1、Designation:A688/A688M10 Designation: A688/A688M 11Standard Specification forWelded Austenitic Stainless Steel Feedwater Heater Tubes1This standard is issued under the fixed designation A688/A688M; the number immediately following the designation indicates the yearof original adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification2covers welded austenitic stainless steel feedwater heater tubes includi
3、ng those bent, if specified, into theform of U-tubes for application in tubular feed-water heaters.1.2 The tubing sizes covered shall be58 to 1 in. 15.9 to 25.4 mm inclusive outside diameter, and average or minimum wallthicknesses of 0.028 in. 0.7 mm and heavier.1.3 The values stated in either SI un
4、its or inch-pound units are to be regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the two systems may result in no
5、n-conformance with the standard.2. Referenced Documents2.1 ASTM Standards:3A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless SteelsA480/A480M Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and StripA94
6、1 Terminology Relating to Steel, Stainless Steel, Related Alloys, and FerroalloysA1016/A1016M Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless SteelTubesE112 Test Methods for Determining Average Grain SizeE527 Practice for Numbering Metals and Al
7、loys in the Unified Numbering System (UNS)2.2 Other Standard:SAE J1086 Practice for Numbering Metals and Alloys (UNS)43. Terminology3.1 Definitions Of TermsFor definitions of terms used in this specification, refer to Terminology A941.4. Ordering Information4.1 It is the responsibility of the purcha
8、ser to specify all requirements that are necessary for material under this specification.Such requirements may include, but are not limited to, the following:4.1.1 Quantity (length or number of pieces),4.1.2 Material description,4.1.3 DimensionsOutside diameter, wall thickness (minimum or average wa
9、ll), and length,4.1.4 Grade (chemical composition) (Table 1),4.1.5 U-bend requirements, if order specifies bending, U-bend schedules or drawings shall accompany the order,4.1.6 Optional requirementsPurchaser shall specify if annealing of the U-bends is required or whether tubes are to behydrotested
10、or air tested (see 11.611.7)4.1.7 Supplementary requirementsPurchaser shall specify on the purchase order if material is to be eddy current tested inaccordance with Supplementary Requirements S1 or S2, and if special test reports are required under Supplementary RequirementS3, and,4.1.8 Any special
11、requirements.1This specification is under the jurisdiction ofASTM CommitteeA01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of SubcommitteeA01.10on Stainless and Alloy Steel Tubular Products .Current edition approved MayApril 1, 2010.2011. Published June 2010.April 20
12、11. Originally approved in 1973. Last previous edition approved in 20082010 asA688/A688M108. DOI: 10.1520/A0688_A0688M-101.2For ASME Boiler and Pressure Vessel Code applications see related Specification SA-688 in Section II of that Code.3For referencedASTM standards, visit theASTM website, www.astm
13、.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http:/www.sae.org.1T
14、his document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior edit
15、ions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-295
16、9, United States.TABLE1ChemicalRequirementsElementGrade.TP304TP304LTP304LNTP316TP316LTP316LNTPXM-29TP304NTP316N.800800H.UNS DesignationAS30400S30403S30453S31600S31603S31653S24000S30451S31651N08367N08800N08810N08811N08926S31254S32654Composition,%Carbon,max0.080.0350.0350.080.0350.0350.0600.080.080.03
17、00.100.050.100.050.100.0200.0200.020Manganese,maxB2.002.002.002.002.002.0011.5014.502.002.002.001.501.501.502.001.002.04.0Phosphorus,max0.0400.0400.0400.0400.0400.0400.0600.0400.0400.0400.0450.0450.0450.030.0300.030Sulfur,max0.0300.0300.0300.0300.0300.0300.0300.0300.0300.0300.0150.0150.0150.010.0100
18、.005Silicon,max0.750.750.750.750.750.751.000.750.751.001.001.001.000.50.800.50Nickel8.0011.008.0013.008.0013.0010.0014.0010.0015.0010.0015.002.253.758.0011.010.0014.0023.5025.5030.035.030.035.030.035.024.0026.0017.518.521.023.0Chromium18.0020.0018.0020.0018.0020.0016.0018.0016.0018.0016.0018.0017.00
19、19.0018.020.016.018.020.0022.0019.0023.019.0023.019.0023.019.0021.0019.520.524.025.0Molybdenum.2.003.002.003.002.003.00.2.003.006.007.00.6.07.06.06.57.08.0NitrogenC.0.100.16.0.100.160.200.400.100.160.100.160.180.25.0.150.250.180.220.450.55Copper.0.75max0.750.750.750.51.50.501.000.300.60Titanium.0.15
20、0.600.150.600.15 0.60D.Aluminum.0.150.600.150.600.15 0.60D.Others.Fe39.5Min.EFe39.5Min.EFe39.5Min.E.ANewdesignationestablishedinaccordancewithPracticeE527andSAEJ1086.BMaximum,unlessotherwisenoted.CThemethodofanalysisfornitrogenshallbeamatterofagreementbetweenthepurchaserandmanufacturer.D(Al+Ti)0.851
21、.20.EFeshallbedeterminedarithmethicallybydifferenceof100minusthesumoftheotherspecifiedelements.A688/A688M 1125. General Requirements5.1 Material furnished to this specification shall conform to the applicable requirements of the latest published edition ofSpecification A1016/A1016M unless otherwise
22、provided herein.6. Materials and Manufacture6.1 The tube shall be made from flat-rolled steel by an automatic welding process with no addition of filler metal.6.2 Subsequent to welding and prior to final heat treatment, the tubes shall be cold worked either in both the weld and basemetal, or in the
23、weld metal only. The method of cold work may be specified by the purchaser. When cold drawn, the purchasermay specify the minimum amount of reduction in cross-sectional area or wall thickness, or both.6.3 Many surface contaminants may have detrimental effects on high temperature properties or corros
24、ion resistance of tubing.Contamination by copper, lead, mercury, zinc, chlorides, or sulfur may be detrimental to stainless steels. The manufacturer shallemploy techniques that minimize surface contamination by these elements.7. Cleaning Before Annealing7.1 All lubricants of coatings used in the man
25、ufacture of straight-length tube or in the bending shall be removed from allsurfaces prior to any annealing treatments. U-bends on which a lubricant had been applied to the inside surface during bendingshall have the cleanness of their inside surface confirmed by blowing close fitting acetone-soaked
26、 felt plugs through 10 % of thetubes of each bend radius. Dry, oil-free, air or inert gas shall be used to blow the plugs through the tubes. If the plugs blown throughany tube shows more than a light gray discoloration, all tubes that have had a lubricant applied to the inside surface during bending
27、shall be recleaned. After recleaning 10 % of the tubes of each bend radius whose inside surface had been subjected to bendinglubricants shall be retested.8. Heat Treatment8.1 All finished straight tubing or straight tubing ready for U-bending shall be furnished in the solution-annealed condition. Th
28、eannealing procedure, except for N08367, S31254, S32654, N08810, N08811, and N08926, shall consist of heating the material toa minimum temperature of 1900 F 1040 C followed by a rapid cooling to below 700 F 370 C. The cooling rate shall besufficiently rapid to prevent harmful carbide precipitation a
29、s determined in Section 13.8.2 UNS N08367 shall be solution annealed at 2025 F 1107 C minimum followed by rapid quenching.8.3 N08926 shall be heat-treated at a minimum temperature of 2010 F 1100 C followed by quenching in water or rapidlycooling by other means.8.4S31254 and S32654 shall be solution
30、annealed at 2100 F 1150 C minimum followed by rapid quenching.8.58.4 S31254, S32654, and N08811 shall be solution annealed at 2100 F 1150 C minimum followed by rapid quenching.8.5 N08810 shall be heat-treated to a minimum temperature of 2050 F 1120 C minimum followed by rapid quenching.8.6 If heat t
31、reatment of U-bends is specified, it shall satisfy the annealing procedure described above, and shall be done asfollows:8.5.1The8.6.1 The heat treatment shall be applied to the U-bend area plus approximately 6 in. 150 mm of each leg beyondthe tangent point of the U-bend.8.5.2If8.6.2 If the heat trea
32、tment specified in 8.58.6 is accomplished by resistance-heating methods wherein electrodes areclamped to the tubes, the clamped areas shall be visually examined for arc burns. Burn indications shall be cause for rejectionunless they can be removed by local polishing without encroaching upon minimum
33、wall thickness.8.56.3 Temperature control shall be accomplished through the use of optical or emission pyrometers, or both. Notemperature-indicating crayons, lacquers, or pellets shall be used.8.5.4The8.6.4 The inside of the tube shall be purged with a protective or an inert gas atmosphere during he
34、ating and coolingto below 700 F 370 C to prevent scaling of the inside surface. The atmosphere should be noncarburizing.9. Surface Condition9.1 The straight tubes, after final annealing, shall be pickled using a solution of nitric and hydrofluoric acids followed byflushing and rinsing in water. If b
35、right annealing is performed, this requirement does not apply.9.2 A light oxide scale on the outside surface of U-bend area shall be permitted for tubes which have been electric-resistanceheat treated after bending.10. Chemical Composition10.1 Product Analysis:10.1.1 When requested in the purchase o
36、rder, a product analysis shall be made by the supplier from one tube or coil of steelper heat. The chemical composition shall conform to the requirements shown in Table 1.10.1.2 A product analysis tolerance of Specification A480/A480M shall apply. The product analysis tolerance is not applicableto t
37、he carbon content for material with a specified maximum carbon of 0.04 % or less.A688/A688M 11310.1.3 If the original test for product analysis fails, retests of two additional lengths of flat-rolled stock or tubes shall be made.Both retests, for the elements in question, shall meet the requirements
38、 of this specification; otherwise all remaining material in theheat or lot shall be rejected, or at the option of the producer, each length of flat-rolled stock or tube may be individually testedfor acceptance. Lengths of flat-rolled stock or tubes that do not meet the requirements of this specifica
39、tion shall be rejected.11. Mechanical Requirements11.1 Tensile Properties:11.1.1 The material shall conform to the tensile properties shown in Table 2.11.1.2 One tension test shall be made on a specimen for lots of not more than 50 tubes. Tension tests shall be made on specimensfrom two tubes for lo
40、ts of more than 50 tubes.11.2 Hardness:11.2.1 Grade TP XM-29 and N08367 tubes shall have a hardness number not exceeding 100 HRB or its equivalent. Tubes ofall other grades shall have a hardness number not exceeding 90 HRB or its equivalent. This hardness requirement is not to applyto the bend area
41、of U-bend tubes which are not heat treated after bending.11.2.2 Brinell or Rockwell hardness tests shall be made on specimens from two tubes from each lot.11.3 Reverse Bend Test:11.3.1 One reverse bend test shall be made on a specimen from each 1500 ft 460 m of finished tubing.11.3.2 A section 4 in.
42、 100 mm minimum in length shall be split longitudinally 90 on each side of the weld. The sample shallthen be opened and bent around a mandrel with a maximum thickness of four times the wall thickness, with the mandrel parallelto the weld and against the original outside surface of the tube. The weld
43、 shall be at the point of maximum bend. There shall beno evidence of cracks, or of overlaps resulting from the reduction in thickness of the weld area by cold working. When thegeometry or size of the tubing make it difficult to test the sample as a single piece, the sample may be sectioned into smal
44、ler piecesprovided a minimum of 4 in. of weld is subjected to reverse bending. Note1The11.3.3 The reverse bend test is not applicable when specified wall is 10 % or more of the specified outside diameter, or the wallthickness is 0.134 in. 3.4 mm or greater, or the outside diameter size is less than
45、0.375 in. 9.5 mm. Under these conditions, thereverse flattening test of Specification A1016/A1016M shall apply.11.4 Flattening TestFlattening tests shall be made on specimens from each end of one finished tube, not the one used for theflange test, from each lot.11.5 Flange TestFlange tests shall be
46、made on specimens from each end of one finished tube, not the one used for theflattening test, from each lot.11.611.6 Grain Size:11.6.1 The grain size of grades N08810 and N08811, as determined in accordance with Test Methods E112, shall be No. 5 orcoarser.11.7 Pressure Test:11.67.1 Each straight tu
47、be or each U-tube after completion of the bending and post-bending heat treatment, shall be pressuretested in accordance with one of the following paragraphs as specified by the purchaser.11.6.1.111.7.1.1 Hydrostatic TestEach tube shall be given an internal hydrostatic test in accordance with Specif
48、icationA1016/A1016M, except that the test pressure and hold time, when other than that stated in Specification A1016/A1016M, shallbe agreed upon between purchaser and manufacturer.11.6.1.211.7.1.2 Pneumatic TestEach tube shall be examined by a pneumatic test (either air underwater or pneumatic leak
49、test) inaccordance with Specification A1016/A1016M.11.711.8 Lot Definitions:11.78.1 For flattening and flange requirements, the term “lot” applies to 125 tube groupings, prior to cutting to length, of thesame nominal size and wall thickness, produced from the same heat of steel and annealed in a continuous furnace.11.78.2 For tension and hardness, the term “lot” applies to all tubes, prior
