ASTM G92 - 20 (2025) 大气测试场地表征的标准实践

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Designation: G92 −20 (Reapproved 2025)
Standard Practice for
Characterization of Atmospheric Test Sites
1
This standard is issued under the ﬁxed designation G92; 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.
1. Scope
1.1 This practice covers procedures for the characterization
of atmospheric test sites. Continuous characterization can
provide corrosion data, environmental data, or both which will
signal changes in corrosivity of the atmospheric environment.
This practice can also provide guidance for classiﬁcation of
future test sites.
1.2 Two methods are deﬁned in this practice for the char-
acterization of atmospheric test sites. The methods are identi-
ﬁed as characterization Methods A and B. The preferred
characterization technique would require using both Method A
and B for concurrent data collection.
1.2.1 Method A is to be used when atmospheric corrosion is
monitored on a continuing basis at a test site using speciﬁed
materials and exposure conﬁgurations.
1.2.2 Method B is speciﬁed when atmospheric factors are
monitored on a continuing basis.
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
standard.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
A36/A36M Speciﬁcation for Carbon Structural Steel
B6 Speciﬁcation for Zinc
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
sion Test Specimens
G50 Practice for Conducting Atmospheric Corrosion Tests
on Metals
G84 Practice for Measurement of Time-of-Wetness on Sur-
faces Exposed to Wetting Conditions as in Atmospheric
Corrosion Testing
G91 Practice for Monitoring Atmospheric SO
2
Deposition
Rate for Atmospheric Corrosivity Evaluation
3. Summary of Methods
3.1 Characterization Method A is to be used when atmo-
spheric corrosion data are to be obtained.
3.1.1 Corrosion tests to measure the corrosivity of the test
site should follow the procedure established by Practice G50.
Additional special instructions are identiﬁed in this procedure
relating to types of materials for corrosion characterization
tests, time of test exposure, positioning of test specimens,
removal of test specimens and proper identiﬁcation, cleaning
practices, and reporting of data.
3.2 Characterization Method B is to be used when atmo-
spheric climatological factors inﬂuencing the corrosion of
metals are to be monitored.
3.2.1 Several atmospheric factors which have been identi-
ﬁed as having signiﬁcant bearing on the corrosion of metals
include, but are not limited to, sulfur dioxide, chlorides,
temperature, humidity, precipitation, time of wetness, and
atmospheric particulate matter.
3.3 The preferred technique utilizes both Methods A and B
for concurrent data to be collected.
3.3.1 Should either Method A or B be singled out as the
primary technique to be used on a continuing basis, both
should be used at some point in time to establish a data base.
The availability of computerized weather stations greatly
facilitates the collection of reliable atmospheric data.
4. Signiﬁcance and Use
4.1 This practice gives suggested procedures for character-
ization of atmospheric test sites. It can be useful to researchers,
manufacturers, engineering ﬁrms, architects, and construction
contractors to provide corrosion and environmental data, ma-
terials selection information, and a materials storage practice.
1
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
of Metals and is the direct responsibility of Subcommittee G01.04 on Corrosion of
Metals in Natural Atmospheric and Aqueous Environments.
Current edition approved May 1, 2025. Published May 2025. Last previous
edition approved in 2020 as G92 – 20. DOI: 10.1520/G0092-20R25.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at www.astm.org/contact. For Annual Book of
ASTM Standards volume information, refer to the standard’s Document Summary
page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1

4.2 This practice does not give speciﬁc parameters for

classifying the type of test site.

PROCEDURES

5. Method A

5.1 Materials:

5.1.1 The materials recommended for conducting atmo-

spheric corrosion characterization studies are copper-bearing

structural carbon steel (such as Speciﬁcation A36/A36M with

0.2 % copper min) and high-purity zinc (Speciﬁcation B6 high

grade).

5.1.2 Materials recommended are the absolute minimum

required to serve as a characterization base for test sites.

Additional materials should be added to meet individual needs.

Sufficient material should be obtained at the start to insure that

an ample supply of the same heat is available to complete the

characterization test. If tests are on-going and additional

materials must be obtained, care should be taken in attempting

to match material compositions.

5.1.3 Sufficient specimens should be prepared to comply

with the speciﬁc criteria for the planned characterization test.

5.2 Material Preparation:

5.2.1 Atmospheric test specimens, as shown for example, in

Fig. 1, shall be cut and ﬁnished in a manner that will not

detrimentally affect the corrosion behavior of exposed edges.

NOTE 1—Shearing may not be practical for some material section

thicknesses, and may introduce stresses and microcrevices that may

accelerate edge attack if not further machined.

5.2.2 An identifying code should be assigned to each

specimen. Locating a permanent code on each test specimen

can be accomplished easily by using a code template (Fig. 1).

5.2.2.1 Pre-assignment of codes for a deﬁnite test period is

suggested. After a temporary mark is placed on the specimen,

a permanent drilled code (a series of 2.5 mm holes) should

perforate the test specimen.

5.2.3 All test specimens of the same alloy should be cleaned

by the same procedure to ensure a comparative surface ﬁnish

following the guidance of Practice G1. The recommended

practice for cleaning is (a) degrease and pickle, if necessary, to

remove grease, mill scale, or other impurities; (b) scrub with

pumice and only a natural ﬁber or synthetic ﬁber bristle brush

* Template contains 126 drilled holes

FIG. 1 Sample Atmospheric Specimen Drill Code Identiﬁcation Template

G92 − 20 (2025)

until free of water-break; (c) dry with towels; and (d) place in

a desiccator for 2 h before weighing.

5.2.4 Specimens should be weighed (61.0 mg) and original

mass recorded on a data sheet (Table 1). Speciﬁc information,

such as nominal composition, density, and exposed area should

also be recorded.

5.2.5 Specimens should be stored in a desiccator or sealed in

airtight storage bags until the time of exposure.

5.3 Exposure of Test Specimens:

5.3.1 The frequency at which test specimens should be

exposed at a test site is dictated by the speciﬁc needs for data.

5.3.2 Triplicate specimens of each material should be ex-

posed for each test period.

5.3.3 An exposure period of one year is suggested as a

minimum; multiple periods should be considered, for example,

3, 6, and 12 months; 1 and 2 years or 1, 2, and 4 years. Shorter

test periods may be necessary where corrosion is severe and

longer test periods where corrosion is less severe.

5.3.3.1 Consideration should also be given to use of test

periods which could allow deﬁnition of changes in environ-

ment corrosivity occurring during an overall longer term

evaluation period. For example, exposure of specimens on the

schedule, 0 to 3, 3 to 6, 6 to 9, 9 to 12, 0 to 6, 6 to 12, and 0

to 12 months, would allow some assessment of relative

changes in corrosivity at a test site during a one year period.

While this is a relatively extensive exposure frequency, it may

prove useful in some instances.

5.3.4 A standard atmospheric exposure test rack (see Prac-

tice G50), or other appropriate devices, should be positioned at

30° to the horizontal facing the Equator in accordance with

Practice G50. The test specimens should be mounted with

porcelain insulators or other appropriate insulating materials.

5.3.5 Atmospheric corrosivity test specimens designated for

speciﬁc exposure periods should be positioned at approxi-

mately the same elevation on the test rack.

5.3.6 It is suggested that the general weather conditions be

documented at the time the specimens are exposed, for

example, clear, cloudy, or rain.

5.3.6.1 Initial weather conditions at time of exposure of test

specimens may have an effect on long term corrosion behavior

(1).

5.4 Removals and Reporting:

5.4.1 After the predetermined exposure period is completed

(for example, one year), the specimens should be removed and

placed in pre-labeled envelopes. Observations or photographs

needed to document appearance can be made at this time or

after the specimens reach the laboratory or other process area.

Wet specimens should be carefully dried if extended storage

(more than 24 h) is anticipated before cleaning.

5.4.2 The test specimens being removed should be identi-

ﬁed as to exposure location, exposure period, specimen code,

original mass, composition, original dimensions, and exposed

area and information documented as shown in Table 1.

5.4.3 As each specimen is clearly identiﬁed and observa-

tions documented, it can be cleaned, in accordance with

Practice G1. Specimens should then be dried and placed in a

desiccator for 2 h or more before ﬁnal weighing.

5.4.4 Each specimen should then be weighed to the nearest

milligram and the mass recorded. Also, a description of the

type of corrosion attack should be recorded, for example,

pitting (depth).

5.4.5 After the mass loss has been calculated, a mass loss

per unit area (mg/m

) and corrosion rate (mm/y) can be

calculated using the following equations (see Practice G1 for

further guidance).

A(1)

where:

= mass loss per unit area, milligrams per square metre,

M= mass loss, milligrams, and

A= exposed surface area, metres squared.

8.76 ×10

a×t×d(2)

Also available are data from the National Climate Data Center, NOAA,

Ashville, NC.

The boldface numbers in parentheses refer to a list of references at the end of

this standard.

TABLE 1 Sample Data Sheet for Atmospheric Corrosion Data

Test Site: Kure Beach (250 m lot) Latitude: 34° 00' N

Exposure Dates: 10/7/61 to 10/6/62 Longitude: 77° 55' W

Mass (g)

Material Code Exposure Period

(days) Original Final Loss

Mass Loss Per

Unit Area

(mg/m

)

Corrosion

Rate

(mm/y)

Cu-steel A1-B2 365 196.583 187.332 9.251 2.86 × 10

0.0365

Zinc A2-B2 365 67.521 66.938 0.583 1.84 × 10

0.0026

Test Method Documentation

Steel Zinc

1. Composition (weight %) 0.15 C, 1.0 Mn, 0.01 P, 0.027 S, 0.24 Si,

0.21 Cu, 0.05 Ni, 0.03 Cr, Balance Fe

0.01 Cu, 0.012 Cd, 0.03 Pb, 0.02 Fe,

Balance Zn

2. Density (g/cm

) 7.85 g/cm

7.13 g/cm

3. Dimensions (mm) 100 mm × 150 mm × 2.00 mm 100 mm × 150 mm × 2.00 mm

4. Exposed area (cm

) 322.9 cm

317.7 cm

G92 − 20 (2025)

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摘要：

ASTM G92 - 20 (2025) 是一项由美国材料与试验协会（ASTM）制定的标准实践，旨在为大气腐蚀测试场地的表征提供统一的方法与指南。该标准详细规定了如何评估和记录测试场地的环境参数，包括大气中的湿度、温度、降雨量、二氧化硫及氯化物沉积速率等关键腐蚀性因素，并指导用户通过标准金属试片的暴露试验来评定场地的腐蚀严酷度等级。通过实施此标准，研究人员和工程师能够确保在不同地理位置、不同季节或不同工业环境下开展的大气暴露试验具有可比性和可重复性，从而更准确地预测材料在真实大气环境中的长期腐蚀

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