가치는 계속 높아지고 있는가?

조상명 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.5

용접경제학(Welding Economics)에서 지식과 데이터의 가치는 20세기부터 지식경영과 디지털 경제로의 전환이 진행됨에 따라 계속적으로 증가되고 있는 추세에 있다. 용접에 의한 제품의 조립이 수동 또는 반자동 용접으로 이루어졌을 때는 용접사의 감각에 근거한 기능과 육체적 활동이 용접 생산성 및 품질을 지배하는 핵심적인 인자로 작용하였기 때문에 그 때의 용접경제학에서 용접사의 기능과 성실성은 중요한 노동력의 핵심이었다. 즉 용접 품질과 생산성을 높이려면 용접사는 감각을 더 집중하고, 더 빨리 근육을 움직여야 하고, 용접사를 더 많이 투입 시켜야 했다. 그러나 21세기에 접어들면서 생산현장의 수동용접과 같은 육체노동은 육체적으로뿐만 아니라 감각적으로도 고도의 집중을 계속해야 되는 가혹한 작업이라는 인식이 커지는 추세가 나타났다. 한국을 비롯한 여러 선진국에서는 젊은 용접사의 유입은 30년 전에 비해 확연히 줄어들고 있다. 따라서 금속3D 프린팅 등 용접수요가 커지고, 철강 소모량 등도 계속 커지고 있는 상황에서 지속가능한 산업으로 자리매김하기 위해서는 새로운 디지털 전환과 솔루션 기반의 패러다임 전환이 요구된다. 실제로 21세기 들어 새롭게 나타나는 용접현장의 추세는 디지털 용접과 로봇 및 자동화의 도입이다. 이에 따라, 토치의 모션제어는 로봇이 담당하고, 아크 제어와 와이어의 송급 제어 및 입열량과 비드단면적 제어는 모두 디지털로 하는 것이 일반적이다. 따라서 용접시공의 현장 노하우는 점차 전문지식과 디지털 데이터로 표현이 가능해졌다. 로봇용접의 상세한 프로세스들도 모두 데이터로 나타낼 수 있게 됨에 따라 용접 솔루션의 가치도 계속적으로 높아지고 있다. 용접 선진국의 앞선 기업에서는 이미 용접 솔루션을 비즈니스 모델의 강점으로 하여 고객 맞춤형 자동 용접시스템과 로봇 용접시스템을 제공하여 고객가치를 획기적으로 높이는데 기여하고 있다. 또한, 용접 솔루션을 쓰면 디바이스, 모재준비 및 모션 데이터, 공정 데이터, 품질 데이터 등을 체계적으로 축적할 수 있어 장차 AI의 적용까지 기대할 수 있는 체계를 확립할 수 있다. 용접 솔루션은 디지털 전환(Digital Transformation)과 함께 동행해야 될 시대적 트랜드이며, 용접원가를 줄이면서 고품질을 얻기 위한 핵심적인 해결 수단이라고 할 수 있다.

미세먼지라는 사회적 문제 해결을 위해 용접 학계와 산업계는 무슨 공헌을 할 것인가?

조상명 대한용접·접합학회 2019 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2019 No.5

6σ에 의한 용접기 출력특성의 평가기법 개발에 관한 연구

조상명,윤훈성 대한용접접합학회 2003 대한용접·접합학회지 Vol.21 No.6

열간단조 금형 육성용접부 내균열성 및 내열충격성 평가방법에 관한 연구

조상명,김성호,정연호,백승희,장종훈,박철규,우희철,정병호,Cho, Sang-Myung,Kim, Sung-Ho,Jung, Yun-Ho,Baek, Seung-Hui,Jang, Jong-Hun,Park, Chul-Gyu,Woo, Hee-Chul,Jung, Byong-Ho 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.3

Hardfacing is one of the frequently applying method to increase surface hardness in hot forging die. Recently, hardfacing receives great attention due to it's repair availability and low cost. In hot forging die, crack resistance and thermal shock resistance have been considered as major properties, However there are few studies for the assessment of these properties. So, it is necessary to establish the assessment method for crack resistance and thermal shock resistance in hardfacing for hot forging die. In this study, flux cored arc welding was applied to make hardfacing welds. Three point bending test was carried out to assess hardfacing weld's crack resistance, and high temperature bending test using salt bath was developed for thermal shock resistance. Consequently, it was possible to assess crack resistance and thermal shock resistance of hardfacing welds for hot forging die quantitatively.

Ti6Al4V C형 용가재를 쓰는 TIG WAAM에 의한 대형 구조물 적층

조상명 대한용접·접합학회 2022 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2022 No.5

GTA용접용 텅스텐 전극팁의 형상과 연마 상태가 아크특성에 미치는 영향

조상명,서상균 대한용접접합학회 2001 대한용접·접합학회지 Vol.19 No.1

The welding quality by Gas Tungsten Arc Welding shows very high level, but the welding speed is lower than that of gas metal arc welding. Also, the welding quality by automatic GTAW is variable as the arc characteristics is changed by the consumption of electrode tip. The purpose of this study is to investigate the relation between the properties of tungsten electrode tip and the various arc characteristics at high current region. In this study, the high welding current 200A was applied to the repeated arc start test and long term arcing test using the $\phi$3.2 tungsten electrodes with cone angle 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$sharp tip, and 60$^{\circ}$surface polished (S.P.) sharp tip. It was confirmed that the maximum arc pressure by the initial electrode condition was highest in 45$^{\circ}$sharp tip, and the next in 60$^{\circ}$sharp tip, the last was in 30$^{\circ}$sharp tip and 60$^{\circ}$S.P.. But, the maximum arc pressure after the repeated arc start test and long term arcing test was decreased considerably. But, the maximum arc pressure was highest also in 45$^{\circ}$ sharp tip after the tests, the next was in 30$^{\circ}$sharp tip, and the last was in 60$^{\circ}$sharp tip and 60$^{\circ}$S.P.. The arc start characteristics was the most excellent in 60$^{\circ}$S.P., By long term arcing test, the lanthania included in tungsten electrode was extinguished at tip surface preferentially, therefore the arc characteristics of electrode tip got worse.