1、Designation: A618/A618M 04 (Reapproved 2015)Standard Specification forHot-Formed Welded and Seamless High-Strength Low-AlloyStructural Tubing1This standard is issued under the fixed designation A618/A618M; the number immediately following the designation indicates the yearof original adoption or, in
2、 the case 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1
3、.1 This specification 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 weldedconstruct
4、ion, the welding procedure shall be suitable for thesteel and the 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 (No
5、te 1). When properlyexposed 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 Gui
6、de G101 or actual data.1.3 The values stated in either SI units 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 oth
7、er. Combining valuesfrom the two systems may result in non-conformance with thestandard.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA700 Guide for Packaging, Marking, and Loading Methodsfor Steel Products for ShipmentA751 Test M
8、ethods, Practices, and Terminology for Chemi-cal Analysis of Steel ProductsG101 Guide for Estimating the Atmospheric Corrosion Re-sistance of Low-Alloy Steels3. Ordering Information3.1 Orders for material under this specification shouldinclude the following as required to describe the materialadequa
9、tely: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 thicknes
10、s forround 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 (A618 or A618M,
11、 includ-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 s
12、trand 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
13、-stretch-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 Sept. 1, 2015. Published
14、 September 2015. Originallyapproved in 1968. Last previous edition approved in 2010 as A618/A618M04(2010). DOI: 10.1520/A0618_A0618M-04R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
15、 information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Chemical Composition6.1 When subjected to the heat and product analysis,respectively, the steel shall con
16、form to the requirementsprescribed in Table 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 atmosphericcorrosion resistan
17、ce 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 chemicalcomposition of the steel
18、as described in Guide G101, shall be6.0 or higher.NOTE 2The user is cautioned that the Guide G101 predictive equationfor calculation of an atmospheric corrosionresistance index has beenverified only for the composition limits stated in that guide.6.1.2 When Grade III is required for enhanced corrosi
19、onresistance, 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 shall be made from a tes
20、t 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 thisspecification, or a
21、n analysis may be made from flat-rolled stockfrom which 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 sample lengths inaccordance w
22、ith the applicable procedures of Test Methods,Practices, and Terminology A751. 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 conform to the requiremen
23、ts 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 Tensile Properties:7.1.1 The m
24、aterial, 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, adeduction from the percentage
25、 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 of thebent portion, to an
26、 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 tubingTABLE 1 Chemical RequirementsElementComposition, %Grade Ia Grade Ib Grade II Grade IIIHea
27、t Product Heat Product Heat Product Heat ProductCarbon, max 0.15 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.
28、035Silicon, max . . . . . . . . . . . . 0.30 0.33 0.30 0.35Copper, 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 wil
29、l be permitted up to 1.45 %for the heat analysis and up to 1.50 % 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
30、 (product).TABLE 2 Tensile RequirementsGrades la, lb, and ll Grade 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
31、in. or 200 mm, min, % 19 18 18AFor Grade II, when the material 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 1Ove
32、r34 to 1 19.0 to 25.0, incl 112Over 1 25.0 2A618/A618M 04 (2015)2representing each heat. However, if tubing from one heatdiffers in the ordered nominal wall thickness, one tension testand one bend test shall be made from both the heaviest andlightest wall thicknesses processed.7.4 Test Specimens:7.4
33、.1 The test specimens required by this specification shallconform to those described in the latest issue of Test Methodsand Definitions A370.7.4.2 The tension test specimen shall be taken longitudi-nally from a section of the finished tubing, at a location at least90 from the weld in the case of wel
34、ded 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 A370, Annex A2. The specimensshall have all burrs removed and s
35、hall 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 bend test specimen may
36、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 A370.7.5.2 The bend test shall be made on square or rectangulartubing manufactured in accordan
37、ce 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 shallconform to the requiremen
38、t 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 requirements. Thereafte
39、r, 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 to be ordered under this
40、specification 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 diameter shall not vary more
41、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 positions at least 2 in. 50 mm
42、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 masstolerance shall be determ
43、ined 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 sizesover 412 in. 114 mm in out
44、side 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 m, in multiple lengths,
45、 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 total length divided by
46、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 sectionshall not exceed t
47、hree 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 down one end of asquare o
48、r 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 not exceed the values
49、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 ofthe structural member, or when their length (measured in aTABLE 4 Outside Dimension Tolerances for Square, Rectangular,and Special Shape Structural TubingLargest Outsid
