1、Designation: A688/A688M 18Standard Specification forSeamless and Welded Austenitic Stainless Steel FeedwaterHeater Tubes1This standard is issued under the fixed designation A688/A688M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision
2、, 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 seamless and welded auste-nitic stainless steel feedwater heater tubes includ
3、ing those bent,if specified, into the form of U-tubes for application in tubularfeed-water heaters.1.2 The tubing sizes covered shall be58 to 1 in. 15.9 to25.4 mm inclusive outside diameter, and average or minimumwall thicknesses of 0.028 in. 0.7 mm and heavier.1.3 The values stated in either SI uni
4、ts or inch-pound unitsare to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining valuesfrom the two systems may result in non-co
5、nformance with thestandard.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organi
6、zation TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsA480/A480M Specification for General Requirements forFlat-Rolled Stainless and Heat-Resisting Steel Plate,Shee
7、t, and StripA941 Terminology Relating to Steel, Stainless Steel, RelatedAlloys, and FerroalloysA1016/A1016M Specification for General Requirements forFerritic Alloy Steel, Austenitic Alloy Steel, and StainlessSteel TubesE112 Test Methods for Determining Average Grain SizeE527 Practice for Numbering
8、Metals and Alloys in theUnified 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 inthis specification, refer to Terminology A941.4. Ordering Information4.1 It is the responsibility of
9、the purchaser to specify allrequirements that are necessary for material under this speci-fication. 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 (seamless or welded),4.1.3 DimensionsOutside diameter, wall t
10、hickness (mini-mum or average wall), 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 an-nealing of the U-bends is required or whe
11、ther tubes are to behydrotested or air tested (see 11.8)4.1.7 Supplementary requirementsPurchaser shallspecify on the purchase order if material is to be eddy currenttested in accordance with Supplementary Requirements S1 orS2, and if special test reports are required under SupplementaryRequirement
12、S3, and,4.1.8 Any additional special requirements.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.10 on Stainless and Alloy Steel Tubular Products.Current edition approved Sept. 1, 201
13、8. Published September 2018. Originallyapproved in 1973. Last previous edition approved in 2015 as A688/A688M 15.DOI: 10.1520/A0688_A0688M-18.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-688 in Section II of that Code.3For referenced ASTM standards, visit the
14、ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001,
15、http:/www.sae.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on st
16、andardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1TABLE1ChemicalRequirementsElementGrade.TP304TP304LTP304LNTP316TP316LTP316LNTPXM-29TP30
17、4NTP316N.800800H.UNS DesignationAS30400S30403S30453S31600S31603S31653S24000S30451S31651N08367N08800N08810N08811N08926S31254S32654Composition,%Carbon,max0.080.0350.0350.080.0350.0350.0600.080.080.0300.100.050.100.060.100.0200.0200.020Manganese,maxB2.002.002.002.002.002.0011.5014.502.002.002.001.501.5
18、01.502.001.002.04.0Phosphorus,max0.0400.0400.0400.0400.0400.0400.0600.0400.0400.0400.0450.0450.0450.030.0300.030Sulfur,max0.0300.0300.0300.0300.0300.0300.0300.0300.0300.0300.0150.0150.0150.010.0100.005Silicon,max0.750.750.750.750.750.751.000.750.751.001.001.001.000.50.800.50Nickel8.0011.008.0013.008
19、.0013.0010.0014.0010.0015.0010.0015.002.253.758.0011.010.0014.0023.5025.5030.035.030.035.030.035.024.0026.0017.518.521.023.0Chromium18.0020.0018.0020.0018.0020.0016.0018.0016.0018.0016.0018.0017.0019.0018.020.016.018.020.0022.0019.0023.019.0023.019.0023.019.0021.0019.520.524.025.0Molybdenum.2.003.00
20、2.003.002.003.00.2.003.006.007.00.6.07.06.06.57.08.0NitrogenC.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.0.150.600.150.600.25 0.60D.Aluminum.0.150.600.150.600.25 0.60D.Others.Fe39.5Min.EFe39.5Min.EFe39.5Min.E.ANe
21、wdesignationestablishedinaccordancewithPracticeE527andSAEJ1086.BMaximum,unlessotherwisenoted.CThemethodofanalysisfornitrogenshallbeamatterofagreementbetweenthepurchaserandmanufacturer.D(Al+Ti)=0.851.20.EFeshallbedeterminedarithmethicallybydifferenceof100minusthesumoftheotherspecifiedelements.A688/A6
22、88M 1825. General Requirements5.1 Material furnished to this specification shall conform tothe applicable requirements of the latest published edition ofSpecification A1016/A1016M unless otherwise providedherein.6. Materials and Manufacture6.1 The tube shall be manufactured by either the seamless or
23、welded and cold worked process.6.2 Seamless Tubing:6.2.1 Seamless tubing shall be supplied from a cold finish-ing process. Hot finishing as the final sizing process is notallowed.6.3 Welded Tubing:6.3.1 The tube shall be made from flat-rolled steel by anautomatic welding process with no addition of
24、filler metal.6.3.2 Subsequent to welding and prior to final heattreatment, the tubes shall be cold worked either in both theweld and base metal, or in the weld metal only. The method ofcold work may be specified by the purchaser. When colddrawn, the purchaser may specify the minimum amount ofreducti
25、on in cross-sectional area or wall thickness, or both.6.4 Many surface contaminants may have detrimental ef-fects on high temperature properties or corrosion resistance oftubing. Contamination by copper, lead, mercury, zinc,chlorides, or sulfur may be detrimental to stainless steels. Themanufacturer
26、 shall employ techniques that minimize surfacecontamination by these elements.7. Cleaning Before Annealing7.1 All lubricants of coatings used in the manufacture ofstraight-length tube or in the bending shall be removed from allsurfaces prior to any annealing treatments. U-bends on whicha lubricant h
27、ad been applied to the inside surface duringbending shall have the cleanness of their inside surfaceconfirmed by blowing close fitting acetone-soaked felt plugsthrough 10 % of the tubes of each bend radius. Dry, oil-free, airor inert gas shall be used to blow the plugs through the tubes.If the plugs
28、 blown through any tube shows more than a lightgray discoloration, all tubes that have had a lubricant applied tothe inside surface during bending shall be recleaned. Afterrecleaning 10 % of the tubes of each bend radius whose insidesurface had been subjected to bending lubricants shall beretested.8
29、. Heat Treatment8.1 All finished straight tubing or straight tubing ready forU-bending shall be furnished in the solution-annealed condi-tion. The annealing procedure, except for N08367, S31254,S32654, N08810, N08811, and N08926, shall consist ofheating the material to a minimum temperature of 1900
30、F1040 C followed by a rapid cooling to below 700 F 370C. The cooling rate shall be sufficiently rapid to preventharmful carbide precipitation as determined in Section 13.8.2 UNS N08367 shall be solution annealed at 2025 F1107 C minimum followed by rapid quenching.8.3 N08926 shall be heat-treated at
31、a minimum temperatureof 2010 F 1100 C followed by quenching in water orrapidly cooling by other means.8.4 S31254, S32654, and N08811 shall be solution annealedat 2100 F 1150 C minimum followed by rapid quenching.8.5 N08810 shall be heat-treated to a minimum temperatureof 2050 F 1120 C minimum follow
32、ed by rapid quenching.8.6 If heat treatment of U-bends is specified, it shall satisfythe annealing procedure described above, and shall be done asfollows:8.6.1 The heat treatment shall be applied to the U-bend areaplus approximately 6 in. 150 mm of each leg beyond thetangent point of the U-bend.8.6.
33、2 If the heat treatment specified in 8.6 is accomplishedby resistance-heating methods wherein electrodes are clampedto the tubes, the clamped areas shall be visually examined forarc burns. Burn indications shall be cause for rejection unlessthey can be removed by local polishing without encroachingu
34、pon minimum wall thickness.8.6.3 Temperature control shall be accomplished throughthe use of optical or emission pyrometers, or both. Notemperature-indicating crayons, lacquers, or pellets shall beused.8.6.4 The inside of the tube shall be purged with a protectiveor an inert gas atmosphere during he
35、ating and cooling to below700 F 370 C to prevent scaling of the inside surface. Theatmosphere should be noncarburizing.9. Surface Condition9.1 The straight tubes, after final annealing, shall be pickledusing a solution of nitric and hydrofluoric acids followed byflushing and rinsing in water. If bri
36、ght annealing is performed,this requirement does not apply.9.2 Alight oxide scale on the outside surface of U-bend areashall 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 order,
37、 a productanalysis shall be made by the supplier from one tube or coil ofsteel per heat. The chemical composition shall conform to therequirements shown in Table 1.10.1.2 A product analysis tolerance of Specification A480/A480M shall apply. The product analysis tolerance is notapplicable to the carb
38、on content for material with a specifiedmaximum carbon of 0.04 % or less.10.1.3 If the original test for product analysis fails, retests oftwo additional lengths of flat-rolled stock or tubes shall bemade. Both retests, for the elements in question, shall meet therequirements of this specification;
39、otherwise all remainingmaterial in the heat or lot shall be rejected, or at the option ofthe producer, each length of flat-rolled stock or tube may beindividually tested for acceptance. Lengths of flat-rolled stockor tubes that do not meet the requirements of this specificationshall be rejected.A688
40、/A688M 18311. Mechanical Requirements11.1 Tensile Properties:11.1.1 The material shall conform to the tensile propertiesshown in Table 2.11.1.2 One tension test shall be made on a specimen for lotsof not more than 50 tubes. Tension tests shall be made onspecimens from two tubes for lots of more than
41、 50 tubes.11.2 Hardness:11.2.1 Grade TP XM-29 and N08367 tubes shall have ahardness number not exceeding 100 HRB, 265 HBW, or 270HV, depending on test method used. Tubes of all other gradesshall have a hardness number not exceeding 90 HRB, 192HBW, or 200 HV, depending on test method used. Thishardne
42、ss requirement is not to apply to the bend area of U-bendtubes which are not heat treated after bending.11.2.2 Brinell or Rockwell hardness tests shall be made onspecimens from two tubes from each lot.11.2.3 For tubing less than 0.354 in. 9.00 mm in insidediameter or less than 0.065 in. 1.65 mm in w
43、all thickness, itis permissible to use the Vickers hardness test in lieu of theRockwell test.11.3 Reverse Bend Test (Welded Product):11.3.1 One reverse bend test shall be made on a specimenfrom each 1500 ft 460 m of finished tubing.11.3.2 Asection 4 in. 100 mm minimum in length shall besplit longitu
44、dinally 90 on each side of the weld. The sampleshall then be opened and bent around a mandrel with amaximum thickness of four times the wall thickness, with themandrel parallel to the weld and against the original outsidesurface of the tube. The weld shall be at the point of maximumbend. There shall
45、 be no evidence of cracks, or of overlapsresulting from the reduction in thickness of the weld area bycold working. When the geometry or size of the tubing make itdifficult to test the sample as a single piece, the sample may besectioned into smaller pieces provided a minimum of 4 in. ofweld is subj
46、ected to reverse bending.11.3.3 The reverse bend test is not applicable when speci-fied wall is 10 % or more of the specified outside diameter, orthe wall thickness is 0.134 in. 3.4 mm or greater, or theoutside diameter size is less than 0.375 in. 9.5 mm. Underthese conditions, the reverse flattenin
47、g test of SpecificationA1016/A1016M shall apply.11.4 Flattening Test (Seamless and Welded Products)Flattening tests shall be made on specimens from each end ofone finished tube, not the one used for the flange test, fromeach lot.11.5 Flange Test (Welded Product)Flange tests shall bemade on specimens
48、 from each end of one finished tube, not theone used for the flattening test, from each lot.11.6 Flaring Test (Seamless Product)Flaring tests shall bemade on specimens from each end of one finished tube, not theone used for the flattening test, from each lot.11.7 Grain Size:11.7.1 The grain size of
49、grades N08810 and N08811, asdetermined in accordance with Test Methods E112, shall beNo. 5 or coarser.11.8 Pressure Test:11.8.1 Each straight tube or each U-tube after completion ofthe bending and post-bending heat treatment, shall be pressuretested in accordance with one of the following paragraphs asspecified by the purchaser.11.8.1.1 Hydrostatic TestEach tube shall be given aninte
