• Title/Summary/Keyword: Laser Welding

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Laser Welding Properties of the S45C using Automobile Brake Parts (자동차 브레이크 부품용 S45C 소재의 레이저 용접특성 평가)

  • Sim, Kijoong;Cho, Wonyoung;Kim, Youngkwan;Choi, Kyujae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.1
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    • pp.103-109
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    • 2014
  • This paper represents the s-cam manufacturing process with the high-carbon steel like S45C using laser welding system. Laser welding of the high-carbon steel is generally difficult because of hardening of the weld zone. Also, existing s-cam manufacturing process, electric resistance welding system, have some problems like increase of production and development cost. To solve those problems, we are introduced the laser welding system with the pre-heating system for precision welding of s-cam with separated shaft and cam part. S-cam manufactured with optimum laser welding conditions is verified the performance like tensile strength, torsional strength and fatigue test. Strength and fatigue test results are described.

Laser Weldability and Formability of Hot Rolled Steels for Hydroforming Applications (하이드로포밍용 열연 강재의 레이저 용접성 및 성형 특성)

  • Lee Won-Beam;Lee Jong-Bong
    • Journal of Welding and Joining
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    • v.22 no.6
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    • pp.19-24
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    • 2004
  • The laser welding and its analysis of thin-sheet carbon steels were carried out with high power $CO_{2}$ laser. The main factor of weld quality of laser welding is gap and edge quality. This work was preformed to focus on the gap tolerance problem during laser welding. First, bead on plate welding of thin sheet was examined to investigate the effect of laser welding variables, and to obtain optimum welding condition. Butt welding was also carried out to show the effect of gap on the laser weldability of thin sheet. In order to investigate the effect of gap on formability of welded thin sheet, LDH test was caried out. At high welding speed, the partial penetration was obtained by low heat input. Otherwise, porosity was formed in the bead at low weld speed because of too much heat input. The optimum welding condition of welding was derived from bead width, penetration and hardness property. The maximum gap tolerance on laser welding was observed to be about 0.2mm. This gap size has good relationship with beam size of laser spot(about 0.3mm). The formability of welded sheet was about $80{\%}$ value of base metal and the gap size has not affected on the formability, although weld quality is dependent on the gap size.

A Study on the Characteristic Change of 2.25Cr-1Mo Steel Welds for Various Welding Processes (용접 공정에 따른 2.25Cr-1Mo강 용접이음부의 특성 변화에 관한 연구)

  • BANG HAN-SUR;OH CHONG-IN;BANG HEE-SUN;KIM HYUNG
    • Journal of Ocean Engineering and Technology
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    • v.19 no.1
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    • pp.49-56
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    • 2005
  • In spite of the merits of laser welding being able to obtain the high welding quality such as smaller width of melting and heat affected zone, smaller welding deformation and fine grains of weldment compared to arc welding, laser welding is mainly used in joining of thin steel parts of electronics industry. Laser welding is getting widely used in joining thick plate and special kinds of steel due to its high power. While the arc welding is still applied for 2.25Cr-1Mo steel which is the essential material of atomic power generation equipment, the laser welding is not yet applied despite its high quality. So it has a trial to a special case demanding high welding quality such as atomic power plant. Accordingly, in this research, the mechanical properties of weldments by arc and laser welding were investigated using FEM to confirm the applicability of laser welding to 2.25Cr-1Mo steel. The Charphy test was carried out to understand the effect on the fracture toughness of weldments. The results of examination and test of the mechanical properties showed the validity of this research.

Effects of Nd:YAG Laser Welding Parameters on Fatigue life of Lap Joint Structure in Stainless Steel (스테인리스강의 Nd:YAG 레이저 겹치기 용접부 피로수명에 미치는 용접변수의 영향)

  • Kim, Yang;Yang, Hyun-Seok;Park, Ki-Young;Lee, Kyoung-Don
    • Journal of Welding and Joining
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    • v.26 no.1
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    • pp.69-75
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    • 2008
  • Spot welding which use the main process for side block production of stainless steel railway vehicle is legged behind in laser welding about a quality and productivity. Although the laser welding has many potential advantages such as low heat input and aspect ratio of weld bead, its application to a new structural component still is required many engineering data including mechanical properties such as tensile, fatigue strength, etc on. Therefore, experimental analysis was carried out to understand the fatigue phenomena of different thickness stainless steel overlap joining panels by Nd:YAG laser welding. The fatigue life curves were obtained through fatigue tests with the various levels of applied load. The fatigue life is related with the parameters such as gap size and penetration depth through experiment. As the results, tensile strength and fatigue life were proportional in heat input level and gap was identified the major factor for fatigue life. Also we could know that deferent a-ferrite content at HAZ depend on welding heat input was important factor to determine a formation of initial crack and total fatigue life cycle.

Study on the Process Parameters for Laser Welding of Coaxial Circular Pipe Inner Flange (동축 파이프 이음부의 레이저용접 공정변수에 관한 연구)

  • Kim, Yong;Park, Ki-Young;Lee, Kyoung-Don
    • Laser Solutions
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    • v.12 no.3
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    • pp.14-17
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    • 2009
  • The laser welding was performed for the flange joint of two overlapped coaxial circular pipes which serve as the inlet and connector pipes of STS 316L. The laser welding test finally resulted in a good penetration depth of 1.8 to 2.0 mm. On the way to get the good welding quality, two important parameters were found to be optimized. One is the focal positioning which is the offset of the laser beam focus to the exact welding seam line, which is more critical in the inner flange laser welding. When the beam spot size was deviated more than $200\;{\mu}m$ from the seam line, welding of two pipes is failed. The other is a gap size since a certain amount of gap is inevitable due to fabrication tolerance, or artificial allowances for smooth insertion of a pipe. However, it is required to restrict the gap allowance within 0.2mm to avoid undesirable undercut on a welding bead.

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Development of Statistical Model and Neural Network Model for Tensile Strength Estimation in Laser Material Processing of Aluminum Alloy (알루미늄 합금의 레이저 가공에서 인장 강도 예측을 위한 회귀 모델 및 신경망 모델의 개발)

  • Park, Young-Whan;Rhee, Se-Hun
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.4
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    • pp.93-101
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    • 2007
  • Aluminum alloy which is one of the light materials has been tried to apply to light weight vehicle body. In order to do that, welding technology is very important. In case of the aluminum laser welding, the strength of welded part is reduced due to porosity, underfill, and magnesium loss. To overcome these problems, laser welding of aluminum with filler wire was suggested. In this study, experiment about laser welding of AA5182 aluminum alloy with AA5356 filler wire was performed according to process parameters such as laser power, welding speed and wire feed rate. The tensile strength was measured to find the weldability of laser welding with filler wire. The models to estimate tensile strength were suggested using three regression models and one neural network model. For regression models, one was the multiple linear regression model, another was the second order polynomial regression model, and the other was the multiple nonlinear regression model. Neural network model with 2 hidden layers which had 5 and 3 nodes respectively was investigated to find the most suitable model for the system. Estimation performance was evaluated for each model using the average error rate. Among the three regression models, the second order polynomial regression model had the best estimation performance. For all models, neural network model has the best estimation performance.

Design of a Laser Welding Machine for the Precision Improvement (용접 정밀도 향상을 위한 레이저 용접기의 구조개선)

  • Ro, Seung-Hoon;Jeong, Pyeung-Soo;An, Jae-Woo;Kang, Hee-Tae;Lee, Tae-Hoon
    • Journal of the Korean Society of Industry Convergence
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    • v.13 no.4
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    • pp.197-203
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    • 2010
  • Laser welding is widely used for precision welding because of superior mechanical properties and high productivity. Generally the accuracy of the welding is determined by the distribution of the bead which is affected by the structural vibrations of the equipment. This study was originated to stabilize a laser welding machine to minimize the bead distribution for the precise joining. The structural properties of the laser welding machine have been investigated to analyze the major factors of the vibrations to cause the bead distribution. The ideas for the design improvement have been applied to the simulation model to identify the effects and further to achieve the stability design and to minimize the bead distribution. The result shows that a few simple design alterations can substantially suppress the structural vibrations and improve the welding accuracy. The procedure used for this study can also be applied to similar welding equipments for improving the structural stability and the welding accuracy.

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Investigation on Nd:YAG Laser Weldability of Zircaloy-4 End Cap Closure for Nuclear Fuel Elements

  • Kim, Soo-Sung;Lee, Chul-Yung;Yang, Myung-Seung
    • Nuclear Engineering and Technology
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    • v.33 no.2
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    • pp.175-183
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    • 2001
  • Various welding processes are now available for end cap closure of nuclear fuel element such as TG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding processes are widely used for manufacturing commercial fuel elements, they can not be recommended for the remote seal welding of a fuel element at a hot cell facility due to the complexity of electrode alignment, difficulity in the replacement of parts in the remote manner and a large heat input for a thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for Zircaloy-4 end cap welding inside hot cell. The laser welding apparatus was developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The weldability of laser welding was satisfactory with respect to the microstructures and mechanical properties comparing with TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in a remote manner have been developed The effects of irradiation on the properties of the laser apparatus were also being studied.

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A Study on the Laser Welding of Cladding Tube with Temp. Sensor for Fuel Irradiation Test (핵연료 조사시험용 온도센서 피복재의 레이저용접 연구)

  • Kim, Su-Seong;Lee, Cheol-Yong;Kim, Ung-Gi;Lee, Jeong-Won;Go, Jin-Hyeon;Lee, Yeong-Ho
    • Proceedings of the KWS Conference
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    • pp.106-108
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    • 2005
  • The instrumented fuel irradiation test at a research reactor is needed to evaluate the performance of the developed nuclear fuel. The fuel elements can be designed to measure the center line temperature of fuel pellets during the irradiation test by using temperature sensor. The thermal sensor was composed of thermocouple and sensor sheath. Micro-laser welding technology was adopted to seal between seal tube and sensor sheath with thickness of 0.15 mm. The soundness of welding area has to be confirmed to prevent fission gas of the fuel from leaking out of the element during the fuel irradiation test. In this study, fundamental data for micro-laser welding technology was proposed to seal temperature sensor sheath of the instrumented fuel element. And, micro-laser welding for dissimilar metals between sensor sheath and seal tube was characterized by investigating welding conditions. Moreover, the micro-laser welding technology is closely related to advanced industry. It is expected that the laser material processing technology will be adopted to various a pplications in the industry.

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A Study on the Distribution of Welding Residual Stresses in $2\frac{1}{4}Cr-1Mo$ Steel by $CO_2$ Laser Welding (수치해석에 의한 $2\frac{1}{4}Cr-1Mo$$CO_2$ 레이저 용접부의 잔류응력 분포 특성에 관한 연구)

  • Bang, Han-Sur;Kim, Young-Pyo;Kim, Hyoung;Yu, Suk-Min
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.274-278
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    • 2003
  • In recent, an application of high energy density beam we/ding is increasing to obtain the high quality in weldments. Laser welding, especially, has been recognized as an useful method and its beam power has also increased according to the development of relevant technology. However, welding method in the fields of power plant is conservative because their structures have required to endure high temperature and pressure. So, authors conduct the numerical simulation in order to consider the possibility of laser welding on the material of the pressure vessels ($2\frac{1}{4}Cr-1Mo$ steel). As a result of this study, we can confirm the advantages of laser welding and obtain useful information for the experiments of weldability.

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