Welding specification for plastics
1 Scope
This standard specifies the terms and definitions of plastic welding specification, hot-gas welding, extrusion welding, fusion welding and electrofusion welding specifications, quality inspection and requirements for welders.
This standard is applicable to the welding specifications for pipes and plates of thermoplastics and plastic alloys, such as polyvinyl chloride [PVC: including chlorinated polyvinyl chloride (PVC-C), unplasticized polyvinyl chloride (PVC-U), soft polyvinyl chloride (PVC-R)], polypropylene [PP: including polypropylene block copolymer (PP-B), polypropylene photopolymer (PP-H), polypropylene random copolymer (PP-R)], polyethylene [PE: including high density polyethylene (PE-HD), medium density polyethylene (PE-MD), low density polyethylene (PE-LD), polyvinylidenefluoride) (PVDF), polytetrafluoroethylene (PTFE-TFM) acrylonitrile/butadiene/styrene plastics (ABS), polyamide (PA).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documents (including any amendment) applies.
GB/T 6111 Thermoplastics pipes for the conveyance of fluids — Resistance to internal pressure — Test method
GB/T 19806 Plastic pipes and fittings — Crushing decohesion test for polythylene (PE) electrofusion assemblies
GB/T 19808 Plastics pipes and fittings — Peel decohesion test for polyethylene (PE) electrofusion assemblies of nominal outside diameter greater than or equal to 90mm
GB/T 19810 Polyethylene (PE) pipes and fittings — Determination of the tensile strength and failure mode of test pieces from a butt-fused joint
GB/T 20674.1 Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 1: Butt fusion
GB/T 20674.2 Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 2: Electrofusion
HG/T 4280 Welding procedure qualification for plastics
HG/T 4282 Test method of tensile for plastics welded test specimen
HG/T 4283 Test method of bending for plastics welded test specimen
CJJ 63-2008 Technical specification for polyethylene (PE) fuel gas pipeline engineering
TSG D2002-2006 Regulation on welding technology for gas supply polyethylene pipe
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
hot-gas welding
welding method by which a plastic welding surface and plastic welding rod/wire are heated to plastic state with hot gas and then connected together under external pressure, including round nozzle hot-gas welding and high-speed nozzle hot-gas welding
Note: This term "热风焊" in Chinese is referred to as "热气焊接" in GB/T 2035-2008 Terms and definitions for plastics (idt ISO 472:1999) (their English terms are the same).
3.2
round nozzle hot-gas welding
welding method by which a welding rod is heated with gas from a round nozzle, and the welding rod and the base metal are welded together by hot gas; by moving the nozzle slowly along the weld, heat up the area of welding rod and base metal at the same time with hot gas; the welding direction should be perpendicular to the base metal, and the nozzle moves up and down along the sector area of the welding rod and base metal
3.3
high-speed nozzle hot-gas welding
welding method by which a welding rod in plasticized state is pressed on the welding surface through heating welding rod with a beam-inclined nozzle, and the welding rod automatically moves along with the nozzle
3.4
extrusion welding
welding method by which the plastic welding rod and the surface to be welded are preheated with hot gas, and the welding rods are connected together after being fed and pressurized by screw
3.5
fusion welding
welding method by which after heating the two plastic end faces of plastics with heating part, remove the heating part quickly, and then weld the two plastic end faces together under appropriate pressure, including butt fusion welding, socket fusion welding and saddle fusion welding
3.6
butt fusion welding
connection method by which two plastic end faces are joined together under certain pressure, with joint cooled for a required period under the pressure, after the two end faces are heated to a viscous flow state with special heating part and the heating part is removed
3.7
socket fusion welding
connection process in which insert the outer surface of a pipe and the inner surface of a fitting into the die of the welding machine without rotation at the same time and heat for seconds, then quickly remove the welding machine, and quickly insert the heated pipe vertically into the fitting, keeping pressure and lowering temperature
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Overview for plastic welding procedures
4.1 Types, codes, characteristics and methods of welding procedures
4.2 Types of welds, joints and grooves
4.3 Welding process record
5 Hot-gas welding
5.1 General
5.2 Welding machinery
5.3 Welding procedure
5.4 Welding parameters
6 Extrusion welding
6.1 General requirements
6.2 Welding machinery
6.3 Welding procedures
6.4 Welding parameters
7 Fusion welding
7.1 General requirements
7.2 Welding machinery
7.3 Welding procedures
7.4 Welding parameters
8 Electrofusion welding
8.1 General requirements
8.2 Welding machinery
8.3 Welding procedures
8.4 Welding parameters
9 Quality inspection
9.1 Welding quality requirements for hot-gas welding and extrusion welding
9.2 Quality inspection for fusion welding
9.3 Electrofusion welding quality inspection
10 Requirements for welders
10.1 Theoretical and technical requirements
10.2 Procedure requirements
10.3 Qualification requirements
Annex A (Informative) Corresponding table of plastic materials and welding methods used
Annex B (Normative) Types of welds, joints and grooves
Annex C (Informative) Record form of welding process
Annex D (Normative) Parameter of welding procedure
Figure 1 Treatment of pipe end slope surface
Figure 2 Butt fusion welding procedure graph
Figure 3 Cut out the slope
Figure 4 Scraping off all slashes
Figure 5 Welding bead formation of the bulge of hot plate butt welding
Figure 6 Accepted and rejected welding beads
Figure 7 Back bending test for cracks of rejected welding beads
Figure 8 Measurement of welding bead width
Table 1 Types, codes and characteristics of plastic welding procedures
Table 2 Selection of welding wire size
Table 3 Requirements and selection of hot-gas welding rods (specification of single welding rod)
Table 4 Requirements and selection of hot-gas welding rods (specification of double welding rods)
Table 5 Maximum gap width between welding surfaces of PVDF pipes, fittings and panels after milling
Table 6 Maximum gap width between welding surfaces of PVC-U pipes, fittings and panels after milling
Table 7 Maximum gap width between welding surfaces of PP pipes, fittings and panels after milling
Table 8 PVDF pipe slope surface and insertion depth
Table 9 PP pipe slope surface and insertion depth
Table 10 Parameters of socket dimension and corresponding nominal outer diameter of electrofusion fitting
Table 11 Welding quality requirements for hot-gas welding and extrusion welding
Table 12 Appearance inspection items and requirements for quality of PE pipeline welding junction
Table A.1 Corresponding table of plastic materials and welding methods used
Table B.1 Types of welds, joints and grooves of hot-gas welding and extrusion welding
Table B.2 Types of welds, joints and grooves of fusion welding and electrofusion welding
Table C.1 Record form of welding process of hot-gas welding and extrusion welding
Table C.2 Operation record form of weld junction of butt fusion welding
Table C.3 Construction log of butt fusion welding
Table C.4 Operation record form of weld junction of electrofusion welding
Table C.5 Construction log of electrofusion welding
Table D.1 Hot-gas welding procedure parameters
Table D.2 Extrusion welding procedure parameters
Table D.3 Procedure parameters of butt fusion welding of PVC-U pipes and fittings
Table D.4 Procedure parameters of butt fusion welding of PP pipes, fittings and panels
Table D.5 Procedure parameters of butt fusion welding of PP-R pipes
Table D.6 Butt fusion welding parameters of SDR11 PE pipes
Table D.7 Butt fusion welding parameters of SDR17.6 PE pipes
Table D.8 Procedure parameters of butt fusion welding of PVDF pipes, fittings and panels
Table D.9 Procedure parameters of socket fusion welding of PP pipes and fittings
Table D.10 Procedure parameters of socket fusion welding of PE pipes and fittings
Table D.11 Procedure parameters of socket fusion welding of PVDF pipes and fittings
