ASTM A767 A767M-2009(2015) Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement《混凝土钢筋用镀锌钢棒的标准规格》.pdf

1、Designation: A767/A767M 09 (Reapproved 2015)Standard Specification forZinc-Coated (Galvanized) Steel Bars for ConcreteReinforcement1This standard is issued under the fixed designation A767/A767M; the number immediately following the designation indicates the yearof original adoption or, in the case

2、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. Scope1.1 This sp

3、ecification covers steel reinforcing bars withprotective zinc coatings applied by dipping the properlyprepared reinforcing bars into a molten bath of zinc.1.2 This specification is applicable for orders in eitherinch-pound units (as Specification A767) or SI units (asSpecification A767M).1.3 The val

4、ues stated in either SI or inch-pound units are tobe regarded as standard. Within the text, the inch-pound unitsare shown in brackets. The values stated in each system are notexact equivalents. Therefore, each system must be used inde-pendently of the other. Combining values from the two systemsmay

5、result in nonconformance with this specification.2. Referenced Documents2.1 ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementA706/A706M

6、 Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete ReinforcementA780/A780M Practice for Repair of Damaged and UncoatedAreas of Hot-Dip Galvanized CoatingsA996/A996M Specification for Rail-Steel and Axle-SteelDeformed Bars for Concrete ReinforcementB6 Specification for ZincB487 T

7、est Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionE376 Practice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) Test-ing Methods2.2 ACI Specification:3ACI 301 Specifications for Structural Concrete3. Ordering

8、 Information3.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered to thisspecification. Such requirements shall include, but are notlimited to, the following:3.1.1 Quantity of bars,3.1.2 Size of bars,3.1.3 Reinforcing bar specification

9、 (ASTM designation andyear of issue) and grade,3.1.4 Class of coating,3.1.5 Galvanization before or after fabrication, andNOTE 1A typical ordering description is as follows: Deformed Grade420 bars to ASTM A615M-_; 1600 m, No. 19, 8 m long in securedlifts; zinc-coated (galvanized) to ASTM A767M-_; in

10、cluding Class 1coating, and galvanization after fabrication.Deformed Grade 60 bars to ASTM A615-_; 4000 linear ft, No. 6,20 ft, 0 in. long in secured lifts; zinc-coated (galvanized) to ASTMA767-_, including Class 1 coating, and galvanization after fabrica-tion.4. Galvanizing4.1 Handling:4.1.1 The ga

11、lvanizer shall be permitted to subject the newlycoated steel reinforcing bars to air or steam wiping to removeexcess zinc from the bars. After the wiping, the coated steelreinforcing bars shall meet the minimum coating massweight.NOTE 2During the wiping process, care should be taken to maintaina uni

12、formly thick coating around the perimeter of the bar.4.1.2 It shall be the responsibility of the galvanizer tomaintain identity of the reinforcing bars throughout the galva-nizing process and to the point of shipment.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainl

13、ess Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Nov. 15, 2015. Published November 2015. Originallyapproved in 1979. Last previous edition approved in 2009 as A767/A767M 09.DOI: 10.1520/A0767_A0767M-09R15.2For referen

14、ced 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.3Available from American Concrete Institute (ACI), P.O. Box 9094, Farming

15、tonHills, MI 48333-9094, http:/www.concrete.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Mass Weight of Coating and Test:4.2.1 This specification includes two classes of coatingmass weight. The mass weight of zinc coating b

16、ased onactual area of the bar shall conform to the requirements shownin Table 1.NOTE 3The nominal diameter of a deformed bar is equivalent to thatof a plain round bar having the same mass per metre weight per foot asthe deformed bar. Coating mass weight shown in is based on an assumedarea ratio of 1

17、.2:1 (actual to nominal surface area of the steel reinforcingbar).4.2.2 Magnetic Thickness MeasurementsThe massweight of the coating shall be determined by magneticthickness gage measurements in accordance with PracticeE376. The thickness measurement is used to calculate the massweight by multiplyin

18、g it by the surface area of coated bar andby the zinc density. One or more of the following methods shallbe permitted to be used to referee the results obtained bymagnetic thickness measurements.4.2.2.1 Stripping MethodThe mass weight shall be de-termined by stripping the coating from the steel rein

19、forcing barsection in accordance with Test Method A90/A90M.NOTE 4This is a destructive test appropriate for small samples of aminimum of 2000 mm23 in.2 of surface area. It does note include themass weight of iron reacted with the zinc coating and may overestimatecoating mass weight by up to 10 %.4.2

20、.2.2 Weighing Before and After GalvanizingThe massweight shall be determined by weighing steel reinforcing barsbefore and after galvanizing. The difference between the twomeasurements divided by the surface area of the bars providesthe mass weight. The original weighing shall occur afterpickling and

21、 drying. The second weighing shall occur aftercooling to ambient temperature.4.2.2.3 MicroscopyThe mass weight shall be determinedby cross-sectional and optical measurement in accordance withTest Method B487. A cross-section sample of the steel shall bepolished and examined with an optical microscop

22、e to deter-mine the coating thickness. The coating mass weight shall bedetermined by multiplying coating thickness by the surfacearea of the coated sample and by the density of zinc.4.2.3 Number of TestsFor determination of the coatingmass weight, three random samples shall be tested from eachlot. F

23、or each magnetic thickness measurement sample, five ormore measurements shall be made at various points throughoutthe sample so as to represent the entire surface of the sample.A total of at least fifteen measurements shall be averaged toobtain the coating thickness. For the microscopy method, fives

24、amples shall be tested per lot. Each sample shall be measuredon four sides and the total of twenty measurements shall beaveraged to obtain the coating thickness. For the strippingmethod and the weighing method, three samples per lot shallbe measured.NOTE 5A lot shall be as follows: All bars of one s

25、ize furnished to thesame steel reinforcing bar specification that have been galvanized withina single production shift.4.2.4 RetestsIf the average zinc coating mass weightfails to meet the requirements of Table 1, six additional randomsamples from the lot shall be permitted to be tested. If theavera

26、ge zinc coating mass weight of the six samples con-forms to the requirements of Table 1, the lot shall be accepted.4.3 ChromatingThe galvanized coating shall be chromatetreated. This is to preclude a reaction between the bars andfresh portland cement paste. Proprietary chromating solutionsof equival

27、ent strength are permitted in place of the genericchemical treatment specified.4.3.1 If the chromate treatment is performed immediatelyafter galvanizing, it may be accomplished by quenching thesteel reinforcing bars in a solution containing at least 0.2 massweight % of sodium dichromate in water (su

28、ch as 2kg/m33oz of each 10 gal of quench water) or by quench chromatingin a minimum of 0.2 % chromic acid solution. The solutionshall be at least 32C 90F. The galvanized reinforcing barsshall be immersed in the solution for at least 20 s.4.3.2 If the galvanized reinforcing bars are at ambienttempera

29、ture, the chromate treatment shall be the same asspecified in except that 0.5 to 1.0 % concentration of sulfuricacid shall be added as an activator of the chromate solution. Inthis case, there is no temperature requirement for the activatedchromate solution.5. General Requirements5.1 The steel reinf

30、orcing bars shall conform to one of thefollowing specifications: A615M, A706M, or A996M A615,A706, or A996.5.2 The zinc used for coating shall be any grade thatconforms to Specification B6.6. Finish and Adherence of Coating6.1 The zinc coating shall have no bare spots. The coatingshall be free of bl

31、isters, flux spots or inclusions, dross, and acidor black spots. Bars that stick together after galvanizing shallbe rejected. In addition, the presence of tears or sharp spikeswhich make the bar hazardous to handle shall be cause forrejection. A matte gray finish appearance shall not be itself acaus

32、e for rejection.NOTE 6Specific concentrations of elements such as silicon, carbon,and phosphorus in steel tend to accelerate the growth of the zinc-iron alloylayer so that the galvanized coating may have a matte finish with little orno free zinc outer layer. The mass, shape, and amount of cold worki

33、ng ofthe bar being galvanized may also affect this condition.6.2 The coating shall be adherent so it cannot be removedby any reasonable process of handling or erection.TABLE 1 Mass Weight of Zinc CoatingCoating ClassMass Weight of ZincCoating,min, g/m2oz ft2 of SurfaceClass IBar Designation Size No.

34、 10 3 915 3.00Bar Designation Size No. 13 4 and Larger 1070 3.50Class IIBar Designation Size No. 10 3 and Larger 610 2.00A767/A767M 09 (2015)27. Fabrication7.1 Before Galvanizing:7.1.1 Steel reinforcing bars that are bent cold prior togalvanizing shall be fabricated to a bend diameter equal to orgre

35、ater than those specified in Table 2.7.1.2 Steel reinforcing bars shall be permitted to be coldbent to tighter diameters than specified in (limited to the extentthat the appropriate reinforcing bar specification allows) ifstress relieved at a temperature from 480 to 560C 900 to1050F for 1 h per 25 m

36、m 1 in. of bar diameter.7.2 After Galvanizing:7.2.1 When galvanizing is performed before bending, somecracking and flaking of the galvanized coating in the area of thebend shall not be cause for rejection (Note 7).7.2.2 Damage to the coating as a result of fabrication shallbe repaired in accordance

37、with Section 9.NOTE 7The tendency for cracking of the zinc coating increases withbar diameter and with severity and rate of bending.8. Inspection8.1 The inspector representing the purchaser shall haveaccess at all times, while work on the contract of the purchaseris being performed, to those areas o

38、f the galvanizers plantwhich concern the manufacture of the material ordered. Thegalvanizer shall afford the inspector all reasonable facilities tosatisfy him that the coating is being furnished in accordancewith this specification.8.2 The material shall be inspected at the galvanizers plantprior to

39、 shipment. However, if specified, the purchaser shallmake the tests which govern the acceptance or rejection of thematerials in his own laboratory or elsewhere.8.3 Visual inspection of materials ready for shipment shallbe made to determine conformity with the requirements of 6.1.For materials that f

40、ail inspection, it shall be permissible for thematerials to be stripped and regalvanized and resubmitted forinspection. They shall conform to the requirements of thisspecification.9. Permissible Amount of Damaged Coating and Repairof Damaged Coating9.1 The maximum amount of repaired damaged coatings

41、hall not exceed 1 % of the total surface area in each 0.3-m1-ft length of the bar. This limit on repaired damaged coatingshall not include sheared or cut ends that are repaired with azinc-rich formulation in accordance with Practice A780/A780M (see 9.3).9.2 All damaged coating due to fabrication and

42、 handling, tothe point of shipment to the job-site, shall be repaired with azinc-rich formulation in accordance with Practice A780/A780M.9.3 When coated bars are sheared, saw-cut, or cut by othermeans during the fabrication process, the cut ends shall becoated with a zinc-rich formulation in accorda

43、nce with PracticeA780/A780M.10. Certification10.1 Upon request of the purchaser in the contract or order,the galvanizers certification that the material was manufac-tured and tested in accordance with this specification, togetherwith the report of the tests results, shall be furnished at the timeof

44、shipment.10.2 When Specification A615/A615M steel is supplied, asilicon analysis shall be provided.10.3 A material test report, certificate of inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beregarded as having the s

45、ame validity as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument must meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstanding theabsence of a signature, the orga

46、nization submitting the EDItransmission is responsible for the content of the report.NOTE 8The industry definition as invoked here is: EDI is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.11. Keywords11.1 corrosion resistance; galvanizing; steel re

47、inforcingbars; zinc-coatedTABLE 2 Minimum Finished Bend DiametersBar No. Grade 28040Grade 35050Grade 42060Grade 5207510,13,16 3,4,5 6dA6 d 6 d .19 6 6d 6d 6d 6d22,25 7,8 6d 8d 8d 8d29,32 9,10 . . . . . . 8d 8d3611 . . 8d 8d43,57 14,18 . . . . . . 10d 10dAd = nominal diameter of the bar.A767/A767M 09

48、 (2015)3APPENDIXES(Nonmandatory Information)X1. GUIDELINES FOR JOB-SITE PRACTICESX1.1 Specification A767/A767M is a product standard.Requirements for zinc-coated (galvanized) steel reinforcingbars from the point of shipment to the job-site and subsequentpractices at the job-site are not delineated i

49、n this productstandard.X1.2 The American Concrete Institute promulgates “Speci-fications for Structural Concrete ACI 301.” SpecificationsACI 301 is intended to be used in its entirety in the projectspecifications. An architect-engineer may cite Standard Speci-fications ACI 301 in the project specifications for any cast-in-place concrete construction project. Standard SpecificationsACI 301 include provisions for zinc-coated (galvanized) steelreinforcing