WPS vs PQR — What Each Document Does and When You Need Both
A WPS tells the Soldador what to do. A PQR proves the WPS works. D1.1 Clause 5 allows Pré-qualificado WPSs without a PQR. Clause 6 requires a PQR for any WPS that falls outside prequalified Limites. Most Aço estrutural Fabricação uses prequalified WPSs and never needs a PQR.
Side-by-Side Comparison
| Property | WPS | PQR |
|---|---|---|
| Purpose | Welding instruction document | Qualification test record |
| Who creates | Fabricator | Fabricator or Ensaio lab |
| When required | Always | Only when Clause 6 qualification needed |
| D1.1 clause | 5 (prequalified) or 6 (qualified) | 6 only |
| Content | Parameter ranges and limits | Actual test parameters and results |
| Number needed | One per joint configuration | One per qualification test |
| Signed by | Fabricator authorized representative | Fabricator authorized representative |
| Valid indefinitely? | Yes, until essential variables change | The test record remains; a process change beyond Tabela 6.6 limits requires WPS requalification, not that the PQR disappears |
What a WPS Contains
A Especificação do Procedimento de Soldagem is the instruction document that tells the welder exactly how to make a Soldagem. Every WPS specifies the essential variables that control weld quality. For prequalified WPSs, Table 5.5 lists the required variables. For qualified WPSs, Table 6.6 defines the essential variables that must be recorded.
The essential variables common to both prequalified and qualified WPSs include the welding process (SMAW, GMAW, FCAW, or SAW), base metal group and Faixa de espessura, filler metal classification and Tamanho, welding position, preheat and interpass temperature, joint design (groove type, angle, Abertura da raiz, Apoio), and electrical parameters (Tipo de corrente, Polaridade, Tensão range, Velocidade de alimentação do arame or Amperagem range).
A EPS pré-qualificada must conform to all the Requisitos of Clause 5. This means the Detalhe da junta must match one of the prequalified joint configurations in Figure 5.1, the Metal de Base must appear in Table 5.6, the Metal de Adição must comply with Table 5.7, and Pré-aquecimento must meet Table 5.11. If all requirements are met, the WPS is valid without any testing.
A prequalified WPS is not a shortcut. It must comply with every requirement in Clause 5, including Tables 5.1, 5.3, 5.4, 5.5, 5.6, 5.7, 5.11, and Figure 5.1. Missing any single requirement means the WPS must be qualified by testing under Clause 6.
What a PQR Contains
A Registro de Qualificação de Procedimento de Soldagem documents the actual Solda de teste parameters used during qualification and the results of destructive testing performed on the test specimens. Unlike a WPS, which specifies ranges, a PQR records the exact values used during the test weld.
The PQR includes the actual Soldagem parameters (amperage, voltage, Velocidade de Soldagem, wire feed speed), the base metal Especificação and Espessura, the filler metal lot and classification, preheat and interpass temperatures measured during the test, and the joint configuration welded. These actual parameters establish the baseline from which the qualified range is determined.
Destructive test results form the core of the PQR. D1.1 Clause 6 requires specific tests depending on the joint type.
For CJP groove-weld WPS qualification, Clause 6.11.3 requires Inspeção Visual of the completed Corpo de prova, NDT of the completed coupon, bend testing, and tensile testing. Macroetch is not in that CJP list. It appears on PJP routes such as Table 6.3 and Clause 6.12.4/6.12.6. Specimen locations are specified in D1.1 Clause 6 figures based on plate thickness and joint type.
All test results must meet the Critérios de aceitação in Clause 6. Bend specimens must show no Trincas or open discontinuities exceeding 1/8 inch. Tensile specimens must meet the Mínimo Resistência à Tração of the base metal. Where macroetch is required (PJP or fillet routes), specimens must show Fusão Completa and acceptable profiles.
The Prequalified Path
D1.1 Clause 5 provides a prequalified path that eliminates the need for PQR testing entirely. A prequalified WPS is one that uses only parameters and configurations that D1.1 has already deemed acceptable based on decades of industry experience and testing. The prequalified path exists because certain process, material, and joint combinations have been proven through widespread successful use.
To use the prequalified path, every element of the WPS must comply with the requirements of Clause 5. The Processo de Soldagem must be one of the four prequalified processes listed in Table 5.1: SMAW, SAW, GMAW (except short-circuit transfer), or FCAW. The base metal must appear in Table 5.6, which lists approved base metals by group.
The filler metal must match the Grupo de metal base per Table 5.7. The joint detail must be one of the prequalified configurations in Figure 5.1. Preheat must meet the minimum temperatures in Table 5.11 based on the material group, thickness, and hydrogen Categoria.
Additional prequalified requirements include WPS limitations from Table 5.3 and Table 5.4 (Máximo Eletrodo diameters, maximum pass sizes, maximum single-pass fillet sizes by position), and the Variável essencial requirements of Table 5.5.
Every table must be satisfied. Failing to meet even one prequalified requirement means the WPS must be qualified by testing under Clause 6, which requires a PQR.
The advantage of the prequalified path is significant: no test welds, no Ensaio Destrutivo, no laboratory costs, and no wait time. The Fabricante writes the WPS, verifies Conformidade with all Clause 5 tables, and the WPS is ready to use. Most structural steel fabrication in the United States follows this path.
When You Need a PQR
A PQR is required whenever the WPS falls outside the prequalified limits of Clause 5. The most common situations that trigger Ensaio de qualificação include:
GMAW short-circuit transfer (GMAW-S): Table 5.3 specifies that the mode of transfer is not short circuit. Any WPS using GMAW-S must be qualified by testing per Clause 6, producing a PQR.
Non-prequalified joint configurations: If the joint detail does not match any configuration in Figure 5.1, or if the fabricator wants to modify a prequalified joint beyond the allowed tolerances, qualification testing is required. Custom groove angles, non-Norma root openings, and unique backing configurations all fall outside prequalified limits.
Base metals not listed in Table 5.6: If the steel grade or specification does not appear in Table 5.6, the base metal is not prequalified regardless of the process or Projeto de junta. High-Resistência steels, weathering steels not in the table, and proprietary grades all require qualification.
ASME IX work: Unlike D1.1, ASME Boiler and Pressure Vessel Código Section IX has no prequalified path. Every WPS used under ASME IX must be supported by a PQR, regardless of how common the process, material, or joint configuration may be. Fabricators working to both codes often have PQRs for ASME work and prequalified WPSs for D1.1 work.
Parameters outside prequalified ranges: Exceeding the maximum electrode sizes in Table 5.3, the maximum pass sizes in Table 5.4, or using parameters outside the ranges specified in Table 5.5 all require qualification testing.
The most common trigger for PQR testing in structural steel work is GMAW-S. Many fabricators use short-circuit transfer for thin material and root passes, and every GMAW-S application requires a qualified WPS supported by a PQR.
One PQR, Multiple WPSs
A single PQR establishes a range of qualified variables, not a single set of parameters. For CJP groove-weld plate qualification, that thickness range comes from Table 6.2, not Table 6.8. Table 6.8 is the supplementary-essential-variable table for CVN testing applications. Any WPS that falls within the qualified ranges established by a PQR can reference that PQR as its supporting documentation.
For example, a CJP plate coupon 1 inch and over with FCAW on A36 using E71T-1 qualifies a base-metal thickness range from 1/8 inch to Unlimited per Table 6.2. Footnote b limits square-groove welds qualified without backgouging to the test thickness. The fabricator can write separate WPSs for 3/8 inch fillet welds, 3/4 inch groove welds, and 1-1/2 inch groove welds, all referencing the same PQR, as long as every essential variable in each WPS falls within the qualified range.
This one-to-many relationship is a key efficiency in qualification management. A well-planned qualification test program can produce a small number of PQRs that support dozens of production WPSs.
The essential variables that define the qualified range include process, base metal group, Classificação do metal de adição, position, thickness range, and electrical characteristics. Changing any essential variable beyond the qualified range requires a new PQR.
Fabricators typically maintain a PQR library covering their standard processes and materials. Before writing a new WPS, they check whether an existing PQR already covers the required parameters. If it does, the new WPS references the existing PQR and no additional testing is needed. If no existing PQR covers the parameters, a new qualification test is scheduled.
Frequently Asked Questions
No. D1.1 Clause 5 provides a prequalified path where WPSs that meet all requirements of Clause 5 are exempt from the qualification testing that produces a PQR. If your WPS uses a prequalified process (SMAW, SAW, GMAW except short-circuit, or FCAW), a base metal from Table 5.6, a filler metal per Table 5.7, a joint detail from Figure 5.1, and preheat per Table 5.11, no PQR is required. Most structural steel fabrication uses prequalified WPSs.
Yes. A single PQR establishes a range of qualified variables. Any WPS that falls within those qualified ranges can reference that PQR. For example, a CJP plate coupon 1 inch and over with FCAW on A36 can support WPSs from 1/8 inch through Unlimited per Table 6.2, subject to footnote b for square grooves qualified without backgouging. Multiple WPSs with different joint details can reference the same PQR if all essential variables remain within the qualified range.
A WPS is written by the manufacturer or Contractor for a specific application. A Standard Welding Procedure Specification (SWPS) is an AWS B2.1-X-XXX series published procedure. D1.1 Clause 6.2.1.2 makes acceptability of qualification to other standards the Engineer's responsibility, and AWS B2.1-X-XXX SWPSs may be accepted in that manner. D1.1 Annex L is Filler Metal Strength Properties, not an SWPS list.
The manufacturer or Contractor shall conduct the tests required by this code to qualify the WPS (Clause 6.2.1.1). D1.1 does not add a separate Clause 6 rule that the individual responsible for welding operations must sign the PQR. Annex J provides sample PQR forms with authorization fields. A testing laboratory may supply test data; qualification responsibility remains with the manufacturer or Contractor.
D1.1:2025 Clause 6.7 assigns preparation of the written WPS to the manufacturer or Contractor, specifying the applicable essential variables in 6.8, with values taken from the PQR. Clause 6.2.1.1 assigns qualification testing to the manufacturer or Contractor. The Engineer's role in Clause 6.2.1.2 is acceptability of qualification to other standards, not a blanket duty to approve every WPS.