WPS, PQR and Welder Qualification Explained in Simple Language

 

WPS, PQR and Welder Qualification Explained in Simple Language

In welding fabrication, three terms are used again:

WPS – Welding Procedure Specification
PQR – Procedure Qualification Record
Welder Qualification – Qualification of the welder to perform the welding

For a beginner, these documents can look complicated. But the basic concept is simple.

Think of welding like cooking.

·                WPS = The recipe

·                PQR = Proof that the recipe works

·                Welder Qualification = Proof that the cook can follow the recipe correctly

Let us understand each one step by step.

 

1. What is WPS?

WPS stands for Welding Procedure Specification.

A WPS is a written document that tells the welder how the welding job has to be performed.

It normally includes important welding parameters and requirements such as:

·                Base material

·                Material thickness

·                Welding process

·                Joint design

·                Welding position

·                Filler metal

·                Electrode/wire size

·                Welding current

·                Voltage

·                Travel speed

·                Preheat temperature

·                Interpass temperature

·                Shielding gas

·                Polarity

·                Number of passes

·                Post-weld heat treatment, when applicable

·                Cleaning requirements

·                Technique requirements

The exact variables depend on the applicable welding code and project requirements.

Simple example

Suppose we are welding a carbon steel pipe using the GTAW + SMAW process.

The WPS may specify:

Root pass: GTAW
Filler/cap: SMAW
Electrode: E7018
Preheat: Minimum 75°C
Position: 6G
Current: As specified in the qualified range
Interpass: Within the specified limit

The welder follows these instructions during production welding.

Why is WPS important?

Without a proper WPS, different welders may use different parameters and techniques.

This can result in:

·                Lack of fusion

·                Lack of penetration

·                Porosity

·                Undercut

·                Excessive reinforcement

·                Cracking

·                Inconsistent weld quality

So, the WPS provides a controlled and repeatable welding method.

 

2. What is PQR?

PQR stands for Procedure Qualification Record.

The PQR is the actual record of a welding procedure qualification test.

In simple words:

The WPS says what we plan to do.
The PQR records what we actually did during the qualification test and the test results.

A test coupon is welded using a proposed welding procedure.

During welding, actual parameters are recorded.

After welding, the test coupon may undergo examinations and mechanical tests according to the applicable code.

These can include:

·                Visual examination

·                Radiographic Testing (RT)

·                Ultrasonic Testing (UT)

·                Tensile test

·                Bend test

·                Impact test, when required

·                Macro examination

·                Hardness testing

·                Other tests specified by the applicable code

If the qualification test meets the applicable acceptance requirements, the procedure can be qualified within the permitted ranges.

 

3. WPS vs PQR

This is one of the most important things to understand.

 

WPS	PQR
Tells the welder how to weld	Records how the qualification test was welded
Used for production welding	Used to qualify the welding procedure
Contains specified/qualified ranges	Contains actual recorded variables and test results
Acts like a welding instruction	Acts like evidence of procedure qualification
Used by Production and QC	Reviewed by QA/QC and relevant authorities

 

Simple example

Imagine we are preparing a WPS for welding a 10 mm carbon steel plate.

A qualification coupon is welded.

During the test, the actual conditions may be recorded as:

·                Base metal: Carbon steel

·                Thickness: 10 mm

·                Process: SMAW

·                Electrode: E7018

·                Electrode diameter: 3.2 mm

·                Current: 110 A

·                Voltage: 24 V

·                Position: 3G

·                Preheat: 80°C

After welding, the required tests are performed.

Suppose the test results are acceptable.

The PQR records these actual values and the test results.

Based on the applicable welding code, a WPS can then be prepared with the qualified ranges supported by the PQR.

 

4. What is Welder Qualification?

Even if we have a qualified WPS, there is another important question:

Can the welder actually produce an acceptable weld using that procedure?

This is where Welder Qualification comes in.

A welder qualification test demonstrates that a particular welder has the required skill to produce an acceptable weld under the conditions covered by the qualification.

The welder performs a test weld using specified conditions.

The test weld is then examined according to the applicable code.

Depending on the requirements, examination may include:

·                Visual examination

·                RT

·                UT

·                Bend testing

·                Other examinations/tests specified by the applicable code

If the weld meets the acceptance requirements, the welder is qualified within the applicable ranges.

The qualification record identifies important information such as:

·                Welder identification

·                Welding process

·                Base material

·                Thickness

·                Pipe diameter, where applicable

·                Welding position

·                Filler metal

·                Joint type

·                Test results

·                Applicable qualification ranges

 

5. WPS, PQR and Welder Qualification – How They Work Together

These three items are connected.

The basic sequence is:

Welding Procedure Development
↓
Procedure Qualification Test
↓
PQR
↓
Qualified WPS
↓
Welder Qualification Test
↓
Qualified Welder
↓
Production Welding
↓
Inspection & NDT

For production welding, QC should verify that:

Qualified WPS + Qualified Welder + Correct Material + Correct Consumable + Correct Parameters = Controlled Welding Process

Of course, welding quality also depends on fit-up, preheat, consumable control, environmental conditions, inspection and other project requirements.

 

6. A Simple Practical Example

Let's take a pipe fabrication project.

Suppose a carbon steel pipe needs to be welded.

Step 1 – Prepare the WPS

The company prepares a proposed welding procedure.

It defines:

·                Welding process

·                Base material

·                Filler metal

·                Position

·                Preheat

·                Welding parameters

·                Number of passes

·                Other applicable requirements

Step 2 – Conduct the Procedure Qualification Test

A test coupon is welded according to the proposed procedure.

The actual welding variables are recorded.

Step 3 – Test the Coupon

The required NDT and mechanical tests are performed.

If the results satisfy the applicable code requirements, the procedure is qualified.

Step 4 – Prepare the PQR

The actual welding variables and test results are documented in the PQR.

Step 5 – Issue the Qualified WPS

The WPS is established based on the applicable code and the supporting qualification.

Step 6 – Qualify the Welder

The welder performs a qualification test using the applicable procedure.

The test weld is examined.

If acceptable, the welder receives a qualification record covering the applicable range.

Step 7 – Start Production Welding

Before allowing production welding, QC verifies:

·                Correct drawing

·                Correct WPS

·                Welder qualification validity/range

·                Correct material

·                Correct consumable

·                Correct joint preparation

·                Fit-up

·                Preheat

·                Welding parameters

·                Traceability

This is where documentation becomes practical quality control.

 

7. Common Mistakes in Welding Documentation

During fabrication inspection, some common mistakes can create problems later.

1. Using an unapproved or incorrect WPS

The WPS may not match the material, thickness, process or project requirement.

2. Welder qualifications do not cover the production job

A welder may be qualified, but the qualification range may not cover the production material, thickness, diameter, position or process.

3. WPS parameters are not followed

For example:

·                Incorrect current

·                Incorrect voltage

·                Insufficient preheat

·                Excessive interpass temperature

·                Wrong electrode

·                Incorrect shielding gas

4. Poor consumable control

Moisture-sensitive electrodes may require proper storage and handling.

Incorrect consumable control can affect weld quality.

5. Traceability problems

The welder ID, WPS number, joint number and consumable details should be properly recorded where required by the project/QAP.

6. Qualification records are incomplete

Missing test results, material identification, essential variables or signatures can create documentation problems during audits or client/class inspections.

 

8. What Should QC Check Before Welding?

A practical QC check can be divided into three stages.

Before Welding

Check:

☑ Approved drawing
☑ Applicable WPS
☑ Supporting PQR
☑ Welder qualification
☑ Correct base material
☑ Material traceability
☑ Correct consumable
☑ Joint preparation
☑ Fit-up
☑ Root gap
☑ Alignment
☑ Preheat requirement
☑ Welding machine calibration, where required

 

During Welding

Monitor:

☑ Welding process
☑ Current and voltage
☑ Welding position
☑ Preheat temperature
☑ Interpass temperature
☑ Consumable control
☑ Welding sequence
☑ Cleaning between passes
☑ Welder identification
☑ Weld traceability

 

After Welding

Check:

☑ Visual inspection
☑ Weld profile
☑ Undercut
☑ Surface defects
☑ Weld size/reinforcement
☑ Required NDT
☑ Repair requirements
☑ Final documentation
☑ Weld traceability

 

9. Important Point: WPS Is Not Just a Paper

In many fabrication shops, documents such as WPS, PQR and welder qualification are sometimes treated as paperwork needed for an audit.

But they have a much bigger purpose.

They create a connection between:

Engineering → Qualification → Production → Inspection → Final Quality

A good QC engineer should not only check whether a WPS exists.

The important question is:

Is the actual welding being performed within the requirements of the applicable qualified procedure?

That is where real welding quality control starts.

 

10. Easy Way to Remember

If you are new to welding inspection, remember these three sentences:

WPS

“How should we weld?”

PQR

“Did this welding procedure actually work during qualification testing?”

Welder Qualification

“Can this welder demonstrate the ability to make an acceptable weld under the qualified conditions?”

That's the complete concept in simple language.

 

Conclusion

WPS, PQR and Welder Qualification are three important parts of a controlled welding system.

WPS provides welding instructions.

PQR provides documented evidence from the procedure qualification test.

Welder Qualification demonstrates the welder's ability to produce an acceptable weld within the applicable qualification range.

For a QC/NDT engineer, understanding the relationship between these documents is very important because welding quality is not checked only after the weld is completed.

Good welding quality starts before the first arc is struck.

Correct WPS + Qualified PQR + Qualified Welder + Proper Execution + Effective Inspection = Controlled Welding Quality

Always apply the requirements of the applicable welding code, project specification and approved QAP/ITP, because qualification requirements and acceptance criteria vary by code and application.