【国外标准】 Standard Practice for Determining the Short Term Tensile Weld Strength of Chemical-Resistant Thermoplastics

5.1 The mechanical performance of welded thermoplastic structures is largely dependent on the quality of the welding operation. It is necessary for fabricators to 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, it can be concluded that, with the same degree of skill and diligence by the welder, acceptable welds can be obtained in fabricated structures.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.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 shall reflect procedures to be used in actual fabrication.1.4 Welding methods to be used include machine welding, extrusion welding, and hot gas welding.1.5 This practice can be utilized by relevant certification bodies to assess welder proficiency and qualification.1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: There is no known ISO equivalent to this standard.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.