Welding procedures shall be qualified by preparing and testing welds in accordance with this Annex. At the option of the manufacturer, the tests specified in the latest issue of the ASME Boiler and Pressure Vessel Code, Section IX, may be substituted herein. For the purpose of this annex, the term “automatic welding” includes both machine welding and automatic welding as defined in the ASME Boiler and Pressure Vessel Code, Section IX.
C.2.2 Essential Variables
C.2.2.1 General
An existing procedure shall not be applicable and new procedure shall be qualified when any of the following essential variables listed under C.2.2.2 to C.2.2.7 are changed beyond the stated limits.
C.2.2.2 Welding Process
The following pertain to the welding process.
a) A change in the welding process (i.e. submerged arc to gas metal arc).
b) A change in the method (i.e. manual to semi-automatic).
C.2.2.3 Pipe Material
The following pertain to the welding process.
a) A change in grade category. When different alloying systems are used within one grade category, each alloying composition shall be separately qualified. Grade categories are as follows.
1) SMYS 42,000 psi or less.
2) SMYS greater than 42,000 psi but less than 65,000 psi.
3) Each grade with SMYS of 65,000 psi or greater.
b) Within each grade category, a thicker material than the material qualified.
c) Within the grade category and thickness range, a carbon equivalent (CE) based on product analysis for the material to be repaired which is more than 0.04 % greater than the CE of the material qualified [see Equation (C.1)].
Mn Cr Mo V Ni Cu
CE C 6 5 15
+ + +
= + + + (C.1)
C.2.2.4 Welding Materials
The following pertain to the welding process.
a) A change in filler metal classification.
b) A change in electrode diameter.
c) A change of more than 5 % in the composition of shielding gas.
d) A change of more than 10 % in the flow rate of shielding gas.
e) A change in submerged arc welding flux from one designation to another.
C.2.2.5 Welding Parameters
The following pertain to the welding process.
a) A change in the type of current (i.e. AC vs DC).
b) A change in polarity.
c) For automatic and semi-automatic welding, schedules of welding current, voltage, and speed may be established to cover ranges of wall thicknesses. Within the schedule, appropriately selected points shall be tested to qualify the entire schedule. Thereafter, a new qualification is required if there is a deviation from the qualified schedule greater than the following:
1) 10 % in amperage;
2) 7 % in voltage; and
3) 10 % in travel speed for automatic welding.
C.2.2.6 Weld Bead
For manual and semi-automatic welding, a change in bead width greater than 50 %.
C.2.2.7 Preheat and Postweld Heat Treat The following pertain to the welding process.
a) Repair welding at a pipe temperature lower than the pipe temperature of the qualification test.
b) The addition or deletion of postweld heat treatment.
C.2.3 Mechanical Testing
C.2.3.1 Number of Tests
Two specimens of each type are required from each test.
C.2.3.2 Transverse Tensile Test
The transverse tensile test specimens shall be approximately 1.5 in. (38 mm) wide and shall have the transverse butt weld perpendicular to the longitudinal axis at the center of the test specimen (see Figure C.1 or Figure 7).
The weld reinforcement shall be removed from both faces. The ultimate tensile strength shall be at least equal to the minimum specified for the pipe grade.
Figure C.1—Transverse Tensile Test Specimen C.2.3.3 Longitudinal Tensile-elongation Test
The longitudinal tensile-elongation test specimens shall conform to Figure C.2. The weld shall be made in a groove as shown. The elongation after complete rupture of each test specimen in tension shall be at least equal to the minimum elongation specified for the pipe grade.
Figure C.2—Tensile-elongation Test Specimen C.2.3.4 Transverse Guided-bend Test
The transverse guided-bend test specimens shall conform to Figure C.3. The weld shall be made in a groove as shown. Each specimen shall be placed on the die with the weld at mid-span, and shall be bent approximately 180° in a jig, substantially in accordance with Figure C.4 and Table C.1, with the exposed surface of the weld in tension. The bend test shall be considered acceptable if no crack or other defect exceeding 1/8 in. (3.18 mm) in any direction is present in the weld metal or base metal after bending. Cracks which both originate along the edges of the specimen during testing and measure less than 1/4 in. (6.35 mm) in all directions shall not be considered.
Figure C.3—Guided-bend Test Specimen
Figure C.4—Jig for Guided-bend Test
Table C.1—Guided-bend Test Jig Dimensions (See Figure C.4)
1 2 3 4
Pipe Grade
LC30-1812
LC30-2242 LC52-1200
LC65-2205 LC65-2206 Radius of male member, RA 3t 4t 41/2t Radius of female member, RB 4t + 1/16 in. 5t + 1/16 in. 51/2t + 1/16 in.
4t + 1.6 mm 5t + 1.6 mm 51/2t + 1.6 mm Width of male member, A 6t 8t 9t Width of groove in female member, B 81/8 in. 10t + 1/8 in. 11t + 1/8 in.
8t +3.2 mm 10t + 3.2 mm 11t + 3.2 mm NOTE t = specified wall thickness of the pipe.
For intermediate grades of pipe, the dimensions in Table C.1 of the bending jig shall conform to those shown for the next lower grade or shall be proportional thereto.
C.2.3.5 Nick-break Test
The nick-break specimens shall conform to Figure C.5. The weld shall be made in a groove as shown. Each specimen shall be saw notched from both edges at the center of the weld and shall be broken by pulling or hammer blows at the center of one end. The exposed surface of the specimen shall be visually examined and shall be considered acceptable if it meets the following criteria.
a) No gas pockets exceeding 1/16 in. (1.59 mm) in any direction.
b) Not more than one gas pocket of any size for specified wall thicknesses of 0.250 in. (6.35 mm) and less.
c) Not more than two gas pockets of any size for specified wall thicknesses of 0.500 in. (12.7 mm) or less, but greater than 0.250 in. (6.35 mm).
d) Not more than three gas pockets of any size for specified wall thicknesses greater than 0.500 in. (12.7 mm).
e) To be acceptable, slag inclusions shall be separated by at least 2 in. (12.7 mm) of sound metal and shall appear no greater than 1/16 in. (1.59 mm) in width or 1/16 in. (4.76 mm) in length.
Figure C.5—Nick-break Test Specimen