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Nov 04, 2016 (Image: Temperature) The welding area is to be protected from unfavourable climatic influences (e.g. moisture and temperatures below +40 °F (+5 °C)). The following measures may help to achieve this:·
In order to prevent stresses due to differing temperatures such as the influence of the sun, temperature equalisation should be achieved by covering the region of the welding seams on time. |
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Nov 04, 2016
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Nov 04, 2016 The visual inspection serves to examine butt weldings with regard to the following aspects:
(Image: Welding bead) |
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Nov 04, 2016 During PE welding processes, different failures may occur, which can be detected by means of ultrasonic non-destructive testing. Incomplete fusion at the interior surface, exterior surface or in the cross section, displaced joints may be detected using this testing procedure. (Image: Conventional sliplining process with annular space [FI-Teerb] - Testing the welded seam) (Image: Conventional sliplining process with annular space [FI-Teerb] - View on … |
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Nov 04, 2016
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Nov 04, 2016 What type of information needs to be documented during the welding process? Welding work has to be monitored. The type and extent of supervision has to be agreed upon between the contract partners. It is recommended to document the information about the welding method used in welding protocols or on data media. (Image: Documentation) Welding protocol
As the welder knows the nominal values from the … |
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Nov 04, 2016 What are the most important causes of heating element butt welding failure?
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Nov 04, 2016 The external and internal welding beads that are formed can be removed if desired. If the weld bead requires finishing, this is best done before cooling, when approximately 2/3 of the cooling time is complete. There is a danger that cutting work on the cold bead will cause notches [Simona11]. (Image: Device for removing the internal welding bead for HD-PE pipes [FI-WIDOS]) (Image: Arrangement for removing the internal welding bead for HD-PE pipes (Locheisen) … |
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Nov 04, 2016 The following measures must be taken to assure the required quality of the heating element butt welding work. (Table: Quality assurance measures during heated element butt welding) |
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Nov 14, 2016 (Table: US standards and regulations for PE pipe joining procedures) |
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Nov 04, 2016 (Table: Standards and regulations for heated tool welding (as of 12/2005) [FI-Steina]) |
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(Image: Attention!) Clamping pipe ends axially and cutting them to length square to the pipe axis A pipe separation that is not square may lead to the fact that parts of the electrofusion coils are not covered by the pipe, which may cause excessive heat, uncontrolled formation of melting material and auto-ignition [Friatec04]. Right (Image: Electrofusion welding – square pipe separation according to [FI-Friat]) Wrong (Image: Electrofusion welding pipe separation (… |
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Removing the oxidation layer The oxidation layer that forms on the pipe surface by solar radiation during storage, has to be removed from the pipe before any welding procedure, otherwise a homogeneous connection of the materials would be hindered. In order to remove the oxidation layer, peeling devices have to be used that guarantee a reproducible quality of the joining layer. (Image: Removal of the oxide layer by a peeling device on the construction … |
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The table below presents the quality assurance measures that must be followed during the process of electrofusion welding. (Table: Quality assurance measures during electrofusion welding) |
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The following standards and regulations offer guidelines for electrofusion welding processes. (Table: US standards and regulations - electrofusion) |
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The following European standards and regulations offer guidelines for electrofusion welding processes. (Table: Standards and regulations for electrofusion welding (as of 12.2005) [FI-Steina]) |
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The table below offers an excellent comparison between the heating element butt welding and electrofusion welding processes. (Table: Comparison of plastic welding methods) |
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