AWS B2.4 pdf free download
AWS B2.4 pdf free download.Welding Procedure and Performance Qualification for Thermoplastics.
elasticity. The property of a substance which enables it to return to its original shape and size after removal of a deforming force.
electrofusion welding (EFW). A thermoplastic welding process where the heat for welding is provided by energizing an electrically resistive coil in the weld zone.
employer. The contractor or manufacturer that adopts this specification for welding procedure and performance qualitication. Closely related companies, including those with different names, for which effective control of welding is as one organization, shall be considered as one employer.
extrusion welding (EX). A joining process in which molten thermoplastic material is forced against preheated work- pieces to produce the weld.
fan welding (HF). A hot gas welding method where the weld rod is fed into the joint without the aid of a welding noZzle: the pressure is applied directly o the welding rod by the welder.
flow fusion welding (FFW). A thermoplastic welding process for sheets or pipe where the melt is constrained during the welding process.
freehand reIding. Sec fan welding (HF).
heated tool butt welding (HT). A method for joining the ends of thermoplastic pipe or fittings in which a hot tool is placed between the pipe ends for a predetermined heating time and then the ends are pushed together with a predetermined amount of force until the joint cools.
hot gas welding (HGW). A thermoplastic welding process in which the parts are softened by hot gas from a welding gun and joined together.
infrared welding (IRW). A thermoplastic welding method in which the heat for welding is generated by infrared radiation.
NPS. Nominal pipe size.
performance qualification variable. A controllable detail which, if changed beyond the limitations specified in this specitication. requires requalitication of the welder or welding operator.
pipe. Used to refer to thermoplastic pipe and tube.
pipe group (PG). A category of thermoplastic pipe dimensions with similar physical attributes requiring similar welding parameters and skills.
polymerization. A chemical reaction in which the molecules of a monomer are linked together to form large molecules whose molecular weight is a multiple of that of the original substance. When two or more monomers are involved, the process is called copolymerization or heteropolymerization.
PP (polypropylene). A tough, lightweight polyolefin plastic made by the polymerization of high-purity propylene gas in the presence of an organomateriallic catalyst at relatively low pressures and temperatures.
PI (polyethylene). A polyolefin composed of polymers of ethylene. It is normally a translucent, tough, waxy solid which is unaffected by water and by a large range of chemicals. There are three general classifications: low-density. medium-density, and high-density.
Performance Qualification Test Record (PQ’I’R). A written record of a test administered to a welder or a welding operator to determine their capacity to perform a specific welding application. Welding performance qualification tests are specific to a WPS.
preheat temperature. The temperature of the base material in the welding area immediately before any welding is performed.
procedure qualification variable. A controllable detail which, if changed beyond the limitations of Essential Procedure Qualification Variables, requires requalilication of the WPS.AWS B2.4 pdf download.
