There are a number of different mechanical test methods available to assess the quality of butt
fusion welded joints in polyethylene (PE) pipes. However, little published information exists
on the correlations that may or may not exist between the results from these methods.
This paper compares the results from five short-term mechanical test methods : three point
bend, dumb-bell tensile, waisted tensile, low temperature (-60°C) tensile, and Charpy impact,
on butt fusion joints in 355mm outside diameter (OD) PElOO pipes. In addition, the size of
the weld beads was measured. Butt fusion joints were produced using one standard and two
non-standard welding parameters, in order to produce joints of nominally different quality.
Results from this study showed that, of the five short-term coupon tests examined, only one,
the waisted tensile test, was able'to differentiate between welds made under the standard and
non-standard welding conditions. Even in this test the failure mode and failure load could not
distinguish between all three welding conditions; only the extension at break and energy to
break values showed differences.
The results also showed that the dimensions of the external weld bead could discriminate
between the welds made under the standard and the hvo non-standard conditions. This
suggests that measuring the bead height rather than the bead width should give a clearer
discrimination between welds made under different conditions.
Please note that the whole article content is available on PPCA website only
the inspection of butt fusion and electrofusion joints in polyethylene (PE) pipes. Depending on the technique and inspection procedure, various types of flaw, including discrete planar lack of fusion, particulate contamination, voids, cold fusions and pipe under-penetration can be detected. However, the usefulness of...
The current practice for assuring the quality of butt fusion and electrofusion welded joints during installation is by recording the welding parameters used, together with a visual inspection of the welded joint, supplemented by the destructive testing of welds on a sample basis using a short-term test. However,...
As part of the Polytec Systems European-funded project, electrofusion (EF) joints in
polyethylene (PE) pipe, containing different flaws, have been subjected to various standard
and non-standard, long-term and short-term, coupon and whole pipe tests. The results were
compared to determine which tests could discriminate...
This paper describes the development of an ultrasonic non-destructive examination (NDE)
system that is incorporated into an automatic butt fusion welding machine and performs an
examination of the joint within the cooling time of the welding cycle. The programme of
work included the optimisation of the ultrasonic NDE...
This paper describes an assessment of the quality of butt and branch joints in polyethylene (PE) pipes, produced using the linear vibration welding technique. Results showed that butt welds in pipes of 165 mm outside diameter(0D) could be produced within a total weld/cool time of 85 seconds, which is less than 15?'0...
For the butt fusion joining of PE80 polyethylene pipes on site, long heat soak and
cooling times predominate in the United Kingdom and other countries. The
literature is reviewed to propose that these heat soak and cooling times can be
significantly reduced via the use of machines with verifiable, reduced short...
This paper describes an initial programme of work to examine the feasibility of joining polyethylene pipe using the linear vibration welding technique. Commercial linear vibration welding equipment was used to join small lengths (100mm) of 125mm SDR11 PE80 and 180mm SDR17.6 PElOO pipe. Welds were achieved in total...