Design and Preparation of a Joint for Production Welding
7.1 General
Piping shall be welded by qualified welders using qualified procedures. The surfaces to be welded shall be
smooth, uniform, and free from laminations, tears, scale, slag, grease, paint, and other deleterious material
that might adversely affect the welding.
For production welding of materials with two separate strength levels, a procedure that is qualified for the
higher-strength material should be used.
NOTE While it is acceptable (according to 5.6.2.3) for the measured tensile strength across the weld to be less than
the actual tensile strength of the pipe material, some pipeline designs (e.g., high longitudinal strains due to geotechnical
reasons) require matching or overmatching strength girth welds. The use of filler metal with yield strength that matches or
overmatches the actual yield strength of the pipe material prevents longitudinal strains from accumulating in the weld
region, which is more likely to contain imperfections than the pipe material.
7.2 Alignment
The root opening, or spacing between abutting members, shall be in accordance with the welding procedure
specification. The alignment of abutting ends shall minimize the offset between surfaces. For pipe ends of
the same OD and specified thickness, the offset at any location should not exceed 1/8 in. (3 mm). Larger
variations are permissible provided the variation is caused by variations of the pipe end dimensions within
the pipe purchase specification tolerances, and such offset has been minimized by distributing around the
WELDING OF PIPELINES AND RELATED FACILITIES 43
circumference of the pipe. Hammering of the pipe to obtain proper lineup should be kept to a minimum and
hinging of the pipe joint (i.e., the use of hinge tacks) to achieve a proper root gap should be prohibited.
7.3 Use of Lineup Clamp for Butt Welds
Use and removal of lineup clamps shall be in accordance with the welding procedure specification. If the
clamp can be removed prior to root pass completion, the percentage required by the welding procedure
specification shall be met and should be equally spaced around the circumference.
7.4 Bevel
The bevels shall conform to the joint design used in the welding procedure specification.
7.5 Weather Conditions
Welding shall not be done when the quality of the completed weld would be impaired by the prevailing
weather conditions, including but not limited to low temperatures, airborne moisture, blowing sands, or high
winds. Windshields or temporary shelters may be used when practical. The company shall decide if weather
conditions are suitable for welding.
7.6 Clearance
When the pipe is welded above ground, the working clearance around the pipe at the weld should not be
less than 16 in. (400 mm). When the pipe is welded in a trench, the bell hole shall be large enough to provide
the welder or welders with ready access to the joint.
7.7 Cleaning Between Beads
Scale and slag should be removed from each bead and groove. Power tools shall be used when called for in
the welding procedure specification; otherwise, cleaning may be performed with either hand or power tools.
When semiautomatic or mechanized welding is used, surface porosity clusters, bead starts, and high points
should be removed by grinding before weld metal is deposited over them. When requested by the company,
heavy glass deposits shall be removed before weld metal is deposited over them.
7.8 Position and Roll Welding
Procedure
All position welds shall be made with the parts to be joined secured against movement and with adequate
clearance around the joint to allow the welder or welders space in which to work. At the company’s option,
roll welding shall be permitted using a qualified welding procedure specification, provided alignment is
maintained using skids or a structural framework with an adequate number of roller dollies to prevent sag in
the supported lengths of pipe.
Filler and Finish Beads
The number of filler and finish beads shall allow the completed weld a substantially uniform cross-section
around the entire circumference of the pipe. At no point shall the crown surface fall below the outside surface
of the pipe, nor should it be raised above the parent metal by more than that specified in the welding
procedure specification.
Two beads shall not be started at the same location. The cap width should conform to the tolerances
specified in the welding procedure specification. The completed weld shall be thoroughly brushed and
cleaned.
44 API STANDARD 1104
7.9 Identification of Welds
Each welder shall identify the welder’s work in the manner agreed by the company.
7.10 Preheat, Interpass Temperature, Postheat, and PWHT
Preheat, interpass temperature, postheat, and PWHT practices as listed on the qualified welding procedure
specification shall be followed.
NOTE Application of postheat can be beneficial to the reduction of solute hydrogen, particularly when using
cellulosic-coated (AWS EXX10-type) electrodes.
8 Inspection and Testing of Production Welds
8.1 Rights of Inspection
The company shall have the right to inspect all welds by nondestructive means or by removing welds and
subjecting them to mechanical tests. The inspection may be made during the welding or after the weld has
been completed. The frequency of inspection shall be as specified by the company.
8.2 Methods of Inspection
The NDT method used shall produce indications of imperfections that can be accurately interpreted and
evaluated. The welds shall be evaluated on the basis of either Section 9 or, at the company’s option,
Annex A. In the latter case, more extensive inspection to determine the imperfection size is required.
Destructive testing shall consist of the removal of completed welds, sectioning of the welds into specimens,
and the examination of the specimens. The specimens shall be prepared in accordance with and shall meet
the requirements of 6.5. The company shall have the right to accept or reject any weld that does not meet
the requirements for the method by which it was inspected.
NOTE 1 The welder who makes a weld that fails to comply with the requirements may be disqualified from further
work.
NOTE 2 Operators of nondestructive inspection equipment may be required to demonstrate the inspection
procedure’s capability to detect defects and the operator’s ability to properly interpret the indications given by the
equipment.
Trepanning methods of testing shall not be used.
8.3 Qualification of Inspection Personnel
Welding inspection personnel shall be qualified by experience and training for the specified inspection task
they perform. Their qualifications shall be acceptable to the company.
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