Welding methods
Overview of all welding processes: materials and diameter ranges
Butt fusion, socket fusion, electrofusion, extrusion, hot air and other processes in one table: which materials they cover and which diameters they are used for.
How to use the table
The table compiles all the processes described in the lexicon and shows which materials and diameter ranges they cover. Click on the process in the first column to go to the article detailing procedure, parameters and inspection.
The diameter ranges indicate the availability of equipment and do not guarantee that your specific combination of material, SDR and fitting is available. At the limits of the range, always check against the supplier's product range and against the standard specified for the project.
Overview: process, material and diameter
The sequence follows typical application areas: from large pressure pipes to small diameters and repairs, through to membranes, sheets and fabricated components. Select a material in the filter to display only the processes suitable for it.
| Method | Materials | Diameter range | Mainly used for |
|---|---|---|---|
| Butt fusion welding (heated tool welding) | PE, PP, PVDF, PVC | approx. Ø16-Ø3200 | Pressure pipes, large mains and long runs. PVC-U is a variant with stricter parameters |
| PVC-U: variant of butt fusionvariant | PVC | According to pipe and sheet range | Lower heating element temperature, short t2 and fume extraction to DVS 2207-12 |
| Socket fusion welding | PE, PP, PVDF | approx. Ø20-Ø125 | Installations, geothermal loops and small fittings |
| Electrofusion welding | PE, PP | approx. d20-d630 | Confined spaces, repairs and documented welding |
| Extrusion welding | PE, PP, PVC, PVDF | All diameters, from sheets approx. 3 mm | Repairs, tie-ins and thick-walled parts - PVC-U requires extraction |
| Hot gas welding (hand welding) | PE, PP, PVC, PVDF | Components and details, not field pipes | Liners, detailing around fittings and repairs |
| Hot wedge and membrane welding | PE, PP, PVC | Foils and membranes, no pipes | Ponds, landfills, tarpaulins and waterproofing membranes |
| Sheet welding | PE, PP | Sheets approx. 3-30 mm | Tanks, vessels, ducts and sheet components |
| Ultrasonic, vibration and spin welding | PE, PP, ABS, PC | Small and medium-sized parts | Series production and injection moulded parts |
| Saddle fusion welding | PE | From approx. d63 up, according to saddle range | Branching on an existing main pipeline |
| Butt welding of casing pipes | PE | According to casing pipe range | Pre-insulated district heating and cooling pipes |
| Pipe branches and tees | PE, PP | According to branch equipment range | Branch pipes and branch connections on pressure pipelines |
| Solvent welding | PE, PP, PTFE, POM | Not diameter-dependent | Parts that cannot be fusion welded |
PVC-U is a variant of butt fusion, not a separate main method. The parameters follow DVS 2207-12.
The diameter ranges indicate the equipment range and are approximate values. The materials are typical; some combinations require special equipment or manufacturer approval.
If you are unsure about the process
Start by determining whether the component is a pressure pipe, a sheet or a component that cannot be fusion welded. Pressure pipes are welded using butt fusion, socket fusion or electrofusion, whereas sheet materials and membranes have their own dedicated processes.
Next, the diameter and accessibility of the joint determine the choice: small diameters in confined spaces point towards socket fusion or electrofusion fittings, large diameters towards butt fusion, and repairs towards extrusion welding. The complete equipment overview can be found in select equipment: complete overview, and material selection is compiled in thermoplastic types.
Butt fusion of PVC: a variant with stricter parameters
PVC-U is not a separate main method alongside butt fusion. It is the same hot-tool butt fusion as PE and PP, but with a narrower process window and stricter precautions.
The heating element runs cooler, typically around 190 degrees, the changeover time t2 must be short and consistent, and the pressure must be monitored closely. PVC-U degrades quickly when overheated and releases hydrogen chloride (HCl), so fume extraction is required at the workplace, and discolouration in the weld seam is a warning sign.
The parameters follow DVS 2207-12 and the manufacturer's table for the specific pipe or semi-finished product. Read the standalone article on butt fusion of PVC-U with stricter parameters and precautions.