• Journal of Welding and Joining
• /
• v.33 no.1
• /
• pp.14-23
• /
• 2015

Recent developing tendency of nuclear power plant are studied by searching of NDSL, KIPRIS, Science Direct and so on. Welding materials such as low alloyed steels, stainless steels, nickel-based alloys, zirconium alloy and welding methods such as narrow gap welding, laser beam welding, friction stir welding, overlay welding are investigated.

• Journal of Welding and Joining
• /
• v.20 no.5
• /
• pp.127-133
• /
• 2002

In this study, metal transfer characteristics in pulsed current metal inert gas (MIG) welding of aluminum was investigated. Based on the metal transfer characteristics from direct current electrode negative MIG welding, the one drop per one pulse(ODOP) condition was predicted and compared with experimental data. The results indicated that experimental pulse range for the ODOP condition is wider than that predicted from the DCEP MIG welding data. In addition, more stable metal trnasfer behavior was obtained at the higher end of the ODOP condition.

• Journal of Welding and Joining
• /
• v.12 no.2
• /
• pp.39-48
• /
• 1994

In comparison to the conventional brazing, laser welding of ceramics has advantages of direct bonding without filler material, which causes the thermal stress due to the differences of thermal expansion coefficients. In pulse-mode, laser welding of dispersion ceramic having high thermal resistance is possible at relatively low preheating temperature of $1300^{\circ}C$ In CW-mode, alumina can be welded at high preheating temperature $1500^{\circ}C$ under the condition of low feed rate of 500 mm/min, respectively. Further studies on developing mechanism of pores in the bead during laser welding of ceramics is required.

• Journal of Welding and Joining
• /
• v.31 no.6
• /
• pp.17-26
• /
• 2013

Recent developing tendency of overlay welding on welding materials are studied by searching of NDSL, Science Direct, KIPRIS and so on. Fe, Co, Ni and WC are selected as welding materials. Development and improvement of various new overlay welding technology, especially improvement of quality and formation of crack are introduced. Also the prospective technologies of overlay welding are anticipated.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.233-234
• /
• 2023

This paper confirms the application sites of dry coupler technology, which is a direct connection method using screw threads, and Unlike wet couplers, this method can stand on its own without proof support and continuous work on the upper part. Furthermore, concludes with personal considerations to improve constructability.

• Proceedings of the KWS Conference
• /
• 1999.10a
• /
• pp.170-173
• /
• 1999

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1995.11a
• /
• pp.136-137
• /
• 1995

• Proceedings of the KWS Conference
• /
• 1998.05a
• /
• pp.242-245
• /
• 1998

• Journal of Welding and Joining
• /
• v.21 no.2
• /
• pp.57-63
• /
• 2003

Since new types of vehicles or structures made from thin aluminum alloy are under rapid development and some products are already on the market, welding of aluminium sheet is increasing. MIG(Metal Inert Gas), MIG-Pulse, TIG(Tungsten Inert Gas) welding are the typical Ai welding. MIG welding has the advantage of high speed, but it is difficult to apply to the thin plate, because of bum-through by the high heat input and spatter. MIG-Pulse welding can weld without spatter and burn-through, but when the gap exists at the welding joint, there is quite a possibility of bum-through. TIG welding is difficult to weld at a high speed. AC Pulse welding alternates between DCEP(Direct Current Electrode Positive) and DCEN(Direct Current Electrode Negative). DCEN is higher wire melting rate than DCEP, while lower temperature of droplet than DCEP. In AC Pulse welding, far fixed welding current, wire melting rate increases as the EN ratio increases. For fixed wire feed rate, welding current decreases as the EN ratio increases. Because of these features, the temperature of droplet, the depth of penetration, the width of bead decrease and the reinforcement height increases as EN ratio increases, and these are able to weld at a high speed, lower heat input. It is the purpose of this study that design of AC pulse current waveform for MIG welding of Al sheet and estimation of output characteristic.

• Journal of Welding and Joining
• /
• v.29 no.1
• /
• pp.52-58
• /
• 2011

In this paper, the direct bonding process between FPCB and HPCB was studied. By using an ultrasonic horn which is mounted on the ultrasonic bonding machine, it is alternatively possible to bond the gold pads attached on the FPCB and HPCB at room temperature without an adhesive like ACA or NCA. The process condition for obtaining more bonding strength than 0.6 Kgf, which is commercially required, was carried out as 40 kHz of frequency, 0.6 MPa of bonding pressure and 2 second of bonding time. The peel off test was performed for evaluating bonding strength which results in more than 0.8 Kgf.