• 한국화재소방학회논문지
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• 제15권2호
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• pp.53-58
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• 2001

본 연구에서는 조선 및 화학공장 등 산업현장에서 용접·용단작업 공정에서 비산 되는 불티에 의한 화재 예방을 위하여 불티 차단막에 관한 방염 및 난연 성능 평가를 실시하였다. 방염성능 실험결과 기존제품의 용접불티 차단막 6종 모두 충분한 방염성능을 갖고 있었다. 그러나, 용접·용단 불꽃에 의한 난연성 실험 결과 섬유유리에 수지코팅한 제품 2종은 용접·용단 불티에 대한 화재예방성능이 부족한 것으로 나타났다. 용접 불티 차단막의 최소산소지수의 국내기준은 30이상으로 고려하는 것이 좋을 것으로 사료된다. 용접 불티 차단막의 성능향상을 위한 제속적인 연구가 필요하며, 방염 및 난연성능 기술지침 개발의 기초자료로서 활용될 수 있을 것으로 사료된다.

• Structural Engineering and Mechanics
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• 제73권5호
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• pp.543-554
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• 2020

This paper aims to investigate the seismic performance of RC short columns and long columns with welding stirrups. Through the low-cyclic horizontal loading test of specimens, the seismic performance indexes such as failure modes, hysteretic curve, skeleton curve, ductility, energy dissipation capacity, stiffness degradation and strength degradation were emphatically analyzed. Furthermore, the effects of shear span ratio, stirrups ratio and axial compression ratio on the performance of specimens were studied. The results showed that the seismic performance of the RC short columns with welding stirrups were basically the same as that of the RC short columns with traditional stirrups, but the seismic performance of RC long columns with welding stirrups was better than that of RC long columns with traditional stirrups. The seismic performance of RC short columns and long columns with welding stirrups could be improved by increasing stirrup ratio and shear span ratio and reducing axial pressure ratio. Moreover, the welding stirrup have the advantages of steel saving, industrialization and standardization production, convenient construction, and reducing time, which indicated that the welding stirrups could be applied in practical engineering.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.556-559
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• 2000

Pulse inverter-type TIG(Tungsten Inert Gas) arc welders are studied to investigate the dynamic performance of welding. Welding currents are controlled to be pulse waveforms resulting in stable are better welding performance. The hybrid-type controller is proposed to control the welding current. Todemonstrate the practical significance of our results we present some simulation results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.581-586
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• 2000

Gas metal arc welding(GMAW) uses a continuously fed electrode as a filler metal. The arc is shielded from atmospheric contamination by an inert gas active or inert/active gas mixture delivered through the welding gun and cable assembly. The recent research topics on $CO_2$ are welding machines are focused mainly on the reduction method of generated spatter by using new type consumable electrode metal or inverter control method. The various current waveform control methods have been researched for welding performance improvement. Until now current waveform control methods reduce to spatter occurred by instantaneous short circuiting,. but these methods is drawback that no reduce spatter occurred by arc reignition. In this paper the previous arc reignition current control method for welding performance improvement of inverter arc welding machine is studied and compared the various current control methods with the previous arc reignition current control method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권10호
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• pp.571-578
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• 1999

Current waveform control of pulse MAG welding power source is studied so that welding of thin plates may obtain high speed and improved performance. In this paper, waveform control method is proposed, digital controller using DSP is able to control the current waveform precisely. High speed welding of thin plates using pulse MAG welding method is made possible. Performance test for 1.2mm thin plates is carried out, output waveform and welding performance is analyzed.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.370-376
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• 2005

Magnesium alloys are becoming important material for light weight car body, due to their low specific density but high specific strength. However they have a poor weldability, caused high oxidization tendency and low vapor temperature. In this study, the welding performance of magnesium alloys was investigated for automobile application. The materials were rolled magnesium alloy sheet contains Al and Zn such as AZ3l , AZ6l and AZ9l. Three types of welding process were studied, that were GTAW, Laser beam welding and FSW. To evaluate the weldability, we examined the appearance of welding bead. Also we checked bead shape and internal defects such as crack and porosity on cross section of welding bead. The mechanical property was measured for welded specimen by tensile test. For determination of the strength change by welding process, the hardness profile across the welding center was measured. For the results, the tensile properties of welded specimen were decreased obviously on all welding process. For the fusion welding process such as GTAW and laser beam welding, the surface of the welding bead was covered with oxidized magnesium dust but it was removed by simple cleaning work as wipe-out with tissue. Also under cut, that caused vaporization of base metal was occurred. for the friction stir welding, there was no oxidation, under-cut or internal defects. However it had poor weld performance, the reason was cleavage fracture occurred at plastic deformation zone. For welding of magnesium alloy, the laser beam welding process was recommended.

• 한국건축시공학회지
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• 제8권6호
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• pp.161-166
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• 2008

This study is focused on the welding performance of automatic gas pressure welding machine adapted to korean construction site by external appearance investigation. As gas pressure welding is more economical and has good performances compared with other steel bar jointing methods, as arc welding and mechanical joint etc, in Japan, the gas pressure welding is one of the typical connection of steel reinforcement when connecting the D29 and thicker steel bars, But in Korea, gas pressure welding joint method is not widely used caused by the shortage of skilled workers. so to activate the gas pressure welding in Korea, the automatic gas pressure welding machine is developed. In this study, the welding performances of gas pressure welding joint samples using korean automatic gas pressure welding machine are measured by external appearance investigation - blown diameters, blown length, welding face disagreement, central axis eccentric ratio, bending, sag and crack. The results of welding performances on the gas pressure welding joint samples show that samples are satisfied with the standard value regulated in KS D 0244 and JIS Z 3120.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.464-469
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• 1998

In the conventional wire feeder drives of welding machine, one thyristor or MOSFET device was used for half-wave phase control circuit and direct EMF measurement was used for sensing the wire feed rate. But the method using one switching device has poor response for sudden disturbance and it has latent speed ripple. It can affect some welding performance such as spatter generation and irregular bead formming. Therefore, the welding performance using full-bridge PWM speed control scheme was compared with conventional driving scheme was compared with conventional driving scheme and experimented in this paper. The results of experiment confirm the posibility of welding performance improvement by proposed constant speed control scheme in wire feeding drive of welding machine.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.553-558
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• 1999

As a process of development of composite beam-column connection system, structural tests have been conducted to verify moment resisting performance of the system. The tests have been proceeded by two steps, the first being welding performance test of the steel connection rod and stiffners, and the second overall moment resisting capacity of the fuly assembled system. Ten welding test specimens and four prototype specimens have been used in the test. Good structural performance of welding test specimens has been observed without any single welding failure, and sufficient moment resisting capacity has been proved from the overall performance test, with the moment magnitude in excess of the calculated plastic moment.

• 한국건축시공학회지
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• 제5권3호
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• pp.131-138
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• 2005

The study is focused on the settling the developing direction of korean gas pressure welding machine which can be applied in korean construction sites with moderate and high performance. Gas pressure welding is more economical and has good performances than other steel bar jointing methods, as arc welding and mechanical joint etc. Therefore in Japan, the gas pressure welding, which has less loss of steel bars and low performance of joints, when connecting the D29 and thicker steel bars, Is one of the typical connection of steel reinforcement. But in Korea, the gas pressure welding method is not widely used caused by the shortage of skilled workers, and this situation in Korea can not be solved in short period. The training of the skilled workers takes long period(around $6\~10$ years), and there is no certification system for gas pressure welding. So to activate the gas pressure welding in Korea, the development of the automatic gas pressure welding machine is necessary, which gives regular performance of the steel bar joints and can be operated by not sufficient skilled workers. The automatic gas pressure welding machine was developed in Japan, but this machine has many problems when applied in korean construction sites. Therefore, it is necessary to develop a korean automatic gas pressure welding machine to overcome this problems. To develop korean automatic gas pressure welding machine, the problems, which shows when applied in korean construction sites, need to be investigated. According to the investigation, counterproposals are presented for the pragmatical development of the korean automatic gas pressure welding machine.