1、Designation: G 146 01 (Reapproved 2007)Standard Practice forEvaluation of Disbonding of Bimetallic Stainless Alloy/SteelPlate for Use in High-Pressure, High-Temperature RefineryHydrogen Service1This standard is issued under the fixed designation G 146; the number immediately following the designatio
2、n indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure fo
3、r the evaluation ofdisbonding of bimetallic stainless alloy/steel plate for use inrefinery high-pressure/high-temperature (HP/HT) gaseous hy-drogen service. It includes procedures to (1) produce suitablelaboratory test specimens, (2) obtain hydrogen charging con-ditions in the laboratory that are si
4、milar to those found inrefinery HP/HT hydrogen gas service for evaluation of bime-tallic specimens exposed to these environments, and (3)perform analysis of the test data. The purpose of this practiceis to allow for comparison of data among test laboratories onthe resistance of bimetallic stainless
5、alloy/steels to hydrogen-induced disbonding (HID).1.2 This practice applies primarily to bimetallic productsfabricated by weld overlay of stainless alloy onto a steelsubstrate. Most of the information developed using this prac-tice has been obtained for such materials. The proceduresdescribed herein
6、, may also be appropriate for evaluation of hotroll bonded, explosive bonded, or other suitable processes forapplying stainless alloys on steel substrates. However, due tothe broad range of possible materials, test conditions, andvariations in test procedures, it is up to the user of this practiceto
7、 determine the suitability and applicability of these proce-dures for evaluation of such materials.1.3 This practice is intended to be applicable for evaluationof materials for service conditions involving severe hydrogencharging which may produce HID as shown in Fig. 1 forstainless steel weld overl
8、ay on steel equipment (see Refs 1 and2inAppendix X1). However, it should be noted that thispractice may not be appropriate for forms of bimetallicconstruction or service conditions which have not been ob-served to cause HID in service.1.4 Additional information regarding the evaluation of bi-metalli
9、c stainless alloy/steel plate for HID, test methodologies,and the effects of test conditions, materials, and weldingvariables, and inspection techniques is given in Appendix X1.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard
10、.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See Section 6
11、 foradditional safety information.2. Referenced Documents2.1 ASTM Standards:2G 111 Guide for Corrosion Tests in High Temperature orHigh Pressure Environment, or BothE3 Guide for Preparation of Metallographic Specimens2.2 ASME Standard:Boiler and Pressure Vessel Code Section V, Article 5, Tech-nique
12、Two33. Terminology3.1 Definitions:3.1.1 HIDa delamination of a stainless alloy surface layerfrom its steel substrate produced by exposure of the material toa hydrogen environment.3.1.1.1 DiscussionThis phenomenon can occur in inter-nally stainless alloy lined steel equipment by the accumulationof mo
13、lecular hydrogen in the region of the metallurgical bondat the interface between the steel and stainless alloy surfacelayer produced by exposure to service conditions involvingHP/HT hydrogen in the refinery hydroprocessing.4. Summary of Practice4.1 Stainless alloy/steel specimens are exposed to a ga
14、seoushydrogen containing environment at HP/HT conditions forsufficient time to produce hydrogen charging in the material.1This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Current e
15、dition approved May 1, 2007. Published May 2007. Originallyapproved in 1996. Last previous edition in 2001 as G 14601.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer t
16、o the standards Document Summary page onthe ASTM website.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
17、 PA 19428-2959, United States.Following exposure, the specimens are cooled to ambienttemperature at a controlled rate. The specimens are then held atroom temperature for a designated period to allow for thedevelopment of HID between the stainless alloy surface layerand the steel. Following the hold
18、period, the specimens areevaluated for HID at this interface using straight beam ultra-sonic methods with metallographic examination to confirm anyHID found. The size and distribution of the disbonded re-gion(s) are then characterized by this practice. Single ormultiple hydrogen exposure/cooling cyc
19、les can be conductedand varying exposure conditions and cooling rates can beincorporated into this evaluation to provide assessment of thedisbonding characteristics of materials and service conditionused for refinery process equipment containing HP/HT hydro-gen containing environments.5. Significanc
20、e and Use5.1 This practice provides an indication of the resistance orsusceptibility, or both, to HID of a metallurgically bondedstainless alloy surface layer on a steel substrate due to exposureto hydrogen-containing gaseous environments under HP/HTconditions. This practice is applicable over a bro
21、ad range ofpressures, temperatures, cooling rates, and gaseous hydrogenenvironments where HID could be a significant problem. Theseprocedures can be used to assess the effects of materialcomposition, processing methods, fabrication techniques, andheat treatment as well as the effects of hydrogen par
22、tialpressure, service temperature, and cooling rate. The HIDproduced by these procedures may not correlate directly withservice experience for particular applications.Additionally, thispractice does not address the evaluation of high-temperaturehydrogen attack in the steel substrate. Typically, long
23、er expo-sure times at the test conditions must be utilized to allow forthe resistance to decarburization, internal blistering or crack-ing, or both, to be evaluated.6. Apparatus6.1 Because this practice is intended to be conducted at highpressures and high temperatures, the apparatus must be con-str
24、ucted to safely contain the test environment while beingresistant to the cumulative embrittling effects of hydrogen.Secondly, the test apparatus must be capable of allowing (1)introduction of the test gas, (2) removal of air from the test cell,(3) uniform heating of the test specimens, and (4) cooli
25、ng ofthe specimens at controlled rates.6.2 There are many types of test cell configurations whichcan be used to conduct evaluations of HID. This practice doesnot recommend or endorse any particular test cell design. Fig.2 shows a schematic representation of a typical test celldesigned to conduct HID
26、 tests in HP/HT gaseous hydrogenenvironments. Other designs may also provide acceptableperformance. However, the typical components should includethe following:6.2.1 Metal Test CellThe test cell should be constructedfrom materials which have been proven to have high resistanceto hydrogen embrittleme
27、nt and high-temperature hydrogenattack under the anticipated test conditions. Materials with lowresistance to these phenomena should be avoided. Typical testcells for high-pressure hydrogen testing are constructed fromstainless steel (UNS S31600 or S34700) or nickel alloys (UNSN10276 or N06625) in t
28、he solution annealed condition. Steelvessels with stainless alloy exposed surfaces may also besuitable.6.2.2 Closure and SealTo facilitate operation of the testcell, the closure should provide for rapid opening and closingof the test cell while retaining reliable sealing capabilities forhydrogen. Th
29、is can include either metallic or nonmetallicmaterials with high resistance to thermal degradation andhydrogen attack.6.2.3 Gas Port(s)The gas port should be designed topromote flow and circulation of the gaseous test environments,NOTE 1Open symbolsno disbonding reported. Filled symbolsdisbonding re
30、ported.FIG. 1 Conditions of Hydrogen Partial Pressure and Temperaturewith Demonstrated Susceptibility to Hydrogen Disbonding inRefinery High-Pressure Hydrogen ServiceFIG. 2 Typical Test CellG 146 01 (2007)2inert gas purging, and evacuation as required to produce theintended test environment. Usually
31、 two ports are used so thatseparate flow-through capabilities are attained to facilitatethese functions.6.2.4 Electrical Feed-ThroughsHigh-temperature condi-tions are required in this practice. It is usually advantageous toutilize an internal heater to heat just the test specimens and thegaseous env
32、ironment in the immediate vicinity of the speci-men. Therefore, feed-throughs are usually needed to makeelectrical contact with an internal resistance or inductionheater. These feed-throughs must also provide (1) electricalisolation from the test cell and internal fixtures and (2)maintain a seal to
33、prevent leakage of the test environment. Ifexternal heaters are used, no electric feed-throughs are re-quired.6.2.5 Electric Resistance or Induction Heater(s)Eitherinternal or external heaters can be used to obtain elevatedtemperature. For lower temperatures (300C), an internal heater is commonly us
34、ed toheat only the test specimen and the gaseous environment in thevicinity of the test specimens to limit power requirements andproblems with high-temperature sealing and pressure contain-ment.7. Reagents7.1 Purity of ReagentsLow oxygen gases (50Distribution RankingADistribution1 isolated disbonded
35、 regions2 interlinking disbonded regions3 disbonding at weld pass overlaps4 disbonding at joint with side overlay5 other (please describe)_AMore than one category may be indicated.12.17 If the effects of multiple exposure cycles are beingevaluated, the sample may be held at 24 6 2.5C for a periodof
36、48 h and then ultrasonically evaluated. If no hydrogendisbonding or crack growth is detected ultrasonically after the48-h hold period, then the subsequent hydrogen pressure/temperature cycle may be initiated. If disbonding or crackgrowth is observed after 48 h, then either (1) the test can bediscont
37、inued or (2) the full seven-day hold period must bemaintained prior to the next hydrogen/temperature cycle.12.18 Upon completion of testing, the test specimen shall besectioned to expose the stainless alloy surface layer, stainlessalloy/steel interface, and the steel substrate. If no disbonding isfo
38、und with the ultrasonic examination, then the section shall bemade through the center of the specimen. If the ultrasonicinspection detects HID, the section shall be positioned throughthe region of maximum disbonding.12.19 The specimen shall be metallographically ground andpolished using procedures g
39、iven in Practice E3. The edgesmay be beveled and the half of the section opposite thestainless alloy layer may be removed to facilitate handlingduring metallographic preparation.12.20 The stainless alloy/steel interface shall be examined.A representative, unetched micrograph shall be taken at 2003.F
40、ollowing the unetched examination, the specimen shall beetched to reveal the structure of the stainless alloy surface layerand the microstructure structure of the steel substrate at thisinterface. Representative micrographs of stainless alloy etchedand steel etched sections shall be taken at 2003. F
41、rom themetallographic examination of the sections, the location andnature of the disbonding, if present, shall be described relativeto the stainless steel surface layer, stainless alloy/steel inter-face, and steel substrate.13. Report13.1 Report the following information for all hydrogendisbonding t
42、ests:13.1.1 Test Conditions:13.1.1.1 Test temperature,13.1.1.2 Hydrogen gas pressure at the test temperature,13.1.1.3 Hold time at test conditions,13.1.1.4 The cooling rate from the test temperature range toambient temperature,13.1.1.5 Number of hydrogen pressure/temperature cycles,13.1.1.6 Post-tes
43、t holding time at 24 6 2.5C prior toultrasonic inspection, and13.1.1.7 Hold time at 24 6 2.5C between temperaturecycles (if applicable).13.1.2 Ultrasonic Inspections:13.1.2.1 Number, size, and distribution of disbonded re-gions at stainless alloy/steel interface for both pre-test inspec-tion and pos
44、t-test inspection, and13.1.2.2 Disbonding ranking for post-test examination usingalphanumeric coding provided in Section 12.13.1.3 Metallographic Examination Following Testing:13.1.3.1 Representative micrographs of sections acrossstainless alloy/steel interface at 2003 which shall include:(1) Unetch
45、ed,(2) Stainless alloy etched, and(3) Steel substrate etched.13.1.3.2 Description of the location and nature of HIDrelative to stainless alloy surface layer, stainless alloy/steelinterface, and steel substrate.13.1.4 Specimen characterization including orientation,type, size, number of specimens tes
46、ted, and surface prepara-tion.13.1.5 Characterization of Material:13.1.5.1 The bulk chemical composition of both the stain-less alloy layer and steel substrate shall be provided includingthe carbon, sulfur, and phosphorus and any carbide-formingelements such as titanium, niobium (columbium) in the s
47、tain-less alloy and chromium, titanium, vanadium, and molybde-num in the steel substrate.G 146 01 (2007)513.1.5.2 A description of the application method of thestainless alloy shall be provided. The details of this descriptionshould be covered in product or purchase specifications and arenot covered
48、 in this practice.14. Keywords14.1 autoclave; disbonding; high pressure; high tempera-ture; hydrogen; hydroprocessing; metallography; refining; ul-trasonic testingAPPENDIX(Nonmandatory Information)X1. PERTINENT LITERATUREX1.1 The following list of references is provided foradditional information reg
49、arding this evaluation of bimetallicstainless alloy/steel plate for HID, test methodologies, and theeffects of test conditions, materials and welding variables, andinspection techniques.(1) Cayard, M. S., Kane, R. D., and Stevens, C. E.,“ Evaluation ofHydrogen Disbonding of Stainless Steel Cladding for High Tem-perature Hydrogen Service,” Paper No. 518, CORROSION/94,NACE International, March 1994.(2) Minutes of Refining Subcommittee on Corrosion and Research,Attachment IV, American Petroleum Institute, Midyear RefiningMeeting, New Orleans, LA, May 1416
