Q. What Is WPS/PQR...?
Q. What is Welding Procedure Specification (WPS)?
A Welding Procedure Specification (WPS) is the formal written document describing welding procedures, which provides direction to the welder or welding operators for making sound and quality production welds as per the code requirements . A WPS is a document that describes how welding is to be carried out in production. Its purpose is to aid the planning and quality control of the welding operation. They are recommended for all welding operations and most application codes and standards make them mandatory.
Q. What is Procedure Qualification Record (PQR)?
A PQR is a record of a test weld performed and tested (more rigorously) to ensure that the procedure will produce a good weld. A PQR is required when it is necessary to demonstrate that your company has the ability to produce welds possessing the correct mechanical and metallurgical properties. A welding procedure must be qualified in accordance with the requirements of an appropriate welding procedure standard, such as ASME Sec IX, as follows:
1. Produce a welding procedure specification (WPS) as stated above.
2. Weld a test piece in accordance with the requirements of your specification. The joint set up, welding and visual examination of the completed weld should be witnessed by a certified welding inspector such as an AWS certified CWI or an Inspection Body. The details of the test such as the welding current, pre-heat etc., must be recorded during the test.
3. Once the welding is complete the test piece must be subject to destructive and non destructive examination such as radiography and mechanical tests as defined by the welding procedure standard. This work must be carried out in a qualified laboratory but the Inspection Body may require witnessing the tests and viewing any radiographs.
4. If the test is successful you or the test body completes the appropriate documents which the test body’s surveyor signs and endorses.
Q. What is Welder Performance Qualification Record (WPQR)?
Once the procedure is approved it is necessary to demonstrate that all your welders working to it have the required knowledge and skill to put down a clean sound weld. If the welder has satisfactorily completed the procedure test then he is automatically approved but each additional welder must be approved by completing an approval test to an appropriate standard such as ASME Sec IX as follows:
1. Complete a weld test as stated above. The test should simulate production conditions and the welding position should be the position that the production welds are to be made in or one more severe.
2. For maximum positional approval a pipe inclined at 45 degrees (referred to as the 6G position) approves all positions except vertical down.
3. Test the completed weld in accordance with the relevant standard to ensure that the weld is clean and fully fused.
4. For a butt weld this is normally a visual examination followed by radiography or bend tests.
5. Once the test is completed the necessary forms have to be completed by you or the test body and signed by the test body’s surveyor.
6. Note that any changes that require a new welding procedure (WPS) may also apply to the welders approval, refer to the referencing code/ standard for precise details
Typical Items That Should Be Recorded On W.P.S:-
- Procedure number
- Process type
- Consumable Size, Type and full Codification.
- Consumable Baking Requirement if applicable
- Parent material grade and spec.
- Thickness range.
- Plate or Pipe, Diameter range
- Welding Position
- Joint Fit Up, Preparation, Cleaning, Dimensions etc.
- Backing Strip, Back Gouging information.
- Pre-Heat (Min Temp and Method)
- Inter-pass If Required (Maximum Temperature recorded )
- Post Weld Heat Treatment. If Required (Time and Temp)
- Welding Technique (weaving, max run width etc.)
- Arc Energy Limits should be stated if impact tests are required or if the material being welded is sensitive to heat input.
PQR/ WPQR Testing
The following tests by Independent Test Laboratory may be required on your PQR and WPQR Coupons:
- Weld Visual Examination by a AWS Certified Welding Inspector
- Bend Test
- Hardness Test
- Transverse Tensile Test
- All Weld Metal Tensile Test
- Charpy Impact Test
- Weld Metal Chemical Analysis
- Macro-etch Test
- Torque Test
- Peel Test
- Nick Break Test
- Radiography Test
- Ultrasonic Test
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