Which AWS document specifies prequalified WPS for welding processes?

AWS D1.1 is the primary document that specifies prequalified Welding Procedure Specifications (WPS) for structural steel welding. This code is part of the American Welding Society's guidelines and is widely used in the construction industry for ensuring that welding practices adhere to established standards. Within AWS D1.1, you will find detailed requirements for various welding processes, including structural welding methods, materials, and prequalified procedures. The inclusion of prequalified WPS allows for certain weldments to be executed without the need for additional testing as long as they conform to the guidelines laid out in the document. This streamlines the process for inspectors and welders, facilitating projects while maintaining safety and quality standards.

The other documents mentioned focus on different materials or applications. For example, AWS D1.4 pertains to the welding of reinforcing steel, AWS D2.1 addresses the procedures for welding aluminum structures, and AWS D3.6 focuses on welding plastic piping materials. Each of these codes has its specific applications and does not cover the broad prequalification of WPS for structural steel that AWS D1.1 provides.