Study on welding of electrofusion fittings for high⁃density polyethylene natural gas pipeline

doi:10.19491/j.issn.1001-9278.2025.02.011

Abstract

Abstract:

In this paper， the effects of ambient temperature and input energy on the mechanical properties of electrofusion joint used in the connection of small⁃caliber high⁃density polyethylene （PE⁃HD） gas pipes and pipe fittings were studied. Seven sets of parameters were applied for experiments， and the voltage， current， and welding interfacial temperature of the pipes and pipe fittings were collected during the welding process. The interfacial temperature increased gradually with an increase in the ambient temperature， and meanwhile the percentage of weld peeling decreases gradually. With an increase in the input voltage， the input energy increased， but the percentage of weld peeling decreased gradually. Furthermore， the higher input energy resulted in a phenomenon of over⁃welding. The failure in the removal of the skin layer of the pipe affected the welding quality. The intelligent electrofusion welding machine and data management software were recommended for use to monitor the energy input throughout the process， adjust the input energy in real time， and intelligently identify the quality of the weld.

Key words: high?density polyethylene pipe, electrofusion fitting, intelligent electrofusion equipment, energy collecting and managing system, stripping strength

CLC Number:

TQ320.6

XU Lu, LIU Jian, WANG Zhenchao, ZHANG Shijun, QIE Jichun, YOU Qijiang, CAI zhihui. Study on welding of electrofusion fittings for high⁃density polyethylene natural gas pipeline[J]. China Plastics, 2025, 39(2): 60-66.

Figures/Tables 13

实验编号	环境温度/℃	管件输入电压/V	熔接时间/s
A	-10	39.5	70
B	40	39.5	70
C	23±2	39.5	70
D	23±2	33.6	70
E	23±2	45.4	70
F	23±2	49.5	70
G	23±2	39.5	70

Tab.1. Experimental plan

Fig.1. Experimental procedure

Fig.2. Schematic diagram of electrofusion welding and data collection

Fig.3. Photos of the experimental process

Fig.4. Welding and stripping test principle of the electric melting tube fittings

Fig.5. Ambient temperature test results

Fig.6. Welding interface temperature test results

Fig.7. Test results of different input energy

Fig.8. Relationship between input energy and fusion interface temperature

Fig.9. Overheated electrofusion fitting caused by high input voltage

Fig.10. Real⁃time value of the current， voltage， resistance and power

Fig.11. Monitoring and analysis software interface

Fig.12. Welded joint without removing the pipe skin at fusion area

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