• Title/Summary/Keyword: Welding Speed

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Effects of Laser Welding Speed on the Tensile and Forming Characteristics of Tailored Blanks (레이저 용접 속도가 테일러드 블랭크의 인장 특성 및 성형성에 미치는 영향)

  • 표창률
    • Journal of the Korean Society of Safety
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    • v.15 no.3
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    • pp.7-13
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    • 2000
  • Forming characteristics of tailored blank are mostly effected by the welding method. Recently, laser welding is widely used for the tailored blank. However, tensile and forming characteristics vary due to welding conditions such as welding speed, heat flux etc. The objective of this paper is to evaluate the effect of welding speed on the tensile and forming characteristics of laser welded tailored blank. For this purpose, tailored blank specimens with different welding speed were prepared and tensile tests were performed. Also forming tests such as LDH and OSU test, were performed to evaluate the effect of welding speed on the forming characteristics. Finally, forming limit diagrams were obtained for different welding speed.

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Effect of the welding speed on the characteristics of Nd:YAG laser welds for automotive application : 600MPa PH high strength steel (600MPa급 자동차용 석출경화형 고장력강판 Nd:YAG 레이저 용접부의 특성에 미치는 용접속도의 영향)

  • Han, Tae-Kyo;Jung, Byung-Hun;Kang, Chung-Yun
    • Laser Solutions
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    • v.10 no.3
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    • pp.25-32
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    • 2007
  • The effect of welding speed on the weldability, microstructures, hardness, tensile property of Nd:YAG laser welding joint in 600MPa grade precipitation hardening high strength steel was investigated. A shielding gas was not used, and bead-on-plate welding was performed using various welding speeds at a power of 3.5kW. Porosity in the joints occurred at 1.8m/min, but were not observed over the welding speed of 2.1m/min. However, spatter occurred over the welding speed of 6.6m/min. The hardness was the highest at heat affected zone(HAZ) near fusion zone(FZ), and was decreased on approaching to the base metal. The maximum hardness increased with increasing welding speed. The microstructure of FZ was composed of coarse grain boundary ferrite and bainite(upper) but the HAZ near the FZ contained bainite(Lower) and fine ferrite at a low welding speed. With increasing welding speed, ferrite at the FZ and the HAZ became finely and upper binite changed to lower bainite. In a perpendicular tensile test to the weld line, all specimens were fractured at the base metal, and the tensile strength and the yield strength of joints was equal to those of raw material. Elongation was found to be lower than that of the raw material.

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STUDY ON WELDABILITY OF CU (OFC) BY FRICTION STIR WELDING

  • Bang, Keuk-saeng;Lee, Won-bae;Yeon, Yun-mo;Jung, Seung-boo
    • Proceedings of the KWS Conference
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    • pp.522-527
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    • 2002
  • The microstructure and mechanical properties of friction stir welded OFC plates with 2mm in thickness were examined with the changing welding parameters such as welding speed, rotation speed in this study. The sounding welding conditions was acquired at the optimum welding conditions of the 41mm/min to 61mm/min of welding speed at 1250 rpm of rotation speed. The microstructure of weld zone was divided into four parts such as the base metal region (EM), thermal mechanical affected zone (TMAZ), heat affected zone (HAZ), stir zone (SZ). The grain size in the SZ and the width of weld nugget were increased with increasing welding speed. The hardness profiles of the base metal were distributed about 80HV. The HAZ is a slightly softened region of about 60~75 HV relative to the base metal. The hardness profiles of the SZ were higher than that of base metal. The tensile strength was increased with increasing welding speed. In case increasing rotation speed, tensile strength was decreased. The maximum tensile strength was about 220:MPa which was 110% of joint efficience of that of base metal at 41mm/min of welding speed, 1250rpm of rotation speed.

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Thermal and mechanical analysis on friction stir welding of AZ31 magnesium alloy by the finite element method (유한요소법에 의한 AZ31마그네슘 합금의 마찰교반용접시 유동 및 강도 해석)

  • Kang, Dae-Min;Park, Kyoung-Do;Jung, Yung-Suk
    • Journal of Power System Engineering
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    • v.17 no.4
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    • pp.64-71
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    • 2013
  • In this paper, finite element method was used for flow and strength analysis of AZ31 magnesium alloy under friction stir welding. The simulations were carried out by SYSWELD s/w, and the modeling of sheet was doned by unigraphics NX3 s/w. Welding variables for analysis were rotating speed and welding speed of tool. Also two-way factorial design method was applied to confirm the effect of welding variables on maximum temperature and stress of material used. From these results, the increaser welding speed of tool the decreaser maximum temperature, but the increaser maximum stress. Also the increaser rotating speed of tool the increaser maximum temperature, but the decreaser maximum stress. In addition the increaser welding speed of tool and the decreaser rotating speed of tool, the narrower heat effect zone. Finally rotating speed of tool influenced on maximum temperature more than welding speed of tool, and welding speed of tool influenced on maximum stress more than rotating speed of tool from the variance analysis.

Comparison of Welding Characteristics of Austenitic 304 Stainless Steel and SM45C Using a Continuous Wave Nd:YAG Laser (오스테나이트계 스테인리스강과 SM45C의 연속파형 Nd:YAG 레이저 용접특성비교)

  • 유영태;오용석;노경보;임기건
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.3
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    • pp.58-67
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    • 2003
  • Welding characteristics of austienite 304 stainless and SM45C using a continuous wave Nd:YAG laser n experimentally investigated Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much Inter than those involved in conventional welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The Nd:YAG laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration. This paper describes the weld ability of SM45C carbon steel for machine structural use by Nd:YAG laser. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.

Weldability of SUS304 and Ti Dissimilar Welds with Various Welding Speed using Single Mode Fiber Laser (싱글모드 파이버 레이저를 이용한 SUS304와 Ti 이종재료의 용접속도에 따른 용접특성)

  • Lee, Su-Jin;Katayama, Seiji;Kim, Jong-Do
    • Journal of Welding and Joining
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    • v.31 no.5
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    • pp.64-70
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    • 2013
  • The joining of Ti and SUS304 dissimilar metals is one of the effective measures to save rare metal. But Ti and SUS304 have differences in materials properties, and Ti and Fe intermetallic compounds such as TiFe and $TiFe_2$ are easily formed in weld fusion zone between Ti and SUS304. Nevertheless, in this study, full penetration lap dissimilar welding of Ti and SUS304 using single-mode fiber laser with ultra-high welding speed was tried, and it was found out that ultra-high welding speed could control the generation of intermetallic compound. To recognize the formation of intermetallic phase in the weld fusion zone and the compound zone of interface weld area were observed and analyzed using energy dispersive X-ray spectroscopy (EDX). And it was confirmed that the ultra-high welding speed could reduce amount of intermetallic compounds, but the intermetallic compounds were existed in the weld fusion zone under the all conditions.

Butt Welding Characteristics of Austenitic 304 Stainless Steel Using a Continuous Wave Nd:YAG Laser Beam (오스테나이트계 304 스테인리스강의 Nd:YAG 레이저 맞대기 용접특성)

  • Yoo, Young-Tae;Oh, Yong-Seok;Shin, Ho-Jun;Im, Kie-Gon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.2
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    • pp.165-173
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    • 2004
  • Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional arc welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameters such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar plates, etc. The following conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/ aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.

Modeling and Control of Welding Mobile Robot for the Tracking of Lattice Type Welding Seam (격자형 용접선 추적을 위한 용접 이동로봇의 모델링 및 제어)

  • Lee, Gun-You;Suh, Jin-Ho;Oh, Myung-Suk;Kim, Sang-Bong
    • Proceedings of the KSME Conference
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    • pp.923-928
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    • 2003
  • This paper presents the motion control of a mobile robot with arc sensor for lattice type welding. Its dynamic equation and motion control method for welding speed and seam tracking are described. The motion control is realized in the view of keeping constant welding speed and precise target line even though the robot is driven along a straight line or comer. The mobile robot is modeled based on Lagrange equation under nonholonomic constraints and the model is represented in state space form. The motion control of the mobile robot is separated into three driving motions of straight locomotion, turning locomotion and torch slider controls. For the torch slider control, the proportional integral derivative (PID) control method is used. For the straight locomotion, a concept of decoupling method between input and output is adopted and for the turning locomotion, the turning speed is controlled according to the angular velocity value at each point of the comer with range of $90^{\circ}$ constrained to the welding speed. The proposed control methods are proved through simulation results and the results have proved that the mobile robot has enough ability to apply the lattice type welding line.

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Multi-thin plate welding characteristics of Low Carbon Steel for Ni-MH battery of using Continuous Wave Nd:YAG laser (연속파 Nd:YAG 레이저를 이용한 Ni-MH전지용 저탄소강의 다층 박판 용접 특성)

  • Yang, Yun-Seok;Hwang, Chan-youn;Yoo, Young-Tae
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.720-728
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    • 2011
  • Lap joint welding conducts low carbon steel plates using a 2.0kW continuous wave Nd:YAG laser beam. The specimen is composed of thin plate of 20 sheets. Process Variables contain two controlled parameters of the laser power and the welding speed. In order to quantitatively examine the characteristics of the lap welding, the welding quality of the cut section, stain-stress behavior, and the hardness of the welded part are investigated. The weld width difference between the top and the bottom because the welding speed is increased. The reason, cooling rate is decreased because of fast welding speed. When the heat input is higher, larger volume of the base metal will melt and the welding heat has longer time to conduct into the bottom from the top. The microstructure and tensile properties of the joints are investigated in order to analyze the effects of heat input on the quality of laser welded specimen. From the results of the investigation, We observe that welding quality is good for the laser power of 1800W, and laser welding speed from 1.8m/min to 2.2m/min.