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Standard Test Method Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking

Standard Test Method Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking
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    Standard Test Method   Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE International assumes no responsibility for the interpretation or use of this standard by other parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE International standard may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at any time without prior notice. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International Membership Services Department, 1440 South Creek Drive, Houston, Texas 77084-4906 (telephone +1 281/228-6200). Revised 2003-01-17 Revised 1996-Mar-30 Reaffirmed 1987-Mar Approved 1984-Feb NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 281/228-6200 ISBN 1-57590-163-3 ©  2003, NACE International NACE Standard TM0284-2003 Item No. 21215 COPYRIGHT 2003; NACE International Document provided by IHS Licensee=Fluor Corporation/2110503105, User=, 05/27/2003 02:17:21 MDT Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. --`   ,  ,  ,  ,` `   ,`   ,  ,` ` ` `   ,`   ,` ` `   ,  ,` ` `   ,  ,` -` -`   ,  ,`   ,  ,`   ,`   ,  ,` ---  TM0284-2003 NACE International i  ________________________________________________________________________    Foreword   Absorption of hydrogen generated by corrosion of steel in a wet hydrogen sulfide (H 2 S) environment can have several effects that depend on the properties of the steel, the characteristics of the environment, and other variables. One adverse effect observed in pipeline and pressure vessel steels is the development of cracks along the rolling direction of the steel. Cracks on one plane tend to link up with the cracks on adjacent planes to form steps across the thickness. The cracks can reduce the effective wall thickness until the pipe or pressure vessel becomes overstressed and ruptures. Cracking is sometimes accompanied by surface blistering. Several service failures attributed to such cracking have been reported. 1,2  The terms stepwise cracking   (SWC), hydrogen pressure cracking  , blister cracking  , and hydrogen- induced stepwise cracking have been used in the past to describe cracking of this type in pipeline and pressure vessel steels, but are now considered obsolete. The term hydrogen-induced cracking   (HIC) has been widely used for describing cracking of this type, and has been adopted by NACE International. Therefore, it is used throughout this standard test method. HIC is related to hydrogen blistering, which has been recognized since the 1940s as a problem in vessels handling sour products. 3  It was not until much later, however, that HIC gained wide recognition as a potential problem in pipelines. As a result of pipeline failures experienced by two companies in the early 1970s, several companies began investigating the cracking and publishing results of tests on various steels. Many investigators found, however, that they could not reproduce published test results. It was eventually determined that lack of reproducibility resulted largely from differences in test procedures. Consequently, NACE Unit Committee T-1F on Metallurgy of Oilfield Equipment established Task Group T-1F-20 to study the problem and prepare a standard test method. This standard was srcinally prepared in 1984 to provide a standard set of test conditions for consistent evaluation of pipeline steels and for comparison of test results from different laboratories. More recently, the concern for HIC damage has turned to plate steels for pressure vessels. Requirements for plate steels have included tests for resistance to HIC using this standard. Therefore, the scope of this standard was revised to include the testing of pressure vessel plate steels. Test conditions are not designed to simulate any particular pipeline or process operation. The test is intended to evaluate resistance to HIC only, and not other adverse effects of sour environments such as sulfide stress cracking, pitting, or weight loss from corrosion. This test may be used for many purposes, and the applications of the results are beyond the scope of this standard. Those who use the test should be aware that in some cases test results can be influenced by variations in properties among different locations in a single length of line pipe or plate, as well as by variations within a heat of steel. When the test is used as a basis for purchasing, the number and location of test specimens must be carefully considered. 4  This standard is intended for end users, manufacturers, fabricators, and testing laboratories. This standard was revised by Task Group T-1F-20 in 1996, and again in 2003 by Task Group 082 (formerly T-1F-20) on Stepwise Cracking of Pipeline Steels, and is published by NACE under the auspices of Specific Technology Group 32 on Oil and Gas Production    Metallurgy (formerly Unit Committee T-1F on Metallurgy of Oilfield Equipment). In NACE standards, the terms shall  , must  , should  , and may   are used in accordance with the definitions of these terms in the NACE Publications Style Manual  , 4th ed., Paragraph 7.4.1.9. Shall   and must   are used to state mandatory requirements. The term should   is used to state something good and is recommended but is not mandatory. The term may   is used to state something considered optional.  ________________________________________________________________________    COPYRIGHT 2003; NACE International Document provided by IHS Licensee=Fluor Corporation/2110503105, User=, 05/27/2003 02:17:21 MDT Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.     -    -        `  ,  ,  ,  ,        `        `  ,        `  ,  ,        `        `        `        `  ,        `  ,        `        `        `  ,  ,        `        `        `  ,  ,        `    -        `    -        `  ,  ,        `  ,  ,        `  ,        `  ,  ,        `    -    -    -  TM0284-2003 ii NACE International  ________________________________________________________________________ NACE International Standard Test Method Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking Contents 1. General..........................................................................................................................1 2. Reagents.......................................................................................................................1 3. Testing Apparatus.........................................................................................................1 4. Test Specimens—Pipeline Steels.................................................................................1 5. Test Specimens—Pressure Vessel Plate.....................................................................5 6. Test Procedure..............................................................................................................7 7. Evaluation of Test Specimens.......................................................................................8 8. Reporting Test Results..................................................................................................9 References..........................................................................................................................9 Appendix A—Safety Considerations is Handling H 2 S Toxicity..........................................10 Appendix B—Explanatory Notes on Test Method.............................................................11 Appendix C—Determination of H 2 S Concentration in Test Solution by Iodometric Titration......................................................................................................11 Figure 1—Schematic Diagram of Typical Test Assembly...................................................2 Figure 2—Seamless Pipe and Parent Metal of Longitudinally Welded Pipe......................2 Figure 3—Weld Area of Longitudinally Welded Pipe..........................................................3 Figure 4—Weld Area of ERW Pipe....................................................................................4 Figure 5—Parent Metal of Spiral-Welded Pipe...................................................................4 Figure 6—Weld Area of Spiral-Welded Pipe......................................................................5 Figure 7—Test Specimen Location for Plates Up to 30 mm Thick, Inclusive.....................6 Figure 8—Test Specimen Location for Plates Over 30 mm to 88 mm, Inclusive...............6 Figure 9—Test Specimen Location for Plates Over 88 mm...............................................7 Figure 10—Orientation of Test Specimens in the Test Vessel...........................................7 Figure 11—Test Specimen and Crack Dimensions to Be Used In Calculating CSR, CLR, and CTR...........................................................................................................9  ________________________________________________________________________  COPYRIGHT 2003; NACE International Document provided by IHS Licensee=Fluor Corporation/2110503105, User=, 05/27/2003 02:17:21 MDT Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.     -    -        `  ,  ,  ,  ,        `        `  ,        `  ,  ,        `        `        `        `  ,        `  ,        `        `        `  ,  ,        `        `        `  ,  ,        `    -        `    -        `  ,  ,        `  ,  ,        `  ,        `  ,  ,        `    -    -    -  TM0284-2003 NACE International 1  ________________________________________________________________________    Section 1: General   1.1 This standard establishes a test method for evaluating the resistance of pipeline and pressure vessel plate steels to HIC caused by hydrogen absorption from aqueous sulfide corrosion. 1.1.1 Special procedures or requirements for testing small-diameter (nominal pipe size [NPS] 2 through 6), thin-wall (up to 6-mm wall thickness), electric-resistance welded (ERW) and seamless line pipe are included. These small-diameter, thin-wall materials shall be tested in the same manner as other line pipe except as otherwise stated in this standard. 1.2 The test method consists of exposing unstressed test specimens to one of the two standard test solutions—either Solution A, a sodium chloride, acetic acid (NaCl, CH 3 COOH) solution saturated with H 2 S at ambient temperature and pressure, or Solution B, a synthetic seawater solution saturated with H 2 S at ambient temperature and pressure. After a specified time the test specimens shall be removed and evaluated. 1.3 The test method is not intended to duplicate service conditions. It is intended to provide reproducible test environments capable of distinguishing the susceptibility of different steel samples to HIC in a relatively short time. NOTE: The length of the test may not be sufficient to develop maximum cracking in any given steel but has been found to be adequate for the purpose of this test. 1.4 This standard does not include acceptance or rejection criteria. The methods used for determining acceptance and rejection, for comparing different steels, for screening of steels, or for other purposes are beyond the scope of this standard.  ________________________________________________________________________    Section 2: Reagents   2.1 The reagents for Solution A shall be nitrogen gas for purging, H 2 S gas, NaCl, CH 3 COOH, and distilled or deionized water. The reagents for Solution B shall be nitrogen gas for purging, H 2 S gas, and synthetic seawater. NOTE: H 2 S IS HIGHLY TOXIC AND MUST BE HANDLED WITH CAUTION (see Appendix A). 2.2 The NaCl and CH 3 COOH shall be reagent grade chemicals. 2.3 The gases shall be reagent grade or chemically pure gases and the water shall be distilled or deionized (see Appendix B). 2.4 The synthetic seawater shall be prepared in accordance with ASTM (1) Standard D 1141, 5  Stock Solutions No. 1 and No. 2 (without heavy metal ions).  ________________________________________________________________________    Section 3: Testing Apparatus   3.1 The test may be performed in any convenient airtight vessel large enough to contain the test specimens with provisions for purging and introduction of H 2 S. None of the materials involved in the test set-up shall contaminate or react with the test environment. Figure 1 is a schematic diagram of a typical test assembly.  ________________________________________________________________________    Section 4: Test Specimens—Pipeline Steels   4.1 Size 4.1.1 Each test specimen shall be 100 ± 1 mm long by 20 ± 1 mm wide. 4.1.2 The test specimen thickness shall be the full wall thickness of the pipe up to a maximum of 30 mm. For wall thickness greater than 30 mm, the test specimen thickness shall be either the full wall thickness of the pipe or limited to a maximum thickness of 30 mm as described in Section 5. A maximum of 1 mm may be removed from each of the surfaces (i.e., internal and external). Test specimen blanks shall not be flattened. 4.1.3 For small-diameter, thin-wall ERW and seamless line pipe, the test specimen thickness must be at least 80% of the full wall thickness of the pipe. In such cases, curved test specimens cut from the line pipe ___________________________ ( 1 )  ASTM International (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. COPYRIGHT 2003; NACE International Document provided by IHS Licensee=Fluor Corporation/2110503105, User=, 05/27/2003 02:17:21 MDT Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.     -    -        `  ,  ,  ,  ,        `        `  ,        `  ,  ,        `        `        `        `  ,        `  ,        `        `        `  ,  ,        `        `        `  ,  ,        `    -        `    -        `  ,  ,        `  ,  ,        `  ,        `  ,  ,        `    -    -    -  TM0284-2003 2 NACE International shall be tested; test specimen blanks shall not be flattened. 4.2 Number, Location, and Orientation 4.2.1 Three test specimens shall be taken from each test pipe. 4.2.2 For welded pipe, the test specimens shall be taken from the weld, 90 degrees from the weld, and 180 degrees from the weld. For seamless pipe, the test specimens shall be taken 120 degrees apart around the circumference. 4.2.3 Test specimens shall be taken from the pipe with the longitudinal axis of the test specimens: (a) parallel to the longitudinal axis of the pipe for seamless pipe and the parent metal of longitudinally welded pipe. (b) parallel to the weld for the parent metal of spiral-welded pipe. (c) perpendicular to the weld for the weld area of welded pipe. (d) parallel to the weld for the weld area of ERW line pipe. The weld shall be approximately on the center line of the test specimen. Figures 2 through 6 show the orientation of test specimens and where they shall be sectioned and examined after exposure. FIGURE 1 Schematic diagram of typical test assembly FIGURE 2 Seamless pipe and parent metal of longitudinally welded pipe (all dimensions in mm) COPYRIGHT 2003; NACE International Document provided by IHS Licensee=Fluor Corporation/2110503105, User=, 05/27/2003 02:17:21 MDT Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. --`,,,,``,`,,````,`,```,,```,,`-`-`,,`,,`,`,,`---
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