• Title/Summary/Keyword: carbon steel pipe

Search Result 139, Processing Time 0.031 seconds

Nonlinear vibration of FG-CNTRC curved pipes with temperature-dependent properties

  • Mingjie Liu;Shaoping Bi;Sicheng Shao;Hadi Babaei
    • Steel and Composite Structures
    • /
    • v.46 no.4
    • /
    • pp.553-563
    • /
    • 2023
  • In the current research, the nonlinear free vibrations of curved pipes made of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) materials are investigated. It is assumed that the FG-CNTRC curved pipe is supported on a three-parameter nonlinear elastic foundation and is subjected to a uniform temperature rise. Properties of the curved nanocomposite pipe are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite pipe are temperature-dependent. The governing equations of the curved pipe are obtained using a higher order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the pipe. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved nanocomposite pipe. For the case of nanocomposite curved pipes which are simply supported in flexure and axially immovable, the motion equations are solved using the two-step perturbation technique. The closed-form expressions are provided to obtain the small- and large-amplitude frequencies of FG-CNTRC curved pipes rested on a nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of CNT distribution pattern, the CNT volume fraction, thermal environment, nonlinear foundation stiffness, and geometrical parameters on the fundamental linear and nonlinear frequencies of the curved nanocomposite pipe.

Analysis of Hydrogen-tightness on the Metal Sealing of a Fuel Pipe for FCEV according to Material Change of the Fitting Body (체결부 재료에 따른 FCEV 연료파이프 메탈 씰링부의 기밀성 분석)

  • Lee, J.M.;Han, E.S.;Chon, M.S.;Lee, H.W.
    • Transactions of Materials Processing
    • /
    • v.28 no.5
    • /
    • pp.266-274
    • /
    • 2019
  • Metal sealing is used to connecting the parts between valves and fuel pipes for a FCEV which utilizes hydrogen gas of 700 bar. Instead of general carbon steel, stainless steel is the primary material used to manufacture fuel pipes due to hydrogen embrittlement. The shape of deformation between metals is an important factor on the air-tightness of the metal to metal contact. Since the stainless steel pipe is hardened using the plastic forming during the tip shaping stage, this work hardening could have an effect on the deformed shape and characteristics of contact surfaces in fastening of pipes. In this paper, the deformation history of the pipe model was considered in order to analyze the hydrogen-tightness on the metal sealing part. The contact distance and the forward displacement for fastening were compared using experimental results and the simulation results. The simulation of the effect of material change on the fitting body demonstrated that the hardness or the strength of the formed tip of the pipe was designed to a proper valued level since the characteristics of the contact surface was exhibited better when the strength of the pipe was lower than that of the fitting body.

Comparative Study on Disinfection Efficiency of Chlorine and Chloramine in the Distribution Systems (배·급수계통에서 유리염소와 클로라민의 소독효과에 관한 비교연구)

  • Choi, Yong-Il;Nam, Sang-Ho
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.13 no.2
    • /
    • pp.82-88
    • /
    • 1999
  • This study was to evaluate disinfection efficiency of chlorine and chloramine as secondary disinfectants in the distribution systems. Indicator organism, HPC in the suspended and attached were measured for copper, galvanized steel, PVC, and carbon steel pipes. For suspended microorganism, the PVC pipe was markedly dense among the assessed pipe materials. The attached microorganism was markedly equivalent roughness of pipe materials. In copper and galvanized pipes, chloramine was more effective that free chlorine to disinfect suspended microorganism in the contact time of 2 hours. The contact time for the 99% inactivation of suspended microorganism by chloramine was longer than that of free chlorine. Regardless of pipe materials, chloramine was effective on both disinfection efficiency and 99% inactivation time for attached microorganism. In conclusion, chloramine which is good disinfectant for long contact time was recommended as secondary disinfectant in distribution system.

  • PDF

Fatigue Properties of the Small Diameter Branch Welded Pipe Joint with variation of Welding Procedures and Welding Shapes. (용접공정 및 용접형상 변화에 따른 소구경 분기배관 용접부의 피로특성)

  • 백종현;김철만;김우식
    • Proceedings of the KWS Conference
    • /
    • 2003.11a
    • /
    • pp.191-193
    • /
    • 2003
  • S-N fatigue tests were conducted to investigate the fatigue strength of the small diameter socket and butt welded joints of carbon steels. Experimental parameters were pipe diameter, throat depth, shape of socket welds and welding procedure. Filler metals used in SMAW and GTAW procedure were E9016-G with diameter of 4.0 mm and ER70S-G with diameter of 2.4 m. API 5L Gr.B pipes were adopted as a small diameter branch pipes. All socket fittings were machined from ASTM A105 carbon steel. Fatigue strength in socket weld joints increased with increasing pipe diameter, area of weld metal and weld leg length of pipe side.

  • PDF

Influence of Welding Shapes and Welding Procedures on Fatigue Strength of Small Diameter Branch Welded Pipe Joint (소구경 분기배관 용접부의 피로강도에 미치는 용접부 형상 및 용접공정의 영향)

  • Baek, Jong-Hyun;Kim, Cheol-Man;Kim, Woo-Sik
    • Proceedings of the KSME Conference
    • /
    • 2003.11a
    • /
    • pp.1092-1097
    • /
    • 2003
  • S-N fatigue tests were conducted to investigate the fatigue strength of small diameter socket and butt welded joints made of carbon steels. Experimental parameters were pipe diameter, throat depth, shape of socket welds and welding procedure. Filler metals used in SMAW and GTAW procedure were E9016-G with diameter of 4.0 mm and ER70S-G with diameter of 2.4 mm. API 5L Gr.B pipes were adopted as a small diameter branch pipes. All socket fittings were machined from ASTM A105 carbon steel. Tensile strength was not affected by the welding procedure. Fatigue strength in socket weld joints increased with increasing pipe diameter, area of weld metal and weld leg length of pipe side.

  • PDF

S-N Fatigue Strength of Small Diameter Branch Welded Pipe with Variation of Welding Shapes and Welding Procedures (용접부의 형상과 공정변화에 따른 소구경 분기배관의 피로강도 특성평가)

  • 백종현;김우식
    • Journal of Welding and Joining
    • /
    • v.22 no.3
    • /
    • pp.50-55
    • /
    • 2004
  • S-N fatigue tests were conducted to investigate the fatigue strength of small diameter socket and butt welded joints made of carbon steels. Experimental parameters were pipe diameter, throat depth, shape of socket welds and welding procedure. Filler metals used in SMAW and GTAW procedure were E9016-G with diameter of 4.0 m and ER70S-G with diameter of 2.4 m. API 5L Gr.B pipes were adopted as a small diameter branch pipes. All socket fittings were machined from ASTM A105 carbon steel. Tensile strength was not affected by the welding procedure. Fatigue strength in socket weld joints increased with increasing pipe diameter, area of weld metal and weld leg length of pipe side.

Effects of Thinning Length on Failure Mode of Local Wall Thinned Pipe (감육 배관의 손상모드에 미치는 감육부 길이의 영향)

  • Kim, Jin-Weon;Park, Chi-Yong;Lee, Sung-Ho;Kang, Tai-Kyung
    • Proceedings of the KSME Conference
    • /
    • 2001.06a
    • /
    • pp.357-362
    • /
    • 2001
  • The pipe fracture tests were performed on 102mm-Sch.80 carbon steel pipe with various local wall thinning shapes, in order to understand failure behavior of thinned pipe. Pipe specimens were subjected to monotonic bending moment, using 4-points loading system, under internally pressurized condition. From the results of experiment, the failure mode, load carrying capacity, and deformability of local wall thinning pipe were investigated. Failure mode of thinned pipe depended on magnitude of internal pressure and thinning length as well as loading direction and thinning depth and angle. The variation in load carrying capacity and deformability of thinned pipe with length of thinned area was determined by stress type appled to thinning region and circumferential thinning angle. Also, the effect of internal pressure on failure behavior was dependent on failure mode of thinned pipe, and it promoted crack occurrence and mitigated local buckling at thinned area.

  • PDF

Evaluation of Material Properties for Yonggwang Nuclear Piping Systems (III) - Main Steam System - (영광원자력 배관소재의 재료물성치 평가 (III) -주증기계통-)

  • 김영진;석창성;김종욱
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.19 no.6
    • /
    • pp.1460-1468
    • /
    • 1995
  • The objective of this paper is to evaluate the material properties of SA106 Gr. C carbon steel and its associated weld manufactured for main steam system of Yonggwang 3,4 nuclear generating stations. A total of 43 tensile and 35 fracture toughness tests were performed and the effects of various parameters such as pipe size, crack plane orientation, test temperature, welding on material properties were discussed. Test results show that the effects of crack plane orientation, test temperature, and welding on fracture toughness were significant while the effects of pipe size, specimen orientation and test temperature on tensile properties were negligible. Especially the dependence of J-R curves on the crack plane orientation appears to be the characteristics of carbon steel.

Deformation and Fracture Behavior of Wall Thinned Carbon Steel Pipes (감육된 탄소강배관의 변형과 파괴거동)

  • Ahn, Seok-Hwan;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
    • /
    • v.20 no.4 s.71
    • /
    • pp.17-23
    • /
    • 2006
  • Monotonic four-point bending tests were conducted on straight pipe specimens, 102 mm in diameter with local wall thinning, in order to investigate the effects of the depth, shape, and location of wall thinning on the deformation and failure behavior of pipes. The local wall thinning simulated natural erosion/corrosion metal loss. The deformation and fracture behavior of the straight pipes with local wall thinning was compared with that of non wall-thinning pipes. The failure modes were classifiedas local buckling, ovalization, or crack initiation, depending on the depth, shape, and location of the local wall thinning. Three-dimensional elasto-plastic analyses were carried out using the finite element method. The deformation and failure behavior, simulated by finite element analyses, coincided with the experimental results.

Effect of Solution Temperature on the Cavitation Corrosion Properties of Carbon Steel and its Electrochemical Effect

  • Jeon, J.M.;Yoo, Y.R.;Kim, Y.S.
    • Corrosion Science and Technology
    • /
    • v.20 no.6
    • /
    • pp.325-334
    • /
    • 2021
  • In the open system (vessel and pipe), the maximum corrosion rate of carbon steel at ca. 80 ℃ was obtained due to the decrease of dissolved oxygen by increasing the solution temperature. Effect of temperature on the cavitation damage can be explained through several mechanisms. Moreover, when cavitation occurs on the surface of metal and alloys, whether cavitation is erosion or corrosion is still controversial. This work focused on the effect of solution temperature on the corrosion of carbon steel under cavitation in an open system, Tests were performed using an electrochemical cavitation corrosion tester in 3.5% NaCl solution and the effect of solution temperature of carbon steel was discussed. Cavitation corrosion rate can be increased by cavitation, but when the temperature increases, a dissolved oxygen content reduces at a very high speed and thus the maximum cavitation corrosion temperature changed from 80 ℃ to 45 ℃. Below the maximum cavitation temperature, the electrochemical effect was more dominant than the mechanical effect by increasing temperature, but over the maximum cavitation temperature, the mechanical effect was more dominant than the electrochemical effect by increasing temperature.