0
Research Papers: Materials and Fabrication

Safety Assessment of Cold Welding Defect in Electro-Fusion Joint of Polyethylene Pipe

[+] Author and Article Information
Jinyang Zheng

e-mail: jyzh@zju.edu.cn

Institute of Process Equipment,
Zhejiang University,
Hangzhou 310027, China

Weican Guo

Institute of Process Equipment,
Zhejiang University,
Hangzhou 310027, China
Zhejiang Inspection Center of Special Equipment,
Hangzhou 310020, China

Cheng Xu

Institute of Applied Mechanics,
Zhejiang University,
Hangzhou 310027, China

1Corresponding author.

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the Journal of Pressure Vessel Technology. Manuscript received August 6, 2012; final manuscript received February 19, 2013; published online September 16, 2013. Assoc. Editor: Marina Ruggles-Wrenn.

J. Pressure Vessel Technol 135(5), 051403 (Sep 16, 2013) (6 pages) Paper No: PVT-12-1121; doi: 10.1115/1.4024447 History: Received August 06, 2012; Revised February 19, 2013

Cold welding defect is the most common defect in electro-fusion (EF) joint for connecting polyethylene (PE) pipe. In our previous study [1], the cold welding defect is successfully inspected by an eigen-line method based on phased array ultrasonic testing technology. However, limited research has been reported on the acceptance criterion of cold welding defect in EF joint. In this paper, the bonding strength of EF joint is measured using a peeling test. The bonding energy of welding interface is calculated both by phenomenological model and deformation energy analysis method. EF joints with different degrees of cold welding are made and used for peeling tests. The results show that the bonding energy of fused interface rises rapidly after bonding and then goes through a plateau region. The starting point of the plateau region in the bonding energy versus welding time curve is regarded as the minimum required welding time of EF joint. Based on bilinear fitting, the acceptance criterion of cold welding defect is proposed.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Shi, J., Zheng, J., Guo, W., and Qin, Y., 2012, “Defects Classification and Failure Modes of Electrofusion Joint for Connecting Polyethylene Pipes,” J. Appl. Polym. Sci., 124(5), pp. 4070–4080. [CrossRef]
Bowman, J., 1997, “A Review of the Electrofusion Joining Process for Polyethylene Pipe Systems,” Polym. Eng. Sci., 37(4), pp. 674–691. [CrossRef]
Wang, H., 2007, “Ultrasonic Testing and Safety Assessment of Defects in Electro-Fusion Joint of Polyethylene Fuel Gas Pipe,” Zhejiang University.
Nakashiba, A., Nishimura, H., Inoue, F., Nakagawa, T., Homma, K., and Nakazato, H., 1993, “Fusion Simulation of Electrofusion Polyethylene Joints for Gas Distribution,” Polym. Eng. Sci., 33(17), pp. 1146–1151. [CrossRef]
Higuchi, Y., Nishimura, H., Inoue, F., Ishikawa, T., and Miyaki, S., 2002, “Investigation of Appropriate Cooling Times for Electrofusion Jointing of PE Pipes for Gas Distribution,” Polym. Eng. Sci., 42(2), pp. 382–394. [CrossRef]
Rosala, G. F., Day, A. J., and Wood, A. S., 1997, “A Finite Element Model of the Electrofusion Welding of Thermoplastic Pipes,” Proc. Inst. Mech. Eng., Part E: J. Process Mech. Eng., 211(E2), pp. 137–146. [CrossRef]
Shi, J., Zheng, J., Guo, W., Xu, P., Qin, Y., and Zuo, S., 2009, “A Model for Predicting Temperature of Electrofusion Joints for Polyethylene Pipes,” ASME J. Pressure Vessel Technol., 131(6), p. 061403. [CrossRef]
Shi, J., Zheng, J., and Guo, W., 2011, “Formation Mechanism of the Eigen-Line in Electrofusion Joints of Polyethylene Pipes,” ASME J. Pressure Vessel Technol., 133(5), p. 051403. [CrossRef]
Wu, D. Y., Meure, S., and Solomon, D., 2008, “Self-Healing Polymeric Materials: A Review of Recent Developments,” Prog. Polym. Sci., 33(5), pp. 479–522. [CrossRef]
Butler, C. A., Mccullough, R. L., Pitchumani, R., and Gillespie, J. W., 1998, An Analysis of Mechanisms Governing Fusion Bonding of Thermoplastic Composites,” J. Thermoplast. Compos. Mater., 11(4), pp. 338–363. [CrossRef]
Shi, J., 2011, “Formation Mechanism, Inspection and Safety Assessment of Electrofusion Joint Containing Cold Welding Defect,” Zhejiang University.

Figures

Grahic Jump Location
Fig. 1

Specimen of peeling test

Grahic Jump Location
Fig. 2

Stages of peeling test, (a) elongation of pipe, (b) bending of pipe, (c) separation of fused interface, and (d) fracture of pipe

Grahic Jump Location
Fig. 3

Tensile curve of peeling test

Grahic Jump Location
Fig. 4

Specimen after peeling test

Grahic Jump Location
Fig. 5

Bonding energy calculated by phenomenological model and deformation energy analysis

Grahic Jump Location
Fig. 6

Four procedures of EF welding

Grahic Jump Location
Fig. 7

Flow diagram of fitting program

Grahic Jump Location
Fig. 8

Safety assessment of EF joint containing cold welding defect

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In