A is a written document that provides the welding variables for a specific application to ensure repeatability. It acts as a set of instructions for the welder.
Voltage, amperage, and preheat/post-weld heat treatment requirements. 2. Procedure Qualification Record (PQR)
The ASME welding standard, also known as ASME Section IX, is a set of guidelines and requirements for welding processes and procedures used in the fabrication, installation, and inspection of boilers, pressure vessels, and piping systems. The standard provides detailed specifications for welding materials, equipment, techniques, and inspection methods to ensure that welds meet the required quality and safety standards.
5. Base and Filler Metal Classification (P-Numbers and F-Numbers)
Each process has unique essential variables. For example, changing from DC+ to DC- in GTAW is an essential variable; in SMAW, it is not.
: Specifies standards for forged steel fittings, including socket-welding and threaded types used in high-pressure and high-temperature applications.
These variables are only considered essential when the referencing construction code requires (impact testing at low temperatures). If impact testing is mandatory for the application, changes to supplementary essential variables—such as an increase in heat input or a change in welding position—will require re-qualification of the procedure. Nonessential Variables
| Variable | Purpose | Example | |----------|---------|---------| | | Groups base metals with similar weldability & mechanical properties. | P-No. 1 = carbon steels (SA-106, SA-516); P-No. 8 = austenitic stainless (SA-240 304) | | F-Number | Groups filler metals by similar handling characteristics. | F-No. 1 = mild steel E6010; F-No. 4 = low-hydrogen E7018 | | A-Number | Groups filler metals by chemical composition (for WPS impact testing). | A-No. 1 = carbon steel; A-No. 8 = austenitic stainless |
Based on audit data from Authorized Inspection Agencies (AIAs), these are the most frequent violations of the welding standard ASME:
Section IX is the cornerstone of ASME welding. It doesn't tell you how to design a pressure vessel, but it absolutely tells you how to prove your welding process and your welders are up to the task. Its primary purpose is to establish rules for qualifying:
ASME Section IX is structured around three critical elements: the Welding Procedure Specification (WPS), the Procedure Qualification Record (PQR), and the Welder Performance Qualification (WPQ). Together, these documents form the foundation of quality control. Welding Procedure Specification (WPS)
: It stops dangerous tanks and pipes from exploding.