Effect of Forced Cooling on Welds in PE Pipes

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Back to Core Research Programme AMorph – 4D Printing for Field Morphing Structures Automation of Composite and Hybrid Joining Process Coaxial Wire Additive Manufacturing Processes and In-Line Monitoring Tools Development of Coded Excitation Technique for Non-Metallic Pipes Inspection Development of Digital Twin technology as a demonstrator for real-time integrity assessment of crack growth in tensile specimens Development of Friction Stir Welding (FSW) for Hydrogen Fuel Storage Tanks Development of Leak-Before-Break Hydrogen Storage Composite Pressure Vessels With Polymeric Liner Establishing Assessment Methods for Determining Safe Service Limits of High-Temperature Materials in Extreme Environments Fracture toughness in aggressive environments: effect of crack monitoring techniques on test results In-process detection and non-destructive testing of electron beam weld imperfections Internal Bore Coatings for Applications in Corrosion and Hydrogen Environment Joining of Additively Manufactured Materials Long term behaviour of polymeric liner materials/coatings in hydrogen service Techniques for High Temperature Ultrasonic Inspection of Arc Welding Ultimate Leverage Fund

Project Code: 0905-03

Objectives

Produce butt fusion and electrofusion joints in PE pipes with outside diameters (ODs) between 110 and 630mm with and without forced air cooling.

Determine the time required for the joint to completely solidify for different degrees of forced cooling.

Determine the short-term and long-term integrity of the joints produced with and without forced cooling.

Produce guidance for industry on whether forced cooling can be used to increase productivity of welding PE pipes.

Project Outline

A number of butt fusion and electrofusion welds will be made using industry-standard welding parameters and also with various degrees of forced air cooling(air temperature, flow rate, distance between air source and joint). Thermocouples will be inserted at the centre of the wall thickness before welding in order to monitor weld temperature against cooling time. The butt fusion joints, once fully cooled, will be subjected to a tensile test using a waisted specimen (which has been found in a previous CRP to be the most sensitive short-term test for assessing butt fusion joints in PE pipes); the electrofusion joints will be subjected to a crush test (which has been found in a previous CRP to be the most sensitive short-term test for assessing these types of joint in PE pipes). Additional welds will be made under identical conditions, but without thermocouples embedded, and these will be assessed using the whole pipe tensile creep rupture test (which is the most realistic long-term test for joints in PE pipes).

Relevant Industry Sectors

Oil, Gas and Chemicals, Power, Construction and Engineering

Technical and Economic Benefits

It is estimated that 300,000km of PE pressure pipe is laid in Western Europe and North America per year. According to Fast Fusion, installation cost savings from using forced cooling range from US$0.04 per foot for 2 OD pipe to US$5.76 per foot for 48 OD pipe. Assuming an average cost saving of US$0.20 per foot, gives a potential saving in Western Europe/North America of US$200M.

Industrial Member Report

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Literature review: Forced cooling of polyethylene pipe butt fusion welds