Significance and Use
5.1 The mechanical performance of welded thermoplastic structures is largely dependent on the quality of the welding operation. Fabricators should determine that the proper welding procedures are being followed and that welders maintain their proficiency. Results from this practice are indicative of skill in proper welding procedures for different thermoplastic materials and the use of appropriate welding equipment. If the welded test specimens have short term weld factors that meet or exceed the minimums as set forth in this practice, or as agreed to by supplier and user, it may be concluded that, with the same degree of skill and diligence by the welder, acceptable welds should be obtained in fabricated structures.
Scope
1.1 This practice covers the preparation and evaluation of joints between two pieces of weldable grades of thermoplastic materials, backed and unbacked, (such as those shown in Table 1) up to 2 in. (50 mm) in thickness.
|
|
| °FA | Recommended Gas TypeB | |
|
| HDPE | 500–600 |
| Nitrogen or Air |
|
| PP | 550–600 |
| Nitrogen or Air |
|
| PVC | 500–550 |
| Air |
|
| CPVC | 550–660 |
| Air |
|
| PVDF | 650–680 |
| Nitrogen or Air |
|
| ECTFE | 665–695 |
| Nitrogen |
|
| ETFE | 675–710 |
| Air |
|
| FEP | 650–725 |
| Air |
|
| PFA | 675–750 |
| Air |
|
| MFA | 536–554 |
| Air |
1.2 Since there are numerous new technologies and techniques constantly being developed for plastic welding, there are no profiles and procedures that can be considered as standard for all plastics at various thicknesses. This practice is not intended to define profiles and procedures; however, it is intended to establish methods to evaluate minimum short term weld factors to be achieved by the welder for the respective plastics.
1.3 Weld procedures used for test pieces should reflect procedures to be used in actual fabrication.
