1、Designation: A 688/A 688M 08Standard Specification forWelded Austenitic Stainless Steel Feedwater Heater Tubes1This standard is issued under the fixed designationA 688/A 688M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification2covers welded austenitic stainlesssteel feedwater heater tubes including those bent, if spec
3、ified,into the form of U-tubes for application in tubular feed-waterheaters.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 inch-pound units or SI unitsa
4、re to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem are not exact equivalents; therefore, each system shallbe used independently of the other. Combining values from thetwo systems may result in nonconformance with the specifi-
5、cation.2. Referenced Documents2.1 ASTM Standards:3A 262 Practices for Detecting Susceptibility to Intergranu-lar Attack in Austenitic Stainless SteelsA 480/A 480M Specification for General Requirements forFlat-Rolled Stainless and Heat-Resisting Steel Plate,Sheet, and StripA 941 Terminology Relating
6、 to Steel, Stainless Steel, Re-lated Alloys, and FerroalloysA 1016/A 1016M Specification for General Requirementsfor Ferritic Alloy Steel, Austenitic Alloy Steel, and Stain-less Steel TubesE 527 Practice for Numbering Metals and Alloys in theUnified Numbering System (UNS)2.2 Other Standard:SAE J1086
7、 Practice for Numbering Metals and Alloys(UNS)43. Terminology3.1 Definitions Of TermsFor definitions of terms used inthis specification, refer to Terminology A 941.4. Ordering Information4.1 It is the responsibility of the purchaser to specify allrequirements that are necessary for material under th
8、is 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,4.1.3 DimensionsOutside diameter, wall thickness (mini-mum or average wall), and length,4.1.4 Grade (chemical composition) (Table 1),4.1.5 U-b
9、end 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 whether tubes are to behydrotested or air tested (see 11.6)4.1.7 Supplementary requirementsPurchaser shal
10、lspecify 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 S3, and,4.1.8 Any special requirements.5. General Requirements5.1 Material furnished to this specifica
11、tion shall conform tothe applicable requirements of the latest published edition ofSpecification A 1016/A 1016M unless otherwise providedherein.6. Materials and Manufacture6.1 The tube shall be made from flat-rolled steel by anautomatic welding process with no addition of filler metal.6.2 Subsequent
12、 to welding and prior to final heat treatment,the tubes shall be cold worked either in both the weld and basemetal, or in the weld metal only. The method of cold work may1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct
13、responsibility of SubcommitteeA01.10 on Stainless and Alloy Steel Tubular Products.Current edition approved March 1, 2008. Published March 2008. Originallyapproved in 1973. Last previous edition approved in 2007 as A 688/A 688M 07.2For ASME Boiler and Pressure Vessel Code applications see related Sp
14、ecifi-cation SA-688 in Section II of that Code.3For 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 to the standards Document Summary page onthe ASTM website.4Available fro
15、m Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, http:/www.sae.org.1*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 19428-2959, United States.be specified
16、 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 ef-fects on high temperature properties or corrosion resistance oftubing. Contamination by copper, lead,
17、mercury, zinc, chlo-rides, or sulfur may be detrimental to stainless steels. Themanufacturer 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
18、be removed from allsurfaces prior to any annealing treatments. U-bends on whicha lubricant had 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. D
19、ry, oil-free, airor inert gas shall be used to blow the plugs through the tubes.If the plugs 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
20、 bend radius whose insidesurface had been subjected to bending lubricants shall beretested.8. 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, and N0
21、8926, shall consist of heating the material to aminimum temperature of 1900 F 1040 C followed by arapid cooling to below 700 F 370 C. The cooling rate shallbe sufficiently rapid to prevent harmful carbide precipitation asdetermined in Section 13.8.2 UNS N08367 shall be solution annealed at 2025 F110
22、7 C minimum followed by rapid quenching.8.3 N08926 shall be heat-treated at a minimum temperatureof 2010 F 1100 C followed by quenching in water orrapidly cooling by other means.8.4 S31254 and S32654 shall be solution annealed at 2100F 1150 C minimum followed by rapid quenching.8.5 If heat treatment
23、 of U-bends is specified, it shall satisfythe annealing procedure described above, and shall be done asfollows:8.5.1 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.8.5.2 If the heat treatment specified in 8.5 is
24、 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 encroachingupon minimum wall thickness.8.5.3 Temperatur
25、e control shall be accomplished throughthe use of optical or emission pyrometers, or both. Notemperature-indicating crayons, lacquers, or pellets shall beused.8.5.4 The inside of the tube shall be purged with a protectiveor an inert gas atmosphere during heating and cooling to below700 F 370 C to pr
26、event 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 bright annealing is performed,this requirement
27、 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:TABLE 1 Chemical RequirementsElementGrade. TP 304 TP 304L TP 304LN TP 316 TP 316L TP 31
28、6LN TP XM-29 TP 304N TP 316N . . . . . . . . . . . .UNSDesignationAS30400 S30403 S30453 S31600 S31603 S31653 S24000 S30451 S31651 N08367 N08926 S31254 S32654Composition, %Carbon, max 0.08 0.035 0.035 0.08 0.035 0.035 0.060 0.08 0.08 0.030 0.020 0.020 0.020Manganese, maxB2.00 2.00 2.00 2.00 2.00 2.00
29、 11.5014.502.00 2.00 2.00 2.00 1.00 2.04.0Phosphorus, max 0.040 0.040 0.040 0.040 0.040 0.040 0.060 0.040 0.040 0.040 0.03 0.030 0.030Sulfur, max 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.030 0.01 0.010 0.005Silicon, max 0.75 0.75 0.75 0.75 0.75 0.75 1.00 0.75 0.75 1.00 0.5 0.80 0.50Ni
30、ckel 8.0011.008.0013.008.0013.0010.0014.0010.0015.0010.0015.002.253.758.0011.010.0014.0023.5025.5024.0026.0017.518.521.023.0Chromium 18.0020.0018.0020.0018.0020.0016.0018.0016.0018.0016.0018.0017.0019.0018.020.016.018.020.0022.0019.0021.0019.520.524.025.0Molybdenum . . . 2.003.002.003.002.003.00. .
31、2.003.006.007.006.07.06.06.57.08.0NitrogenC. . 0.100.16. . 0.100.160.200.400.100.160.100.160.180.250.150.250.180.220.450.55Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 max 0.51.5 0.501.00 0.300.60ANew designation established in accordance with Practice E 527 and SAE J1086.BMaxim
32、um, unless otherwise noted.CThe method of analysis for nitrogen shall be a matter of agreement between the purchaser and manufacturer.A 688/A 688M 08210.1.1 When requested in the purchase order, a productanalysis shall be made by the supplier from one tube or coil ofsteel per heat. The chemical comp
33、osition shall conform to therequirements shown in Table 1.10.1.2 A product analysis tolerance of Specification A 480/A 480M shall apply. The product analysis tolerance is notapplicable to the carbon content for material with a specifiedmaximum carbon of 0.04 % or less.10.1.3 If the original test for
34、 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; otherwise all remainingmaterial in the heat or lot shall be rejected, or at the option ofthe producer, e
35、ach 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.11. Mechanical Requirements11.1 Tensile Properties:11.1.1 The material shall conform to the tensile properti
36、esshown 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 50 tubes.11.2 Hardness:11.2.1 Grade TP XM-29 and N08367 tubes shall have ahardness number not exceeding 100 HRB or it
37、s equivalent.Tubes of all other grades shall have a hardness number notexceeding 90 HRB or its equivalent. This hardness requirementis not to apply to the bend area of U-bend tubes which are notheat treated after bending.11.2.2 Brinell or Rockwell hardness tests shall be made onspecimens from two tu
38、bes from each lot.11.3 Reverse Bend Test: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 longitudinally 90 on each side of the weld. The sampleshall then be opened and bent around a mandre
39、l 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 be no evidence of cracks, or of overlapsresulting from the reduction in thickness of the we
40、ld 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 subjected to reverse bending.NOTE 1The reverse bend test is not applicable when specified wall i
41、s10 % or more of the specified outside diameter, or the wall thickness is0.134 in. 3.4 mm or greater, or the outside diameter size is less than0.375 in. 9.5 mm. Under these conditions, the reverse flattening test ofSpecification A 1016/A 1016M shall apply.11.4 Flattening TestFlattening tests shall b
42、e made onspecimens from each end of one finished tube, not the one usedfor the flange test, from each lot.11.5 Flange TestFlange tests shall be made on specimensfrom each end of one finished tube, not the one used for theflattening test, from each lot.11.6 Pressure Test:11.6.1 Each straight tube or
43、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.11.6.1.1 Hydrostatic TestEach tube shall be given aninternal hydrostatic test in accordance with SpecificationA 1016/A 1
44、016M, except that the test pressure and hold time,when other than that stated in Specification A 1016/A 1016M,shall be agreed upon between purchaser and manufacturer.11.6.1.2 Air Underwater TestEach tube shall be air un-derwater tested in accordance with Specification A 1016/A 1016M.11.7 Lot Definit
45、ions:11.7.1 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 sameheat of steel and annealed in a continuous furnace.11.7.2 For tension and hardness, the term “lot” applies to
46、 alltubes, prior to cutting to length, of the same nominal diameterand wall thickness, produced from the same heat of steel andannealed in a continuous furnace at the same temperature, timeat temperature, and furnace speed.12. Nondestructive Test (Electric Test)12.1 Each straight tube shall be teste
47、d after the finish heattreatment by passing it through a nondestructive tester capableof detecting defects on the entire cross section of the tube, inaccordance with Specification A 1016/A 1016M.13. Corrosion Resisting Properties13.1 One full section sample 1 in. 25.4 mm long from thecenter of a sam
48、ple tube of the smallest radius bend which isTABLE 2 Tensile RequirementsGrade 304, 316304L,316LXM-29304N,316N304LN,316LN. . . . . .UNS DesignationS30400,S31600S30403,S31603S24000 S30451,S31651S30453,S31653N08367t # 0.187N08367t 0.187N08926 S31254t # 0.187S31254t 0.187S32654Tensile strength, min ksi
49、MPa75 515 70 485 100 690 80 550 75 515 100 690 95 655 94 650 100 690 95 655 120 825Yield strength, minksi MPa30 205 25 175 55 380 35 240 30 205 45 310 45 310 43 295 45 310 45 310 65 450Elongation in 2 in. or 50mm, min, %35 35 35 35 35 30 30 35 35 35 40A 688/A 688M 083heat treated shall be tested in the heat treated condition inaccordance with Practices A 262.13.2 One full-section sample 1 in. 25.4 mm long fromeach lot of straight tube
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