INTRODUCTION OF ASME SEC. IX
ASME SECTION IX deals with
- Part QW (Welding)
- Part QB (Brazing)
Each part divided into 4 articles as,
1. General Requirement.
2. Procedure Qualification.
3. Performance Qualification.
4. Data
LIMITATION :
1. To be referred only when the design code (Such as Section VIII Div. 1)
2. Does not guide the selection of electrode.
3. Does not guide the design of joints.
4. Does not specify the type and extend of radiography/NDT to be used.
5. Does not specify the acceptance criteria for extend of discontinuities acceptable.
WELDING PROCEDURE QUALIFICATION
When WPS/PQR Qualified,
Proves the quality and properties of weld joints prepared by a set of welding variables.
- Welding Process.
- Base Material.
- Welding Consumables.
- Welding parameters and techniques (Position, Polarity, preheat, Inter-pass Temperature etc)
- PWHT
Qualification is limited to the essential variables of the Specific Process
WPS :
- Written document showing all the applicable welding variables
- Provide direction for making production welds which will meet code requirements.
WELDING VARIABLES :
ESSENTIAL VARIABLE: significant effect on the weld properties if changed.
NON-ESSENTIAL VARIABLE: N0 significant effect on weld properties if changed.
SUPPLEMENTARY ESSENTIAL VARIABLE: When other Sections specify notch-toughness tests and are in addition to the essential variables.
Variables are listed for each welding process in QW-252 to QW-265
WPS should be available for reference and review by the inspector.It should also be made available with welding supervisors, welders
PROCEDURE QUALIFICATION RECORDS :
- A mock up : Represent welding done in a shop under similar conditions.
- Some codes call for a production weld coupons as an additional measure.
- Production coupons also act as qualification tests for the PQR
- Prepare A Weld Coupon Using an Preliminary WPS.
- Weld Coupon Undergoes Destructive Test
- Testing Requirements are specified in Sec IX
- Acceptance norms shall be as per Construction Code.
- PQR is limited to the essential variables of the Specific Process
- Process of testing capability of the welder is known as "Welder Performance Qualification test"
- Ascertain the skill of a welder or a welding operator to Produce defect free/Sound weld
- Makes A Weld Coupon Using an Approved WPS
- Weld Coupon Undergoes Soundness Test (NDT or DT)
- Each Qualified Welder Shall be Assigned by A Unique Welder Number
- Welders’ Qualifications Records Are Documented
- Performance Qualification is limited to the essential variables of the Specific Welding Process
REQUIREMANTS OF ASME SECTION IX
Section has two parts : welding and brazing. [UW & UB]
Under Welding there are 4 chapters (Article I to V), in addition to initial introduction.
Article I: General.
- Positions of welding
- Examinations (Various Types of Tests, Testing Procedures, Specimen Details, Acceptance Criteria) etc.
Article II - Welding Procedure Qualifications.
- WPS, PQR
- Their contents, Format
- List of variables
- Qualification ranges
- Type and number of examinations required
Article III - Welding Performance Qualifications.
- WPQ
- List of Variables
- Qualification ranges
- Type and number of examinations required
Article IV
- Compiled welding data meant for using with articles I, II, III
Hence, for example, one who wants to qualify a welder can directly refer article III.
Article V – Standard Welding Procedure Specifications (SWPs).
- Useful for small manufacturers, whose knowledge of welding is miniscule
- SWPSs will have to purchase them from AWS
- Instead of performing more PQR tests, manufacturer to perform and document a demonstration weld following a typical SWPS.
- Manufacturer to demonstrate and document that he knows enough about welding to follow the SWPS.
- After welding and testing one demonstration coupon, many other SWPSs may typically be used without further demonstrations.
- Not permitted for construction where impact testing of the WPS is required
- The specific requirements of SWPSs are covered in Article V (i.e., QW-500)
- Sample form (QW 485) is demonstrated in non mandatory Appendix B.
- The permitted SWPSs are listed in Appendix E
- These SWPSs cover welding of P-1 and P-8 metals using SMAW, GTAW and GMAWFC. • Typi
- Typical thickness ranges permitted are 1/8” to 1-1/2” and both as-welded and post weld heat treated procedures (for P-1 metals) are available
Important points for reading the welding data:
- Never read the welding data given in article IV unless called upon to do so by articles I, II or III
- Normally adding "a new qualification shall be done when …" before reading data against essential variable given in the tables of Article II and III (such as QW 253), makes the reading easy
- Welding Data - Essential, Non Essential & Supplementary Essential Variables.
- Parent Metal Grouping - “P” No
- Filler Metal Grouping – “ F” No
- Weld Metal Composition Grouping – “A” No
- Welding Positions, Groove & Fillet
- Types of Tests – Tension, Guided Bend, Notch Toughness
- Test Requirements & Acceptance Limits
- Test Specimen – Location, Dimension & Testing Procedure
- Qualifications – Range in Thickness & Diameter
- Record & Documentation of WPS , PQR & WP
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