Chapter 10: Welding Procedure Specification (WPS), PQR & Welder Performance Qualification (WPQ)

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📘 10.1 What is a WPS (Welding Procedure Specification)?

A WPS is a formal, written document that describes how welding is to be performed on a specific job, in compliance with applicable codes (like ASME Section IX, AWS D1.1, etc.).

It includes:

Welding process (e.g., SMAW, GTAW)

Base metal & filler material
Preheat & interpass temperature
Joint design
Welding position
Amperage, voltage, travel speed
Post-weld heat treatment (PWHT)

🔍 Purpose: Ensures consistency, code compliance, and quality across all welds.

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🧪 10.2 What is a PQR (Procedure Qualification Record)?

A PQR is a record of test welds made according to a WPS and mechanically tested (e.g., tensile, bend, impact tests) to qualify the WPS.

PQR proves:

That the procedure works in actual conditions

That welds made with this procedure will meet required mechanical properties

📌 Key tests include:

Tensile strength

Bend test
Impact (Charpy V-notch)
Hardness test (in some cases)

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🧑‍🏭 10.3 What is WPQ (Welder Performance Qualification)?

A WPQ certifies that a welder is capable of making sound welds under specific conditions defined in the WPS.

Test weld is made by the welder

Visually inspected + NDT + mechanical test
If acceptable → Welder is qualified to weld under similar conditions

🗓️ Validity usually:

• 6 months to 1 year (unless welder regularly performs that process)

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🔄 10.4 Interrelation: WPS – PQR – WPQ

1️⃣ Prepare a Draft WPS  
2️⃣ Perform test welds as per WPS  
3️⃣ Record results in PQR (Destructive Tests)  
4️⃣ If PQR is acceptable → Approve WPS  
5️⃣ Qualify welder via WPQ (practical test)

📌 WPS is supported by PQR
📌 WPQ ensures the welder can implement the WPS properly

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🧰 10.5 Real Industrial Application

Example: Pressure Vessel Fabrication (ASME Sec VIII)

A company prepares a WPS for GTAW welding of SS304 to SS304

A test plate is welded and tested (PQR)
Results meet tensile & bend requirements
Several welders are qualified using this PQR (WPQ)
Only those qualified welders are allowed to work on the actual vessel

📌 This ensures:

Code compliance

Traceability
Reduced risk of weld failure

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📄 10.6 Key Contents of a WPS

Parameter	Example
Process	SMAW, GTAW, GMAW, FCAW
Joint Type	Butt, Lap, T-joint
Base Material	SA 516 Gr. 70, SS304
Filler Material	E7018, ER308L
Preheat Temperature	100°C
Welding Position	1G, 2G, 3G, 6G
Voltage & Amperage	22–28V, 100–150A
Travel Speed	As per code
PWHT	620°C for 2 hrs (if applicable)

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📑 10.7 Code References

ASME Section IX – Qualification of Welding Procedures & Welders

AWS D1.1 – Structural Welding Code (Steel)
API 1104 – Welding Pipelines & Related Facilities

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🛡️ 10.8 Benefits of WPS/PQR/WPQ System

✅ Ensures code compliance
✅ Reduces risk of weld failures
✅ Enhances traceability & accountability
✅ Provides legal & quality assurance records

Quiz: WPS, PQR & WPQ

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Q1. What does WPS stand for in welding QA/QC?
A) Welding Performance Standard
B) Weld Penetration Strength
C) Welding Procedure Specification
D) Weld Production Strategy
🟩 Correct Answer: C

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Q2. Which document proves that a welding procedure can produce acceptable welds?
A) WPQ
B) NDT Report
C) PQR
D) ITP
🟩 Correct Answer: C

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Q3. What is WPQ used for?
A) To control welding machines
B) To check consumable cost
C) To qualify a welder’s skill
D) To document surface treatment
🟩 Correct Answer: C

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Q4. Which of the following is a required test for PQR approval?
A) XRF test
B) Tensile & bend tests
C) Visual inspection only
D) Pressure test
🟩 Correct Answer: B

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Q5. How long is a WPQ typically valid if the welder continues welding in the process?
A) 3 months
B) 6 months
C) Indefinitely
D) 2 years
🟩 Correct Answer: C (As long as the welder doesn’t stop welding that process for more than 6 months)

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Q6. Which code governs welding procedure qualification in pressure vessel manufacturing?
A) ASME Section IX
B) ISO 9001
C) AWS D1.2
D) API 650
🟩 Correct Answer: A

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Q7. What is the relationship between WPS and PQR?
A) PQR supports WPS
B) WPS proves the PQR
C) They are unrelated
D) WPS is optional if PQR exists
🟩 Correct Answer: A

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Q8. In which position is a 6G welder test performed?
A) Flat only
B) Horizontal only
C) Fixed pipe inclined at 45°
D) Overhead
🟩 Correct Answer: C

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Q9. Which of the following is not included in a WPS?
A) Welding voltage
B) Heat treatment
C) Paint color code
D) Travel speed
🟩 Correct Answer: C

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Q10. Why is PQR essential in QA/QC welding practices?
A) For invoicing
B) To train welders
C) To validate that a proposed WPS can produce sound welds
D) To meet HR requirements
🟩 Correct Answer: C