용접 조건이 소형 용기용 Sn 도금 강재의 와이어 심 용접성에 미치는 영향

김기철,이기호,이목영 대한용접접합학회 1997 대한용접·접합학회지 Vol.15 No.5

Effect of welding parameters such as current, speed and electrode pressure on the weld quality of tin coated steels for small containers was discussed in this paper. Welding was performed with low frequency wire seam welding system which was loaded with 1.5mm in diameter copper wire electrode. The welding parameters were monitored at the position close to the welding spot so as to minimize the instrumentation error, and the signals were stored into a digital data acquisition system before analysis. Results showed that critical current for sufficient nugget size increased as the base material thickness increased, while the width of the optimum welding range was reduced. The acceptable welding condition derived from this study was found to be effective within the thickness range of $\pm$10% of the nominal (0.25mm) thickness. Tin coating layer was proved not to affect seriously on the weld quality, i.e. strength and formability, since consumable wire electrode was used in this process. Test results also demonstrated that the welding current was thought to be the most effective parameter to form an acceptable weld, while welding speed or electrode pressure exerted less effect on the nugget formation. However, these two parameters played an important role because the former was related to the nugget overlap interval, and the latter, to the formation of expulsion during welding.

Plasma Arc Welding of 780CP High Strength Steel Sheet Lap Joint for Tensile Strength of 100% Compared to Base Metal

Sang-Woo Han,Seungcheol Shin,Hansol Kim,Geonho Lee,Jongho Jeon,Sangjun Han,Gyuyeol Bae,Jung-Ho Cho 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.5

Homogeneous and heterogeneous PAW (plasma arc welding) experiments were conducted to obtain weld beads with tensile strength of 100% or more compared to that of the base metal in lap joint fillet welding of CP (complex phase) 780 MPa grade high strength steel sheet. Homogeneous and heterogeneous welding mean welding technic without and with welding wire in each. Common basic welding parameters of both homogeneous and heterogeneous PAW wire were applied, including welding speed of 21 cm/min, arc length of 3.5 mm, weaving amplitude of 3 mm, work angle of 30°, and Ar 99.99% shielding gas with 12 L/min. In homogeneous PAW, the optimized additional welding conditions were a welding current of 90 and 95 A, push angle of 20°, and weaving frequency of 5 Hz. The fracture strengths of all the samples were less than that of the base metal, and all fractures occurred at the weld bead fusion zone due to insufficient reinforcement. In heterogeneous PAW, the optimized additional welding conditions were a welding current of 125 A, push angle of 0°, weaving frequency of 4 Hz, and wire feed speeds of 1.53 and 1.38 m/min. Moreover, the welding wire was fed from behind the arc. The fracture strengths of all the samples were greater than that of the base metal, and fractures occurred at the base metal or fusion zone boundary. The reason for higher tensile in heterogeneous PAW wire is deduced as the large cross-section area of reinforcement provided by the welding wire comparing to homogeneous welding. It is well known that small radius of welding heat source clearly produces narrow heat affected zone. Therefore, the PAW produces relatively narrower heat affected zone, then resulted as fully enough strength of weldment. This is another reason of the current achievement.

Flux Cored Wire의 최신 기술 개발 동향

임희대(Hee-Dae Im),최창현(Chang-Hyun Choi),정재헌(Jae-Heon Jung),길웅(Woong Kil) 대한용접·접합학회 2016 대한용접·접합학회지 Vol.34 No.6

Flux Cored Wire is the most widely used welding material for Flux Cored Arc Welding these days. This paper introduces the technical aspects of manufacturing FCW and the development trend of FCW for each type of steel and metal. The studies are ongoing to lower the production cost of seamless-type FCW since it has not been generally used in welding shops so far because of it high cost even though the seamless-type FCW has various advantages than folded-type FCW in terms of manufacturing technology. Meanwhile, a technical research has been carried out to develop a rutile type of FCW products which satisfies high toughness after post heat treatment. In addition, for high-speed fillet welding, there has been a development of welding materials which can be welded in Single Auto-Carriage 100 cpm or more and up to Twin Tandem 200 cpm without occurring any welding defect in order to improve the welding productivity. As Zn coated steel is being used recently to improve the corrosion resistance of the automotive parts, a research and development for Metal Cored Wire has been conducted to reduce the Si island produced in welding operation than those produced when using the former solid wires. A development of welding material that guarantees CTOD performance beyond -40 ℃ CTOD to -60 ℃ is underway by different steel grades, and FCW for super austenitic stainless steel is being developed as the corrosion resistant steel has been upgraded.

Al 5083 합금 용접부의 기계적 물성에 미치는 Mg의 영향

김동윤 ( Dongyoon Kim ),김동철 ( Dongcheol Kim ),강문진 ( Munjin Kang ),김영민 ( Young-min Kim ) 대한금속ㆍ재료학회 2017 대한금속·재료학회지 Vol.55 No.10

A new aluminum welding wire with 0.8 wt% higher in Mg content was developed and compared with commercial welding wire of the 5000 series. The weldability of the Al5083 base material was evaluated using high current metal inert gas (MIG) welding, using the developed Al5183 and commercial Al5183 welding wire. For the wire with 5.1 wt% Mg content, the hardness of the weld metal decreased with increasing heat input to the center of the weld under low and high heat input conditions. For the wire with 5.9 wt% Mg content, the hardness of the weld metal did not decrease under low and high heat input conditions. The wire with 5.1 wt% Mg content exhibited a tensile strength of about 300 MPa under the low/medium heat input conditions. The tensile strength decreased to 284 MPa under high heat input conditions. However, the welding wire with 5.9 wt% Mg content exhibited a tensile strength of 300 MPa regardless of the heat input condition. Dendritic microstructures were observed in the center of the welds in both wires, with Mg contents of 5.1 wt% and 5.9 wt%, and the second dendrite arm spacing (SDAS) increased with increasing heat input. (Received May 8, 2017; Accepted July 10, 2017)

용접 와이어 직경이 용접 상태 검출에 미치는 영향

류정탁(Jeong Tak Ryu) 한국산업정보학회 2016 한국산업정보학회논문지 Vol.21 No.2

본 연구에서는 용접전류 및 용접전압 신호처리에 의한 용접 상태 검출에 있어 용접 와이어의 직경이 미치는 영향에 관하여 연구하였다. 실험을 위하여 인위적으로 모재의 간격을 용접 와이어보다 작은 경우와 큰 경우에 대하여 분석하였다. 사용된 용접 와이어의 직경은 1.2 mm이었으며 인위적으로 형성한 용접 모재 사이의 간격은 1.0 mm와 2.0 mm 두 종류를 사용하였다. 실험결과 용접 와이어의 직경보다 큰 용접 결함 요인에 대하여서는 용접전류 및 용접전압의 변화를 감지할 수 있으나 직경보다 작은 용접 결함 요인에 대하여서는 용접전류 및 용접전압의 변화를 감지할 수 없었다. Using the welding current and voltage signal processing, we have studied the influence that the diameter of the welding wire to the welding quality detection. For the experiments, We have analyzed the signal with respect to large and small artificially a gap between base materials than the welding wire. In this experiment, the 1.2 mm diameter of the welding wire was used, and distance between the welding base materials was respectively 1.0 mm and 2.0 mm. In the welding with a large defect than the diameter of the welding wire it was able to detect a change in the welding current and welding voltage. But it could not detect a change in the welding current and welding voltage in the welding has a small defect than the welding wire diameter.

Storage of High-Strength Steel Flux-Cored Welding Wires in Urbanized Areas

Adrian Wolski,Aleksandra Świerczyńska,Grzegorz Lentka,Dariusz Fydrych 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.11 No.1

The condition of the consumables is a key factor determining the waste reduction in the welding processes and the quality of the welded joint. The paper presents the results of tests of four types of flux-cored wires dedicated for welding high-strength steels, stored for 1 month and 6 months in Poland in two urbanized areas: in a large seaside city (Gdańsk) and in Warsaw, located in the center of the country. The wires were subjected to macroscopic and microscopic (stereoscopic, SEM) observations, EDS analysis, technological tests assessing elastic properties and targetability. The degree of degradation of the wires was also tested using resistance measurements. In order to assess the effect of storing wires on the weldability of steel, the diffusible hydrogen content in deposited metal was determined by high-temperature extraction. It was found that the storage caused changes in the surface condition of the wires, affected their elasticity and electrical properties, which affects the behavior of the wires during welding. A significant influence of storage conditions on the hydrogenation of deposited metal was found: in the case of three types of wires, the level of low hydrogen processes was exceeded and the maximum result was 15.18 ml/100 g of deposited metal. It was also found that copper-plated wire showed a significantly increased resistance to storage conditions compared to non-copper-plated wires.

Effects of Welding Parameters on Droplet Transfer and Bead Geometry in Laser Welding with Aluminum and Stainless Steel Filler Wires

Joonghyeon Shin,이승환,Minjung Kang 대한용접접합학회 2023 대한용접·접합학회지 Vol.41 No.5

Laser welding is increasingly used in industries because it allows high production cycle time and single-sided welding, but is characterized by a high sensitivity to joint preparation. By inserting filler wires, the sensitivity to joint preparation can be suppressed. In this study, the effect of welding variables on the bead geometry and melted droplet transfer were investigated. Two wires with different thermal diffusivities and densities were selected: stainless steel (STS) and aluminum (Al) wires. According to the wire feeding angle, the melting area tended to differ between the STS and Al wires. This implied that the wire feeding angle had to consider the absorption rate of the material for the laser wavelength. With an increase in the distance between the wire tip and the substrate, the dominant force acting on the droplet was changed from surface tension to gravity. Therefore, the distance was considered as a major factor in determining the droplet transfer mode. In all cases, the droplet transfer period exhibited relatively small deviation when the wire feeding direction was leading. Furthermore, the focal length effects on droplet transfer were irrelevant.

Effects of Flux Composition on the Element Transfer and Mechanical Properties of Weld Metal in Submerged Arc Welding

방국수,박찬,정홍철,이종봉 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.3

Submerged arc welding was performed using metal-cored wires and fluxes with different compositions. The effects of wire/flux combination on the chemical composition, tensile strength, and impact toughness of the weld metal were investigated and interpreted in terms of element transfer between the slag and the weld metal, i.e., △ quantity. Both carbon and manganese show negative △ quantity in most combinations, indicating the transfer of the elements from the weld metal to the slag during welding. The amount of transfer, however, is different depending on the flux composition. More basic fluxes yield less negative △C and △Mn through the reduction of oxygen content in the weld metal and presumably higher Mn activity in the slag, respectively. The transfer of silicon, however, is influenced by Al2O3, TiO2 and ZrO2 contents in the flux. △Si becomes less negative and reaches a positive value of 0.044 as the oxides contents increase. This is because Al, Ti, and Zr could replace Si in the SiO2 network, leaving more Si free to transfer from the slag to the weld metal. Accordingly, the Pcm index of weld metals calculated from chemical compositions varies from 0.153 to 0.196 depending on the wire/flux combination, and it almost has a linear relationship with the tensile strength of the weld metal. Submerged arc welding was performed using metal-cored wires and fluxes with different compositions. The effects of wire/flux combination on the chemical composition, tensile strength, and impact toughness of the weld metal were investigated and interpreted in terms of element transfer between the slag and the weld metal, i.e., △ quantity. Both carbon and manganese show negative △ quantity in most combinations, indicating the transfer of the elements from the weld metal to the slag during welding. The amount of transfer, however, is different depending on the flux composition. More basic fluxes yield less negative △C and △Mn through the reduction of oxygen content in the weld metal and presumably higher Mn activity in the slag, respectively. The transfer of silicon, however, is influenced by Al2O3, TiO2 and ZrO2 contents in the flux. △Si becomes less negative and reaches a positive value of 0.044 as the oxides contents increase. This is because Al, Ti, and Zr could replace Si in the SiO2 network, leaving more Si free to transfer from the slag to the weld metal. Accordingly, the Pcm index of weld metals calculated from chemical compositions varies from 0.153 to 0.196 depending on the wire/flux combination, and it almost has a linear relationship with the tensile strength of the weld metal.

API X-100의 레이저-아크 하이브리드 용접성에 미치는 용접와이어의 영향

김성욱,이목영,Kim, Sungwook,Lee, Mok-Young 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.5

In this study, API-X100 steel pipes were welded with various kinds of welding wires in the laser-arc hybrid welding process. 10kW fiber laser source was combined to MIG arc welding process. API X-100 steel of base metal was of 16.9mm thickness, and butt welding applied. After welding, full penetration weld was acquired by 1-pass welding. A root porosity and the lack of fusion was observed in some welding conditions. By the mixing the melted wire, acicular ferrite, polygonal ferrite, pro-eutectoid, aligned side plate, and bainite structures were observed at the weld metal. From the observation of hybrid weld, unmixed zone had more Ni and Cr. The unmixed zone was a 1/3 area of the weld metal. As the mechanical test of the hybrid welding, tensile test and impact test applied. From the tensile test, all of the welding except SM70S was fractured at the base metal. The result of the impact test at -30 degree C led 60J~320J of the absorbed energy. The result of the low-absorbed energy might be from the coarse equiaxed structures of the weld metal.

GMA용접에서 콘택트 팁 재질에 따른 용접특성 평가

김동윤,황인성,김동철,강문진,Kim, Dong Yoon,Hwang, In Sung,Kim, Dong Cheol,Kang, Moon Jin 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

The contact tip for gas metal arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. If the contact tip is damaged, it is a cause of lowering the welding productivity due to removal of welding defects and replacement of contact tip. In case of the use of a contact tip for a long time the arc is unstable because the processed hole in the contact tip center is larger, and the variation of aiming position of the welding wire causes a seam tracking error. In this study, gas metal arc welding experiments using contact tip of three different materials were performed. The contact tips with Cu-P, Cu-Cr, and Cu-ODS were used at the experiments, and the welding characteristics by each contact tip were evaluated. After welding contact tip appearance, welding spatter adhesion amount of the nozzle, and weld bead appearance were evaluated. The welding current and welding voltage were measured to verify arc stability during arc welding.