1、Designation: A 618/A 618M 04Standard Specification forHot-Formed Welded and Seamless High-Strength Low-AlloyStructural Tubing1This standard is issued under the fixed designation A 618/A 618M; the number immediately following the designation indicates the yearof original adoption or, in the case of r
2、evision, the year 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This specifica
3、tion covers grades of hot-formed weldedand seamless high-strength low-alloy square, rectangular,round, or special shape structural tubing for welded, riveted, orbolted construction of bridges and buildings and for generalstructural purposes. When the steel is used in welded construc-tion, the weldin
4、g procedure shall be suitable for the steel andthe intended service.1.2 Grade II has atmospheric corrosion resistance equiva-lent to that of carbon steel with copper (0.20 minimum Cu)Grades Ia and Ib have atmospheric corrosion resistance sub-stantially better than that of Grade II (Note 1). When pro
5、perlyexposed to the atmosphere, Grades Ia and Ib can be used bare(unpainted) for many applications. When enhanced corrosionresistance is desired, Grade III, copper limits may be specified.NOTE 1For methods of estimating the atmospheric corrosion resis-tance of low alloy steels see Guide G 101 or act
6、ual data.1.3 The values stated in either inch-pound units or SI unitsare 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 val
7、ues from thetwo systems may result in nonconformance with the standard.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 700 Practices for Packaging, Marking, and LoadingMethods for Steel Products for Domestic ShipmentA 751 Test Me
8、thods, Practices, and Terminology forChemical Analysis of Steel ProductsG 101 Guide for Estimating the Atmospheric CorrosionResistance of Low-Alloy Steels3. Ordering Information3.1 Orders for material under this specification shouldinclude the following as required to describe the materialadequately
9、:3.1.1 Quantity (feet, metres, or number of lengths),3.1.2 Grade (Table 1 and Table 2),3.1.3 Material (round, square, or rectangular tubing),3.1.4 Method of manufacture (seamless, buttwelded, orhot-stretch-reduced electric-resistance welded),3.1.5 Size (outside diameter and nominal wall thickness fo
10、rround tubing and the outside dimensions and calculated nomi-nal wall thickness for square and rectangular tubing),3.1.6 Length (specific or random, see 8.2),3.1.7 End condition (see 9.2),3.1.8 Burr removal (see 9.2),3.1.9 Certification (see 12.1),3.1.10 Specification designation (A 618 or A 618M, i
11、nclud-ing yeardate),3.1.11 End use, and3.1.12 Special requirements.4. Process4.1 The steel shall be made by one or more of the followingprocesses: open-hearth, basic-oxygen, or electric-furnace.4.2 Steel may be cast in ingots or may be strand cast. Whensteels of different grades are sequentially str
12、and cast, identifi-cation of the resultant transition material is required. Theproducer shall remove the transition material by any estab-lished procedure that positively separates the grades.5. Manufacture5.1 The tubing shall be made by the seamless, furnace-buttwelded (continuous-welded), or hot-s
13、tretch-reducedelectric-resistance-welded process.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of SubcommitteeA01.09 on Carbon Steel Tubular Products.Current edition approved March 1, 2004. Published
14、March 2004. Originallyapproved in 1968. Last previous edition approved in 2001 as A 61801.2For 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 to the standards Document Sum
15、mary page onthe ASTM website.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.6. Chemical Composition6.1 When subjected to the heat and product analysis, respec-tively,
16、 the steel shall conform to the requirements prescribed inTable 1.6.1.1 For Grades Ia and Ib, the choice and use of alloyingelements, combined with carbon, manganese, and sulfur withinthe limits prescribed in Table 1 to give the mechanicalproperties prescribed in Table 2 and to provide the atmospher
17、iccorrosion resistance of 1.2, should be made by the manufac-turer and included and reported in the heat analysis forinformation purposes only to identify the type of steel applied.For Grades Ia and Ib material, the atmospheric corrosion-resistance index, calculated on the basis of the chemicalcompo
18、sition of the steel as described in Guide G 101, shall be6.0 or higher.NOTE 2The user is cautioned that the Guide G 101 predictiveequation for calculation of an atmospheric corrosionresistance index hasbeen verified only for the composition limits stated in that guide.6.1.2 When Grade III is require
19、d for enhanced corrosionresistance, copper limits may be specified and the minimumcontent shall be 0.20 % by heat analysis and 0.18 % by productanalysis.6.2 Heat AnalysisAn analysis of each heat of open-hearth,basic-oxygen, or electric-furnace steel shall be made by themanufacturer. This analysis sh
20、all be made from a test ingottaken during the pouring of the heat. The chemical compositionthus determined shall conform to the requirements specified inTable 1 for heat analysis.6.3 Product Analysis:6.3.1 An analysis may be made by the purchaser fromfinished tubing manufactured in accordance with t
21、his specifi-cation, or an analysis may be made from flat-rolled stock fromwhich the welded tubing is manufactured. When productanalyses are made, two sample lengths from a lot of each 500lengths, or fraction thereof, shall be selected. The specimensfor chemical analysis shall be taken from the sampl
22、e lengths inaccordance with the applicable procedures of Test Methods,Practices, and Terminology A 751. The chemical compositionthus determined shall conform to the requirements specified inTable 1 for product analysis.6.3.2 In the event the chemical composition of one of thesample lengths does not
23、conform to the requirements shown inTable 1 for product analysis, an analysis of two additionallengths selected from the same lot shall be made, each of whichshall conform to the requirements shown in Table 1 for productanalysis, or the lot is subject to rejection.7. Mechanical Requirements7.1 Tensi
24、le Properties:7.1.1 The material, as represented by the test specimen,shall conform to the requirements prescribed in Table 2.7.1.2 Elongation may be determined on a gage length ofeither 2 in. 50 mm or 8 in. 200 mm at the manufacturersoption.7.1.3 For material under516 in. 8.0 mm in thickness, adedu
25、ction from the percentage elongation of 1.25 percentagepoints in 8 in. 200 mm specified in Table 2 shall be made foreach decrease of132 in. 0.8 mm of the specified thicknessunder516 in. 8.0 mm.7.2 Bend TestThe bend test specimen shall stand beingbent cold through 180 without cracking on the outside
26、of thebent portion, to an inside diameter which shall have a relationto the thickness of the specimen as prescribed in Table 3.7.3 Number of TestsTwo tension and two bend tests, asspecified in 7.4.2, and 7.4.3, shall be made from tubingrepresenting each heat. However, if tubing from one heatdiffers
27、in the ordered nominal wall thickness, one tension testand one bend test shall be made from both the heaviest andlightest wall thicknesses processed.TABLE 1 Chemical RequirementsElementComposition, %Grade Ia Grade Ib Grade II Grade IIIHeat Product Heat Product Heat Product Heat ProductCarbon, max 0.
28、15 0.18 0.20 . . . 0.22 0.26 0.23A0.27AManganese 1.00 max 1.04 max 1.35 max 1.40 max 0.851.25 1.30 max 1.35 maxA1.40 maxAPhosphorus, max 0.15 0.16 0.025 0.035 0.025 0.035 0.025 0.035Sulfur, max 0.025 0.045 0.025 0.035 0.025 0.035 0.025 0.035Silicon, max . . . . . . . . . . . . 0.30 0.33 0.30 0.35Cop
29、per, min 0.20 0.18 0.20B0.18B0.20 0.18 . . . . . .Vanadium, min . . . . . . . . . . . . 0.02 0.01 0.02C0.01AFor each reduction of 0.01 % C below the specified carbon maximum, an increase of 0.05 % manganese above the specified maximum will be permitted up to 1.45 %for the heat analysis and up to 1.5
30、0 % for the product analysis.BIf chromium and silicon contents are each 0.50 % min, then the copper minimums do not apply.CFor Grade III, columbium may be used in conformance with the following limits: 0.005 %, min (heat) and 0.004 %, min (product).TABLE 2 Tensile RequirementsGrades la, lb, and ll G
31、rade lllWalls34 in.19.0 mmand UnderWalls over34to 112 in.19.0 to 38.0mm, inclTensile strength, min, ksi MPaA70 485 67 460 65 450Yield strength, min, ksi MPaA50 345 46 315 50 345Elongation in 2 in. or 50 mm, min, % 22 22 20Elongation in 8 in. or 200 mm, min, % 19 18 18AFor Grade II, when the material
32、 is normalized, the minimum yield strength andminimum tensile strength required shall be reduced by 5 ksi 35 MPa.TABLE 3 Bend Test RequirementsThickness of Material, in. mm Ratio of Bend Diameter toSpecimen Thickness34 19.0 and under 1Over34 to 1 19.0 to 25.0, incl 112Over 1 25.0 2A 618/A 618M 0427.
33、4 Test Specimens:7.4.1 The test specimens required by this specification shallconform to those described in the latest issue of Test Methodsand Definitions A 370.7.4.2 The tension test specimen shall be taken longitudi-nally from a section of the finished tubing, at a location at least90 from the we
34、ld in the case of welded tubing, and shall notbe flattened between gage marks. If desired, the tension testmay be made on the full section of the tubing; otherwise, alongitudinal strip test specimen shall be used as prescribed inTest Methods and Definitions A 370, Annex A2. The specimensshall have a
35、ll burrs removed and shall not contain surfaceimperfections that would interfere with the proper determina-tion of the tensile properties of the metal.7.4.3 The bend test specimen shall be taken longitudinallyfrom the tubing, and shall represent the full wall thickness ofmaterial. The sides of the b
36、end test specimen may have thecorners rounded to a maximum radius of116 in. 1.6 mm.7.5 Test Methods:7.5.1 The yield strength shall be determined in accordancewith one of the alternatives described in Test Methods andDefinitions A 370.7.5.2 The bend test shall be made on square or rectangulartubing m
37、anufactured in accordance with this specification.7.6 Retests:7.6.1 If the results of the mechanical tests representing anyheat do not conform to a requirement, as specified in 7.1 and7.2, retests may be made on additional tubing of double theoriginal number from the same heat, each of which shallco
38、nform to the requirement specified, or the tubing representedby the test is subject to rejection.7.6.2 In case of failure on retest to meet the requirements of7.1 and 7.2, the manufacturer may elect to retreat, rework, orotherwise eliminate the condition responsible for failure tomeet the specified
39、requirements. Thereafter, the material re-maining from the respective heat originally represented may betested, and shall comply with all requirements of this specifi-cation.8. Dimensions and Permissible Variations8.1 The dimensions of square, rectangular, round, andspecial shape structural tubing t
40、o be ordered under thisspecification shall be subject to prior negotiation with themanufacturer. The dimensions agreed upon shall be indicatedin the purchase order.8.2 Permissible Variations:8.2.1 Outside Dimensions:8.2.1.1 For round tubing 2 in. 50 mm and over in nominaldiameter, the outside diamet
41、er shall not vary more than 61%from the specified outside diameter. For sizes 112 in. 38 mmand under, the outside diameter shall not vary more than164 in.0.4 mm over and more than132 in. 0.8 mm under thespecified outside diameter.8.2.1.2 The specified dimensions, measured across the flatsat position
42、s at least 2 in. 50 mm from either end of square andrectangular tubing and including an allowance for convexityand concavity, shall not exceed the plus and minus toleranceshown in Table 4.8.2.2 MassThe mass of structural tubing shall not be lessthan the specified value by more than 3.5 %. The massto
43、lerance shall be determined from individual lengths or forround tubing sizes 412 in. 114 mm in outside diameter andunder and square and rectangular tubing having a periphery of14 in. 356 mm and under shall be determined from masses ofthe customary lifts produced by the mill. On round tubing sizesove
44、r 412 in. 114 mm in outside diameter and square andrectangular tubing having a periphery in excess of 14 in. 356mm the mass tolerance is applicable to the individual length.8.2.3 LengthStructural tubing is commonly produced inrandom mill lengths of 16 to 22 ft 4.9 to 6.7 m or 32 to 44 ft9.8 to 13.4
45、m, in multiple lengths, and in definite cut lengths(Section 3). When cut lengths are specified for structuraltubing, the length tolerances shall be in accordance with Table5.8.2.4 StraightnessThe permissible variation for straight-ness of structural tubing shall be18 in. times the number of feetof t
46、otal length divided by 5 2 mm times length in metres).8.2.5 Squareness of SidesFor square or rectangular struc-tural tubing, adjacent sides may deviate from 90 by atolerance of 62, maximum.8.2.6 Radius of CornersFor square or rectangular struc-tural tubing, the radius of any outside corner of the se
47、ctionshall not exceed three times the specified wall thickness.8.2.7 Twist:8.2.7.1 The tolerance for twist, or variation with respect toaxial alignment of the section for square, rectangular, or specialshape structural tubing, shall be as prescribed in Table 6.8.2.7.2 Twist is measured by holding do
48、wn one end of asquare or rectangular tube on a flat surface plate with thebottom side of the tube parallel to the surface plate, and notingthe height that either corner at the opposite end of the bottomside of the tube extends above the surface plate. The differencein the height of the corners shall
49、 not exceed the values in Table6.9. Workmanship, Finish, and Appearance9.1 The structural tubing shall be free of defects and shallhave a commercially smooth finish.9.1.1 Surface imperfections shall be classed as defects whentheir depth exceeds 15 % of the specified wall thickness andwhen the imperfections materially affected the appearance ofTABLE 4 Outside Dimension Tolerances for Square,Rectangular, and Special Shape Structural TubingLargest Outside Dimension Across Flats,in. mmTol
