Welding Procedures and Welders Qualifications

Preview on WPS, PQR & WPQ

WPS — Welding Procedure Specification

A Welding Procedure Specification (WPS) is a detailed written document that provides technical instructions for performing a specific weld.

It defines the exact parameters and conditions needed to ensure consistent, repeatable, and compliant welds.

Key details included in a WPS:

  • Positions and thickness ranges qualified
  • Welding process (GTAW, GMAW, PAW)
  • Base metals and filler materials
  • Joint design and preparation
  • Shielding gases and flow rates
  • Amperage, voltage, and travel speed
  • Preheat and post-weld heat treatment requirements

Example of Variables on the WPS According to D17.1

(1) Joint type(s) qualified, including dimensions, and fitup requirements
(2) Treatment of backside, including method of gouging/preparation
(3) Backing material, if used

(4) Base metal alloy
(5) Thickness range qualified
(6) Diameter range qualified (tubular only)
(7) Coating description or type, if present

(8) Specification, classification, alloy, or nominal composition
(9) Filler metal size or diameter
(10) Supplemental filler metal, including specification and size
(11) Filler metal feed rate
(12) Consumable insert, including material and type
(13) Hot filler metal amperage
(14) For cladding and hardfacing: the minimum surfacing thickness

(15) Welding positions(s) allowed
(16) Progression for vertical welding

(17) Minimum preheat temperature
(18) Method of preheat maintenance
(19) Interpass temperature maximum, if applicable

(20) PWHT including specification or temperature, time, method, and heating/ cooling rates when applicable

(21) Torch shielding gas, including composition and flow rate range
(22) Backing gas, including composition and flow rate range
(23) Supplemental shielding gas, including composition and flow rate range
(24) Environmental shielding (i.e. purge chamber, gas composition, purity)
(25) Vacuum pressure

Procedure Qualification Record (PQR)

A Procedure Qualification Record (PQR) is a formal document required by the AWS D17.1 Aerospace Welding Specification. It provides objective evidence that a Welding Procedure Specification (WPS) consistently produces high-quality welds. By capturing actual parameters, test results, and inspection data from controlled test coupons, the PQR validates the WPS through rigorous destructive and nondestructive testing—ensuring the critical quality and safety standards required in aerospace and defense manufacturing are strictly met.

Compliance with AWS D17.1 / NADCAP / Prime Specifications

  • Aerospace primes such as Boeing, Lockheed Martin, Gulfstream, and RTX require validated WPSs supported by qualified PQRs.
  • It is a mandatory requirement for NADCAP AC7110/12 and AWS standards.

Objective Evidence of Weld Quality

  • The PQR verifies that a procedure produces defect-free welds on specific base materials, joint types, and thickness ranges.

  • It records actual test results, including:
    • Visual inspection
    • Dye penetrant testing (PT)
    • Radiographic testing (RT / X-ray)
    • Destructive tests.
  • This ensures the procedure meets AWS D17.1 Class A or B acceptance criteria.

Compliance with AWS D17.1 / NADCAP / Prime Specifications

  • The PQR provides traceable, audit-ready documentation showing your company follows controlled, repeatable processes.

  • Customers and prime contractors expect a complete PQR package linked to every WPS.
  • Without a qualified PQR, companies risk:
    • Audit findings
    • Contract noncompliance with aerospace primes
    • Costly rework and delays

Welder Performance Qualification (WPQ)

A Welder Performance Qualification (WPQ), also known as a Welder Qualification Test (WQT), is a formal certification that verifies a welder’s ability to consistently produce defect-free welds according to a qualified Welding Procedure Specification (WPS). Under AWS D17.1 aerospace standards, welders undergo practical testing using precise materials, joint configurations, and parameters. The resulting test coupons are then rigorously evaluated through visual and nondestructive testing to ensure strict compliance with Class A, B, or C acceptance criteria.

Benefits of WPQ Certification

Ensures Welder Competency

  • Confirms the welder can consistently produce high-quality welds.

  • Tests proficiency in specific welding processes

  • Verifies capability on aerospace-grade materials like aluminum, titanium, stainless steel, Inconel, and nickel alloys.

Reduces Risk of Weld Defects

  • WPQ testing simulates production conditions, ensuring welders follow the qualified WPS correctly.

  • Properly certified welders help prevent costly rework, scrap, and part failures.

  • Ensures that welds meet tight aerospace tolerances and prime contractor specifications.

Builds Customer Confidence & Compliance Traceability

  • Provides audit-ready records linking each welder to the WPS and PQR they are qualified under.

  • Demonstrates to customers and auditors that your company:
    • Uses certified welders
    • Follows controlled, repeatable processes
    • Produces welds that meet AWS D17.1 Class A/B/C criteria