Annex B In-service Welding- CWI Part C

Quiz- Annex B In-service Welding- CWI Part C- 9 Questions

1.

The two main concerns with welding on in-service pipelines are:

 
 
 
 
 

2.

For in-service welds on a full encirclement fitting:

 
 
 
 
 

3.

All welders performing repair work should be familiar with the safety precautions associated with cutting and welding on piping that contains or has contained crude petroleum, petroleum products, or fuel gases. Additional guidance can be found in:

 
 
 
 
 

4.

For the qualification testing of in-service branch and sleeve weld procedures, each macro section test specimen:

 
 
 
 

5.

For in-service welder qualification for longitudinal seam welds on pipe with a 0.375 inch wall thickness, the type and number of test specimens required are:

 
 
 
 
 

6.

For the qualification of in-service fillet weld procedures, specified minimum yield strength (SMYS) is:

 
 
 
 
 

7.

When the maximum allowable heat input to avoid burning through is insufcient to provide adequate protection against hydrogen cracking, an alternative precaution that can be used is:

 
 
 
 
 

8.

When qualifying the welding procedure for in-service welding, the face bend specimens from branch and sleeve welds should not be tested:

 
 
 
 
 

9.

For hydrogen cracking to occur, how many conditions must be satisfied simultaneously?

 
 
 
 
 


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Annex B: In-service Welding

B.1 General

This annex provides welding practices for making repairs to and installing appurtenances on piping systems that are in service. Of particular importance are the welds that melt into the carrier pipe since they cool at an accelerated rate due to the quenching effect of the fluid flowing through the carrier pipe.

The welds that melt into the carrier pipe are either fillet welds or branch connection welds. Fillet welds are used to join the ends of encirclement sleeves to the carrier pipe. These fillet welds are also referred to as “sleeve welds” and “circumferential welds.” Groove welds are used to join split sleeves using longitudinal welds, but these, unlike sleeve welds and branch connection welds, do not melt into the carrier pipe.

Welding attachments onto in-service pipelines pose two major risks: (1 ) burning through the pipe wall and (2) hydrogen cracking. Burning through the pipe wall is unlikely when the wall thickness is 0.250 inches or greater, although many companies successfully weld onto thinner wall pipe with regularity. Although Annex B explains how to prevent both of these problems, the major focus of Annex B is on the prevention of hydrogen cracking.

For hydrogen cracking to occur, three conditions must be satisfied simultaneously:

(1 ) Hydrogen in the weld,

(2) A crack susceptible microstructure, and

(3) Tensile stress acting on the weld. Conversely, to prevent hydrogen cracking, one of these must be reduced or eliminated. Since these welds are made on pipelines that have been in service, hydrogen is always present and cannot be reduced to sufficient levels. In addition, residual tensile stresses are present in every weld due to the inherent shrinkage resulting from solidification and subsequent cooling from high temperatures. As a result, the primary technique used to prevent hydrogen cracking in in-service welds is the prevention of a crack-sensitive microstructure.

To make matters worse, in-service welds are made onto pipe carrying flowing fluids which accelerate the cooling rate and, therefore, promote the formation of crack-sensitive phases in steels, particularly martensite. Because of this combination of factors, the most effective approach for preventing hydrogen cracking in in-service welds is the use of a welding procedure that has a high enough heat input to overcome the quenching effects of the fluids flowing through the carrier pipe. As an alternative, temper bead welding sequences are also effective at producing multi-pass welds in which the heat-affected zone in the carrier pipe has a tempered microstructure, known to be more resistant to
hydrogen cracking.

B.2 Qualification of In-service Welding Procedures

This subsection lists the essential variables and tests required to qualify in-service welding procedures.

Paragraph B.2.1 refers the reader to Section 5 for the basic requirements for qualifying welding procedures for making fillet welds and states that the requirements and exceptions in this annex will then be added to those requirements.

Paragraph B.2.2 lists the additional information required to be addressed on the procedure specification. One of these variables is the carbon equivalent of the carrier pipe to be welded. For determining the carbon equivalent, the following equation is provided:

CEIIW = %C + %Mn/6 + (%Cu + %Ni)/1 5 + (%Cr + %Mo + %V)/5

Also included here is the provision that carbon equivalents may be grouped for the purposes of procedure qualification, as will be discussed shortly.

The pipeline operating conditions must also be addressed on the procedure specification. This can be addressed by specifying the fluid type and its flow rate. Again, conditions may be grouped.

For procedures designed to overcome the quenching effect of the flowing contents by using a sufficiently high heat input, the heat input range should be specified. The minimum value of this range should be that used to weld the procedure qualification coupon. Heat input is given in the Note as Heat Input = Amps x Volts x 60 / Travel Speed.

For procedures designed to overcome the quenching effect of the flowing contents by using a temper bead sequence, the weld deposition sequence, including bead size and overlap, should be specified. The required heat input range for each temper bead layer should also be specified on a temper bead procedure specification.

Paragraph B.2.3 lists additions and changes to the essential variable rules specified in Section 5. For in-service welds, specified minimum yield strength is no longer an essential variable, meaning that in-service welding procedures are valid for all pipe grades. However, since hydrogen cracking is more likely on pipe materials having greater hardenability (as measured by the carbon equivalent), an increase in the carbon equivalent over that used to qualify the procedure is now an essential variable. So, for in-service welds, the MTR of the carrier pipe to be welded should be available so that the carbon equivalent can be calculated from the listed composition. When the in-service welding procedure is qualified, the carrier pipe used in the test coupon should have a carbon equivalent no less than that of the production carrier pipe. Ideally, the carrier pipe used for the qualification test should have a very high carbon equivalent. In that case, the in-service welding procedure would be qualified for a large range of carbon equivalents, up to and including that used in the qualification test weld.

For in-service fillet and branch welds, pipe wall thickness is no longer an essential variable, so these procedures are qualified for all wall thicknesses; however, the note in paragraph B.2.3.1 .3 provides an exception, which states that, for weld deposit repairs, the welding procedure is qualified only for wall thicknesses equal to or greater than that used in the qualification test.

Finally, for in-service welds, pipeline operating conditions are an important essential variable, with an increase in the severity of the conditions being a cause for requalification. So, the procedure should be qualified under the most severe quenching conditions. This can be accomplished by making the test weld on the water canister set up at a 45 ° angle as shown in Figure B.2 on page 1 05. By implication, this variable rule also suggests that the use of a heat input value less than that used to qualify a “heat input the procedure” is also an essential variable and would require the requalification of the procedure. By the same logic, paragraph B.2.3.1 .4 states that, for a temper bead procedure, a change in the deposition sequence or the bead spacing (or overlap) from that qualified is also an essential variable and would require requalification of the procedure.

Paragraph B.2.4 addresses the welding of the test joints and refers to Figure B.2 on page 1 05 showing the carrier pipe coupon filled with flowing water with the sleeve being welded to it using fillet welds or branch connection welds as appropriate. This condition has been shown to produce thermal conditions more severe than typical in-service welding applications. Therefore, a procedure qualified under this condition qualifies for all in-service conditions.

Paragraph B.2.5 addresses the testing of the welded joints. In general, in-service welds that melt into the carrier pipe, including repairs to weld depositions, will be tested using the nick break tests described in subsection 5.8, except that the test locations are shown in Figures B.3 and B.4 on pages 107 and 108, respectively, and the number of specimens required is specified in Table B.1 on page 109. The additional tests required in this table are macro section tests, detailed in paragraph B.2.5.4, and face bend tests, detailed in paragraph B.2.5.5, and both are described below.

Longitudinal seam welds of full-encirclement sleeves should be tested with the tension tests, bend tests, and nick break specimens required in subsection 5.6, as a function of sleeve wall thickness and diameter. Branch and sleeve welds should be tested with the nick break tests in Section 5.8 plus the additional required tests in B.2.5.1.

Paragraph B.2.5.4 gives details about the macro section tests to be removed from the in-service branch and sleeve welds. These are shown schematically in Figure B.5 on page 1 09. They may be machine-cut or oxygen cut oversized.

When they are oxygen cut, the oxygen-cut surface must be machined by a non-thermal process to remove at least ¼ inch from the side to be examined. These weld cross-sections shall then be ground, polished, etched with a suitable etchant, and examined visually without dye penetrants and with little or no magnification (typically at 1 0X or less).

Two of the four micro etch specimens for branch and sleeve welds and both of the specimens for weld deposition repair shall be examined by hardness testing in accordance with ASTM E384. At least five indentations shall be made in the coarse-grained HAZ at the toe of each weld cross-section using a Vickers indenter and a 1 0 kg load to determine the maximum hardness.

Paragraph B.2.5.4.4 gives the requirements for visual examination of each micro etch specimen:

(a) The weld should show complete fusion at the root of the joint.
(b) The weld must be free from cracks.
(c) The legs of the fillet welds must meet the requirements of the procedure specification.
(d) The fillet weld surface (convexity and concavity) must be fat within +/- 1 /1 6 inches.
(e) The undercut depth should not exceed the lesser of 1 /32 inch or 1 2.5% of the pipe wall thickness.
(f) Heat-affected zone (HAZ) hardness values over 350 HV should be evaluated to determine the risk of hydrogen cracking

Paragraph B.2.5.5 describes the face bend specimens that are required. Specific specimens may be cut for these tests or the remaining portion of the nick break specimens can be used. Both options are shown in Figure B.6 on page 110. They may be machine-cut or oxygen cut oversized. When they are oxygen cut, they must be machined by a nonthermal process to remove at least 1 /8 inch from each side. When remnants of the sleeve or branch welds are used, the sleeve and branch welds must be removed to, but not below, the surface of the sleeve. Undercut should not be removed.

Paragraph B.2.5.5.2 addresses the method of bending the specimens. This is identical to the requirements in paragraph 5.6.4.2 except that the specimens shall not be tested sooner than 24 hours after welding.

The acceptance criteria for these bend specimens is exactly the same as that found in paragraph 5.6.4.

B.3 In-service Welder Qualification

Paragraph B.3.1 requires welders performing in-service welding to qualify by making a single qualification test weld in accordance with subsection 6.2 using the specific procedure (heat input or temper bead) used to overcome the quenching effects of the fluid flowing through the pipeline. A welder with only that qualification is qualified for in-service welding in accordance with the essential variable limits of subsection 6.2. However, this annex modifies those qualification ranges as explained in the next few paragraphs.

If that qualification test is welded on pipe less than 1 2.750 inches in OD, the welder is qualified for diameters up to and including the diameter on which he tested. If that qualification test is welded on pipe 1 2.750 inches in OD or larger, the welder is qualified to weld all pipe diameters.

A welder who meets both the multiple qualification requirements of subsection 6.3 and the additional qualification test of this annex is qualified as an in-service branch or sleeve welder in accordance with the essential variable rules of subsection 6.3. Welders who perform weld deposition repairs are limited based on the positions in which they perform the test welds.

Paragraph B.3.2 states that the qualification test required by this annex should be welded on a coupon that simulates the ability of the flowing contents to remove heat from the pipe during welding. Similar to the weld coupon required for the procedure qualification test, falling the carrier pipe with flowing water during welding should produce conditions equal to or more severe than typical in-service conditions.

Welders qualified on such a coupon are therefore qualified for all typical in-service applications. The coupon should also be welded following either the heat input, temper bead, or weld deposition repair welding procedure, as applicable.

Paragraph B.3.3 requires the test coupon to meet the visual inspection requirements of subsection 6.4 and the mechanical testing requirements of subsection 6.5. For longitudinal seam welds in full encirclement sleeves, the type and number of test specimens required for welder qualification are listed in Table B.2 on page 1 1 1.

Paragraph B.3.4 requires that records of these qualifications be maintained.

B.4 Suggested In-service Welding Practices

When making actual in-service welds, the requirements of Section 7 apply, except for the alternative or additional requirements of subsection B.4. Paragraph B.4.1 reminds the reader that safety is the primary concern when welding onto these in-service lines. Factors such as operating pressure, flow conditions, and minimum wall thickness in the area to be welded should be considered. Ultrasonic testing of the pipe wall in the area to be welded is commonly used to determine minimum wall thickness and/or to verify that there are no laminations in the pipe wall that could compromise in-service weld quality or pressure integrity. Additional safety precautions can be found in API’s Recommended Practice 2201.

Paragraph B.4.2 addresses important alignment and ft.-up issues. For saddle and sleeve welds, the gap between the sleeve and the carrier pipe should be minimized to permit easy fusion of the carrier pipe. Weld metal build-up on the carrier pipe is one way to minimize any gap that might be present. Clamping devices are recommended. For longitudinal butt welds of full encirclement sleeves, the root opening should be sufficient to permit full penetration. Use of a mild steel backup strip or suitable tape may be necessary to prevent penetration into the carrier pipe.

Recommended welding sequences, sleeve designs, and geometries are provided in paragraph B.4.3 and shown graphically in Figures B.7 through B.12 on pages 112 through 115. For full encirclement sleeves requiring circumferential fillet welds, the longitudinal seams should be completed before beginning the sleeve welds to minimize the residual stresses on the sleeve welds. When making the circumferential fillet welds, one sleeve weld should be completely welded before beginning the other.

Regardless of the type of fitting used, the welding sequence should always be chosen to minimize residual stresses. Heat input limits and/or temper bead sizes and locations as specified in the welding procedure must be followed.

Paragraph B.4.4 recommends that in-service beads should be deposited in the circumferential direction when possible.

B.5 Inspection and Testing of In-service Welds

In-service welds must meet the acceptance criteria of Section 8 except for the additional or alternative requirements in subsection B.5. Since hydrogen cracking is the primary weld quality concern and most hydrogen cracks are located under the weld bead and do not break the surface, the inspection method must be able to detect under bead and toe cracks. A combination of magnetic particle and ultrasonic testing is recommended for inspecting sleeve-to-saddle and branch-to-carrier pipe welds. Radiographic testing is not a good candidate for detecting these types of cracks.

Since it takes time for hydrogen trapped in the weld to diffuse to the coarse-grained region of the HAZ to cause the cracking, it is important to establish a suitable delay time after welding prior to the inspection to ensure that inspection is conducted after the cracking has had adequate time to develop.

B.6 Standards of Acceptability: NDT (Including Visual)

The standards of acceptability in Section 9 apply to imperfections located in in-service welds. For weld deposition repair, the weld length is defined as the maximum weld length in the direction in which the flaw is oriented.

B.7 Repair and Removal of Defects

The requirements in Section 1 0 apply to the repair and removal of defects found in in-service welds. In addition, care should be taken to ensure that excavation of the defect does not reduce the wall thickness of the pipe to less than that required to contain the pipe’s operating pressure.

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Section 10 Repair and Removal of Weld Defects- CWI Part C

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Section 1 0: Repair and Removal of Weld Defects

0.1 General

Paragraph 1 0.1 states that weld defects may be identified at any time.

1 0.2 Authorization for Repair

Paragraph 1 0.2.1 states that company authorization is required for crack repairs, back weld repairs, and double repairs. Company authorization is not required for any repair that does not require the application of heat or weld metal, such as grinding or fling.

Paragraph 1 0.2.2 gives the conditions under which company-authorized repairs can be made to cracked welds. In general, if the length to be repaired is less than 8 % of the weld length, the repair is permitted if a qualified repair procedure is used.

Paragraph 1 0.2.3 addresses repair of defects other than cracks and states that these defects in the root, filler and finish beads may be repaired with prior company authorization. A qualified repair procedure is required for repair welds when using a welding process, method of application, or filler metal different than that used for the original weld, or when repairs are made in a previously repaired area, or when required by the company.

Paragraph 1 0.2.4 permits the use of grinding to remove defects in the reinforcement of root beads and cover passes, as long as contour, minimum wall, and weld thickness requirements are not violated.

Paragraph 1 0.2.5 permits the repair of back welds as long as a qualified repair welding procedure is used and the company permits the repair.

Paragraph 1 0.2.6 requires prior company authorization for double repairs. Further repair of a double repair is only permitted with company authorization and when the repair procedure to be used has been qualified by replicating the number of thermal cycles that the pipe will have seen after the repair.

Paragraph 1 0.2.7 places limits on the lengths of repairs. For pipes having a specified OD of 2.375 inches and greater, the limit on the length of repairs shall be established by the company. For pipes having a specified OD of less than 2.375 inches, all repairs require prior company authorization.

Paragraph 1 0.2.8 establishes a minimum required repair length of 2 inches unless the company
authorizes a shorter repair.

1 0.3 Repair Procedure

This section provides detailed requirements for qualifying repair welding procedures. Repairs are categorized as full-thickness repairs, internal partial-thickness repairs, external partial-thickness repairs, cover pass repairs, or back weld repairs, and the type and number of test specimens required for each type of repair procedure are given in Table 5 on page 49, with detailed instructions in paragraph 1 0.3.3. The tests required are fewer in number to, and different than, the tests required to qualify a butt weld procedure in Table 2. This table adds macro sections and hardness tests for all of the repair procedures but Charpy impact specimens are only required if the original production welding procedure was qualified with Charpy impact tests and when specified by the company.

Paragraph 1 0.3.4 lists the information required to be on a repair welding procedure and includes:

(a) Location and method for exploration of the defect.
(b) Method of defect removal and subsequent inspection for verification of removal.
(c) Requirements for preheating and inter-pass temperature.
(d) Welding processes and all of the other specification information required in paragraph 5.3.2.
(e) Requirements for inter pass NDT, if applicable.
(f) Methods for filler metal control or storage, including electrodes, fluxes, and/or shielding gases
when hydrogen control is recommended by the manufacturer.
(g) Repair type and procedure limitations.
(h) Time delay before final inspection, when required.

Paragraph 1 0.3.5 adds three new essential variables to the list in paragraph 5.4.2: (1 ) the location of excavation in paragraph 1 0.3.5.2, (2) type of repair in paragraph 1 0.3.5.3, and (3) the preheat and inter pass temperature in paragraph 1 0.3.5.4

Paragraph 1 0.3.6 addresses the welding of the test joint and specifies a minimum length of 8 inches. In addition, multiple repair procedures may be qualified in a single test joint.

Paragraph 1 0.3.7 addresses the testing of the weld joints and provides specific requirements for visual examination and the hardness tests to be conducted on the macro sections. Hardness tests are required for both the deposited weld metal and the heat-affected zones of the macro sections at the locations specified in Figures 21 through 26 on pages 51 through 53, depending on the type of repair. Hardness tests shall be conducted per ASTM E384 using a Vickers indenter and a 1 0 kg load. Maximum hardness values shall not exceed those listed in Table 6 on page 54, but the company can specify other maximum hardness values if they choose to do so. When hardness testing is required, chemical analysis is also necessary to determine the carbon equivalent of the base metal.

Charpy impact testing shall also be performed when the production welding procedure was qualified by Charpy impact tests and shall be performed at locations specified by the company. The company shall specify the minimum design temperature at which the specimens shall be tested and the minimum required absorbed energy for those tests.

1 0.4 Repair Welder Qualification

This subsection lists the rules for qualifying welders who perform repair welds. Welders performing repair welds must have an existing qualification to subsections 6.2 or 6.3 in addition to the requirements in this subsection. The welder must then make an additional qualification weld using the applicable repair welding procedure and the number and type of test specimens required are provided in Table 7 on page 54 for the specific type of repair welding procedure.

Paragraph 1 0.4.3 gives the changes in essential variables that would require the requalification of repair welders. They are:
(a) Any change from one repair type to another except qualification on a full-thickness repair qualifies all partial-thickness repairs.
(b) A change in filler metal groups as defined in Table 1.
(c) An increase in depth of the repair area greater than twice that deposited in the qualification weldment.
(d) A change in position from that for which the repair welder has already qualified.

1 0.5 Supervision

Repair welds shall be made under the supervision of an individual experienced in repairs who is acceptable to the company. Inspection of repairs and the qualification of those conducting the inspections shall be as specified by the company. Repairs shall be documented and the records maintained by the company.

1 0.6 Acceptance Criteria

Repaired areas shall be inspected by and evaluated in accordance with the same NDT methods and acceptance criteria as used for the original weld. NDT of a repair weld must include the entire length of the repair plus the greater of 2 inches or 1 0 % of the repaired length on both ends of the repair.

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Section 9 Acceptance Standards for NDT – CWI Part C

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Section 9: Acceptance Standards for NDT

9.1 General

This section presents acceptance standards for imperfections found by radiographic, magnetic particle, liquid penetrant, ultrasonic, and visual testing. NDT shall not be used to select welds that are to be destructively tested for welder qualification.

9.2 Rights of Rejection

The acceptance criteria presented in this Section are based primarily on discontinuity length, given the fact that NDT methods, other than ultrasonic testing, can offer no information about a discontinuity’s depth into the weld. For this reason, the company retains the right to reject any weld that meets the limitations specified in this Section if, in their opinion, the depth of any acceptable discontinuity could be detrimental to the weld.

Section 9 defines each discontinuity and, for radiographic testing, clarifies the definition with a figure which shows a schematic. For each discontinuity, this section then provides acceptance criteria, which are typically expressed as both a limit on the size of any single indication as well as a limit on the total length of acceptable discontinuities per weld length. To be acceptable, welds must meet the criteria for each discontinuity as well as for the total accumulated flaws per weld as described in paragraph 9.3.1 2.

Rather than repeat the verbiage in Section 9, this part of the Study Guide will simply point the reader to the applicable paragraphs for the criteria for each discontinuity.

9.3 Radiographic Testing

Paragraph 9.3.1 provides the acceptance criteria for inadequate penetration without high-low, referred to as IP. The schematic is shown in Figure 1 3 on page 35.

Paragraph 9.3.2 provides the acceptance criteria for inadequate penetration due to high-low, referred to as IPD. This condition exists when inadequate penetration is associated with misalignment of the pipe. The schematic is shown in Figure 1 4 on page 36.

Paragraph 9.3.3 provides the acceptance criteria for inadequate cross penetration, referred to as ICP. This discontinuity can only exist in welds made from both the inside and outside of the pipe. A schematic of this is shown in Figure 1 5 on page 36.

Paragraph 9.3.4 provides the acceptance criteria for incomplete fusion, referred to as IF. API 1 1 04’s definition of this limits it to incomplete fusion that is open to the surface. A schematic of this is shown in Figure 1 6 on page 36.

Unlike many other welding standards, API 1 1 04 identifies two categories of incomplete fusion, based on whether it is open to the surface or not. While paragraph 9.3.4 addresses incomplete fusion open to the surface (IF), paragraph 9.3.5 provides criteria for incomplete fusion when it is not open to the surface. This type of incomplete fusion said to be the result of a “cold lap,” is referred to as IFD. A schematic of this is shown in Figure 1 7 on page 37.

Paragraph 9.3.6 provides the acceptance criteria for internal concavity, referred to as IC. A schematic of this is shown in Figure 1 8 on page 37. These criteria are stated in terms of the density of the radiographic image on the radiographic flam. Simply stated, this criterion permits any length of internal concavity as long as the weld thickness is no less than the thinner of the two pipe wall thicknesses being joined. When the minimum wall thickness has been violated, the criteria for burn-through in paragraph 9.3.7 apply instead.

Paragraph 9.3.7 addresses burn-through, referred to as BT. No schematic for this discontinuity is provided. Paragraph 9.3.7.1 defines it and the acceptance criteria are provided for pipe having a specified OD of 2.375 inches and greater in paragraph 9.3.7.2 and for pipe having a specified OD less than 2.375 inches in paragraph 9.3.7.3.

Paragraph 9.3.8 addresses slag inclusions and defines two categories – elongated slag inclusions, referred to as ESIs, and isolated slag inclusions, referred to as ISIs. No schematic is provided for these discontinuities. ESIs are typically linear, separated by approximately the width of the root bead, and usually located between the root bead and the hot pass. ISIs have an irregular shape and may appear anywhere in the weld. The acceptance criteria for slag inclusions are located in paragraph 9.3.8.2 for pipe having a specified OD of 2.375 inches and greater and in paragraph 9.3.8.3 for pipe having a specified OD less than 2.375 inches. The note on page 38 is an exception to the acceptance criteria
and specifies that ESIs separated by approximately the width of the root bead are to be considered a single ESI unless the width of either one exceeds 1 /32 inch, in which case the two indications are to be considered separately as ESIs.

Paragraph 9.3.9 addresses porosity and defines it in paragraph 9.3.9.1. Acceptance criteria are specified based on the types of porosity. Criteria for individual or scattered porosity are given in paragraph 9.3.9.2. Criteria for cluster porosity, referred to as CP, are given in paragraph 9.3.9.3, which only applies to the final or cover (cap) passes. For CP in other than the finish pass, the criteria in 9.3.9.2 apply. Criteria for hollow bead porosity, referred to as HB, are given in paragraph 9.3.9.4.

Paragraph 9.3.1 0 provides the acceptance criteria for cracks. Cracks (previously referred to as ‘C’ ) are prohibited, except for shallow crater cracks or star cracks 5/32 inch in length or less. These cracks are acceptable and it is worth noting that API 1 1 04 is probably the only construction code that explicitly permits cracks of any size. The note at the bottom of this paragraph defines these shallow crater cracks or star cracks as the cracks at the terminations of welds due to shrinkage. These shrinkage cracks are basically solidification cracks that occur when the welding arc is terminated suddenly while the weld puddle surface is still fat. Solidification and further shrinkage cause the weld surface to become concave and pull away from the center, leaving cracks. These cracks, however, can be easily prevented with proper welding techniques.

Paragraph 9.3.1 1 addresses undercutting, which is divided into two categories depending on whether it is on the outside surface of the pipe, referred to as EU, or whether it is on the inside of the pipe, referred to as IU. The acceptance criteria here provide limits for the length of undercut when it is discovered using radiography. However, the depth of undercut is just as important, if not more so, than the length. As a result, the note sends the reader to subsection 9.7 for undercut criteria when the undercut is accessible for visual and mechanical measurement, i.e., accessible for depth measurement. Subsection 9.7 on page 46 sends the reader to Table 4 also on page 46 for the permissible lengths of undercut as a function of depth.

Paragraph 9.3.1 2 provides acceptance criteria for the sum of all acceptable indications in a single weld, referred to as the accumulation of imperfections (previously referred to as ‘AI ’ ). In addition to the acceptance criteria for each individual discontinuity as provided in paragraphs 9.3.1 through 9.3.1 1, the sum of the lengths of all of the different acceptable flaws, excluding IPD, EU, and IU, in any given weld may not exceed the limits given in this paragraph.

Paragraph 9.3.1 3 requires that base metal (pipe or fitting) discontinuities discovered during radiography of the welds be reported to the company for disposition.

9.4 Magnetic Particle Testing

Paragraph 9.4.1 states that not all indications produced by magnetic particle testing (MT) are the result of weld imperfections. The examiner must be able to distinguish between indications produced by magnetic and metallurgical variations and those produced by imperfections. Indications produced by magnetic and metallurgical variations are to be considered nonrelevant. In addition, indications having a maximum dimension of no more than 1 /1 6 inches are also considered to be nonrelevant unless proven otherwise.

After that, all relevant indications are then considered to be the result of weld imperfections and they are divided into two categories, depending on their aspect ratio. Those whose length is more than three times their width are referred to as linear indications. Those having a length three times their width or less are rounded indications.

Paragraph 9.4.2 provides the acceptance criteria for linear indications and refers the reader to paragraphs 9.3.9.2 (individual or scattered porosity) and 9.3.9.3 (cluster porosity) for the acceptance criteria for rounded indications.

Paragraph 9.4.3 addresses flaws found in base material during MT of a weld and requires that these be reported to the company for disposition.

9.5 Liquid Penetrant Testing

The requirements for liquid penetrant testing (PT) are exactly the same as those stated above for MT.

9.6 Ultrasonic Testing

Paragraph 9.6.1 .1 emphasizes that the indications produced by ultrasonic testing (UT) are not necessarily defects. The difference between relevant indications, which are those that result from weld imperfections, and nonrelevant indications, which are the result of changes in the weld geometry, reinforcement profiles, internal chamfering, or other geometric issues must be understood.

Paragraph 9.6.1 .2 classifies relevant indications as linear when their longest dimension is parallel to the direction of welding.

Paragraph 9.6.1 .3 classifies relevant indications as transverse when their longest dimension is across
the direction of welding.

Paragraph 9.6.1 .4 classifies three-dimensional indications as volumetric.

Paragraph 9.6.2 provides acceptance criteria for indications found by UT based on the definitions in the following paragraphs:

(a) 9.6.2.2 for linear surface (LS) indications.
(b) 9.6.2.3 for linear buried (LB) indications.
(c) 9.6.2.4 for transverse (T) indications.
(d) 9.6.2.5 for volumetric cluster (VC) indications.
(e) 9.6.2.6 for volumetric individual (VI ) indications.
(f) 9.6.2.7 for volumetric root (VR) indications and.
(g) 9.6.2.8 for the accumulation of relevant indications.

Paragraph 9.6.3 addresses imperfections in the base metal found during UT of welds and, similar to RT, MT, and PT, requires disposition of these flaws by the company.

9.7 Visual Acceptance Standards for Undercutting

Paragraph 9.7.1 reminds the reader that these criteria supplement, but do not replace, VT acceptance criteria found elsewhere in the Standard.

Paragraph 9.7.2 refers the reader to Table 4 on page 46 for acceptance criteria for undercut when visual and mechanical means can be used to determine depth. The table states, for instance, that there is no limit on the length of undercut in a weld if it is no deeper than the lesser of 1 /64 inch or 6 % of the wall thickness. As undercut becomes deeper, the length permitted decreases.

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Section 8 Inspection and Testing of Production Welds- CWI Part C

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Section 8: Inspection and Testing of Production Welds

8.1 Rights of Inspection

The company shall determine whether inspection will be non-destructive or destructive, whether the inspection will occur during or after welding, and the frequency of inspections.

8.2 Methods of Inspection

NDT will usually be radiographic testing but may be any method specified by the company. The acceptance criteria will be that found in either Section 9 or, at the company’s option, Annex A. The company has the right to accept or reject any weld that doesn’t meet the requirements for the method by which it was inspected. Welders who make welds that fail to meet production acceptance criteria maybe, but do not have to be, disqualified from further work.
Operators of NDT equipment may be required to demonstrate the inspection procedure’s ability to detect defects and the operator’s ability to interpret the indications given by the equipment. This is particularly important for highly sophisticated techniques like a phased array – UT and time-of-flight UT. 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 inspection task they perform. Those qualifications shall be acceptable to the company. Documentation of the qualifications shall be maintained by the company and shall address:

(a) Education and experience.
(b) Training.
(c) Results of any qualification examinations.

8.4 Certification of NDT Personnel

The certification of nondestructive testing personnel must be to the American Society for Nondestructive Testing’s (ASNT’s) Recommended Practice (RP) No. SNT-TC-1 A, ASNT’s Central Certification Program (ACCP), or any other nationally recognized program with company approval. Only Level II or III personnel are permitted to interpret test results.

A record of certified NDT personnel shall be maintained by the company. All levels of NDT personnel shall be recertified at intervals no greater than five years or sooner if required by the company or if a question arises about their competence.

Vision examinations are required for all NDT personnel.

The near-distance visual acuity requirement is the ability to read a Jaeger Number 1 test chart or equivalent at a distance of no less than 1 2 inches, documented by a test administered at least annually.

The color contrast requirement is the ability to differentiate between the colors used in the NDT method, documented by a test administered at least every five years.

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

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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 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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