• 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.32 no.1
• /
• pp.28-33
• /
• 2014

In this paper, I-butt welding with 6mm thickness using Plasma-GMA welding was carried out. And weld characteristics of the Al-5083 aluminium alloy for Plasma-GMA hybrid welding was evaluated. The orthogonal experimental design was used to investigate the influence of plasma-MIG welding parameters such as plasma current, wire feeding rate, MIG-welding voltage and welding speed on the weld bead geometry and tensile strength using the ANOVA(Analysis of Variation). Then we conducted evaluation of contribution for process parameters. ANOVA results show that bead dimensions are affected by wire feeding speed, welding voltage and welding speed and tensile strength is mainly affected by welding speed and plasma arc current. Tensile strength was decreased by rise in plasma welding current because GMA welding current was decreased by plasma arc.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.3
• /
• pp.7-12
• /
• 2009

This study aims to find the friction welding and induction harden conditions, which are obtained by welding conditions, and the friction welding characteristics and induction harden conditions of tubular shaft were investigated with respect to low load test, high load test. Friction welding and induction harden machine have been widely used in manufacturing reflects of metal. The material of solid and tubular shaft selected that is used for parts of automobile steel. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of friction welding conditions makes good and the condition of friction and get the tubular condition. The purpose of this study is to find fatigue test condition and induction harden characteristics design for tubular shaft.

• Transactions of Materials Processing
• /
• v.28 no.6
• /
• pp.347-353
• /
• 2019

The porthole extrusion process is a classic metal forming process to produce complex cross-section shaped aluminum profile. It is very difficult to design porthole die and extrusion process because of the complex shape of extrusion die and internal metal flow. The main variables in this process are ram speed, initial billet and tool temperature, and die shape. In general, the metal flow of porthole extrusion process can be divided into two steps. During the first step, the billet is divided into several parts in the porthole die bridge. During the second step, the divided billets are welded in the welding chamber. In the welding chamber, the level of welding pressure is very important for the quality of the final product. The purpose of this study is to increase the welding pressure in the welding chamber by using a two stage welding chamber. The porthole extrusion die was designed by using the Taguchi method with orthogonal array. The effectiveness of the optimized porthole die was verified by using the finite element analysis.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.459-470
• /
• 2014

During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.4
• /
• pp.77-82
• /
• 2013

In this paper, the design of experiment with two-way factorial design was adopted and from that, optimum values of welding variables including the welding speed and rotation speed were found to improve the strength of AZ31 magnesium alloy sheets joined by the friction stir technique. Tool with shoulder diameter of 12 mm and pin diameter of 3.5 mm was used. Also the welding direction was aligned with the material rolling direction, and dimensions of the AZ31 magnesium alloy sheets were $100{\times}100{\times}2mm$. Conditions of rotation speed were 1000, 1100 and 1200 rpm and those of welding speed were 200, 300 and 400 mm/min. As far as this work is concerned, the optimal conditions for friction stir joint were predicted as the rotation speed of 1200 rpm and welding speed of 200 mm/min.

• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.1
• /
• pp.57-62
• /
• 2017

These days, shipbuilding companies are making an effort to adopt the IT technology in order to improve the production efficiency. One such effort is to utilize a planning and scheduling system to predict the production cost in advance. In this system, assessing the welding material quantity is an important factor. Unfortunately, obtaining the welding material quantity in the early design stage is extremely difficult because the detailed production information, which is essential in deriving the cost associated with welding, is normally available at a later stage. This paper aims at developing a computerized program that produces an index to estimate the welding material quantity in the early design stage. By using only three-dimensional geometric information, the program analyzes the production process and estimates the welding material quantity at any design or production stage when no production information is available. The results can be used for the planning and scheduling system.

• Journal of Korean Society for Quality Management
• /
• v.48 no.1
• /
• pp.69-86
• /
• 2020

Purpose: This study aims to determine the optimal conditions for the spot welding process that mechanically connects the case of a cylindrical secondary battery and the negative tab. Methods: We use 33 factorial design to derive the optimal conditions for the spot welding process. The pulling strength, the cross-sectional area of nugget, and the shock test life are selected as response variables, which can represent the resistance welding quality. The input variables are selected as the welding time, welding voltage, and pressure, which are the controllable factors in the spot welding process. Results: The main effects of welding time and welding voltage and the interaction effect of welding time and welding voltage are significant. Conclusion: The optimal conditions for the spot welding process to mechanically join the negative electrode tab of the cylindrical secondary battery and the battery case are developed. The result shows that the pulling strength is increased by 44% compared to before improvement under optimal conditions.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2002.05a
• /
• pp.25-27
• /
• 2002

Most of automotive companies make use of spot welding in order to assemble car body. Even though spot welding has been developed for last 60 years, there were some limitations in upgrading production line. Laser welding has advantages In productivity and degree of freedom in design. Thanks to fast speed, we can reduce body assembly line by 80%. Also with non-contact & one-side approach, it is possible to design various car body structures. New project launched the laser welding technology in mass production has started in 1999. In this paper, a new type of cur named 'next generation vehicle (NGV)' is introduced. The car body of NGV is welded with 4㎾ Nd: YAG laser.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.8 no.1
• /
• pp.57-64
• /
• 2008

There are many problems in present truss-deck slab system for example welding defect, segregation, water leakage, rust and tarnish etc. These problems may be caused by spot welding thin galvanized steel plate and lattice bar. The TOX Joining Systems is to join metal sheets of different material and thickness with and without coating or painting without adding heat or a joining part. Newly developed TOX-deck slab system using non-welding joint is free from above mentioned problems. The objects of this study are suggestion of design strength of TOX joint by experimental and statistical analyses and development of window based program to design the TOX-deck slab system.