• Title, Summary, Keyword: Similar Metal Weld

Search Result 75, Processing Time 0.035 seconds

Effects of Similar Metal Weld on Residual Stress in Dissimilar Metal Weld According to Safe End Length (동종금속용접이 이종금속용접부 잔류응력에 미치는 영향 평가 시 안전단 길이에 따른 효과)

  • Song, Tae-Kwang;Chun, Yun-Bae;Oh, Chang-Young;Bae, Hong-Yeol;Kim, Yun-Jae;Lee, Sang-Hoon;Lee, Kyoung-Soo;Park, Chi-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.33 no.7
    • /
    • pp.664-672
    • /
    • 2009
  • Nozzle in nuclear power plant is connected to pipe using safe end. Dissimilar metal weld between nozzle and safe end is followed by similar metal weld between safe end and pipe. And thus residual stress in dissimilar metal weld can be affected by similar metal weld. Similar metal weld impose bending stress on dissimilar metal weld, which is according to the length of safe end. In this study, simple nozzle model which covers various radius to thickness ratios was proposed to quantify residual stress in dissimilar metal weld based on finite element analyses. As a result, short length of safe end was proved to be more effective to mitigate residual stress in dissimilar metal weld and critical effective length of safe end is provided according to the radius to thickness ratio.

Evaluation of Similar Metal Weld Effects on Residual Stress of Nozzle Dissimilar Metal Weld (노즐 이종용접부 잔류응력에 미치는 동종용접의 영향 평가)

  • Yu, Seung-Cheon;Jeong, Jae-Uk;Chang, Yoon-Suk;Kim, Young-Jin
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.110-114
    • /
    • 2008
  • Determination of weld-induced residual stress has been an important issue in nuclear power industry because several failures were reported in dissimilar metal weld parts due to primary water stress corrosion cracking. In this context, a couple of remarkable round robin analyses were conducted to quantify the welding simulation variables and to establish optimized numerical analysis process. The purpose of the present research is to introduce welding simulation results for a safety and relief nozzle, which has a dissimilar metal weld part as well as a similar metal weld part. First, finite element analyses are carried out to calculate residual stresses at the inside of nozzle considering only dissimilar metal welding. Subsequently, residual stresses taking into account both the dissimilar and similar metal welding are computed. The similar metal weld effect is evaluated by compa

  • PDF

Electron beam weldability of Niobium (니오븀의 전자빔 용접성)

  • An, Byung-Hun;Yoon, Jong-Won;Kim, Sook-Hwan
    • Journal of Korean Society of Laser Processing
    • /
    • v.11 no.2
    • /
    • pp.15-19
    • /
    • 2008
  • Electron beam (EB) weldability of pure grade Nb sheet was studied. One of Nb sheets was as-annealed and the other was cold rolled. Microstructures, Vickers hardness, and transverse weld tensile test were carried out for the base metal, the heat affected zone (HAZ) and weld metal. In the case of the EB welds made using the annealed Nb sheeet, fine equiaxed grains and coarse grains were dominant at the base metal and the HAZ, respectively, and columnar grains were observed at the weld metal. For the EB welds made using the cold rolled Nb sheet, elongated grains in the rolling direction at the base metal, and the microstructures of the weld metal and the HAZ are similar to those of the EB welds made using the annealed Nb sheet, respectively. For both annealed and cold rolled Nb sheet, the width of the HAZs are unusually wide in spite of using high density heat source, i.e. electron beam, and the grain sizes of both HAZs are similar. When tensile test was carried out using the transverse weld specimens, the failure occurred at the HAZ for both EB welds made using Nb sheets annealed and cold rolled, respectively and the tensile strengths of both specimens were 161MPa. Vickers hardness of EB welds made using annealed Nb was 56-57 Hv at both base metal and weld metal, 52-53 Hv at the HAZ. On the other hand, Vickers hardness of EB welds made using cold rolled Nb was 97-99 Hv at the base metal, but the hardness values of weld metal were similar to those obtained at the weld metal of annealed Nb.

  • PDF

The Low Cycle Fatigue behavior of Laser Welded Sheet Metal (박판형 레이저 용접재의 저주기 피로 특성)

  • 김웅찬;곽대순;김석환;오택열
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.1025-1028
    • /
    • 2004
  • In this paper, we studied low cycle fatigue behavior of laser welded sheet metal that used automobile body panel. Specimens were manufactured as weld condition and sheet metal using automobile manufacturing company at present. For to know mechanical properties, micro Vicker's hardness test was performed of specimens. But, we can't confirm mechanical properties of weld bead and heat affected zone because laser weld makes very narrow weld bead and heat affected zone than other welding method. Therefore, we performed low cycle fatigue test with similar weldment, dissimilar weldment, similar thickness and dissimilar weldment, and dissimilar thickness and dissimilar weldment for fatigue properties of thickness and welding direction. As well, we analysis stress distribution of base metal, weld bead, and heat affected zone according to strain load using finite element method.

  • PDF

Effects of PWHT on Tensile Properties and Impact Toughness of FCAW Weld Metal of FH Steels for Cargo Tank in LPG Carrier (LPG선 탱크용 FH 강재 FCAW 용접금속의 인장성질과 충격인성에 미치는 후열처리의 영향)

  • Jeong, Sang-Hoon;Kang, Chang-Yong
    • Journal of Welding and Joining
    • /
    • v.32 no.4
    • /
    • pp.63-68
    • /
    • 2014
  • This paper has an aim to study the effect of PWHT and its conditions(peak temperature and holding time) on the tensile properties and impact toughness of FCAW weld metal in relation to microstructure. Impact toughness was evaluated to apply the cargo tank of liquified gas carriers under the various PWHT condition of each class societies. On the basis of these study, it was found that PWHT conditions within all class societies affect charpy absorbed energy of weld metal little or no, all PWHT weld metals kept similar level of charpy absorbed energy as as-weld weld metal down-to $-60^{\circ}C$ and finally indicated lower energy value than that of as-weld weld metal at $-75^{\circ}C$. It is because the precipitation of 2nd phase was controlled from welding consumable and the grain size was grown by PWHT.

Effect of Flux Composition on Weld Metal Toughness and Workability in Submerged Aye Welding with 60kgf/$\textrm{mm}^2$ Grade C-Mo Type Wires (60kgf/$\textrm{mm}^2$급 C-MO계 와이어를 사용한 서브머지드 아크 용접금속 인성 및 작업성에 미치는 플럭스 조성의 영향)

  • 방국수;안영호
    • Journal of Welding and Joining
    • /
    • v.14 no.6
    • /
    • pp.93-100
    • /
    • 1996
  • Effect of a flux composition on weld metal toughness in submerged arc welding with 60kgf/$\textrm{mm}^2$ grade C-Mo type wires was investigated and interpreted in terms of weld metal microstructure and hardenability. Flux workability was also studied by characterizing a weld bead profile. Compared to other weld metals, .weld metal used alumina basic flux with nickel showed lowest oxygen content, highest hardenability and the most acicular ferrite. The highest impact toughness of that weld metal, however, was attributed to the tough matrix due to the nickel rather than to the larger amount of acicular ferrite. Manganese silicate flux had better workability than alumina basic flux, showing broader welding conditions resulting in a depth-to-width ratio of 0.5. The composition of oxides in the weld metal was dependent on the flux composition, showing MnO-SiO$_2$-TiO in manganese silicate flux and MnO-SiO$_2$-Al$_2$O$_3$-TiO in alumina basic flux. MnO-SiO$_2$composition in both oxides was similar to a tephroite.

  • PDF

Effect of Welding Parameters on the Friction Stir Weldability of 5052 Al alloy (5052 알루미늄 합금 마찰교반접합부 특성에 미치는 접합인자의 영향)

  • 이원배;김상원;이창용;연윤모;장웅성;서창제;정승부
    • Journal of Welding and Joining
    • /
    • v.22 no.3
    • /
    • pp.69-76
    • /
    • 2004
  • Effects of friction stir welding parameters such as tool rotation speed and welding speed on the joints properties of 5052 Al alloys were studied in this study. A wide range of friction stir welding conditions could be applied to join 5052 AA alloy without defects in the weld zone except for certain welding conditions with a lower heat input. Microstructures near the weld zone showed general weld structures such as stir zone (SZ), thermo-mechanically affected zone (TMAZ) and heat affected zone (HAZ). Each zone showed the dynamically recrystallized grain, transient grain and structure similar to base metal's, respectively. Hardness distribution near the weld zone represented a similar value of the base metal under wide welding conditions. However, in case of 800 rpm of tool rotation speed, hardness of the stir zone had a higher value due to the fine grain with lots of dislocation tangle, a higher angle grain boundary and some of Al3Fe particles. Except joints with weld defects, tensile strength and elongation of the joints had values similar to the base metal values and fracture always occurred in the regions approximately 5mm away from the weld center.

Fatigue Crack Growth Characteristics on The Weld Joint of Bimaterial (이종재료 용접부의 피로균열진전 특성)

  • 권재도;김우현;박중철;배용탁;김중형
    • Proceedings of the KWS Conference
    • /
    • /
    • pp.81-85
    • /
    • 1997
  • This paper was conducted the fatigue crack growth test on the base metal and weld joint of bimaterial(carbon-stainless steel), carbon steel and stainless steel. As the result, the fatigue crack growth rate of weld joint on the stainless-stainless steel is faster than stainless base metal, and weld joint on the carbon-carbon steel heat affected zone is slower than carbon base metal. And fatigue crack growth rate of carbon-stainless steel weld joint and heat affected zone is similar to the behavior of stainless base metal. In conclusion, weld joint of bimaterial is stable in the fatigue crack growth behavior.

  • PDF

High Fatigue Life and Tensile Strength Characteristics of Low Activation Ferritic Steel(JLE-1) by TIG Welding (TIG용접한 저방사화 페라이트강(JLF-1)의 고온강도 및 피로수명특성)

  • Yoon, H.K.;Lee, S.P.;Kim, S.W.;Park, W.J.;Kohyama, A.
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.181-186
    • /
    • 2001
  • JLF-1 steel (Fe-9Cr-2W-V-Ta), low activation ferritic steel, is one of the promising candidate materials fer fusion reactor applications. High temperature fatigue life and tensile strength of JLF-1 steel and its TIG welded joints were investigated at the room temperature and $400^{\circ}C$. The strength of base metal (JLF-1) is in between those of weld metal and the HAZ. When the test temperature was increased from room temperature to $400^{\circ}C$, both strength and ductility decreased for base metal, weld metal and the HAZ. The longitudinal specimens of base metal showed similar strength and ductility compared with those of the transverse specimens at room temperature and $400^{\circ}C$. Little anisotropy was observed in the JLF-1 steel base metal in terms of rolling direction. Fatigue limit of weld metal which was obtained from cross-weld specimen is 495MPa. Thus, the weld metal showed the higher fatigue limit than those of base metal at both room temperature and $400^{\circ}C$. Little anisotropy of fatigue properties was observed for JLF-1 base metal in terms of rolling direction. When the test temperature was increased from room temperature to $400^{\circ}C$, the fatigue limit of both base metal and weld metal decreased substantially.

  • PDF

Cold Cracking Susceptibility in Weld Metal of High Strength-Toughness Steel (고강도 고인성강 용접금속의 저온균열 감수성에 관한 연구)

  • 이종봉;안상곤;안영호;김영우
    • Journal of Welding and Joining
    • /
    • v.13 no.4
    • /
    • pp.46-54
    • /
    • 1995
  • The cold cracking susceptibility of a variety of weld metals deposited by GMAW with several kinds of commercial solid wires for high strength-toughness steel was investigated. G-BOP test and LB-TRC test were carried out to study the effects of preheat, chemical composition and hydrogen level on the weld metal cold cracking. The results obtained are as follows. 1) 10% CPT obtained by G-BOP test was the most valuable criteria for evaluating the cold cracking susceptibility of weld metals compared with percentage of cracking at room temperature and crack free temperature, and it had good correlation with the results of LB-TRC test. 2) Cold cracking susceptibility of weld metals was high in the row of MG100A, MG100C, MG100D and MG100B. Welds deposited with MG130 and MG80 showed similar icidents of cracking with MG100C and MG100B respectively, even though their strength levels were different. 3) Diffusible hydrogen level in weld metals which has good relation with hydrogen content in wire itself was the most critical factor for controlling the cold cracking susceptibility of weld metal.

  • PDF