ASTM A767/A767M-09(2015)
(Specification)Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement
Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement
ABSTRACT
This specification covers steel reinforcing bars with protective zinc coatings applied by dipping the properly prepared reinforcing bars into a molten bath of zinc. Galvanization shall be used to prepare reinforcing bars. The galvanizer shall be permitted to subject the newly coated steel reinforcing bars to air or steam wiping to remove excess zinc from the bars. The mass of zinc coating shall conform to specified requirements. The mass of the coating shall be determined by magnetic thickness gage measurements. Stripping method, weighing before and after galvanizing, and microscopy method shall be used to referee the results obtained by magnetic thickness measurements. A retest shall be provided if the average zinc coating mass fails to meet the requirements. The galvanized coating shall be chromate treated.
SCOPE
1.1 This specification covers steel reinforcing bars with protective zinc coatings applied by dipping the properly prepared reinforcing bars into a molten bath of zinc.
1.2 This specification is applicable for orders in either inch-pound units (as Specification A767) or SI units (as Specification A767M).
1.3 The values stated in either SI or inch-pound units are to be regarded as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents. Therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this specification.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A767/A767M −09(Reapproved 2015)
Standard Specification for
Zinc-Coated (Galvanized) Steel Bars for Concrete
Reinforcement
This standard is issued under the fixed designationA767/A767M; the number immediately following the designation indicates the year
of original adoption or, in 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. Scope E376 Practice for Measuring Coating Thickness by
Magnetic-Field or Eddy-Current (Electromagnetic) Test-
1.1 This specification covers steel reinforcing bars with
ing Methods
protective zinc coatings applied by dipping the properly
2.2 ACI Specification:
prepared reinforcing bars into a molten bath of zinc.
ACI 301 Specifications for Structural Concrete
1.2 This specification is applicable for orders in either
inch-pound units (as Specification A767) or SI units (as
3. Ordering Information
Specification A767M).
3.1 It shall be the responsibility of the purchaser to specify
1.3 The values stated in either SI or inch-pound units are to
all requirements that are necessary for material ordered to this
be regarded as standard. Within the text, the inch-pound units
specification. Such requirements shall include, but are not
are shown in brackets.The values stated in each system are not
limited to, the following:
exact equivalents. Therefore, each system must be used inde-
3.1.1 Quantity of bars,
pendentlyoftheother.Combiningvaluesfromthetwosystems
3.1.2 Size of bars,
may result in nonconformance with this specification.
3.1.3 Reinforcing bar specification (ASTM designation and
year of issue) and grade,
2. Referenced Documents
3.1.4 Class of coating,
3.1.5 Galvanization before or after fabrication, and
2.1 ASTM Standards:
A90/A90M Test Method for Weight [Mass] of Coating on
NOTE 1—Atypical ordering description is as follows: Deformed Grade
Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
420 bars to ASTM A615M-____; 1600 m, No. 19, 8 m long in secured
A615/A615M SpecificationforDeformedandPlainCarbon- lifts; zinc-coated (galvanized) to ASTM A767M-____; including Class 1
coating, and galvanization after fabrication.
Steel Bars for Concrete Reinforcement
[Deformed Grade 60 bars to ASTM A615-____; 4000 linear ft, No. 6,
A706/A706M Specification for Deformed and Plain Low-
20 ft, 0 in. long in secured lifts; zinc-coated (galvanized) to ASTM
Alloy Steel Bars for Concrete Reinforcement
A767-____, including Class 1 coating, and galvanization after fabrica-
A780/A780M PracticeforRepairofDamagedandUncoated
tion.]
Areas of Hot-Dip Galvanized Coatings
4. Galvanizing
A996/A996M Specification for Rail-Steel and Axle-Steel
Deformed Bars for Concrete Reinforcement
4.1 Handling:
B6 Specification for Zinc
4.1.1 The galvanizer shall be permitted to subject the newly
B487 Test Method for Measurement of Metal and Oxide
coated steel reinforcing bars to air or steam wiping to remove
Coating Thickness by Microscopical Examination of
excess zinc from the bars. After the wiping, the coated steel
Cross Section
reinforcing bars shall meet the minimum coating mass
[weight].
NOTE 2—During the wiping process, care should be taken to maintain
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
a uniformly thick coating around the perimeter of the bar.
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.05 on Steel Reinforcement. 4.1.2 It shall be the responsibility of the galvanizer to
Current edition approved Nov. 15, 2015. Published November 2015. Originally
maintain identity of the reinforcing bars throughout the galva-
approved in 1979. Last previous edition approved in 2009 as A767/A767M – 09.
nizing process and to the point of shipment.
DOI: 10.1520/A0767_A0767M-09R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
the ASTM website. Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A767/A767M − 09 (2015)
4.2 Mass [Weight] of Coating and Test: samples shall be tested per lot. Each sample shall be measured
4.2.1 This specification includes two classes of coating on four sides and the total of twenty measurements shall be
mass [weight]. The mass [weight] of zinc coating based on averaged to obtain the coating thickness. For the stripping
actual area of the bar shall conform to the requirements shown method and the weighing method, three samples per lot shall
in Table 1. be measured.
NOTE 3—The nominal diameter of a deformed bar is equivalent to that NOTE 5—Alot shall be as follows:All bars of one size furnished to the
of a plain round bar having the same mass per metre [weight per foot] as same steel reinforcing bar specification that have been galvanized within
thedeformedbar.Coatingmass[weight]showninisbasedonanassumed a single production shift.
area ratio of 1.2:1 (actual to nominal surface area of the steel reinforcing
4.2.4 Retests—If the average zinc coating mass [weight]
bar).
failstomeettherequirementsofTable1,sixadditionalrandom
4.2.2 Magnetic Thickness Measurements—The mass
samples from the lot shall be permitted to be tested. If the
[weight] of the coating shall be determined by magnetic
average zinc coating mass [weight] of the six samples con-
thickness gage measurements in accordance with Practice
forms to the requirements of Table 1, the lot shall be accepted.
E376.The thickness measurement is used to calculate the mass
4.3 Chromating—The galvanized coating shall be chromate
[weight] by multiplying it by the surface area of coated bar and
treated. This is to preclude a reaction between the bars and
bythezincdensity.Oneormoreofthefollowingmethodsshall
fresh portland cement paste. Proprietary chromating solutions
be permitted to be used to referee the results obtained by
of equivalent strength are permitted in place of the generic
magnetic thickness measurements.
chemical treatment specified.
4.2.2.1 Stripping Method—The mass [weight] shall be de-
4.3.1 If the chromate treatment is performed immediately
termined by stripping the coating from the steel reinforcing bar
after galvanizing, it may be accomplished by quenching the
section in accordance with Test Method A90/A90M.
steel reinforcing bars in a solution containing at least 0.2 mass
NOTE 4—This is a destructive test appropriate for small samples of a
[weight] % of sodium dichromate in water (such as 2kg/m [3
2 2
minimum of 2000 mm [3 in. ] of surface area. It does note include the
oz of each 10 gal] of quench water) or by quench chromating
mass [weight] of iron reacted with the zinc coating and may overestimate
in a minimum of 0.2 % chromic acid solution. The solution
coating mass [weight] by up to 10 %.
shall be at least 32°C [90°F]. The galvanized reinforcing bars
4.2.2.2 Weighing Before and After Galvanizing—The mass
shall be immersed in the solution for at least 20 s.
[weight]shallbedeterminedbyweighingsteelreinforcingbars
4.3.2 If the galvanized reinforcing bars are at ambient
before and after galvanizing. The difference between the two
temperature, the chromate treatment shall be the same as
measurements divided by the surface area of the bars provides
specified in except that 0.5 to 1.0 % concentration of sulfuric
the mass [weight]. The original weighing shall occur after
acid shall be added as an activator of the chromate solution. In
pickling and drying. The second weighing shall occur after
this case, there is no temperature requirement for the activated
cooling to ambient temperature.
chromate solution.
4.2.2.3 Microscopy—Themass[weight]shallbedetermined
by cross-sectional and optical measurement in accordance with
5. General Requirements
Test Method B487.Across-section sample of the steel shall be
5.1 The steel reinforcing bars shall conform to one of the
polished and examined with an optical microscope to deter-
following specifications: A615M, A706M, or A996M [A615,
mine the coating thickness. The coating mass [weight] shall be
A706, or A996].
determined by multiplying coating thickness by the surface
area of the coated sample and by the density of zinc. 5.2 The zinc used for coating shall be any grade that
4.2.3 Number of Tests—For determination of the coating conforms to Specification B6.
mass [weight], three random samples shall be tested from each
6. Finish and Adherence of Coating
lot. For each magnetic thickness measurement sample, five or
more measurements shall be made at various points throughout
6.1 The zinc coating shall have no bare spots. The coating
the sample so as to represent the entire surface of the sample.
shallbefreeofblisters,fluxspotsorinclusions,dross,andacid
A total of at least fifteen measurements shall be averaged to
or black spots. Bars that stick together after galvanizing shall
obtain the coating thickness. For the microscopy method, five
be rejected. In addition, the presence of tears or sharp spikes
which make the bar hazardous to handle shall be cause for
TABLE 1 Mass [Weight] of Zinc Coating
rejection. A matte gray finish appearance shall not be itself a
Mass [Weight] of Zinc cause for rejection.
Coating,
2 2
NOTE 6—Specific concentrations of elements such as silicon, carbon,
min, g/m [oz ⁄ft ] of Surface
Coating Class andphosphorusinsteeltendtoacceleratethegrowthofthezinc-ironalloy
layer so that the galvanized coating may have a matte finish with little or
Class I
no free zinc outer layer. The mass, shape, and amount of cold working of
Bar Designation Size No. 10 [3] 915 [3.00]
Bar Designation Size No. 13 [4] and Larger 1070 [3.50] the bar being galvanized may also affect this condition.
Cl
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A767/A767M − 09 A767/A767M − 09 (Reapproved 2015)
Standard Specification for
Zinc-Coated (Galvanized) Steel Bars for Concrete
Reinforcement
This standard is issued under the fixed designation A767/A767M; the number immediately following the designation indicates the year
of original adoption or, in 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. Scope*Scope
1.1 This specification covers steel reinforcing bars with protective zinc coatings applied by dipping the properly prepared
reinforcing bars into a molten bath of zinc.
1.2 This specification is applicable for orders in either inch-pound units (as Specification A767) or SI units (as Specification
A767M).
1.3 The values stated in either SI or inch-pound units are to be regarded as standard. Within the text, the inch-pound units are
shown in brackets. The values stated in each system are not exact equivalents. Therefore, each system must be used independently
of the other. Combining values from the two systems may result in nonconformance with this specification.
2. Referenced Documents
2.1 ASTM Standards:
A90/A90M Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
A706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
A780/A780M Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings
A996/A996M Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
B6 Specification for Zinc
B487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
E376 Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing Methods
2.2 ACI Specification:
ACI 301 Specifications for Structural Concrete
3. Ordering Information
3.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for material ordered to this
specification. Such requirements shall include, but are not limited to, the following:
3.1.1 Quantity of bars,
3.1.2 Size of bars,
3.1.3 Reinforcing bar specification (ASTM designation and year of issue) and grade,
3.1.4 Class of coating,
3.1.5 Galvanization before or after fabrication, and
NOTE 1—A typical ordering description is as follows: Deformed Grade 420 bars to ASTM A615M-____; 1600 m, No. 19, 8 m long in secured lifts;
zinc-coated (galvanized) to ASTM A767M-____; including Class 1 coating, 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 ASTM A767-____,
including Class 1 coating, and galvanization after fabrication.]
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.05
on Steel Reinforcement.
Current edition approved July 1, 2009Nov. 15, 2015. Published August 2009November 2015. Originally approved in 1979. Last previous edition approved in 20052009
as A767/A767M – 05.A767/A767M – 09. DOI: 10.1520/A0767_A0767M-09.10.1520/A0767_A0767M-09R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.concrete.org.
*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
A767/A767M − 09 (2015)
4. Galvanizing
4.1 Handling:
4.1.1 The galvanizer shall be permitted to subject the newly coated steel reinforcing bars to air or steam wiping to remove
excess zinc from the bars. After the wiping, the coated steel reinforcing bars shall meet the minimum coating mass [weight].
NOTE 2—During the wiping process, care should be taken to maintain a uniformly thick coating around the perimeter of the bar.
4.1.2 It shall be the responsibility of the galvanizer to maintain identity of the reinforcing bars throughout the galvanizing
process and to the point of shipment.
4.2 Mass [Weight] of Coating and Test:
4.2.1 This specification includes two classes of coating mass [weight]. The mass [weight] of zinc coating based on actual area
of the bar shall conform to the requirements shown in Table 1.
NOTE 3—The nominal diameter of a deformed bar is equivalent to that of a plain round bar having the same mass per metre [weight per foot] as the
deformed bar. Coating mass [weight] shown in is based on an assumed area ratio of 1.2:1 (actual to nominal surface area of the steel reinforcing bar).
4.2.2 Magnetic Thickness Measurements—The mass [weight] of the coating shall be determined by magnetic thickness gage
measurements in accordance with Practice E376. The thickness measurement is used to calculate the mass [weight] by multiplying
it by the surface area of coated bar and by the zinc density. One or more of the following methods shall be permitted to be used
to referee the results obtained by magnetic thickness measurements.
4.2.2.1 Stripping Method—The mass [weight] shall be determined by stripping the coating from the steel reinforcing bar section
in accordance with Test Method A90/A90M.
2 2
NOTE 4—This is a destructive test appropriate for small samples of a minimum of 2000 mm [3 in. ] of surface area. It does note include the mass
[weight] of iron reacted with the zinc coating and may overestimate coating mass [weight] by up to 10 %.
4.2.2.2 Weighing Before and After Galvanizing—The mass [weight] shall be determined by weighing steel reinforcing bars
before and after galvanizing. The difference between the two measurements divided by the surface area of the bars provides the
mass [weight]. The original weighing shall occur after pickling and drying. The second weighing shall occur after cooling to
ambient temperature.
4.2.2.3 Microscopy—The mass [weight] shall be determined by cross-sectional and optical measurement in accordance with
Test Method B487. A cross-section sample of the steel shall be polished and examined with an optical microscope to determine
the coating thickness. The coating mass [weight] shall be determined by multiplying coating thickness by the surface area of the
coated sample and by the density of zinc.
4.2.3 Number of Tests—For determination of the coating mass [weight], three random samples shall be tested from each lot. For
each magnetic thickness measurement sample, five or more measurements shall be made at various points throughout the sample
so as to represent the entire surface of the sample. A total of at least fifteen measurements shall be averaged to obtain the coating
thickness. For the microscopy method, five samples shall be tested per lot. Each sample shall be measured on four sides and the
total of twenty measurements shall be averaged to obtain the coating thickness. For the stripping method and the weighing method,
three samples per lot shall be measured.
NOTE 5—A lot shall be as follows: All bars of one size furnished to the same steel reinforcing bar specification that have been galvanized within a single
production shift.
4.2.4 Retests—If the average zinc coating mass [weight] fails to meet the requirements of Table 1, six additional random
samples from the lot shall be permitted to be tested. If the average zinc coating mass [weight] of the six samples conforms to the
requirements of Table 1, the lot shall be accepted.
4.3 Chromating—The galvanized coating shall be chromate treated. This is to preclude a reaction between the bars and fresh
portland cement paste. Proprietary chromating solutions of equivalent strength are permitted in place of the generic chemical
treatment specified.
4.3.1 If the chromate treatment is performed immediately after galvanizing, it may be accomplished by quenching the steel
reinforcing bars in a solution containing at least 0.2 mass [weight] % of sodium dichromate in water (such as 2kg/m [3 oz of each
TABLE 1 Mass [Weight] of Zinc Coating
Mass [Weight] of Zinc
Coating,
2 2
min, g/m [oz ⁄ ft ] of Surface
Coating Class
Class I
Bar Designation Size No. 10 [3] 915 [3.00]
Bar Designation Size No. 13 [4] and Larger 1070 [3.50]
Class II
Bar Designation Size No. 10 [3] and Larger 610 [2.00]
A767/A767M − 09 (2015)
10 gal] of quench water) or by quench chromating in a minimum of 0.2 % chromic acid solution. The solution shall be at least
32°C [90°F]. The galvanized reinforcing bars shall be immersed in the solution for at least 20 s.
4.3.2 If the galvanized reinforcing bars are at ambient temperature, the chromate treatment shall be the same as specified in
except that 0.5 to 1.0 % concentration of sulfuric acid shall be added as an activator of the chromate solution. In this case, there
is no temperature requirement for the activated chromate solution.
5. General Requirements
5.1 The steel reinforcing bars shall conform to one of the following specifications: A615M, A706M, or A996M [A615, A706,
or A996].
5.2 The zinc used for coating shall be any grade that conforms to Specification B6.
6. Finish and Adherence of Coating
6.1 The zinc coating shall have no bare spots. The coating shall be free of blisters, flux spots or inclusions, dross, and acid or
black spots. Bars that stick together after galvanizing shall be rejected. In addition, the presence of tears or sharp spikes which
make the bar hazardous to handle shall be cause for rejection. A matte gray finish appearance shall not be itself a cause for rejection.
NOTE 6—Specific concentrations of elements such as silicon, carbon, and phosphorus in steel tend to accelerate the growth of the zinc-iron alloy layer
so that the galvanize
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.