• Title/Summary/Keyword: Welded Joints

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Studies on weldment performance of Ti/Al dissimilar sheet metal joints using laser beam welding

  • Kalaiselvan, K.;Elango, A.;Nagarajan, N.M.;Mathiazhagan, N.;Vignesh, Kannan
    • Coupled systems mechanics
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    • v.7 no.5
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    • pp.627-634
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    • 2018
  • Laser beam welding is more advantageous compared to conventional methods. Titanium/Aluminium dissimilar alloy thin sheet metals are difficult to weld due to large difference in melting point. The performance of the weldment depends upon interlayer formation and distribution of intermetallics. During welding, aluminium gets lost at the temperature below the melting point of titanium. Therefore, it is needed to improve a new metal joining techniques between these two alloys. The present work is carried for welding TI6AL4V and AA2024 alloy by using Nd:YAG Pulsed laser welding unit. The performance of the butt welded interlayer structures are discussed in detail using hardness test and SEM. Test results reveal that interlayer fracture is caused near aluminium side due to low strength at the weld joint.

Effects of Hybria Welding Parameters on the Toughness of Weld Metal in Ship Structural Steel (조선용강재의 레이저-아크 하이브리드 용접금속부 충격인성에 미치는 용접변수의 영향)

  • Hong, Seung-Gab;Lee, Jong-Bong
    • Journal of Welding and Joining
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    • v.24 no.6
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    • pp.33-38
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    • 2006
  • Since the 1990's, European shipbuilding industries introduced hybrid welding process in order to decrease thermal distortion of welded joints in passenger shipbuilding. In this study, we investigated effects of hybrid welding parameters on the toughness of weld metal using DH36 steel in order to obtain more sound welds in passenger shipbuilding. Type of leading process, joint gap distance and chemical composition of consumables were considerably correlated with the toughness of weld metal. Especially, the toughness was considerably increased with high-Ti containing consumables. In addition, hybrid welding speed increased by using plasma cut edges, the oxides layer of which increased absorption efficiency of laser beam.

Development of Reinforced Concrete Column and Steel Beam Composite Joints (철근콘크리트 기둥과 철골 보 합성구조 접합부 시스템 개발)

  • 김도균;정하선;최완철
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.691-698
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    • 2001
  • Recent trends in the construction of long span or tall building frames feature the increase use of composite members that steel and concrete is functioning together in what terms of mixed structural systems. One of such systems, RCS (reinforced concrete column and steel beam) system is introduced and closely examined focusing on bearing strength of the composite joint in this paper. The main objective of this study was to develope detail to increase bearing capacity while bearing failure is one of the two primary modes of failure in RCS system. The results show that specimens with the U-type bearing reinforcement detail developed in this study enhanced the bearing strength by 1.20-1.50. The U-type reinforcement is the effective details to increase joint bearing strength compared to others like vertical reinforcement welded to beam flanges.

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The Analysis of Circumference Through-Wall Cracked Pipe Considering Weld Characteristic (용접부 강도불균질을 고려한 원주방향관통균열 배관의 파괴역학 해석법)

  • Park, Bo-Gyu;Oh, Chang-Kyun;Kim, Yun-Jae;Kim, Young-Jin;Kim, Jong-Sung;Jin, Tae-Eun
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.31-36
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    • 2004
  • Defective components of interest include not only homogeneous components, but also components with weldments where tensile properties vary across the weldment. Noting that the region near the weldment is the most vulnerable place for crack initiation and subsequent growth, defect assessment methods for homogeneous structure. Moreover, weldment width and crack location also affects the deformation and fracture behavior of the welded joints. These weld characteristics can evaluate using plastic limit load. So in this paper, evaluate plastic limit load both full circumference part-throughwall cracked pipes and circumference through-wall cracked pipes considering weld characteristics. And using evaluate results, proposed J-integral and crack opening displacement(COD) estimate method based on reference stress method.

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A Study on the Joint Properties according to the Friction Welding Area Change of Carbon Steel(SM25C) (탄소강(SM25C)의 접합면적의 변화에 따른 마찰용접의 접합특성에 관한 연구)

  • Park Keun Hyung;Min Taeg Ki;Yoon Young Joo;Park Chang Soo
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.1
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    • pp.102-107
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    • 2006
  • This study investigates the properties as the difference friction welding area on SM25C steel rod. The tensile and bending strength and of welded joints, the hardness distribution of welds, the microstructure of welds and the tensile fracture surfaces were mainly investigated through this experiment. The fixed friction welding conditions were revolution 2000rpm, friction pressure 70Mpa, friction time 1.5sec, upset pressure 100Mpa, upset time 2.0sec, upset length 2.8mm and changeable friction welding parameter was friction welding area.

A Study on the In-plane Displacement Measurement of Spot welded Joints by Electronic Speckle Pattern Interferometry Method (레이저 스패클 간섭법에 의한 점 용접부의 면내변위 측정에 관한연구)

  • 성백섭
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.04a
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    • pp.48-53
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    • 1997
  • Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar laserm, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment wpecimen was loaded in parallel with a loadcell. The specimen was the cold rolled sdteel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

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Plastic Flow Direction and Strength Evaluation of Dissimilar Fiction Bonding Interface Joints (이종마찰 접합계면부의 소성유동 방향성 및 강도 평가)

  • Oh, Jung-Kuk;Sung, Back-Sub
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.5
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    • pp.43-50
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    • 2002
  • Friction welding has many merits such as energy efficiency, simple processing, etc butt difficult to obtain good weld at the welded interface and heat affected zone. To date, the continuum mechanics and fracture mechanics are utilized to analyse stresses at the interface and propagation of cracks. In this study. STS304 and SM15C are selected because they can be differentiated distinctively from metallic point of view and crack can be observed easily. It is ovserved during friction welding that STS304, rotary part is hatter than SH15C, fixed part. The last fracture occurs around the center because the surface of fatigue fracture has smooth regions, due to the separation phenomenon in plastic flows layers and striation dimple pattern.

A Study on Corrosion Fatigue Properties of Welded Joints for TMCP High Strength Steels (TMCP 고장력강 용접부의 부식도영 특성에 관한 연구)

  • 이택순;이휘원;김영철
    • Journal of Ocean Engineering and Technology
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    • v.10 no.3
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    • pp.14-23
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    • 1996
  • The corrosion fatigue test were carried out to evaluate the fatigue characteristics of accelerated cooled (ACC) TMCP high tensile strength steels and weld joint with high heat input by one side one run submerged are welding. In this paper, the fatigue crack growth behaviors were investigated with the center crack tension specimen of base metal and heat affected zone in substitute sea water and air, respectively Main results obtained are sunnarized as follows: 1. The fatigue crack growth rates in sea water faster than those in air environment for the different heat input values, crack growth rate of base metal is very fast and effect of heat input is not remarkable. 2. In HAZ (82kJ/cm, 116kJ/cm), the crack branching phenomena were observed in both air and sea water environment, 3. In SEM observation, the corrosion effect on base metal was larger than that on HAZ in corrosion environment.

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An experimental study on different socket base connections under cyclic loading

  • Pul, Selim;Husem, Metin;Arslan, Mehmet Emin;Hamzacebi, Sertac
    • Computers and Concrete
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    • v.13 no.3
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    • pp.377-387
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    • 2014
  • This paper presents an experimental study on socket base connections of precast reinforced concrete columns. The main purpose of this study is to determine socket base connection which has the closest behavior to monolithic casted column-base joints. For this purpose, six specimens having different column-socket base connection details were tested under cyclic loading. For each test, strength, stiffness, ductility and drift ratios of the specimens were determined. Test results indicated that a suggested connection type is 10%-30% stronger than the other type of connections under lateral loading. The welded connection (PC-5) had better lateral load carrying capacity and ductility. On the other hand, performance of standard connection (PC-1) which is commonly used in construction was weaker than other connections. Thus, decision of connection type should be referred not only performance but also applicability.

Characteristics of Welded Zone Using Solar Energy Concentration (태양광선을 이용한 용접부 특성)

  • Prasad, K.D.V.;Kim, I.S.;Sung, B.S.;Kim, B.C.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.2
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    • pp.9-17
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    • 2001
  • In this paper the attempts made by the authors to explore the feasibility of utilising concentrated solar beam radiation for joining engineering thermoplastics such as Acrylonitrilc/Butadiene/Styrene (ABS), Polycarbonate(PC) and Polymethylmethacrylate(PMMA) are presented. In addition, to study the joining of the materials, necessary experimentation with applying primer was performed. Tensile tests were conducted to determine the bond strength achieved at the specimen joint interface. Microscopic examinations of the fractured joints were performed in order to analyse the overall bond quality. Finally, the results in terms of bond strength achieved at the joint interface and energy consumed in the process were compared with those obtained with similar thermoplastic joining technique utilising microwave energy. In conclusion some advantages and limitations were outlined and necessary improvements of the jointing technique were recommended.

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