• Title/Summary/Keyword: Welding Speed

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Al-7020의 Pulse-GMA 용접에 관한 연구 1

  • 김재웅;허장욱;나석주;이용연
    • Journal of Welding and Joining
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    • v.6 no.2
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    • pp.47-55
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    • 1988
  • This paper reports on a study of the influence of welding variables on the weld shape of Al-7020 in pulse-GMA welding. Five variables, i.e., wire feed rate, peak pulse current, welding speed, welding votage, and pulse frequency were investigated for their effects on the weld shape. From the results of the 2$^{n-1}$ fractional factorial design, quantitative effects of each variable and the interaction of two variables were obtained, and consequently wire feed rate, welding voltage, and welding speed were determined as the main welding variables. Supplementary experiment was performed for ivestigating the detailed relationship between the main variables nd the seld shape. In this experiment, the penetation of the seldment increased when the wire feed rate was raised, nad the bead width increased when the welding voltage was raised or the welding speed was reduced.d.

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Evaluation of Mechanical Properties of AZ61 Magnesium Alloy Joints at various Welding Speeds (용접 속도에 따른 AZ61 마그네슘 합금 마찰교반용접부 기계적 특성 평가)

  • Sun, Seung-Ju;Kim, Jung-Seok;Lee, Woo-Geun;Lim, Jae-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.5
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    • pp.278-284
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    • 2017
  • In this study, the heat input conditions suitable for the AZ61 magnesium alloy were derived by controlling the welding speed at a constant rotational speed. In addition, from an economic point of view, industry demands higher welding speeds. Therefore,the effects of the welding speed were studied. The rotational speed applied was 800rpm, and the welding speed was varied from 100 to 500mm/min to evaluate the behavior of the welded regions. Tensile and hardness tests were conducted to examine the mechanical properties. Optical microscopy was used to observe the microstructure and soundness of the welded regions. Defects were observed at the welded region when the welding speed was more than400mm/min. As the welding speed increased, the grain size of the stir zone decreased and the hardness tended to increase proportionally. When the rotational speed was 800 rpm and the welding speed was 200mm/min and 300mm/min, there wereno defects in the welded region and excellent mechanical properties were recorded. In addition, the joint efficiencies were 100.5% and 101.2%, respectively, and the ultimate tensile strength was similar to that of the base metal. Fracture of the tensile specimen occurred between the advancing side and stir zone, and the fracture location coincided with the region where the hardness decreased temporarily.

Dissimilar Friction Stir Welding Characteristics of Mg Alloys(AZ31 and AZ61) (AZ31와 AZ61 마그네슘 합금의 이종 마찰교반용접 특성)

  • Park, Kyoung Do;Lee, Hae Jin;Lee, Dai Yeol;Kang, Dae Min
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.5
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    • pp.99-104
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    • 2017
  • Friction stir welding is a solid-state joining process and is useful for joining dissimilar metal sheets. In this study, the experimental conditions of the friction stir welding were determined by the two-way factorial design to evaluate the characteristics of the dissimilar friction stir welding of AZ31 and AZ61 magnesium alloys. The levels of rotation speed and welding speed, which are welding variables, were 1000, 2000, 3000 rpm and 100, 200, 300 mm/min, respectively. From the results, the greater the rotation speed and the lower the welding speed of the tool were, the greater the tensile strength of the welded part was. The contribution of the welding speed of the tool is larger than that of the rotation speed of the tool. In addition, the optimal conditions for tensile strength in the dissimilar friction stir joint were predicted to be the rotation speed of 3000 rpm and welding speed of 100 mm/min, and the tensile strength under the optimal conditions was estimated to be $214{\pm}6.57Mpa$ with 99% reliability.

A Study on the Friction Stir Welding Characteristics of AZ31 Mg Alloy by the Design of Experiment (실험계획법에 의한 AZ31 마그네슘 합금의 마찰교반용접 특성에 관한 연구)

  • Kang, Dae Min;Park, Kyoung Do;Jung, Yung Suk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.4
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    • pp.77-82
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    • 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.

Dissimilar Metal Welding of Nd:YAG Laser of Austenitic Stainless Steel and Medium Carbon Steel (중탄소강과 오스테나이트계 스테인레스강의 Nd:YAG 레이저의이종금속 용접)

  • Shin H.J.;Yoo Y.T.;Ahn D.G.;Im K.;Shin B.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1560-1565
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    • 2005
  • 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.

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Microstructural Features of Al Alloy 7N01 Welded by $CO_2$ Laser - Microsturctural Features of Full Penetration Joints - ($CO_2$ 레이저 용접한 7N01 Al합금의 미세조직 특징(I) - 완전용입 용접부의 미세조직 -)

  • 윤재정;강정윤;김인배;김대업
    • Journal of Welding and Joining
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    • v.19 no.4
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    • pp.429-436
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    • 2001
  • The effect of welding condition on the microstructures of the weld metal in A7N01 welded by $CO_2$ laser was investigated. The number of ripples was increased with decreasing power and increasing welding speed. In the bead without ripple lines, the subgrain microstructures distribution from the fusion line toward the center of the bead were in the order of cellular, dendritic and equiaxed dendrite. However, in the bead with ripple lines, cellular and dendritic were formed between the fusion boundary and the ripple line. Inaddition, those structures were also observed between the ripple line. Equiaxed dendrites were formed only at the center line region. Cellular and dendritics formed near the ripple line were larger than those formed near the fusion boundary. The cooling rates estimated by the dendrite arm spacing were in the range of 200 to 1150oC/s. Cooling rate was increased with decreasing the power and increasing the welding speed. Mg and Zn segregated at the boundaries of cellulars and dendritics, Mg was segregated more than Zn. The segregation of Mg and Zn decreased with increasing cooling rate. Hardness of the weld metal was lower than that of the base metal in all welding conditions and increased as the cooling rate increased.

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$CO_2$ Laser Weldablity of High Strength Al Alloy A5038 and A7N01 (고강도 Al합금 A5083 및 A7N01의 $CO_2$ 레이저 용접성)

  • 김장량;하용수;강정윤;김인배
    • Laser Solutions
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    • v.4 no.2
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    • pp.1-12
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    • 2001
  • This study has been performed to evaluate basic characteristics of CW-CO$_2$ laser welding process of A5083 and A7N01 Al alloy. The effect of welding parameters, such as shielding gas, gas flow rate, laser power and welding speed on the bead shape and porosity from bead on plate welding tests have been investigated. Welds shielded by He gas had deeper penetration and better bead shape than those shielded by Ar. The penetration depth was augmented with the increase of laser Power and the decrease of welding speed. Welds of A7N01 alloy had deeper penetration than those of A5083 alloy In beads of A5083 alloy which has deeper penetration, the volume fraction of porosities was high due to the number of its was few, but size of its was larger. The case of deeper penetration beads of A7N01 alloy, the porosity reduced under relatively higher power The Volume fraction of porosities in weld of A5083 alloy was significantly higher than that in weld of A7N01 alloy.

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Microstructure and Tensile Strength of Butt Joint between AA6063 Aluminum Alloy and AISI304 Stainless Steel by Friction Stir Welding

  • Sadmai, Karuna;Kaewwichit, Jesada;Roybang, Waraporn;Keawsakul, Nut;Kimapong, Kittipong
    • International Journal of Advanced Culture Technology
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    • v.3 no.1
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    • pp.179-187
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    • 2015
  • This study presents the experimental results of the Friction Stir Welding (FSW) of AA6063 aluminum alloy and AISI304 stainless steel butt joint by varying the welding parameters such as the rotating speed and the welding speed. The main results are as follows. The variation of the welding parameters produced various characteristic interfaces and had distinct influences on the joint properties. Increasing the rotating speed and the welding speed decreased the joint tensile strength because it produced the defect on the joint interface. The optimum welding parameter that could produce the sound joint was a rotating speed of 750 rpm and the welding speed of 102 mm/min with the tensile strength of 71 MPa.

The Effects of Welding Conditions on the Joint Properties of the Friction Stir Welded AZ31B-H24 Mg Alloys (마찰교반용접한 AZ31B-H24 마그네슘 합금의 용접특성에 미치는 용접조건의 영향)

  • 이원배;방극생;연윤모;정승부
    • Journal of Welding and Joining
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    • v.20 no.5
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    • pp.87-92
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    • 2002
  • Weldability of Friction Stir Welded(FSW) AZ31B-H24 Mg alloy sheet with 4m thick was evaluated by changing welding speed. The sound welding conditions mainly depended on the suffiicient welding heat input during the process. The insufficient heat input resulted in the void like defect in the weld zone. Higher welding speed caused a larger inner void or lack of bonding. The defects were distributed at the stir zone or the transition region between stir zone and thermo-mechanical affected zone (UE). The size of defects slightly increased with increasing welding speed. These defects had a great effect on the joint strength of weld zone. The weld zone was composed of stir zone, TMAZ and heat affected zone. The stir zone was cosisted of fine recrystallized structure with $5-8\mu\textrm{m}$ in the mean grain size. The hardness of weld zone was near the 60HV, which was slightly lower than that of base metal. The maximum joint strength was about 219MPa that was 75% of that of base metal and the yield strength was also lower than that of base metal partly due to the existance of defects.

Weldability Evaluation in Plasma-GMA Hybrid Welding for Al-5083 Using Analysis of Variance (AL5083 합금에 대한 Plasma-GMA 용접에서 분산분석을 이용한 공정변수의 특성 평가)

  • Jung, Jin Soo;Lee, Jong Jung;Lee, Hee Keun;Park, Young Whan
    • Journal of Welding and Joining
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    • v.32 no.1
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    • pp.28-33
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    • 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.