Re: UT on PVC welds and bonded joints
: : We are looking for information on ultrasonic techniques
: : and equipment to inspect PVC pipe and plate joints.
: : Is there literature on this subject that is easily
: : available?
: : Three joining methods are used, butt-fusion,
: : epoxy bonding and PVC filler welding.
: : Testing is now just an air pressure test. Future
: : requirements will require better test methods.
: : Also, are there applicable acceptance codes for
: : UT inspection of these joints?
: : Thank you in advance.
: : S.B. Lee
: The following article is available on NDTnet:
: ULTRASONIC AND RADIOGRAPHIC NDT OF BUTT FUSION WELDS IN
: POLYETHYLENE PIPE
: Paper presented at Plastic Pipes IX Heriot-Watt University,
: Edinburgh, Scotland, UK,
: 18-21 September 1995
: by I.J. Munns and G.A. Georgiou TWI, Abington UK
: This paper summarises work at TWI on NDT of butt fusion welds in polyethylene
: and compares this work with results from other published
: literature on this topic. The major objectives of this study were to develop
: ultrasonic and radiographic testing procedures for the inspection of
: butt fusion welds in polyethylene pipe systems. The procedures were developed
: on pipes with diameters greater than 180mm and thicknesses
: greater than 12mm. The underlying techniques, however, can be used on testpieces
: other than pipes, and on a range of different polyethylene types and thicknesses.
: 4. Conclusions
: The main conclusions are based on the work undertaken at TWI on a range of
: polyethylene materials and pipes with diameters greater than
: 180mm and thicknesses greater than 12mm.
: - Ultrasonic creeping waves can be used to inspect the fusion area immediately
: beneath the outer weld bead in polyethylene pipes.
: - Ultrasonic tandem and TOFD techniques can be used to detect and image
: perpendicular planar flaws in butt fusion joints in polyethylenepipes.
: - Ultrasonic techniques are currently unable to detect nominally cold welds.
: - Radiographic intensities of between 16kV and 26kV are optimum when inspecting
: thicknesses of polyethylene pipe between 5mm and 50mm.
: - With radiography it is possible to infer the presence of a cold weld from
: local radiographic density measurements.
: - Polyethylene wire type IQIs have been proven to achieve radiographic
: sensitivities at least as good as polyethylene plaques and step
: wedges with holes, and have other practical handling advantages with regard
: to pipe inspection.