• Journal of Welding and Joining
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• 제4권3호
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• pp.32-42
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• 1986

In this study, the influence of carbon equivalents on friction welds of dissimilar steels was investigated. Four types of carbon steels with 10mm diameter were welded to a high-speed tool steel SKH 9. Main experimental results could be summarized as follows (1) Under constant friction pressure, the friction time increased almost linearly with the increasing burn-off length, while the forge length decreased almost linearly. (2) The maximum hardness in carbon steels increased almost linearly with the increasing carbon equivalent, but was much lower than that in the high speed steel. (3) After quenching and tempering of dissimilar steel friction welds, the hardness in carbon steel weldments became similar as that in the base metal, while the hardness in SKH 9 weld was still higher that of the base metal. (4) Relative movement in the friction phae occurred not at the interface of the weldments, but in the high speed steed steel near the interface. (5) For considered material combinations and welding parameters, most of fractures in tension and twisting tests occurred in the base metal. And welds with so high strength could produced in a wide range of welding parameters.

• 한국정밀공학회지
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• 제22권8호
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• pp.17-26
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• 2005

Dissimilar-metal welds(DHWs) are used widely in various industrial applications due to the pratical importance from the technical and economic aspect. However, DMWs have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMWs have used the various of heat source to decrease such as faults. In this paper, the weldability on dissimilar metal welds of Austenite stainless steel and Low carbon steel using a continuous wave Nd:YAG laser was experimentally investigated. Experiments were conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.250-256
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• 2004

For many years and primarily for economical reasons, Dissimilar Metal Welds have been used as transition joints in a variety of equipment and applications. But Dissimilar Metal Welds have several fabrication and metallurgical drawbacks that can often lead to in-service failures. In this paper, the laser weldability of STS304 stainless steel and SM45C at dissimilar metal welds using a continuous wave Nd:YAG laser are experimentally investigated. An experimental study was conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser were tested.

• 한국정밀공학회지
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• 제21권11호
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• pp.53-60
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• 2004

Laser welding techniques have been characterised for various materials. In this paper, the laser weldability of STS304 stainless steel and Inconel 600 at dissimilar metal welds using a continuous wave Nd:YAG laser are experimentally investigated. Inconel 600 is being used in a steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion. Stress corrosion cracking can occur on this material. An experimental study was conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser were tested.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 추계학술발표대회 개요집
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• pp.202-204
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• 2004

The purpose of this study is to evaluate the effects of welding conditions on the shape of arc of FCAW using high speed camera system. Length and deflection of arc were evaluated from images of arc which were transformed by threshold processing. Based on the experimental results, a regression model for the length of arc was established. A major factor affecting deflection of arc was the length of arc.

• 전산구조공학
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• 제6권3호
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• pp.113-123
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• 1993

대부분의 선체 및 해양구조물은 용접을 통해서 만들어지며 이러한 구조물들은 항상 변화되는 하중에 노출된다. 본 논문에서는 T형 용접이음부의 응력집중과 피로특성규명을 위하여 수치해석적 방법을 통한 연구결과를 실험결과와 비교 검토하였다. 특히 필렛용접, 완전 용입용접, 부분 용입용접부의 특성을 응력집중과 피로강도면에서 연구하여ㅛ으며 이를 위한 파라메터로는 불 용입부의 길이, 각장의 크기 및 형태, 삽입판의 각도등을 채택하였다. 최적의 용접을 위하여 각 파라메터의 선정을 효과적으로 할 수 있도록 응력 및 피로수명분표, S-N선도를 정리하엿으며 필렛용접이 용입용접을 대신하여 사용될 수 있는 근거를 제시하였다. 본 연구결과는 실제 현장에서 구조의 용접이음부 형태 선정에 지침이 될 수 있다.

• 한국기계가공학회지
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• 제18권11호
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• pp.47-56
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• 2019

A deep neural network (DNN) model was proposed to predict the upset in the inertia friction welding process using a database comprising results from a series of FEM analyses. For the database, the upset length, upset beginning time, and upset completion time were extracted from the results of the FEM analyses obtained with various of axial pressure and initial rotational speed. A total of 35 training sets were constructed to train the proposed DNN with 4 hidden layers and 512 neurons in each layer, which can relate the input parameters to the welding results. The mean of the summation of squared error between the predicted results and the true results can be constrained to within 1.0e-4 after the training. Further, the network model was tested with another 10 sets of welding input parameters and results for comparison with FEM. The test showed that the relative error of DNN was within 2.8% for the prediction of upset. The results of DNN application revealed that the model could effectively provide welding results with respect to the exactness and cost for each combination of the welding input parameters.

• 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 $P_L=0.5kW$, ${\nu}=2.5m/min$과 $P_L=1.5kW$, ${\nu}=6m/min$ 조건에서 양호한 접합길이를 가진 용접부를 얻을 수 있었으며, 용접부는 고출력보다 저출력 조건일 때 더 우수한 연성을 나타냈다.

• Journal of Welding and Joining
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• 제20권3호
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• pp.98-104
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• 2002

A study on microstructures of welds for Zircaloy-4 sheath end closure by the resistance upset welding methods was carried out. Two upset welding process variations such as magnetic farce and multi-impulse resistance welding were used. Grain size and microhardness across welds were analysed in terms of welding parameters. Magnetic farce resistance weld with one cycle of unbalanced mode has smaller upset length and $\alpha-grain$ size in heat affected zone than those of multi-impulse resistance weld because of lower heat input and shorter welding time. Heat affected zone formed by two upset resistance welding variations revealed fine Widmanstatten structure or martensitic ${\alpha}'$ structure due to the high heating rate and foster cooling rate. Magnetic force resistance welds showed recrystallized grains before grain growth, whereas multi-impulse resistance welds showed full grain growth.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.343-345
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• 2005

In comparison to general purpose step-up/down transformer, welding transformer for resistance spot welding requires strict design criteria. The major significant specifications include duty cycle, arm length and its geometric configuration(window area) as well as various current/voltage conditions and material properties. This interactive program propose new promising procedure for weldling transformer. Users can input design variables and modify in accordance with graphic Output.