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Mar 13, 2006 During PE-welding processes, different failures may occur, which can be detected by means of ultrasonic non-destructive testing according to DVS 2203. Incomplete fusion at the interior surface, exterior surface or in the cross section, displaced joints. (Image: Conventional sliplining process with annular space [FI-Teerb] - Testing the welded seam) (Image: Conventional sliplining process with annular space [FI-Teerb] - View on the complete welding joint) |
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Mar 13, 2006
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Mar 13, 2006 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 method information in welding protocols or on data media [DVSR2207-1]. (Image: Documentation) Welding protocol
As the welder knows the nominal values from the regulations and standards, these values will always remain within the stipulated tolerances. |
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Mar 13, 2006
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Mar 13, 2006 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 – approx. 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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Mar 13, 2006 (Table: Quality assurance measures during heated element butt welding) |
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Mar 13, 2006 (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 … |
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Removing the oxide layer The oxide layer that forms on the pipe surface by solar radiation during storage, has to be removed from the pipe before any welding procedure as otherwise a homogeneous connection of the materials would be inhibited. In order to remove the oxide 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 site [… |
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(Table: Quality assurance measures during electrofusion welding) |
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(Table: Standards and regulations for electrofusion welding (as of 12.2005) [FI-Steina]) |
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(Table: Comparison of plastic welding methods) |
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