AWS CWI Part B - Module 2 (Contents and PPT)

Module 2 - Clause 2

2.0 Workmanship Requirements and Visual Acceptance Criteria – Structural Steel

The  Module 2 of the AWS CWI Part B covers - Workmanship Requirements and Visual Acceptance Criteria – Structural Steel. The following would be covered in details

2.0 Workmanship Requirements and Visual Inspection Acceptance Criteria – Structural Steel

2.1 Base Metal Preparation

2.2 Workmanship Requirements

2.3 Visual Inspection Acceptance Criteria

2.4 Fillet Weld Dimensional Tolerances

2.1 Base Metal Preparation

2.1.1 Mill-Induced Discontinuities. The length of these discontinuities is the visible long dimension on the cut surface of material and the depth is the distance that the discontinuity extends into the

material from the cut surface. The limits of acceptability and the repair of visually observed cut surface discontinuities shall be as follows:

(a)  Any discontinuity 25 mm in length or less need not be repaired and the depth need not be explored.

(b)  Any discontinuity over 25 mm in length with maximum depth of 3 mm need not be repaired, but the depth should be explored.

(c)  Any discontinuity over 25 mm in length with depth over 3 mm but not greater than 6 mm shall be completely removed and repair welded.

(d)  Any discontinuity over 25 mm in length with depth over 6 mm shall be referred to the Engineer for disposition.

 

2.2 Workmanship Requirements

2.2.1 Roughness Requirements. Weld edge prep and other edge surfaces shall be evaluated with the surface roughness guide AWS C4.1-77. Acceptance criteria shall be as follows:

2.2.1.Weld edge prep surfaces for manual and semiautomatic welding processes shall not be rougher than Sample 3 and shall have no gouges deeper than 1.5 mm.

2.2.1.Weld edge prep surfaces for mechanized and automatic welding processes (except SAW)

shall not be rougher than Sample 4 and shall have no gouges.

2.2.1.Weld edge prep surfaces for SAW shall not be rougher than Sample 3 and shall have no gouges.

2.2.1.Edges of members not subject to calculated stresses shall not be rougher than Sample 2 and shall have no gouges deeper than 3 mm.

2.2.1.All other edges shall not be rougher than Sample 3 and shall have no gouges deeper than 1.5 mm.

2.2.2 Arc Strikes. Base metal shall be free of arc strikes.

2.2.3 Cleaning of Completed Welds. Slag shall be removed from all completed welds. Spatter is acceptable unless NDT other than visual inspection is to be performed or otherwise specified.

2.2.4 Fillet Weld Terminations and Starts. Fillet welds shall not be terminated on corners of lap joints. Terminations and starts shall be as follows:

2.2.4.1 Statically Loaded Connections. Terminations and starts shall be made by either holding the weld back from the corner for a distance not less than the specified fillet weld size or by wrapping the weld around the corner not less than two times nor more than four times the specified fillet weld size.

2.2.4.2 Cyclically Loaded Connections. Terminations and starts shall be made by wrapping the weld around the corner for a distance not less than two times nor more than four times the specified fillet weld size.

2.2.5 Repairs. The removal of weld metal or portions of the base metal may be done by machining, grinding, chipping, or gouging. It shall be done in such a manner that the adjacent weld metal or base metal is not nicked or gouged. Unacceptable portions of the weld shall be removed without substantial removal of the base metal. The surfaces shall be cleaned thorough ly before welding. Weld metal shall be deposited to compensate for any deficiency in size in the weld metal.

2.3 Visual Inspection Acceptance Criteria. All welds shall be visually inspected and meet the acceptance criteria of Table 1.

2.3.1 Weld Profiles. Weld profiles shall be in accordance with Table 1, Table 2, and Table 3, Figure A, Figure B, except as otherwise allowed in 2.3.1.1, 2.3.1.2 and 2.3.1.3.

2.3.1.1 Fillet Welds. Unless otherwise specified, the faces of fillet welds may be slightly convex, flat, or slightly concave as shown in Figure B.

2.3.1.2 Exception for Intermittent Fillet Welds. Except for undercut, as allowed by this specification, the profile requirements of Figure B shall not apply to the ends of intermittent fillet welds outside their effective length.

2.3.1.3 Groove Welds. Groove weld reinforcement shall comply with Table 2 and Table 3 . Welds shall have a gradual transition to the plane of the base-metal surfaces.

2.3.1.4 Overlap. All welds shall be free of overlap.

  

2.4  Fillet Weld Dimensional Tolerances

2.4.1  Weld length and spacing. Unless otherwise specified, the weld length indicated is the minimum weld length and there is no maximum. The length of a fillet weld is the overall length of the full size fillet, including end returns (boxing) as measured along the center line of the effective throat and excluding the undersize portions of starts and stops. The tolerances of sub-clause 1.3.2 shall be applied to determine if the minimum length is acceptable, e.g., a 74.2 mm weld length satisfies the requirement for a 75 mm weld.

Unless otherwise specified, the weld spacing (pitch) is the maximum spacing between the centers of adjacent welds and there is no minimum. The tolerances of sub-clause 1.3.2 shall be applied to determine if the actual measured maximum spacing is acceptable, e.g., a 75.8 mm spacing satisfies the requirement for a 75 mm spacing.

2.4.2  Fillet Weld Size. Unless otherwise specified in the visual inspection acceptance criteria, the fillet weld size is the minimum weld size and there is no maximum. The tolerances of sub-clause 1.3.2 do not apply.