Improving API for the. Twenty-second Edition. 1. API-AGA Joint Committee on Oil and Gas Pipeline Field Welding Practices. Bill Bruce – Secretary. January . Adoption of the 21 st edition. • Notice of Proposed Rulemaking. (NPRM) anticipated Fall Could API encourage a risk based approach to hydrogen. API Standard , 21st Edition is the industry standard for welding practices. Wide in scope and filled with years of accumulated industry knowledge, the latest edition of presents inspection methods to ensure the proper Print + PDF.
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API (Welding of pipelines and related facilities).pdf - Free download as PDF Download as PDF or read online from Scribd . API 5L 45TH subiecte.info of the publication can be ascertained from the API Pipeline Segment to time, revisions of this standard will be necessary to keep current with tech- of the standard that have been changed from the previous edition, but API. API - Standard for Welding of Pipelines Updates from the 21st Edition Committee Southwest Gas Southwe API Standard Welding of Pipelines and.
An increase or decrease in the range of flow rates established c. Alberta, Canada. More than four ISI indications with the maximum width of a. Whenever more than one image is a. The tensile strength shall be computed A5. The following standards, codes, and specifications are www.
Processing—whether automatic or manual; the time and of radiographic inspection and the frequency of its use shall temperature for development and the time for stop bath or be at the option of the company. The company and the radiographic contractor should agree g. Materials—the type and thickness range of material for on the radiographic procedure or procedures to be used prior which the procedure is suitable.
The company h. Heat shields—material, thickness, and the distance from contractor to use such procedures for production radiography. The minimum distance between the source or focal spot a. Radiation source—the type of radiation source, the size of and the source side of the object being radiographed shall be the effective source or focal spot, and the voltage rating of the determined by the following formula using constant units of x-ray equipment. The image collection system used. The image processing system used.
The image viewing system used. The image storage system used. Exposure conditions—whether milliampere or curie min- side of the weld and the film, utes, the x-ray voltage or the input voltage and amperage, and when applicable, the exposure time. Image quality indicators IQI —the type of material, iden- forcement shall be used.
DWV procedures, the outside diameter of the weld that is, j. Heat shields—material, thickness, and the distance from the outside diameter of the pipe plus twice the average height the imaging side of the heat shield to the pipe surface. When the outside diameter of the piping containing cally similar to the material being welded. When this procedure is used and the radia- The plete weld. At the radiographic con- complete weld.
For purposes of IQI selection, the thickness of the weld shall graphic images of production welds. Radiographers shall mean nominal wall thickness plus the weld reinforcement internal report to the company all defects observed in the images plus external combined. The company shall determine the final disposition of the weld. The image of the essential wire diameter shall appear clearly across the entire area of interest. The company may specify the identifica- The IQI shall be placed as follows: Whenever more than one image is a.
When a complete weld is radiographed in a single expo- used to inspect a weld, identification markers shall appear on sure using a source inside the piping, at least four IQI placed each image, and adjacent images shall overlap. The last refer- across the weld and spaced approximately equally around the ence marker on each end of the image shall appear on the circumference shall be used. If any question arises about the condition of the unex- length to be interpreted and the other shall be at the center of posed film, sheets from the front and back of each package or the film.
When the film length to be interpreted is 5 in. If the processed film shows fog, the entire box or roll from which the test film was removed shall preted. When a repaired weld is radiographed, an additional be discarded, unless additional tests prove that the remaining IQI shall be placed across each repaired area.
When it is not practical to place an IQI on the weld due to 0. Separate blocks shall be made of the same or radiographically similar material and may be used to facilitate Note: IQI positioning.
The thickness of the separate block material should be the same as the thickness of the weld. Heat shields: Acceptability of such IQI place- film shall not be less than 0. Transmit- ment shall be demonstrated during procedure qualification. The protection and monitoring shall comply than 1. The company and the nondestructive testing contractor densities within the range specified in It shall be should agree on the magnetic particle testing procedure or equipped to prevent light, coming from around the outer edge procedures prior to the performance of production testing.
Viewing facilities shall provide subdued background light- ing of an intensity that will not cause troublesome reflections, When liquid penetrant testing is specified by the company, a detailed written procedure for liquid penetrant testing shall When requested by the company, film or other imaging The company and the nondestructive testing contractor media shall be processed, handled, and stored so that the should agree on the liquid penetrant testing procedure or pro- images are interpretable for at least 3 years after they are cedures prior to the performance of production testing.
The company shall require the contractor to demonstrate that the proposed procedures will produce acceptable results The image processing area and all accessories shall be kept clean at all times. A detailed j. Calibration requirements—the interval at which calibra- procedure for use of the individual ultrasonic techniques shall tion of the instrument or system is required, the sequence of be established and recorded. The use of ultrasonic testing and set-up calibration prior to inspecting welds, including all the scope of its use shall be at the option of the company.
The company shall require the ultrasonic contrac- bration settings. Scanning level—the sensitivity setting in decibels dB to acceptable and accurate results and shall require the contrac- be added to the reference sensitivity for scanning.
Evaluation level—the level or height of echoes detected Caution is advised when this method is applied to in-ser- during scanning at which further evaluation is required, and vice weld inspection due to potential parent material and sur- any sensitivity adjustment to be made before evaluating for face imperfections that can interfere with the use of the acceptance or rejection. Recording of results—type of record e. For new construction projects, the coat- unacceptable reflectors will be recorded.
Pipe seams should be ground flush with the pipe sur- face for the distance necessary for ultrasonic scanning. As a minimum, each procedure shall include the The ultrasonic testing personnel shall perform examina- applicable details listed in Personnel responsible for testing shall be capable As a minimum the procedure for ultrasonic testing of The company has the right, at any time, to require person- welds shall include the following specific application details: Type of welds to be tested, joint preparation dimensions ments of the qualified procedure.
Material type i. Prior to final written approval, the company shall require the c. Stage at which examination is to be performed. A procedure demonstration report shall be e. The demonstration process shall be as follows: Automatic or manual. Welds containing defects and acceptable imperfections h. Testing technique: Frequencies MHz. Changes in wall thickness, bevel design, acoustic velocity, 3.
Temperatures and ranges. Scanning patterns and speeds. Reference datum and location markers i. Welder qualifi- i. Reference standards—detail sketches showing plan-view cation welds may be used. Radiographs shall be made of the welds and the results reference-standard blocks and all reference reflectors. The UT procedure shall be applied, within the detailed Differences in detection results shall be documented. Dif- correction [DAC] or time corrected gain [TCG] derived from ferences in detectability and resolution between ultrasonics an N10 notch introduced into a sample of the pipe to be and radiography shall be noted.
If required by the company, inspected. See Figures 21A and 21B. The reference standard shall also be used to determine e. In addition, the procedure must accurately manufacturer are to be inspected. This may be accomplished determine the acceptability of welds in accordance with the by using two probes of the same nominal angle and frequency criteria listed in 9.
See Figure 21C. When a difference is noted in velocity, angle, or sound path distance another reference standard shall be made from the different pipe material. Verify that the outside notch echo peak is at or near zero depth reading.
This will establish that refracted angle and velocity settings are sufficiently accurate. Figure 21B—Establishing Distance, Refracted Angle, and Velocity Using two transducers of equal angle and frequency, one transmitting and the other receiving, maximize peak up the echo received.
Measure the surface distance between the transducer exit points. Half the surface distance divided by measured wall thickness equals the refracted angle tangent. Without changing instrument settings, repeat this process on pipe with unknown velocity, refracted angle, and attenuation to determine any differences.
Figure 21C—Transfer Procedure For automated ultrasonic testing and when required by the The company may elect to waive this requirement in lieu of company for manual ultrasonic testing, flat bottom holes shall lamination checks performed by the mill. This sample shall be used as calibration reflectors in addition to The diam- eter of each flat bottom hole should be approximately equal to The flat reflecting sur- face of each hole shall be installed at the same angle and posi- Manual compression wave testing of parent material shall tion as the weld joint preparation for each fill pass required by be performed with the second backwall echo from the refer- the welding procedure.
A transfer technique using probes of the same nominal All interfering partial and full beam reflectors shall evaluation sensitivity and levels have been established, they be noted datum location and distance from the weld edge shall be qualified, then incorporated into the final procedure and recorded on the examination record.
Evalua- qualification test. Forms similar to those shown in Figures 1 tion sensitivity should be the same as scanning sensitivity. This record shall be maintained as long Evaluation level screen height recording threshold should as the procedure is in use.
This shall include the type of welding The ultrasonic testing report of inspected welds shall The range of outside diameters over which the procedure is applicable shall be identified. Submerged-arc welding. Gas metal-arc welding. Gas tungsten-arc welding. Sequence of Beads d. Flux-cored arc welding with or without external shielding.
Plasma arc welding. The range of wall thicknesses over which the procedure is applicable shall be identified, as shall the range of number of Before production welding is started, a detailed procedure specification shall be established and qualified to demonstrate Two pipe lengths, full joints or nipples, joint that show the type of joint e. If a specification. The quality of the weld shall be determined by backup is used, the type shall be designated.
These procedures shall be adhered to except where a change is specifically autho- The size and AWS classification number of the filler metal, rized by the company, as provided for in These may include the location and angle of arc for submerged arc welding, the con- A welding procedure must be re-established as a new pro- cedure specification and must be completely requalified when Changes other than those listed in A change from the welding process established in the pro- cedure specification constitutes an essential variable.
A change in pipe material constitutes an essential variable. For the purposes of this standard, all carbon steels shall be The methods, width to be heated, minimum temperature at a.
Specified minimum yield strength less than or equal to the start of the weld, and minimum ambient temperature 42, psi MPa. For carbon steels with a specified minimum yield strength The methods, width to be heated, minimum and maximum greater than or equal to 65, psi MPa , each grade temperature, time at temperature, and temperature control shall receive a separate qualification test.
The groupings specified above in A major change in joint design for example, from V groove to U groove or any change beyond the range estab- A change from one filler-metal group to another see Composition b. For pipe materials with a specified minimum yield strength greater than or equal to 65, psi MPa , a change in the For plasma arc welding, a change in orifice gas nominal AWS classification of the filler metal see 5.
Changes in filler metal may be made within the groups Each welding operator shall be qualified by producing an acceptable weld using the qualified welding procedure. The Prior to the start of welding, each welding operator shall have received adequate training in the operation of the If the welding procedure involves more An increase in the maximum time between completion of than one operation, welding operators shall be qualified on the root bead and the start of the second bead constitutes an the type of welding equipment that will be used in production essential variable.
Changes in the essential variables described in A change from one welding process, mode of transfer, variable. Example would be short arc, A change from one shielding gas to another or from one b. A change in the direction of welding from vertical uphill mixture of gases to another constitutes an essential variable. An increase or decrease in the range of flow rates established c.
A change in the filler metal type solid wire, metal core, for the shielding gas also constitutes an essential variable. Outside diameter less than Outside diameter equal to or greater than Refer to Table 1, Footnote a, for changes in shielding flux Welding operator shall qualify on the heaviest wall thickness.
A change in welding bug manufacturer or model. A change in the method of applying the root bead. Exam- Radiographic testing shall be in accordance with A major change in joint design for example, from a V groove to a U groove or J groove or any change beyond the 13 Automatic Welding Without Filler- range established.
For such factors as spacing, root face, and metal Additions angle of bevel constitutes an essential variable. Welders shall be qualified if all tests are acceptable. At least two welds shall be made by joining the detailed results of each test. A form similar to that shown pipe lengths, full joints, or nipples and by following all the in Figure 2 should be used.
This form should be developed to details of the procedure specification. The quality of the weld suit the needs of the company but must be sufficiently shall be determined by both destructive and nondestructive detailed to demonstrate that the qualification test meets the testing and shall meet the requirements of A list of qualified operators These procedures shall be adhered to except where a change is and the procedures for which they are qualified shall be main- specifically authorized by the company, as provided for in An operator may be required to requalify if a question arises about their competence.
Appendix A. Section This record shall show complete results of not be greater than or equal to the actual tensile-strength of the procedure qualification test and shall be maintained as the material. If the specimen breaks outside the weld and long as the procedure is in use. The procedure specification shall include all the informa- If the specimen breaks in the weld or fusion zone, the tion that is pertinent to setting up and maintaining the proper observed strength is greater than or equal to the specified operation of the equipment as indicated in the following minimum tensile-strength of the pipe material, and the weld items: Welding process.
Pipe material. Pipe wall thickness and outside diameter. Pipe end preparation and outside diameter. The number of 2-in. Nick-break specimens required by e.
Preparation of the pipe, including grinding of the pipe seam weld, if any, and cleaning of the pipe ends for electrical Table 7 shall be prepared in accordance with Figure The contact. The sides of the specimen shall be notched along f. Welding position. Requirements for preheat treatment. In addition, the inside- and outside diam- h. Requirements for cleaning and inspection of contact eter weld reinforcement shall be notched to a depth of not shoes.
Range of welding amperage, which shall be recorded on a Nick-break specimens shall be tested in accordance with strip chart. Range of axial speed, which shall be recorded on a strip Time intervals in weld cycle, which shall be identified and The exposed surfaces of each Nick-break specimen shall recorded on a strip chart.
Slag inclusions shall m. There shall be at chart. Time delay before removal of clamps. Method of removing internal flash.
Method of removing external flash. Requirements for post-heat treatment, including heating time, maximum temperature, time of temperature, method of Side-bend specimens shall be prepared in accordance with determining heating around circumference, and cooling rate.
Changes other than those given in All Nick-break specimens shall be in accordance with Figure Each welding unit and each operator shall be qualified by producing an acceptable weld using the qualified welding a. The completed weld shall be tested by both radio- b. Pipe wall thickness or outside diameter. Pipe preparation dimensions. Each operator shall have received adequate training in the d. Requirements for pre-heat treatment. Welding voltage tolerances.
Welding current tolerances. Axial speed tolerances. Time intervals in weld cycle. A record shall be made of the tests required by Upset stroke tolerances. A form similar to that shown k. Requirements for post-heat treatment.
A list of qualified operators quency of such additional inspections and tests shall be as and the procedures for which they are qualified shall be main- specified by the company. If the strip chart is found to be unacceptable them to metallurgical or mechanical tests, or both. The fre- after welding has been completed, the joint shall be rejected and removed from the line.
They may also be applied to visual inspection. Each production weld shall be inspected visually and radiographically after flash removal and post-heat treatment Other nondestructive tests may also be required by the company. The inside-diameter weld reinforcement shall not be raised The outside diameter weld reinforcement shall not be raised above The following repairs are permissible: As a minimum, each completed flash butt weld shall be b. Defects may be removed from the weld by grinding, chip- heated after welding to a temperature above the Ac3 tempera- ping, gouging, or a combination of these methods, followed ture, followed by either controlled cooling or still-air cooling.
The heat treatment cycle shall be documented using a strip- Repair by welding is permitted only by agreement with the chart recorder, and any deviation beyond the ranges specified company. Option 3 should only be exercised, when neces- The acceptance standards given in Section 9 are based sary, by skilled practitioners with demonstrated knowledge on empirical criteria for workmanship and place primary of fracture mechanics and pipeline load analysis.
With importance on imperfection length. Such criteria have pro- these three options this current revision of the appendix vided an excellent record of reliability in pipeline service should provide a more complete approach to determine for many years.
The use of fracture mechanics analysis inspection and acceptance limits for imperfections. Typically, but not always, the fitness-for-purpose to establish the required mechanical properties for the weld- criteria provide more generous allowable imperfection ing procedure under consideration.
Additional qualification tests, stress analysis, and This appendix provides procedures to determine the maxi- inspection are required to use the fitness-for-purpose crite- mum allowable imperfection sizes.
It does not prevent the use ria. Performing analysis based on the principles of fitness- of Section 9 for determining imperfection acceptance limits for-purpose is alternatively termed engineering critical for any weld. Use of this appendix is completely at the com- assessment, or ECA.
The fitness-for-purpose criteria in the prior versions of In this appendix, the use of the phrase imperfection accep- this appendix required a minimum CTOD toughness of tance limits and other phrases containing the word imperfec- either 0. Improvements in of weld integrity. All welds contain certain features variously welding consumables and with more precise welding pro- described as artifacts, imperfections, discontinuities, or flaws. At the same time, basis of a technical analysis, the effect of various types, sizes, 07 toughness values below 0.
CTOD specimens than those in the prior versions of this This use of this appendix is restricted to the following appendix. Welds with toughness below 0. The first two options were developed with a sin- A. Option 3 is provided primarily for those cases where fatigue loading exceeds the limit estab- To use this appendix, a stress analysis shall be performed to lished for the first two options. Option 3 is not prescriptive determine the maximum axial design stresses to which the girth welds may be subjected to during construction and opera- 7Wang, Y.
DOT Agreement No. The enlargement of weld imperfections due to fatigue is a A. In the absence of contami- A. Water, brine, and aqueous solutions that contain CO2 or The cyclic stress analysis shall include the determination of H2S may, however, increase the growth rate.
It is normal for the predicted fatigue spectrum to which the pipeline will be minor amounts of these components to be present in nominally exposed over its design life. This spectrum shall include but is noncorrosive pipelines.
When the concentration of either CO2 or not limited to stresses imposed by hydrostatic testing, operation H2S exceeds typical historical levels experienced in noncorro- pressure, installation stresses, and where applicable, thermal, sive pipelines, this appendix shall not be used, unless evidence seismic, and subsidence stresses.
The spectrum should consist of exists that the proposed levels do not result in acceleration of several cyclic axial stress levels and the number of cycles appli- fatigue crack growth or adequate corrosion inhibition is applied. If the stress levels vary from cycle to cycle, a suit- The effects of environment on fatigue crack growth external to able counting method, such as the rainflow method, should be the pipe at girth welds are normally mitigated by external coating used to determine cyclic stress levels and cycle count9.
These environments typically where contain H2S but may contain strong hydroxides, nitrates, or car- bonates. However, circumferential 4, BS The use of be applied. Using actual stress-strain relations may result in the overes- The stress analysis shall include consideration of potential timation of the applied load level, as the flow stress is computed dynamic loading on girth welds, such as loads from closure of from the minimum specified values, e. Dowl- check valves.
A change in the requirements for post-weld heat treatment A. The controls of the variables necessary to ensure an accept- p. A change in the nominal pipe outside diameter more than able level of fracture toughness in a welding procedure are —0. An appropriate q. Qualification of welding procedures to be used with this appendix shall be in accordance with Section 5 or 12 Note: The heat input may be calculated from the following equation: A change in the grade or manufacturing process of the A.
A major change in joint design e. Minor changes in the angle of bevel or the land of A. The specimens shall be pre- d. A change in position from roll to fixed, or vice versa.
The e. A change in the nominal qualified wall thickness of more weld reinforcement does not need to be removed.
A change in the size, type, or heat number of filler metal, A. A change of heat number of the same consumable can be a. The tensile strength shall be equal or greater than the spec- qualified by a single nominal weld that is tested for weld tensile ified minimum tensile strength of the pipe, and A. The specimen should not fail in the weld.
Gross weld g. An increase in the time between the completion of the root strength under matching that may result in preferential strain- bead and the start of the second bead.
A change in direction e. A change from one shielding gas to another or from one A. A change in the nominal qualified flow rate of shielding with their lengths parallel to the pipe axis. A change in the shielding flux, including a change in man- used. The thickness of subsized specimens should have at least ufacturer within an AWS classification.
Six specimens shall be removed l. A change in the type of current AC or DC , or polarity. A change in the requirements for pre-heat temperature. A change in the interpass temperature11, if the interpass 12An example of assessing weld strength undermatching is given in temperature is lower than the minimum interpass temperature Wang, Y.
IPC, September , , Calgary, passes multi-arc processes. Alberta, Canada. R min. The location of the Charpy specimen rela- minimum amount of milling and grinding necessary to pro- tive to the pipe wall is shown in Figure A The weld A. The specimen should be The test shall be performed at the minimum design temper- etched after initial preparation to reveal the weld deposit and ature in accordance with the requirements of ASTM E For weld-metal tests, the notch and fatigue crack tip should be located at the center A.
The minimum and averaged Charpy impact energy shall be 07 For the HAZ tests, the fatigue precracks shall be aimed to greater than 22 ft-lbs 30 J and 30 ft-lbs 40 J for each notch intersect the largest unrefined coarse grain HAZ regions within location, respectively.
If there are A. Multiple speci- ness of the weld shall be determined by testing in accordance men sampling of the cap pass coarse grain HAZ should be with BS Part 2, as supplemented by this appendix. No more than one specimen should be devoted to the cap pass HAZ.
To identify coarse grain HAZ regions, it may be A. As shown HAZ regions that have undergone the least amount of temper- in Figure A-3, the specimen should be oriented so that its ing by subsequent weld passes.
The test report shall The three specimens shall consist of one each from the nominal include all items specified in Section 13 of BS Part 2. The test report shall also include a legible copy of the deal with the geometry of the fatigue crack front. These are mutually-exclusive terms defined in BS Conventional radi- a. Specimens are incorrectly machined. Sponsored Links -. Originally Posted by acier Join Date Jun Posts Join Date May Posts Join Date Apr Posts 2, API latest edition and erratas My threads; Marty Thompson: API latest edition addendum 1.
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