Quiz- Section 12 Mechanized Welding with Filler Metal Additions- CWI Part C- 5 Questions
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Section 12: Mechanized Welding with Filler Metal Additions
Section 12 provides the rules for qualifying welding procedures and personnel for mechanized welding with filler metal additions. It further addresses production welding along with inspection and NDT of production welds..
12.1 Acceptable Processes
Mechanized welding shall be performed using one or more of the following processes:
(a) Submerged arc welding (SAW).
(b) Gas metal arc welding (GMAW).
(c) Gas tungsten arc welding (GTAW).
(d) Flux-cored arc welding (FCAW) with or without external shielding gas.
(e) Plasma arc welding (PAW).
(f) Any of the above processes combined with a manual or semiautomatic process.
12.2 Procedure Qualifications
The rules in Section 1 2 are basically identical to those in Section 5 with a few additions and exceptions. Only the differences from Section 5 will be discussed here.
The quality of test welds shall be determined by both destructive testing and non-destructive testing and shall meet the requirements of subsection 5.6, except that nick break tests are not required, and Section 9. The use of nondestructive testing is in addition to the destructive tests required in Section 5.
12.3 Record
Identical to Section 5, this subsection refers the reader to Figures 1 and 2 on pages 1 0 and 1 1 for recommended forms that can be used to document a welding procedure specification and the record of the procedure qualification test coupon, respectively. The record of the procedure qualification must be maintained as long as the welding procedure specification is in use.
2.4 Welding Procedure Specification
Subsection 1 2.4 lists the variables required to be recorded on a welding procedure specification for mechanized welding. The list is the same as that in subsection 5.3, with the following additions and exceptions:
(a) This section does not provide suggested groupings for diameters or wall thicknesses.
(b) Paragraph 1 2.4.2.1 requires the welding procedure specification to include a description of the equipment to be used.
(c) Paragraph 1 2.4.2.4 requires that the welding machine used for each bead be recorded on the welding procedure specification.
(d) Flame characteristics are not listed in subsection 1 2.4 because oxyfuel welding cannot be mechanized.
(e) The minimum percentage of root bead welding that must be completed before a lineup clamp can be removed is not listed in paragraph 1 2.4.2.1 1.
(f) Paragraph 1 2.4.2.1 2 includes the requirements for joint end and inter pass cleaning but does not require that the type of cleaning tools (power or hand) be specified on the welding procedure specification.
(g) Paragraphs 1 2.4.2.1 3 and 1 2.4.2.1 4 require the width of material to be heated during preheating and PWHT to be specified on the welding procedure specification.
(h) Paragraph 1 2.4.2.1 9 requires the welding procedure specification to list any other important factors necessary to produce a good weld and gives examples.
2.5 Essential Variables
Subsection 1 2.5 lists the essential variables for the qualification of welding procedures using mechanized welding processes. This list is essentially the same as that in subsection 5.4 with the following additions and exceptions:
(a) Paragraph 1 2.5.2.3 adds that any change to the root spacing, root face, or angle of bevel to a value not specified on the welding procedure specification is an essential variable.
(b) Paragraph 1 2.5.2.4 adds that any change in wall thickness beyond the range listed in the welding procedure specification is an essential variable.
(c) Paragraph 1 2.5.2.5 adds that any change in specified pipe OD beyond the range listed in the welding procedure specification is an essential variable.
(d) Paragraph 1 2.5.2.7 adds that a change in the size of the filler metal wire is an essential variable.
(e) Change in welding position is NOT an essential variable.
(f) Paragraph 1 2.5.2.1 0 specifies that a change in the range of flow rates established for the shielding gas is an essential variable (whereas subsection 5.4 addresses a specific percentage change).
(g) Paragraph 1 2.5.2.1 6 adds that, for plasma arc welding, any change in the orifice gas nominal composition or change in the orifice diameter is an essential variable.
12.6 Qualifications of Welding Equipment and Operators
This subsection lists the essential variables and the tests required to qualify the welding operators.
Paragraph 1 2.6.1 provides the general rules applicable to welding operator qualification. Similar to Section 6, welding operators shall be qualified by welding a test coupon which shall be tested either by destructive methods or nondestructive methods, or both and shall meet the requirements of subsection 6.4 (visual examination) and either 6.5 (mechanical testing) or 6.6 (radiographic testing), except that nick break tests are not required. When required, tensile strength tests may NOT be omitted in lieu of nick break tests. In addition, welding operators shall be qualified on the type of equipment to be used in production welding.
Paragraph 1 2.6.2 lists the essential variables for welding operator qualification. They are:
(a) A change from one welding process, mode of transfer, polarity, or method of application to another.
(b) A change in the direction of welding from vertical uphill to downhill or vice versa.
(c) A change in the filler metal type (solid wire, metal-cored, flux-cored, etc. ).
(d) A change from one specified OD group to another where the OD groups are defined as:
1 ) OD less than 1 2.75 inches.
2) OD equal to or greater than 1 2.75 inches.
(e) An increase in wall thickness over that welded during the qualification test.
(f) A change in position from that qualified (a change from rolled to fixed or a change from vertical to horizontal). A welding operator who qualifies in the fixed position shall also be qualified to perform welds in the rolled position.
(g) A change in welding bug manufacturer or model.
(h) A change in the method of applying the root bead (e.g., external root versus internal root).
(i) A major change in joint design (e.g. from a V-groove to a U-groove) or any change beyond the range established for root spacing, root face, or angle of the bevel.
(j) At the option of the company, welding operators whose work is limited to specific passes in a multi-pass butt weld may qualify by depositing only those passes in a joint, with other passes necessary to complete the joint being wielded by others.
2.7 Records of Qualified Operators
A record shall be made of the tests and results required by subsection 1 2.6. A form similar to that shown in Figure 2 on page 1 1 should be used, but any form is suitable as long as it records all of the required information. A list of qualified operators and the procedures for which they are qualified shall be maintained. An operator may be required to requalify if a question arises about his competence.
12.8 Inspection and Testing of Production Welds
Production welds shall be inspected and tested in accordance with Section 8.
12.9 Acceptance Standards for NDT
Acceptance criteria for production welds shall be those found in Section 9 or, at the company’s option, Annex A.
12.1 0 Repair and Removal of Defects
Repair and removal of defects shall be in accordance with Section 10.
12.1 1 Radiographic Testing
Radiographic testing procedures shall be in accordance with subsection 1 1 .1.
12.1 2 Ultrasonic Testing
Ultrasonic testing procedures shall be in accordance with subsection 1 1 .4.