1、 Standard Test Method Slow Strain Rate Test Method for Screening Corrosion-Resistant Alloys for Stress Corrosion Cracking in Sour Oilfield Service This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its accep
2、tance does not in any respect preclude anyone, whether he or she 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 standard is to be construed as granting any r
3、ight, 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
4、 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 assumes no responsibility for the int
5、erpretation or use of this standard by other parties and accepts responsibility for only those official NACE interpretations issued by NACE in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE standard ar
6、e 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 standard may not necessarily address all potential health and safety problems or environmental hazards asso
7、ciated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities i
8、f necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE technical committee procedures. NACE requir
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10、information on all standards and other NACE publications by contacting the NACE FirstService Department, 1440 South Creek Dr., Houston, TX 77084-4906 (telephone +1 281-228-6200). Revised 2011-10-28 Revised 2004-02-12 Approved 1998-02-23 NACE International 1440 South Creek Drive. Houston, Texas 77084
11、-4906 +1 281-228-6200 ISBN 1-57590-051-3 2011, NACE International NACE Standard TM0198-2004 Item No. 21232 TM0198-2011 NACE International i _ Foreword Failures of metals exposed to hydrogen sulfide (H2S)-containing (sour) oilfield production environments have been reported for more than 50 years and
12、 have usually occurred in carbon or low-alloy steels.1,2 Failures of high-strength steels by brittle cracking (sulfide stress cracking SSC) and of lower-strength plate and pipe steels by blistering and hydrogen-induced (stepwise) cracking have also been reported. As a result, engineers and scientist
13、s have developed test methods to evaluate steels for resistance to failure by these mechanisms in sour environments. These and other considerations led to the establishment of NACE Task Group (TG) T-1F-9, Metallic Materials Testing Techniques for Sulfide Corrosion Cracking, which originally develope
14、d NACE Standard TM01773 in 1977. The task group (now TG 085) has continued to revise that standard. An additional interest of the original TG T-1F-9 was the application of corrosion-resistant alloys (CRAs), primarily stainless steels and nickel-based alloys, in oilfield production environments. Some
15、 of these CRAs have experienced stress corrosion cracking (SCC) when exposed to H2S, carbon dioxide (CO2), and brine. Therefore, a standardized method for screening CRAs for use in oilfield production environments is of extreme importance to the entire petroleum industry, and work group TG T-1F-9e (
16、now TG 133) was formed to address this issue. Several screening methods were considered: autoclave tests with statically stressed specimens, fracture mechanics methods, and the slow strain rate (SSR) test methods. Each has advantages and disadvantages that make the selection of a single test method
17、for standardization difficult. However, the SSR test has emerged as a relatively quick, simple method that can be used for the evaluation of CRAs for resistance to a variety of environmental cracking phenomena, including SCC, hydrogen embrittlement, and liquid metal cracking.1,2 The use of SSR test
18、methods, particularly in screening tests, has become more common in many laboratories for evaluation of CRAs for downhole applications. The SSR test incorporates a slow (compared with conventional tensile tests), dynamic strain applied at a constant extension rate. Extension rates of 2.54 x 109 to 2
19、.54 x 107 m/s (1.00 x 107 to 1.00 x 105 in/s) are commonly used. The principal effect of the constant extension rate, in combination with environmental or corrosive attack, is to accelerate the initiation of cracking in susceptible CRAs. By doing so, the SSR acts in much the same way as a notch or p
20、recrack in statically stressed environmental cracking tests. Failure is obtained within a few days for commonly used extension rates. Because of its relatively short test duration, the SSR test has been found useful in evaluating CRAs for resistance to SCC in simulated oilfield production environmen
21、ts at elevated temperatures.4,5 By comparison, it has been observed that it may take thousands of hours of exposure time to evaluate CRAs using more conventional statically stressed specimens.6,7 TM0198-2011 ii NACE International In a SSR test, the test specimen is pulled to failure. One benefit of
22、this method is that the ultimate failure of the test specimen is a positive result. That is, parameters (including reduction in area and plastic elongation) and visual observations can always be quantified. These results are usually further quantified by comparison with the results of similar tests
23、performed in an inert environment. Accelerating the crack initiation by this mechanical technique tends to make the SSR test appear to be a rather severe test by being able to fail CRAs under environmental conditions in which no other test method (at reasonable exposure times) can produce failures.
24、Because the exposure time is short and the strain rate is somewhat arbitrary, the results of SSR testing are not intended to be used directly to infer service performance. It is primarily a screening or ranking method that should be used in combination with a more extensive laboratory evaluation inv
25、olving complementary testing for corrosion and environmental cracking. Service experience should be reviewed before material selection decisions are made. A round-robin testing program was conducted by former TG T-1F-9 during the early development of this standard to evaluate the variability of SSR
26、test data and the influences of various testing-related parameters. Draft #5 of the proposed test method was used as the basis for the round-robin testing program, and a total of seven companies participated. The results of the round-robin testing program indicated that large deviations in the SSR t
27、est data were observed for some conditions. However, with the evaluation of the procedures used by the round-robin participants, several recommendations for changes in SSR test procedures were made. Most of the recommended changes were included in this standard to reduce the amount of deviation in t
28、he test results. These changes included: (1) Ground surfaces (not turned) and finer surface finish on the test specimen gauge section; (2) Additional specifications regarding testing machine compliance; (3) Improved calculation technique for reduction in area; and (4) References to industry standard
29、s containing accepted procedures for autoclave and SSR testing. Based on the above-mentioned considerations, TG T-1F-9 developed this standard test method incorporating the SSR test to be used by laboratory investigators for screening CRAs for SCC in sour oilfield service. This NACE standard was ori
30、ginally developed by TG T-1F-9 in 1998 under the direction of Unit Committee T-1F, Metallurgy of Oilfield Equipment. It was revised in 2004 and 2011 by TG 133, Review and Revise as Necessary NACE Standard TM0198-2004. TG 133 is administered by Specific Technology Group (STG) 32, Oil and Gas Producti
31、onMetallurgy. This standard is issued by NACE under the auspices of STG 32. 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. The terms shall and must are used to state a requirement, and are co
32、nsidered mandatory. The term should is used to state something good and is recommended, but is not considered mandatory. The term may is used to state something considered optional. _ TM0198-2011 NACE International iii _ NACE International Standard Test Method Slow Strain Rate Test Method for Screen
33、ing Corrosion-Resistant Alloys for Stress Corrosion Cracking in Sour Oilfield Service Contents 1. General 1 2. Reagents . 1 3. Test Specimen 1 4. Test Equipment 3 5. Determination of Baseline Material Properties 4 6. Environmental Test Conditions . 5 7. Mechanical Test Conditions 6 8.Test Procedure
34、. 7 9.Analysis and Reporting of Test Results References 11 Appendix A: Safety Considerations in Handling H2S (Nonmandatory) 19 Appendix B: Explanatory Notes on Test Method (Nonmandatory) 20 FIGURES: Figures 1: Standard SSR test specimen . 2 Figures 2: Schematic presentation of the possible effects o
35、f strain rate on various types of cracking behavior 7 Figure 3: Schematic of typical SSR test system . 9 Figure 4: Typical load-versus-time plots for SSR test of a Ni-Fe-Cr-Mo alloy performed at an extension rate of 1x10-7 m/s (4x10 -6 in/s) in several test environments . 10 Figure 5: Schematic illu
36、stration based on data for a super-13 Cr stainless steel showing basis for determining the failure (Ep) based on the total strain to failure (Etot) and the elastic contribution (Eel) . 13 Figure 6: Typical nickel alloy stress-strain curve, where there is no work-hardening . 14 Table 1: NACE Uniform
37、Material Testing Report Form (Part 1) Testing in Accordance with NACE SSR Test 17 _ TM0198-2011 NACE International 1 _ Section 1: General 1.1 This standard establishes a SSR test method for screening CRAs (i.e., stainless steels and nickel-based alloys) for resistance to SCC at elevated temperatures
38、 in sour oilfield production environments. The fact that this test method is a screening method implies that further evaluation or additional experience may be required before materials selection decisions can be made. 1.2 This standard specifies reagents, test specimen, test equipment, determinatio
39、n of baseline material properties, environmental and mechanical test conditions, test procedure, and analysis and reporting of test results. 1.3 The test procedure can be summarized as follows: A SSR test specimen is exposed to a continuously increasing uniaxial tensile stress imposed by a slow and
40、constant extension rate in the presence of an acidic aqueous environment containing H2S, CO2, and brine at an elevated temperature. The ductility parameters (plastic elongation and reduction in area) obtained from evaluation of the SSR test specimen along with visual observation of its gauge section
41、 and fracture surface morphology are used as indicators of the materials resistance to SCC in the test environment. These results are then compared to the results of a similar test performed in an inert environment to quantify the resistance or susceptibility to SCC in the test environment. 1.4 Proc
42、edures for SSR testing shall be consistent with those provided in ASTM(1) G129.8 Tests involving high pressure or high temperature, or both, shall be performed using procedures consistent with those provided in ASTM G111.9 The only deviations from these procedures shall be those specifically stated
43、in this standard. 1.5 Safety Precautions 1.5.1 H2S is an extremely toxic gas that must be handled with extreme care. (See Appendix A nonmandatory for a discussion of safety considerations and toxicity of this gas.) 1.5.2 Precautions must be taken to protect personnel from the hazards of rapid releas
44、e of hot gases and fluids and explosion when working with the high-pressure, high-temperature test conditions. 1.6 This standard is not intended to include procedures for cyclic SSR testing. However, such procedures are currently under development and are in use in some laboratories. _ Section 2: Re
45、agents 2.1 Reagent Purity 2.1.1 The gases, sodium chloride (NaCl), and solvents shall be reagent or chemically pure grade chemicals. The reasons for this reagent purity are discussed in Appendix B (nonmandatory). 2.1.2 The water shall be distilled or deionized and of quality equal to or greater than
46、 ASTM Type IV in accordance with ASTM D1193.10 Tap water shall not be used. 2.2 Inert gas shall be used for removal of oxygen. Inert gas shall mean high-purity nitrogen, argon, or other suitable nonreactive gas. _ Section 3: Test Specimen 3.1 A uniaxial tensile test specimen shall be used for this t
47、est because it provides for a simple stress state and a common basis for comparison of test results. 3.2 The SSR test specimen shall be machined from the CRA to be tested in the most appropriate location and orientation relative to the specific evaluation being performed. The material form of the CR
48、A, however, can often place restrictions on the (1) ASTM International (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959. TM0198-2011 2 NACE International SSR test specimen location and orientation. Furthermore, the location and orientation of the SSR test specimen can affect the test results. 3.3 Standard SSR test specimens shall be fabricated in acc
