Section 7 Design and Preparation of a Joint for Production Welding – CWI Part C

Quiz- Section 7 Design and Preparation of a Joint for Production Welding – CWI Part C- 7 Questions

1.

Who shall decide if weather conditions are suitable for production welding?

 
 
 
 
 

2.

For production welds made in the fixed position, the face reinforcement should not exceed:

 
 
 
 
 

3.

When pipe is welded above ground, the working clearance around the pipe should not be less than?

 
 
 
 
 

4.

Which of the following are acceptable means for welders to identify their production welds?

 
 
 
 
 

5.

Pipe ends of the same specified wall thickness should not be offset by more than:

 
 
 
 
 

6.

Under what conditions may roll welding be used?

 
 
 
 
 

7.

When is the removal of surface porosity clusters, bead starts, and high points required before welding?

 
 
 
 
 


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Section 7: Design and Preparation of a Joint for Production Welding

The purpose of Section 7 is to establish requirements for production welding.

7.1 General

Production welding shall be performed only by qualified welders using qualified welding procedures. This paragraph identifies the cleanliness requirements for the surfaces to be welded. Further, any base material or handling conditions (e.g. lamination, tears, etc.) that might adversely affect welding are prohibited.

7.2 Alignment

Ideally, the abutting ends of adjoining pipe lengths should align with little or no axial misalignment. In practice, this is unlikely, so API 1 1 04 suggests a maximum of no more than 1 /8 inch of offset (high-low) between adjoining pipe lengths of the same wall thickness. Larger variations are acceptable if the pipe meets the ovality (maximum and minimum diameter) requirements in the applicable material (or purchase) specifications and the offset is distributed evenly around the outside of the joint. API 1 1 04 suggests that hammering on pipes to obtain proper lineup be kept to a minimum.

7.3 Use of Lineup Clamp for Butt Welds

In production and fabrication, the use of a clamping device or fixture is a common practice to help bring adjoining pipe lengths into proper alignment. If external clamps are to be removed before completion of the root bead, at least half of the root bead must be in place, uniformly distributed around the joint. If internal clamps are to be used and removing them before completion of the root bead would permit movement of the pipe or result in undue stress on the unfilled joint, the internal clamps shall remain until the root pass is completed. When it is permissible to remove any clamp prior to the completion of the root bead, the completed portions of the root bead must be in approximately equal segments spaced approximately evenly around the joint.

7.4 Bevel

Bevels placed on pipe ends by the pipe manufacturer, referred to as “mill bevels,” must meet the requirements of the welding procedure specification. Pipe ends may be beveled in the field by any machine tool or machine oxygen cutting. The company, however, must approve the use of manual oxygen cutting. The dimensions of these manual bevels must also conform to those specified in the applicable welding procedure specification.

7.5 Weather Conditions

Welding shall not be done when the weather conditions, such as airborne moisture, winds, or blowing sands, pose a significant threat to the quality of the completed weld. Responsibility for determining how or whether to conduct welding operations lies with the company.

7.6 Clearance

For pipe welded above ground, the working clearance around the joint should be at least 1 6 inches in all directions. For pipe welded in a trench, the cavity beneath the pipe, sometimes referred to as the “bell hole,” shall be large enough to give the welder or welders adequate working space, but no minimum dimension is specified.

7.7 Cleaning Between Beads

Slag and scale shall be removed from each pass in a multi-pass weld using tools as specified in the welding procedure specification. High spots in beads deposited by semiautomatic or mechanized welding processes shall be removed by grinding to prevent contact between the filler metal and/or electrode and the weld deposit during welding. In addition, surface porosity clusters and bead starts shall be removed by grinding on semiautomatic and mechanized welds.

This requirement to remove slag from weld beads does not address the black “glass deposits” sometimes seen at the ripples of carbon steel weld beads deposited with GMAW. These deposits are black silicon oxide deposits whose black color comes from the manganese and iron in the base metal. Since they do not come from the flux used in flux-shielded processes, they are technically not slag. As a result, these are only required to be removed when specifically requested by the company.

7.8 Position Welding and 7.9 Roll Welding

For position (or “fixed”) welding, the pipes shall be secured against movement and the welders shall have adequate space to work. At the company’s option, roll welding may be used, provided the pipe is adequately supported to prevent sag.

API 1104 has established a target weld profile for all pipe welds, regardless of whether they are welded in the fixed or rolled position. Face reinforcement should be no more than 1 /1 6 inches and the face of the completed weld should be about 1 /8 inches wider than the width of the original groove. Note that this profile is a target, not a requirement. It is commonly referred to as “nickel-wide and dime-high.” In no case, however, shall the crown surface of the weld fall below the outside surface of the pipe. For both position and roll welding, the number of filler and finish ends shall allow the completed weld a substantially uniform cross-section around the entire circumference

In position welding, two beads shall not be started in the same location. Instead, the starts and stops of a multiphase weld should be located so that they do not coincide to avoid the creation of high-stress areas by multiplying the residual stresses associated with weld terminations. This applies to welds made in the fixed position, but not those made by roll welding.

7.1 0 Identification of Welds

Each welder shall identify his welds in a manner prescribed by the company.

7.1 1 Preheat and PWHT

Preheat and PWHT shall be conducted as specified by the welding procedure specification.

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Section 6 Qualification of Welders – CWI Part C

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Section 6: Qualification of Welders

6.1 General

The purpose of welder qualification is to prove the welder’s ability to make sound welds using qualified procedures. Welders must qualify by testing before they perform any production welding. A welder who satisfactorily completes a welding procedure qualification test is also qualified as long as all of the test specimens required by subsection 6.5 are successfully tested. These standards also require qualification to be conducted in the presence of a representative acceptable to the company.

The essential variables for welder qualification are different than the essential variables for procedure qualification. The essential variables for welder qualification are listed in paragraphs 6.2.2 and 6.3.2 and will be discussed in detail below.

There are two options for qualifying welders: (1 ) a single qualification and (2) multiple qualifications.
The multiple qualifications qualify the welder for the widest range of variables and is generally preferred.

6.2 Single Qualification

Single qualification requires separate qualification tests for fillet and groove welds. Note that a fillet weld qualification will qualify for welding both socket welds and branch connection welds. However, butt welds do not always qualify the welder to make fillet welds in API 1104.

Paragraph 6.2.1 describes the requirements for the single qualification. In this test, the welder qualifying to make butt welds will make a butt weld in either the fixed or rolled position with the axis of the pipe either horizontal, vertical, or inclined from horizontal at an angle of no more than 45 degrees. The welder qualifying to make branch connections or fillet welds will make a branch or socket connection weld in the position and orientation specified by the welding procedure. The test welds shall meet the requirements of subsection 6.4 (visual examination) and either subsection 6.5 (destructive testing) or 6.6 (nondestructive testing for butt welds only).

Paragraph 6.2.2 is entitled “Scope,” but it really just lists the essential variables for the single qualification of welders. The welder who has completed the single qualification test must requalify if he changes any variables outside the following ranges:

(a) A change in the welding process or combination of welding processes (with the exception that a welder qualified separately for each process used in the combination is also qualified to use the processes in combination).
(b) A change in the direction of welding from uphill to downhill or vice versa.
(c) A change in filler metal classification from Group No. 1 or Group No. 2 to any other group or from any Group No. 9 filler metal to a Group No. 1 or Group No. 2 filler metal. Note that this implies that a welder qualified for SMAW may switch between Group No. 1 electrodes (E601 0, E6011, E701 0, and E701 1 ) and Group No. 2 electrodes (E801 0, E801 1, and E901 0) without having to requalify. However, if a welder qualifies for SMAW using a low-hydrogen electrode (Group No. 3), he must requalify to weld using an E601 0 electrode (Group No. 1 ). In addition, each filler metal classification not listed in Table 1 requires a separate qualification.
(d) A change from one OD group to another (note that OD group was NOT an essential variable for the qualification of welding procedures).
(e) A change from one wall thickness group to another.
(f) A change in position with the following exceptions: a welder who qualifies for fixed (position) welding is also qualified to perform roll welding; a welder who qualifies for making butt welds is also qualified to make lap fillet welds (socket welds), but NOT branch connection welds; a welder who qualifies by making a butt weld in the fixed position at a 45 ° angle is qualified to make butt welds and lap fillet welds (but NOT branch connection welds) in all positions.
(g) A change in the joint design, such as the deletion of a backing strip or a change in edge preparation from a V bevel (i.e. V groove) to a U bevel (i.e. U groove), although this variable is rather
vague.

6.3 Multiple Qualification

Multiple qualifications qualify a welder to weld in all positions, on all wall thicknesses, joint designs, and fittings. However, the widest range of pipe diameters qualified depends on the diameters he welded during the test.

Paragraph 6.3.1 describes the requirements for the multiple qualifications, which require the welder to complete two test weld joints. They are:

(a) A butt weld in the fixed position with the axis of the pipe either horizontal or inclined from horizontal at an angle of no more than 45 degrees. The weld shall be made on pipe with a minimum outside diameter of 6.625 inches and a minimum wall thickness of 0.250 inches. The weld is also required to be welded without a backing strip.

The weld must meet the requirements of API 1 1 04 subsection 6.4 (visual examination) and either subsection 6.5 (destructive testing) or 6.6 (nondestructive testing).

(b) A branch-on-pipe connection weld, for which the welder is required to layout, cut, fit, and weld two pipes of equal diameter together in the form of a T (see Study Guide Figure 5.1 ). The weld shall be made with the axis of the run pipe horizontal and with the branch connection extending vertically down, such that the weld is made in the overhead position.

In addition to the workmanship requirements of paragraph 6.3.1, four nick break specimens shall be removed from the weld as shown in Figure 1 0 and they must also meet the nick break test requirements of subsection 5.8.3.

Paragraph 6.3.2 describes the essential variable rules for multiple qualifications. A welder who successfully completes the butt weld test on pipe 1 2.750 inches in diameter or larger and the branch connection weld on pipes 1 2.750 inch in diameter or larger is qualified to weld in all positions, on all wall thicknesses, joint designs, fittings, and on all pipe diameters. Successful testing on pipes smaller than 1 2.750 inches in diameter qualifies for welding in all positions, on all wall thicknesses, joint designs, fittings, and on all pipe diameters equal to or less than that on which he tested.

A welder holding multiple qualifications shall be required to be requalified if any of the following are changed:

(a) A change from one welding process to another process or combination of processes (aging with the exception that a welder qualified separately for each process used in the combination is also qualified to use the processes in combination).
(b) A change in the direction of welding from uphill to downhill or vice versa.
(c) A change in filler metal classification from Group No. 1 or Group No. 2 to any other group or from any Group No. 3 through 9 to Group No. 1 or Group No. 2. Also, a change in filler metal classification not listed in Table 1 to any other filler metal or vice versa.

6.4 Visual Examination

Visual examination of the test weld must precede any preparation of samples for mechanical testing. If the visual examination reveals cracks, inadequate penetration, burn-through, or unacceptable amounts of undercut, rejection is automatic and another test weld must be prepared. In addition, an inspector may reject the weldment if it does not present a neat, workman-like appearance. Welds made by semiautomatic (e.g. GMAW) or mechanized (e.g. SAW) processes may be rejected if too much filler wire protrudes into the interior of the pipe (sometimes referred to as “bird’s nests” or “whiskers”), although API 1104 offers no definition of what “shall be kept to a minimum” means.“

6.5 Destructive Testing

Paragraph 6.5.1 details the testing requirements for butt weld qualifications. Test specimens shall be cut from the test welds at the locations shown in Figure 1 2 on page 28. The number and type of specimens required are listed in Table 3 on page 30. Figure 1 2, Table 3, and paragraph 6.5.1 should be used together for determining welder qualification test requirements. The test specimen locations are exactly the same as those required for procedure qualification, shown in Figure 3 on page 1 8. The number and type of specimens required for welder qualification, however, are slightly different. Table 3 for welder qualification on page 30 is arranged the same as Table 2 for procedure qualification on page 1 9. The only difference is in the number of specimens required. The similarity of these two tables makes them easy to confuse. Make sure you are referencing the correct table in API 1104: Table 2 on page 1 9 when welding procedures are being qualified and Table 3 on page 30 when welders are being qualified.

Since smaller pipes have less material from which to remove specimens, for pipes less than 2.375 inches in OD, it may be necessary to weld an additional test joint to obtain the required number of test specimens. Furthermore, for pipe 1 .31 5 inches in OD or less, footnote a of Table 3 on page 30 (and Note 2 of Figure 1 2 on page 28 and paragraph 6.5.1 ) provides the option of pulling a single full-section tension test specimen in lieu of performing the required two root bend and nick break tests.

When welders qualify by making butt welds, paragraph 6.5.2 states that the specimens shall be prepared for tensile strength, nick break, and bend tests, as applicable, and the tests shall be performed as described for procedure qualification testing in subsection 5.6. Since the purpose of welder qualification is to determine the welder’s ability to deposit sound weld metal, it is not necessary to determine the tensile strength of the tension test specimens. The tension test may even be omitted, in which case the specimens designated for the tension test shall be subjected to the nick break test.

The tensile strength test requirements for welder qualification are detailed in paragraph 6.5.3. This test is really just a weld metal soundness test. If any of the reduced-section specimens or the full section specimen fails in the weld or at the junction of the weld and the base metal, the fractured surface must meet the soundness requirements of paragraph 5.6.3.3, which is the acceptance criteria for the fractured surface of a nick break specimen. If the specimen fails in the parent material, the weld metal is considered to be acceptable.

Paragraph 6.5.4 gives the requirements for the nick break tests for welder qualification and states that these specimens must meet the same acceptance criteria as those for procedure qualification. See paragraph 5.6.3.3.

The requirements for the bend tests for welder qualification are given in paragraph 6.5.5, which references the same acceptance criteria as those for procedure qualification in paragraphs 5.6.4.3 or 5.6.5.3, as applicable. However, there are two exceptions: Welds in the high-strength pipe may crack or break before they bend to a full U shape. In that case, the specimen is acceptable as long as the exposed surfaces meet the requirements for nick break tests as given in paragraph 5.6.3.3. The other exception is that the company may permit the testing of an additional bend specimen removed from the same test weld to replace a failed bend specimen if, in their opinion, the failure was not representative of the weld. The welder shall be disqualified if this additional specimen fails.

Paragraph 6.5.6 requires that fillet welds be tested using nick break specimens, as shown in Figure 1 0 on page 25. Four specimens shall be removed from locations approximately 90 degrees apart to qualify each welder.

Paragraph 6.5.7 gives the instructions for cutting, preparing, and testing the nick break specimens for welder qualification. When specimens are removed from a complete circumferential test weld, subsection 5.8 and Figures 1 0 and 1 1 on page 25 apply. If the test weld consists of multiple pipe segments (weldments), each segment must supply the same number of specimens. The acceptance criteria for each specimen are given in paragraph 5.8.3.

6.6 Nondestructive Testing (NDT) – Butt Welds Only

At the company’s option, the qualification butt weld may be examined by radiographic testing or automatic ultrasonic testing instead of mechanical testing and meet the requirements in 9.3 or 9.6, respectively. It is not permitted to use NDT methods to purposely locate sound areas or defective areas and subsequently making tests of such areas to qualify or disqualify a welder. Be aware that jurisdictional limitations may override API 1 1 04 and, in doing so, may restrict the use of NDT methods in lieu of mechanical testing for welder qualification.

6.7 Retesting

If a welder fails a test but the company and the welder’s representatives mutually agree that the welder wasn’t at fault, the welder may be given a second chance to qualify. If the welder fails the second time, the welder must submit proof of additional welder training that is acceptable to the company before taking the test for the third time.

6.8 Records

A record that documents the test results for each welder shall be maintained. Furthermore, a list of welders and the procedures for which they are qualified shall also be maintained. If the abilities of a welder come into question, the welder may be required to requalify.

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Section 5 Qualification of Welding Procedures with Filler Metal Additions – CWI Part C

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Section 5 Qualification of Welding Procedures with Filler Metal Additions

5.1 Procedure Qualification

AWS A3.0 defines a welding procedure as “the detailed methods and practices involved in the production of a weldment.” These methods and practices are communicated to the welder in the form of a document referred to as a welding procedure specification. Some codes and standards refer to a welding procedure specification as a “WPS,” but API 1 1 04 does not use that acronym. AWS A3.0 further defines a welding procedure specification as “a document providing the required welding variables for a specific application to assure repeatability by properly trained welders and welding operators.” The welding procedure specification should provide meaningful instructions to the welder for the successful completion of a production weldment.

These definitions set the stage for a detailed discussion of welding procedure qualification, which involves:

(a) Qualifying a welding procedure by testing to prove that welds with suitable mechanical properties can be made by the procedure.
(b) Documenting the results of the procedure qualification test.
(c) Establishing conditions under which requalification of the welding procedure by testing is required.

Note that Section 5 covers only manual and semi-automatic welding using filler metal additions; mechanized welding with filler metal additions is addressed in Section 1 2, while automatic welding without filler metal additions is addressed in Section 1 3 of the standard.

5.2 Record

Subsection 5.2 requires the company to record the complete details of each procedure qualification and to keep that record as long as the welding procedure specification is in use. The record of the procedure qualification is the record of the pipe grade and wall thickness, as well as all of the other required welding variables, used to weld the test coupon; this record also includes the results of the tests (tension, bends, and/or nick breaks) performed. Some codes refer to this document as a procedure qualification record or “PQR,” although API 1 1 04 does not use that term. API 1 1 04 provides sample forms for this purpose. Figure 2 on page 1 1 shows a Sample Coupon Test Report, which can be used to document the results of the procedure qualification test. When the form is used in this manner, the box on the left side of the form, in the middle of the page, labeled “Procedure,” should be checked. This form can be referred to as either a “Coupon Test Report” (“CTR”) or a “Weld Test Report” (“WTR”), although API 1 1 04 does not use these terms.

Figure 1 on page 1 0 is a Sample Welding Procedure Specification Form. The contents of this form are dictated by paragraph 5.3.2 of API 1 1 04.

5.3 Welding Procedure Specification and 5.4 Essential Variables

These subsections list the variables and the ranges thereof required to be specified on a welding procedure specification. Paragraph 5.3.2 describes the variables that must be listed on the welding procedure specification and paragraph 5.4.2 identifies which of those variables are essential variables and the ranges permitted on the welding procedure specification for each of those essential variables.

There are some variables that are listed in paragraph 5.3.2 that are not listed in paragraph 5.4.2. Paragraph 5.4.1 states of those variables, “Changes other than those given in 5.4.2 may be made in the procedure without the need for requalification, provided the welding procedure specification is revised to show the changes.” In other words, the variables that are listed in 5.3.2 that are not listed in 5.4.2 are not essential variables and may be changed by a simple editorial revision of the welding procedure specification. However, in all cases, the welder must ALWAYS weld within the ranges of all of the variables specified in the welding procedure specification.

In the discussion that follows, each variable in 5.3.2 will be described, followed by a reference to the corresponding provision in paragraph 5.4.2 if it is an essential variable. If it is an essential variable, the range qualification rule from 5.4.2 will be explained. Variables listed in 5.3.2 but not listed in 5.4.2 will be so identified. Some codes and standards refer to these types of variables as “nonessential” variables, but API 1 1 04 does not use that term.

5.3.2.1 Process – States the welding process or processes to be used shall be identified and whether they are manual, semiautomatic, mechanized, or automatic.

Paragraph 5.4.2.1 indicates that this is an essential variable.

5.3.2.2 Materials – The materials to which the procedure applies shall be identified by SMYS. The materials may be grouped; but to achieve a “group” qualification, the procedure shall be qualified on the highest SMYS material in that group, resulting in qualification for that SMYS material and all pipe grades below it in that particular group. SMYS groupings are provided in paragraph 5.4.2.2 as follows:

a) SMYS ≤ 42,000 psi.
b) 42,000 psi < SMYS < 65,000 psi.
c) For pipe having a SMYS of 65,000 psi or greater, each pipe grade shall receive a separate qualification test.

For example, qualification on API 5L Grade X42 pipe would qualify for welding Grades X42, B, A, and X25 pipe. Furthermore, qualification on API 5L Grade X56 pipe would qualify for welding Grades X56, X52, and X46, but not Grade X60 because Grade X60 is a higher SMYS grade than that used for qualification. Qualification on API 5L Grade X70 would only qualify for welding Grade X70 pipe. However, a welding procedure specification for API 5L Grade X70 pipe could be used for welding Grade X70 to Grade X56 pipe (see paragraph 5.4.2.2).

Paragraph 5.4.2.2 indicates that a change in the base material, group, or SMYS, as applicable, is an essential variable.

5.3.2.3 Diameters and Wall Thicknesses – The welding procedure specification shall specify the range of outside diameters (ODs) and wall thicknesses that may be welded.

API 1 1 04 provides suggested groupings for outside diameters and wall thicknesses in paragraphs 6.2.2 d) and e), respectively. The OD groups are:

(a) OD less than 2.375 inches.
(b) ODs from 2.375 through 1 2.750 inch.
(c) ODs greater than 1 2.750 inches.
`
The wall thickness groups are:

(a) Wall thickness less than 0.1 88 (3/1 6) inch.
(b) Wall thicknesses from 0.1 88 (3/1 6) inch through 0.750 (3/4) inches.
(c) Wall thicknesses greater than 0.750 (3/4) inches.

Paragraph 5.4.2.5 indicates that a change from one specified wall thickness range to another is an essential variable. Outside diameter is not listed in paragraph 5.4.2, so it is not an essential variable.

5.3.2.4 Joint Design – The welding procedure specification must provide a sketch showing the angle of the bevel, the size of the root face, the root opening, as well as the shape and size of fillet welds. If a backing material is used, the type shall be identified.

Paragraph 5.4.2.3 states that a major change in joint design is an essential variable, but a minor change in the angle of the bevel or the size of the root face is not. These definitions are vague, at best.

5.3.2.5 Filler Metal, Flux, and Number of Beads – The size (diameter) and AWS classification number of the filler metal and flux must be identified. In addition, the number and sequence of beads shall be listed.

This means that the welding procedure should be developed by welding a coupon using the smallest number of beads possible; then, as a result, the welding procedure generated can specify a weld schedule having that number of beads or greater.

Paragraph 5.4.2.6 states that a change from one filler metal Group Number in Table 1 to any other Group Number is an essential variable. It is important to restate here that API 1 1 04 uses a different grouping system for electrodes than the F-Numbers used by AWS and the rest of the welding world. API 1 104 uses Group Numbers, which are different than F-Numbers. So a SMAW procedure specification qualified by welding a coupon with an E601 0 electrode could list E601 0, E601 1, E701 0, and/or E701 1 electrodes because these are all Group No. 1 electrodes. However, a SMAW procedure qualified by welding a coupon with an E701 8 electrode could not list E601 0 or E701 0 or E801 0 electrodes because E701 8 electrodes are Group No. 3 electrodes while the E601 0, E701 0, and E801 0 electrodes are Group No. 1 and No. 2 electrodes. For Group No. 1 through Group No. 3, any change in suffix designator is an essential variable. Also, for any filler metal with a G suffix only, a change in the manufacturer or trade
name is an essential variable.

Furthermore, paragraph 5.4.2.6 states that, for welding pipe having a SMYS of 65,000 psi or higher, a change in the electrode classification is an essential variable. So, for welding a Grade X70 pipe with SMAW, a change in electrode classification from E801 6 to E801 8 requires requalification, even though the specified minimum ultimate tensile strength of the weld deposits made by these two low-hydrogen electrode classifications is the same.

Also, the general note at the bottom of Table 1 states that electrodes, filler metals, and fixes other than those listed can be used, but each would require a separate qualification. This includes commonly used higher-strength SMAW electrode classifications, such as E901 5 or E1 001 8.

Filler metal size (diameter) is not listed in paragraph 5.4.2 and, therefore, is not an essential variable.

5.3.2.6 Electrical Characteristics – The type of current used shall be identified. Specify either alternating current (AC) or direct current (DC). For DC, the polarity must be identified as well. Either reverse polarity [electrode positive or (EP)] or straight polarity [electrode negative or (EN)] must be listed. A range of voltage and current values must also be specified for each size and type of electrode or filler metal to be used. Typically, the amperage and voltage ranges should provide reasonable flexibility for the welders while being narrow enough to ensure the production of an acceptable weld. The inspector should always verify that these ranges are consistent with the manufacturer’s recommendations.

Paragraph 5.4.2.7 states that a change in current type or polarity is an essential variable. However, changes in the voltage and current ranges are not essential variables.

5.3.2.7 Flame Characteristics – For oxyacetylene welding, designate the type of fame being used. Three options exist. They are:

(a) Carburizing (also referred to as reducing fame), in which an excess of acetylene results in unburned acetylene at the tip of the fame that can deposit carbon on or “carburize” the surface of the base metal.
(b) Oxidizing, in which an excess of oxygen results in unburned oxygen at the tip of the fame that can oxidize the surface of the base metal.
(c) Neutral, in which there is no unburned acetylene or oxygen at the tip of the fame. Also, the size of the orifice in the torch tip must be specified for each size of rod or wire. The inspector should always verify that tip sizes and gas pressures are within manufacturers’ recommendations.

This variable is not listed in paragraph 5.4.2 and, therefore, is not an essential variable.

5.3.2.8 Position – Designate whether the pipe is rolled or fixed during welding (roll or position welding).

Paragraph 5.4.2.4 states that a change from roll to a fixed position, or vice versa, is an essential variable.

5.3.2.9 Direction of Welding – Designate whether welding is to be performed in the uphill or downhill
direction. Sometimes this is referred to as the “progression” of welding.

Paragraph 5.4.2.9 states that a change in the direction of welding is an essential variable.

5.3.2.1 0 Time Between Passes – The maximum time between the end of the root bead and the start of the second bead (hot pass) must be specified as well as the maximum time between the completion of the second bead (hot pass) and the start of other beads.

Paragraph 5.4.2.8 states that an increase in the time between the end of the root bead and the start of the hot pass is an essential variable. If the welding procedure is qualified by welding a coupon in which the hot pass is begun 1 0 minutes after the completion of the root bead, the welding procedure specification should state, “Ten minutes, maximum, permitted between the end of the root bead and the start of the hot pass.” Obviously, it could state a length of time shorter than ten minutes may pass between the end of the root bead and the start of the hot pass, but it could NOT state a period of time longer than ten minutes. This is an ingenious way to control the inter pass temperature for the hot pass, as generated by the root pass, during field welding

The time between the completion of the hot pass and the start of other beads is not listed in paragraph 5.4.2, so this is not an essential variable and, although it is required to be listed on the procedure specification, it may be changed to any value by a simple editorial revision of the procedure specification without requalification by testing.

5.3.2.1 1 Type and Removal of Lineup Clamp – Specify whether a lineup clamp is required, and if so, what type (external or internal) is to be used and how much of the root bead must be deposited before the clamp is released. Typically, a prescribed amount of the joint must be welded before removing the clamp so that the partially welded joint is not subject to undue stress prior to completion of the weld. 

This variable is not listed in paragraph 5.4.2 and, therefore, is not an essential variable.

5.3.2.1 2 Cleaning and/or Grinding – Describe whether hand tools or power tools are to be used when cleaning or grinding is necessary. This applies to pre-weld cleaning, inter-pass cleaning, and post-weld cleaning.

This variable is not listed in paragraph 5.4.2 and, therefore, is not an essential variable.

5.3.2.1 3 Preheat and Postweld Heat Treatment (PWHT) – For preheat, specify the minimum required temperature at the start of the weld, the minimum temperature below which preheat is required, and the method of preheating required. For PWHT, specify the temperature range, the time at temperature, the method of heating, and the temperature control methods used to measure the temperature.

Paragraph 5.4.2.1 3 states that a decrease in the minimum preheat temperature is an essential variable. As a result, if a welding procedure is qualified by welding a test coupon at 70 °F, using this welding procedure specification when the temperature outside is 50 °F would require the welder to heat the joint to 70 °F before welding, regardless of pipe grade.

Paragraph 5.4.2.1 4 states that the addition of PWHT or a change in the range of values for the time, temperature, or technique specified in the welding procedure specification are all essential variables.

5.3.2.1 4 Shielding Gas and Flow Rate – The composition of the shielding gas and the range of flow rates permitted shall be specified.

Paragraph 5.4.2.1 0 states that a change in the nominal composition of the shielding gas is an essential variable. In addition, an increase or decrease in the flow rate of more than 20 % of the nominal value is also an essential variable.

5.3.2.1 5 Shielding Flux – The type of shielding flux must be specified. This variable only applies to submerged arc welding (SAW).

Paragraph 5.4.2.1 1 refers the reader to Table 1, footnote a for changes in shielding flux that constitute essential variables. Table 1, footnote a applies to Group No. 4 filler metals, which are those for SAW. This footnote states that any combination of electrode and flux can be used to qualify a welding procedure specification and that the combination is identified by its complete AWS classification, which, by definition in AWS Specifications A5.1 7, specifies both the flux and the electrode. Only substitutions that have the same AWS classification (for both flux and electrode) can be used without requalification.

So, if the welding procedure was qualified by welding a test coupon using a SAW consumable whose AWS classification was F7A0-EL1 2, any flux with the “F7A0” designation could be used with that welding procedure specification, whether it was made by the same manufacturer as that used on the test coupon or not. Conversely, the use of a flux whose AWS classification is different from that used during qualification would require the requalification of the welding procedure by testing.

5.3.2.1 6 Speed of Travel – The range for speed of travel for each pass must be specified on the welding procedure specification, but this range is defined by the range(s) of travel speed(s) used on the test coupon used to qualify the welding procedure.

Paragraph 5.4.2.1 2 states that a change in the range for speed of travel is an essential variable. This means that if the test coupon was welded at 1 0 inches per minute, only 1 0 inches per minute can be specified on the welding procedure specification. Fabricators must realize that test coupons for qualifying welding procedures must be welded using a range of travel speeds to allow a range of travel speeds to be permitted on the welding procedure specification.

5.3.2.1 7 Method of Cooling After Welding – When controlled cooling from the welding operation is used, the welding procedure must specify the method used (e.g., water) and the maximum temperature at which the cooling is applied.

This variable is not listed in paragraph 5.4.2 and, therefore, is not an essential variable.

5.5 Welding of Test Joints – Butt Welds

For qualifying a welding procedure for making butt welds (sometimes referred to as girth or circumferential welds), a butt weld shall be made joining two pieces of pipe. Notice that a butt weld procedure is only qualified for making butt welds. For making fleet or branch connection welds, a separate welding procedure must be qualified.

5.6 Testing of Welded Joints – Butt Welds

Paragraph 5.6.1 gives directions for the preparation of the test coupons. The welded test joint is to be cut into sections, as shown in Figure 3 on page 1 8. Table 2 on page 1 9 gives the number of required specimens. Figure 3 and Table 2 should be used in tandem, along with 5.6.1, for procedure qualification testing requirements.

Figure 3 illustrates the locations from which test specimens shall be removed for procedure qualification testing. It contains four-pipe illustrations, each representing a different range of pipe diameters. Think of each illustration as a clock face. For pipe diameters greater than 4.5 inches, the pipe is big enough that specimens can be removed from four locations approximately 90 degrees apart: at the two, four, eight, and 10 o’clock positions. At each location, arrows outside the pipes indicate the locations where the required specimens shall be taken. For pipes smaller in diameter than 4.5 inches, there is simply not enough room to remove samples from four locations 90 degrees apart, so the illustrations indicate that the specimens should be removed from the two and eight o’clock locations instead. In no case shall the specimens be removed from the area of the pipe containing the longitudinal (long seam) weld. Footnote an of Table 2 and paragraph 5.6.1 identify that for diameters less than 2.375 in. with a wall thickness of 0.500 in. or less, two test welds are required to provide the required number of nick break and root been specimens. The same note of Table 2 and Note 2 of Figure 3 specify that for pipe of 1 .31 5 in. diameter and smaller, one full section tension specimen is tested. 

Notice that footnote b of Table 2 states that no tension tests are required for pipes having a SMYS of 42,000 psi or less. For such a low-strength pipe, it is not even necessary to determine the tensile strength of the tested coupon – only nick break tests and bend tests are needed.

One other feature to notice about Table 2 is that side bend tests are required in lieu of face and root bend tests when the wall thickness is greater than 0.500 inches. This is because heavier wall pipes can require significantly more force to bend the specimens in the face and root orientation. For thicker pipe, the use of side bend specimens 1 /2 inch wide by the wall thickness thick (see Figure 9 on page 24) allows the thicker pipe to be more easily tested in a field setting. All welding qualification codes have a thickness above which side bends are permitted in lieu of face and root bends. For ASME Section IX and AWS D1 .1, that thickness is 3/8 inch. For API 1 1 04, that thickness is 1 /2 inches.

Subsection 5.6 discusses these specimens and tests in detail, describing the preparation of the specimens, the test methods, and the acceptance criteria for each. The discussion refers the reader to Figures 4 through 9 on pages 20 through 24.

Tensile strength test requirements are given in paragraph 5.6.2. Tension specimens are approximately 9 inches long by about 1 inch wide. They are required to be full-thickness specimens and they may be made to either one of the two configurations shown in Figure 4 on page 20. Note that weld reinforcement is not removed when testing a specimen prepared according to Figure 4 a). However, Figure 4 b) provides an option of removing a full-thickness specimen with a reduced width section, in which case the removal of weld reinforcement is optional.

The specimens shall be broken in any device capable of measuring the load at which failure occurs

The tensile strength of the weld shall be no less than that specified for the base metal. If the specimen fails in the weld metal, then the fracture surface must also meet the requirements of paragraph 5.6.3.3, which is the criteria for evaluating the fractured surface of a nick break specimen. If the specimen fails in the pipe material and produces a tensile strength not less than 95 % of that specified for the pipe material, the test is acceptable.

Testing of nick break specimens is described in paragraph 5.6.3. The term “nick break” refers to the hacksaw notch or “nick” cut into each edge of each transverse specimen, such that the reduction of the overall cross-section of the specimen helps facilitate the fracture. These specimens are to be approximately 9 inches long by about 1 inch wide and are shown in Figure 5 on page 21. The specimens may be broken by any convenient method, which may include pulling them apart using a tension-testing machine or hitting one end with a hammer while holding the other end.

Figure 6 on page 22 is a schematic of the exposed surface of such a specimen after breaking and it defines the directions in which discontinuity length, depth, and separation are to be measured.

The exposed weld metal surfaces of a nick break specimen must show complete fusion and penetration. The maximum permitted pore size is 1 /1 6 inch and the combined area of all acceptable pores shall not exceed 2 % (1 /50th) of the fractured surface area. Slag inclusions shall not exceed 1 /32 inches in depth and shall not exceed the lesser of 1 /8 inch or one-half the specified wall thickness. There shall be at least 1 /2-inch separation between the edges of adjacent acceptable slag inclusions.

Root and face bend testing is described in paragraph 5.6.4. These specimens are approximately 9 inches long by roughly 1 inch wide and are shown in Figure 7 on page 22. They may be machine or oxygen cut. A maximum corner radius of 1 /8 inches is permitted in order to help prevent corner cracks that could originate from the rough-cut corner rather than from flaws in the weld. In addition, the reinforcement on both the face and root surfaces is required to be removed flush with the surface of the specimen prior to bending in order to maintain smooth and consistent contact with the contour of the plunger. The bend test jig is shown in Figure 8 on page 23, which shows that the radius of the plunger is the same for all pipe grades.

Root and face bend testing is described in paragraph 5.6.4.

The maximum few sizes permitted on the convex surface of a bent specimen is the lesser of 1 /8 inch or one-half the specified wall thickness. Corner cracks that are less than ¼ inch shall not be considered unless they contain obvious weld-related imperfections. In that case, the maximum 1 /8-inch few sizes apply.

Side bend testing is described in paragraph 5.6.5. The side bend test is similar to the root and face bend tests, except that the specimens are bent such that one side of these transverse specimens becomes the convex surface instead of the face or root surfaces. The specimens are to be approximately 9 inches long by about 1 /2 inches wide and are shown in Figure 9 on page 24. The remainder of the preparation details, the method of testing, and the acceptance criteria are similar to those for face and root bends.

5.7 Welding of Test Joints – Fillet Welds

Figure 1 0 on page 25 illustrates the two options for qualifying fillet weld procedures. One option is a branch connection weld (see Study Guide Figure 5.1 on the previous page), assembling two pipes in the form of a T; the other is a socket-weld configuration (see Study Guide Figure 5.2 below), where the end of one pipe is inserted into the end of a slightly larger pipe to create a lap joint.

5.7 Welding of Test Joints - Fillet Welds

5.8 Testing of Welded Joints – Fillet Welds

Paragraph 5.8.1 describes the details of fillet weld testing. Regardless of the test joint configuration selected, qualification of fillet weld procedures requires four nick break specimens to be removed from the welded coupon at 90° intervals (see Figure 1 0 on page 25).

Figure 1 1 on page 25 shows schematics of the nick break specimens. When a branch connection weld is used, two of the four nick break specimens must be removed from the 90° intersection areas, or “crotches,” of the joint (shown in the bottom right corner of page 25) and two must be removed from the tangential area (shown in the bottom left corner of page 25). Due to the large amount of reinforcement that can be present in these welds, the cut edges of all four specimens are subject to fame cut at the weld edge to narrow the specimen width to ensure failure in the weld in addition to the hacksaw cut (nick) made in the weld direction on the weld face. In the nick break specimens removed from the socket weld, no fame cut is used and the hacksaw cut (nick) in the weld is on the sides of the specimen (not the weld face) and is shown in the top right corner of Figure 1 1 on page 25.

The specimens should be about 1 inch wide and long enough that they can be gripped to be broken. As with the butt joints, if the pipe OD is smaller than 2.375 inches, two pipe joints may be needed to obtain the required number of specimens. In this case, two specimens shall be removed from each of the two test welds.

Paragraph 5.8.2 states that the specimens may be broken by any convenient method.

The acceptance criteria for these specimens is given in paragraph 5.8.3 and is exactly the same as that for nick break specimens used to qualify butt weld procedures in paragraph 5.6.3.3.

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Section 4: Specifications – CWI Part C

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Section 4: Specifications

4.1 Equipment

This subsection calls for good judgment, sound engineering, suitable operating practices, and attention to safety in the operation of welding equipment. Arc welding equipment shall be operated within the voltage and current ranges specified on the welding procedure specification. Gas welding equipment shall be operated with the fame characteristics and tip sizes given in the qualified WPS.

4.2 Materials

Paragraph 4.2.1 says that pipe and fittings must conform to API or any applicable ASME, ASTM, MSS, or ANSI specifications, but it then further states that materials that comply with the chemical and mechanical properties of any of these specifications are also acceptable, even if they are not manufactured in accordance with the specification. This suggests that the chemical and mechanical properties of any such material must be identified, preferably on the welding procedure specification, when used for an API 1104 application.

Paragraph 4.2.2.1 states that filler metals must conform to one of the listed AWS filler metal specifications. Other filler metals may be used as long as the applicable welding procedures are qualified.

Table 1, in Section 5 on pages 1 5-1 6, divides filler metals into nine groups, based on electrode characteristics and the welding processes that use them. It is important to note that the Group Numbers that API 1104 uses are different than the F-Numbers that AWS uses to group filler metals. For instance, the low-hydrogen SMAW electrodes are F-No. 4 electrodes as defined by AWS, but they are Group No. 3 electrodes in API 1104. Table 1 lists:

(a) Group Numbers for filler metals, electrodes, and fluxes.
(b) AWS Specifications.
(c) AWS Classifications for filler metals and electrodes.
(d) AWS Classifications for fluxes.

Group Nos. 1, 2, and 3 electrodes are for SMAW. Group No. 4 electrodes and fluxes are for SAW. Group No. 5 electrodes are for GMAW, GTAW, and PAW. Group No. 6 electrodes are for OFW and Group Nos. 7, 8, and 9 are for FCAW.

Be attentive to the footnotes in Table 1, which modify the requirements for use of certain electrodes, filler metals, or fluxes and may give additional rules.

Paragraph 4.2.2.2 requires protection of filler metals and fluxes from deterioration and excessive changes in moisture, although no definition of “excessive” is provided. Obviously, if the flux coating on a SMAW electrode is damaged, it should not be used because it will not operate properly. Low hydrogen SMAW electrodes (AWS classifications which end in 5, 6, or 8) must be stored in such a way that their coatings do not absorb excessive moisture from the atmosphere prior to use for welding.

Although it is not specifically required by API 1104, there are recommended good manufacturing practices for the storage and use of low-hydrogen SMAW electrodes in applicable AWS filler metal specifications. These include

(a) The storage of these electrodes in a heated, vented oven at a prescribed temperature after removal from their hermetically sealed containers,

(b) Limited exposure to the atmosphere, and

(c) Recommended minimum baking times and temperatures after atmospheric exposure.

Paragraph 4.2.3.1 addresses the various types of shielding gases used for welding. Inert shielding gases do not react chemically with the weld pool; they work by simply shielding the weld pool from interacting with the gases in the atmosphere. An active gas, however, does interact with either the arc, the weld pool, or in some cases, both. Inert gases include argon and helium. Active gases include carbon dioxide and oxygen. In GMAW, sometimes mixtures of inert and active shielding gases are used.

Gases must be relatively pure and dry and the shielding gas or gases to be used shall be qualified in accordance with the applicable essential variable rules for procedure qualification. API 1104 does not reference AWS A5.32 for purity requirements for shielding gases.

Paragraph 4.2.3.2 addresses storage and handling of gases for welding. Gases shall not be fled intermixed in their containers and gases of questionable purity or gases from damaged containers shall not be used.

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Section 3 Terms, Definitions, Acronyms, and Abbreviations – CWI Part C

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Section 3: Terms, Definitions, Acronyms, and Abbreviations

For the purposes of this standard, the welding terms, and definitions in AWS A3.0 Standard Welding Terms and Definitions apply with the additions and modifications listed in subsection 3.1.

Terms defined in AWS A3.0 are not defined again here. Additional key terms not defined in Section 3 of the standard or
AWS A3.0 are defined below:

Butt Weld. A nonstandard term for a groove weld in a butt joint.

Classification (AWS). The AWS designation lists rods, electrodes, and filler metals according to their chemical composition and operating characteristics. Examples include, for SMAW—E701 8, for GMAW—ER70S-6, and for GTAW— with-2.

Coupon test report. A form that can be used to record either procedure qualification or welder qualification test results or report on a weld coupon from a production weld. It is sometimes referred to as a “weld test report.”

Crown surface. A nonstandard term for weld face, usually referring to the final bead placed on the outside of a pipe.

Destructive testing. Mechanical testing destroys a sample or part in the process of measuring a specific material property.

Essential variable. A variable that has a significant effect on mechanical properties for procedure qualification or welder/operator skill for performance qualification. In general, if the value for an essential variable is changed to a value outside the range qualified, as defined by the code or standard in question, requalification of the procedure or welder/operator by testing is required. The essential variables for procedure and performance qualification are not the same within any given code or standard. Similarly, the essential variables for procedure or performance qualification are not usually the same from one code or standard to the next.

Image quality indicator (IQI). A device used to confirm the resolution sensitivity of radiographic images. This is sometimes referred to as penetrometers or “penny.” See Study Guide Figure 3.1 below.

Lineup clamp. An external or internal device used to bring two pipe segments into alignment for pre-weld tacking or for welding.

Nick break test. A destructive test used to determine the soundness of weld metal by fracturing the specimen through the weld so the fractured surface of the weld metal can be visually examined for the presence of discontinuities.

Pipe nipple. A short length or section of a pipe, usually used for qualifying a procedure or a welder. shielding atmosphere. A gas envelope surrounding the weld area during welding to prevent or reduce the formation of oxides or other detrimental surface substances and facilitate their removal. socket weld. A fillet weld joining two pipes or a pipe to a pipe fitting, where one pipe is inserted into the other pipe or into the fitting. See Study Guide Figure 3.2 below.

Shielding atmosphere. A gas envelope surrounding the weld area during welding to prevent or reduce the formation of oxides or other detrimental surface substances and facilitate their removal.

Socket weld. A fillet weld joining two pipes or a pipe to a pipe fitting, where one pipe is inserted into the other pipe or into the fitting. See Study Guide Figure 3.2 below.

Terms, Defnitions, Acronyms, and Abbreviations

Soundness. Relative freedom from imperfections.
Soundness testing. Testing is done to verify a weldment is free from defects. API 1104 permits the use of bend and nick break destructive tests, as well as radiographic and ultrasonic testing, which are both nondestructive tests.
Specifications (AWS). An AWS document that lists the rods, electrodes, or filler metals that can be used to weld a given category of base metals with a given category of welding processes. An example is AWS A5.1, Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding.
Specified minimum tensile strength (SMTS). The minimum ultimate tensile strength, specified by the pipe specification, for any given grade of pipe. For instance, the API 5L Grade X52 pipe has an SMTS of 66,000 psi, meaning that a tension test of this pipe will result in an ultimate tensile strength no less than 66,000 psi.

Specified minimum yield strength (SMYS). The minimum yield strength, specified by the pipe specification, for any given grade of pipe. For instance, the API 5L Grade X52 pipe has a SMYS of 52,000 psi, meaning that a tension test of this pipe will result in a yield strength no less than 52,000 psi.

Speed of travel. The rate of welding progression along the weld joint.

Tensile strength test. A test in which the specimen is loaded in tension until failure occurs. This is also referred to as a tension test.

Trepanning. A process, typically using a hole saw, in which a disc-shaped specimen containing a section of the weld is removed from a pipe weld. The disc is removed so the inspector can evaluate the weld quality and/or the degree of penetration. Trepanning is generally not permitted for production piping applications. See Study Guide Figure 3.3 below.

Yield strength. The point at which a metal’s response to the application of tensile load changes from elastic to plastic.

In some cases, API 1104 uses different terms to refer to the same feature or characteristic. For instance, the terms “discontinuity,” “imperfection,” “few,” “irregularity,” and “anomaly” are used interchangeably in the text. However, only “imperfection” is defined in paragraph 3.1 .1 1 .

All of these terms, however, have the same meaning. Similarly, the terms “position” welding and “fixed” welding are used interchangeably, although only “position welding” is defined in paragraph 3.1 .1 7. In addition, the term “porosity” is defined in AWS A3.0 and is used in API 1104, but the term “voids,” is used as well; “voids” is not defined in API 1104 but has the same meaning as “porosity.” Root face is a standard term defined in AWS A3.0, but API 1104 also uses the nonstandard term “land” to refer to the root face of a
weld joint.

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Section 1 Scope – CWI Part C

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Section 1: Scope

Study Guide for API 1 1 04 (21 st Edition)

API  1 1 04 provides a list of eight permitted welding processes.  They are listed below:

(a) Shielded metal arc welding (SMAW).

(b) Submerged arc welding (SAW).

(c) Gas tungsten arc welding (GTAW).

(d) Gas metal arc welding (GMAW).

(e) Flux-cored arc welding (FCAW).

(f) Plasma arc welding (PAW).

(g) Oxyacetylene welding (OAW).

(h) Flash butt welding (FW).

API  1 1 04 also states that these processes may be applied using manual,  semiautomatic,  mechanized, or automatic welding techniques or a combination of these techniques.  All of these techniques,  except manual welding,  are defined in  Section  3.  Study Guide Table 1 . 1  indicates which  techniques are

API  1 1 04 covers procedures for various NDT methods and the acceptance standards to be applied to production welds.   The NDT methods are listed below,  along with their AWS abbreviations:

(a) Radiographic Testing (RT).

(b) Magnetic particle testing (MT).

(c) Liquid penetrant testing (PT).

(d) Ultrasonic testing (UT).

(e) Visual testing (VT).

The numerical values stated in API  1 1 04 are given in either U. S.  Customary units or metric (SI) units.

The U. S.  Customary values typically appear first,  followed by the SI  units in parentheses,  but the SI  units are approximations of the corresponding U. S.  customary units.  API  1 1 04 emphasizes that you must use one system or the other and not combine them.

Process  Manual Semi-automatic  Mechanized  Automatic
Shielded metal arc welding (SMAW) X      
Submerged arc welding (SAW)   X X  
Gas tungsten arc welding (GTAW) X X X X
Gas metal arc welding (GMAW)   X X X
Flux-cored arc welding (FCAW)   X X X
Plasma arc welding (PAW) X   X X
Oxyacetylene welding (OAW) X      
Flash butt welding (FW)       X

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