Welder Performance Qualification (WPQ) in AWS D1.1
The performance qualification tests given by this code are specifically devised tests to determine a welder’s, welding operators, or tack welder’s ability to produce sound welds. The qualification tests are not intended to be used as guides for welding or tack welding during actual construction. The latter shall be performed in conformance with a WPS.
AWS D1.1 requirements welder/ welding operator qualification & certification in two ways:
- Non-Tubular Sections
- Tubular Sections
AWS D1.1 2020 Edition, Section 6: Qualification, Part-C Performance qualification lists the requirements for welder/ welding operator qualification for non-tubular applications.
Tack Welders: A tack welder shall be qualified by one test plate in each position in which the tack
welding is to be performed.
Types of Test Required for Welder qualification as per AWS D1.1
The type and number of qualification tests required for welders/ welding operators are given in Table 6.11 of AWS D1.1. The standard test used for welder testing are:
- Visual Inspection
- Bend Test (Face, root, and side bend)
- Macro Testing
- Fillet weld break test
AWS D1.1 allow to substitute RT test in lieu of bend test as specified in clause 126.96.36.199: Substitution of RT for Guided Bend Tests. As per D1.1, Except for weld test coupons welded by GMAW-Short-circuit mode, radiographic examination of a welder or welding operator qualification test plate or test pipe may be done instead of bend tests. Excerpt of AWS D1.1, Table 6.11 is given below for reference. Here, as allowed you can substitute bend test with RT. So, for groove weld, you will need to do visual inspection and RT to qualify a welder as per AWS D1.1.
Welder qualification test acceptance criteria as per AWS D1.1
Visual Acceptance Criteria
Visual inspection acceptance for welder qualification as per AWS D1.1 is given in Clause 6.10.1: Visual Inspection (VT) of Welds. The criteria is given for:
- Groove Welds
- Fillet Welds
For groove weld, the VT acceptance is as below:
- Cracks are not acceptable of any sizes.
- Weld craters must be filled o match the weld.
- Weld reinforcement height shall not be more than 1/8 in [3 mm].
- Maximum Undercut allowed is 1/32 in [1 mm] as per AWS D1.1.
- The weld root for CJP grooves shall be free from any cracks, incomplete fusion, or inadequate joint penetration.
- For CJP grooves welded from one side without backing, root concavity or melt-through shall conform to the following:
(a) The maximum root concavity shall be 1/16 in [2 mm], provided the total weld thickness is equal to or greater than that of the base metal.
(b) The maximum melt-through shall be 1/8 in [3 mm].
For fillet weld, the VT acceptance is as below:
(1) Cracks are not acceptable.
(2) All craters shall be filled to the full cross section of the weld.
(3) The fillet weld leg sizes shall not be less than the required leg sizes.
(4) The weld profile shall meet the requirements of Figure 1.4. of AWS D1.4
(5) Base metal undercut shall not exceed 1/32 in [1 mm].
Bend Test Acceptance Criteria
Bend Test (Root, Face, and Side Bend Specimens) the acceptance is given in AWS D1.1, clause 188.8.131.52. The explanation of AWS D1.1 bend test acceptance criteria is given below:
The convex face of the bend test coupon shall be VT examined for surface imperfection. To accept the bend test result, the bend surface of the specimen shall not show any discontinuities more than following:
(1) maximum permitted discontinuity size is 1/8 in [3 mm] in any side of surface.
(2) 3/8 in [10 mm]-the total of the highest sizes of all discontinuities more than 1/32 in [1 mm], but less than or equal to 1/8 in [3 mm].
(3) The maximum size of any crack is 1/4 in [6 mm] unless it can be established that the crack is due to any slag inclusion or other fusion issues, then the maximum size allowed will be be 1/8 in [3 mm].
Bend coupon showing corner crack more than 1/4 in [6 mm] with no indication of slag inclusions or other fusion type defects shall be ignored, and new bend specimen shall be made from the actual welder test coupon.
Radiographic Acceptance as per AWS D1.1 for welder/ operator qualification
RT Acceptance Criteria for welder/ operator qualification is given in AWS D1.1, clause 8.12.2 and as follows for welder test (WQT) acceptance:
- Cracks are not acceptable.
- For other discontinuities, the acceptance is based on the combination of weld size and distance between two defects.
Rounded discontinuities greater than a maximum size of S/3, not to exceed 1/4 in [6 mm]. However, when S. is greater than 2 in [50 mm], the maximum rounded indication may be 3/8 in [10 mm].
Macro test Acceptance Criteria
The macro etch specimens shall meet the following acceptance at minimum:
(1) Fillet welds shall have fusion to the root of the joint but not necessarily beyond.
(2) Minimum leg size shall meet the specified fillet weld size.
(3) Plug welds shall have:
(a) No cracks
(b) Thorough fusion to backing and to sides of the hole
(c) No visible slag in excess of 1/4 in [6 mm] total accumulated length