GB/T 19292 consists of the following parts, under the general title Corrosion of Metals and Alloys — Corrosivity of Atmospheres:
— Part 1: Classification, Determination and Estimation;
— Part 2: Guiding Values for the Corrosivity Categories;
— Part 3: Measurement of Environmental Parameters Affecting Corrosivity of Atmospheres;
— Part 4: Determination of Corrosion Rate of Standard Specimens for the Evaluation of Corrosivity.
This is Part 1 of GB/T 19292.
This part was drafted in accordance with the rules given in the GB/T 1.1-2009.
This part replaces GB/T 19292.1-2003 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Classification. The following technical deviations have been made with respect to GB/T 19292.1-2003 (the previous edition):
— Category CX is added to C1, C2, C3, C4 and C5 based on the characteristics of specific marine and marine/industrial atmospheres;
— the functional relationship between first year corrosion rates of carbon steel, zinc, copper, and aluminum and the pollutant concentrations (sulfur dioxide deposition and chloride deposition), relative humidity and temperature is established. The corrosivity categories of atmospheric environment are defined by the first year corrosion rate calculated according to the environmental parameters..
This standard is identical with International Standard ISO 9223:2012 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Classification, Determination and Estimation.
The China documents referenced in this part, with corresponding relationship to the international documents, are given below:
GB/T 10123-2001 Corrosion of Metals and Alloys — Basic Terms and Definitions (eqv ISO 8044:1999);
GB/T 19292.2-2018 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Part 2: Guiding Values for the Corrosivity Categories (ISO 9224:2012, MOD);
GB/T 24513.1-2009 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 1: Determination and Estimation of Indoor Corrosivity (ISO 11844-1:2006, IDT);
GB/T 24513.2-2010 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 2: Determination of Corrosion Attack in Indoor Atmospheres (ISO 11844-2:2005, IDT);
GB/T 24513.3-2012 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 3: Measurement of Environmental Parameters Affecting Indoor Corrosivity (ISO 11844-3:2006, IDT).
For the purposes of this part, the following editorial changes have also been made:
— the standard name is modified;
This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this part are as follows:
— GB/T 19292.1-2003.
Introduction
Metals, alloys and metallic coatings can suffer atmospheric corrosion when their surfaces are wetted. The nature and rate of the attack depends upon the properties of surface-formed electrolytes, particularly with regard to the level and type of gaseous and particulate pollutants in the atmosphere and to the duration of their action on the metallic surface.
The character of the corrosion attack and the corrosion rate are consequences of the corrosion system, which comprises the metallic materials, the atmospheric environment, technical parameters and operation conditions.
The corrosivity category is a technical characteristic which provides a basis for the selection of materials and protective measures in atmospheric environments subject to the demands of the specific application, particularly with regard to service life.
Data on the corrosivity of the atmosphere are essential for the development and specification of optimized corrosion protection for manufactured products.
The corrosivity categories are defined by the first-year corrosion effects on standard specimens as specified in GB/T 19292.1. The corrosivity categories can be assessed in terms of the most significant atmospheric factors influencing the corrosion of metals and alloys.
The measurement of relevant environmental parameters is specified in GB/T 19292.3.
The ways of determining and estimating the corrosivity category of a given location according to this part and the relationships among them are presented in Figure 1. It is necessary to distinguish between corrosivity determination and corrosivity estimation. It is also necessary to distinguish between corrosivity estimation based on application of a dose-response function and that based on comparison with the description of typical atmospheric environments.
This part does not take into consideration the design and mode of operation of the product, which can influence its corrosion resistance, since these effects are highly specific and cannot be generalized. Steps in the choice of optimized corrosion protection measures in atmospheric environments are defined in GB/T 20852.
Figure 1 Classification of Atmospheric Corrosivity
Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Part 1: Classification, Determination and Estimation
1 Scope
This part of GB/T 19292 establishes a classification system for the corrosivity of atmospheric environments.
This part defines corrosivity categories for the atmospheric environments by the first-year corrosion rate of standard specimens, gives dose-response functions for normative estimation of the corrosivity category based on the calculated first-year corrosion loss of standard metals, and makes possible an informative estimation of the corrosivity category based on knowledge of the local environmental situation.
This part specifies the key factors in the atmospheric corrosion of metals and alloys. These are the temperature-humidity complex, pollution by sulfur dioxide and airborne salinity.
Temperature is also considered an important factor for corrosion in areas outside the temperate macroclimatic zone. The temperature-humidity complex can be evaluated in terms of time of wetness. Corrosion effects of other pollutants (ozone, nitrogen oxides, particulates) can influence the corrosivity and the evaluated one-year corrosion loss, but these factors are not considered decisive in the assessment of corrosivity according to this part.
This part does not characterize the corrosivity of specific service atmospheres, e.g. atmospheres in chemical or metallurgical industries.
The classified corrosivity categories and introduced pollution levels can be directly used for technical and economical analyses of corrosion damage and for a rational choice of corrosion protection measures.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8044 Corrosion of Metals and Alloys — Basic Terms and Definitions
ISO 9224 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Guiding Values for the Corrosivity Categories
ISO 11844-1 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 1: Determination and Estimation of Indoor Corrosivity
ISO 11844-2 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 2: Determination of Corrosion Attack in Indoor Atmospheres
ISO 11844-3 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 3: Measurement of Environmental Parameters Affecting Indoor Corrosivity
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
3.1
corrosivity of atmosphere
ability of the atmosphere to cause corrosion in a given corrosion system
3.2
category of corrosivity of atmosphere
standardized rating of corrosivity of atmosphere in relation to the one-year corrosion effect
3.3
type of atmosphere
characterization of the atmosphere on the basis of appropriate classification criteria other than corrosivity or of complementary operation factors, such as rural, urban, industrial, marine, chemical, etc.
3.4
temperature-humidity complex
combined effect of temperature and relative humidity on the corrosivity of the atmosphere
3.5
time of wetness
period when a metallic surface is covered by adsorptive and/or liquid films of electrolyte to be capable of causing atmospheric corrosion
3.6
pollution level
numbered rank based on quantitative measurements of specific chemically active substances, corrosive gases or suspended particles in the air (both natural and the result of human activity) that are different from the normal components of the air
3.7
category of location
conventionally defined typical exposure conditions of a component or structure; for example, exposure in the open air, under shelter, in a closed space, etc.
3.8
dose-response function
relationship derived from results of field tests for calculation of corrosion loss from average values of environmental parameters
4 Symbols and Abbreviated Terms
4.1 Symbols
For the purposes of this document, the following symbols apply.
rcorr: Corrosion rate for the first year of atmospheric exposure.
T: Air temperature.
Pd: SO2 deposition rate.
Pc: SO2 concentration.
Sd: Cl- deposition rate.
τ: Time of wetness.
4.2 Abbreviation terms
For the purposes of this document, the following abbreviation terms apply.
C: Atmospheric corrosivity category.
RH: Relative humidity.
5 Category of Corrosivity of the Atmosphere
The corrosivity of the atmosphere is divided into six categories (see Table 1).
Table 1 Categories of Corrosivity of the Atmosphere
Category Corrosivity
C1 Very low
C2 Low
C3 Medium
C4 High
C5 Very high
CX Extreme
6 Classification of Corrosivity of the Atmosphere
The corrosivity of atmospheric environments shall be classified either by determination of the corrosivity in accordance with Clause 7 or, where this is not possible, by estimation of the corrosivity in accordance with Clause 8. Both methods of the corrosivity evaluation represent a generalized approach and are characterized by some uncertainties and limitations.
A corrosivity category determined from the first-year corrosion loss reflects the specific environmental situation of the year of exposure.
A corrosivity category estimated from the dose-response function reflects the statistical uncertainty of the given function.
A corrosivity category estimated using the informative procedure based on the comparison of the local environmental conditions with the description of typical atmospheric environments can lead to misinterpretations. This approach is to be used if experimental data are not available.
Annex A defines uncertainties related to the determination and normative estimation of atmospheric corrosivity categories.
Detailed classification of low corrosivity of indoor atmospheres covering the corrosivity categories C1 and C2 in terms of this part is specified in ISO 11844-1, ISO 11844-2 and ISO 11844-3.
Foreword II
Introduction IV
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and Abbreviated Terms
5 Category of Corrosivity of the Atmosphere
6 Classification of Corrosivity of the Atmosphere
7 Corrosivity Determination Based on Corrosion Rate Measurement of Standard Specimens
8 Corrosivity Estimation Based on Environmental Information
Annex A (Informative) Sources of Uncertainty Associated with the Determination and Estimation of Atmospheric Corrosivity
Appendix B (Informative) Characterization of the Atmosphere in Relation to Its Corrosivity
Annex C (Informative) Description of Typical Atmospheric Environments Related to the Estimation of Corrosivity Categories
Bibliography
GB/T 19292 consists of the following parts, under the general title Corrosion of Metals and Alloys — Corrosivity of Atmospheres:
— Part 1: Classification, Determination and Estimation;
— Part 2: Guiding Values for the Corrosivity Categories;
— Part 3: Measurement of Environmental Parameters Affecting Corrosivity of Atmospheres;
— Part 4: Determination of Corrosion Rate of Standard Specimens for the Evaluation of Corrosivity.
This is Part 1 of GB/T 19292.
This part was drafted in accordance with the rules given in the GB/T 1.1-2009.
This part replaces GB/T 19292.1-2003 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Classification. The following technical deviations have been made with respect to GB/T 19292.1-2003 (the previous edition):
— Category CX is added to C1, C2, C3, C4 and C5 based on the characteristics of specific marine and marine/industrial atmospheres;
— the functional relationship between first year corrosion rates of carbon steel, zinc, copper, and aluminum and the pollutant concentrations (sulfur dioxide deposition and chloride deposition), relative humidity and temperature is established. The corrosivity categories of atmospheric environment are defined by the first year corrosion rate calculated according to the environmental parameters..
This standard is identical with International Standard ISO 9223:2012 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Classification, Determination and Estimation.
The China documents referenced in this part, with corresponding relationship to the international documents, are given below:
GB/T 10123-2001 Corrosion of Metals and Alloys — Basic Terms and Definitions (eqv ISO 8044:1999);
GB/T 19292.2-2018 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Part 2: Guiding Values for the Corrosivity Categories (ISO 9224:2012, MOD);
GB/T 24513.1-2009 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 1: Determination and Estimation of Indoor Corrosivity (ISO 11844-1:2006, IDT);
GB/T 24513.2-2010 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 2: Determination of Corrosion Attack in Indoor Atmospheres (ISO 11844-2:2005, IDT);
GB/T 24513.3-2012 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 3: Measurement of Environmental Parameters Affecting Indoor Corrosivity (ISO 11844-3:2006, IDT).
For the purposes of this part, the following editorial changes have also been made:
— the standard name is modified;
This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee 183 on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this part are as follows:
— GB/T 19292.1-2003.
Introduction
Metals, alloys and metallic coatings can suffer atmospheric corrosion when their surfaces are wetted. The nature and rate of the attack depends upon the properties of surface-formed electrolytes, particularly with regard to the level and type of gaseous and particulate pollutants in the atmosphere and to the duration of their action on the metallic surface.
The character of the corrosion attack and the corrosion rate are consequences of the corrosion system, which comprises the metallic materials, the atmospheric environment, technical parameters and operation conditions.
The corrosivity category is a technical characteristic which provides a basis for the selection of materials and protective measures in atmospheric environments subject to the demands of the specific application, particularly with regard to service life.
Data on the corrosivity of the atmosphere are essential for the development and specification of optimized corrosion protection for manufactured products.
The corrosivity categories are defined by the first-year corrosion effects on standard specimens as specified in GB/T 19292.1. The corrosivity categories can be assessed in terms of the most significant atmospheric factors influencing the corrosion of metals and alloys.
The measurement of relevant environmental parameters is specified in GB/T 19292.3.
The ways of determining and estimating the corrosivity category of a given location according to this part and the relationships among them are presented in Figure 1. It is necessary to distinguish between corrosivity determination and corrosivity estimation. It is also necessary to distinguish between corrosivity estimation based on application of a dose-response function and that based on comparison with the description of typical atmospheric environments.
This part does not take into consideration the design and mode of operation of the product, which can influence its corrosion resistance, since these effects are highly specific and cannot be generalized. Steps in the choice of optimized corrosion protection measures in atmospheric environments are defined in GB/T 20852.
Figure 1 Classification of Atmospheric Corrosivity
Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Part 1: Classification, Determination and Estimation
1 Scope
This part of GB/T 19292 establishes a classification system for the corrosivity of atmospheric environments.
This part defines corrosivity categories for the atmospheric environments by the first-year corrosion rate of standard specimens, gives dose-response functions for normative estimation of the corrosivity category based on the calculated first-year corrosion loss of standard metals, and makes possible an informative estimation of the corrosivity category based on knowledge of the local environmental situation.
This part specifies the key factors in the atmospheric corrosion of metals and alloys. These are the temperature-humidity complex, pollution by sulfur dioxide and airborne salinity.
Temperature is also considered an important factor for corrosion in areas outside the temperate macroclimatic zone. The temperature-humidity complex can be evaluated in terms of time of wetness. Corrosion effects of other pollutants (ozone, nitrogen oxides, particulates) can influence the corrosivity and the evaluated one-year corrosion loss, but these factors are not considered decisive in the assessment of corrosivity according to this part.
This part does not characterize the corrosivity of specific service atmospheres, e.g. atmospheres in chemical or metallurgical industries.
The classified corrosivity categories and introduced pollution levels can be directly used for technical and economical analyses of corrosion damage and for a rational choice of corrosion protection measures.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8044 Corrosion of Metals and Alloys — Basic Terms and Definitions
ISO 9224 Corrosion of Metals and Alloys — Corrosivity of Atmospheres — Guiding Values for the Corrosivity Categories
ISO 11844-1 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 1: Determination and Estimation of Indoor Corrosivity
ISO 11844-2 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 2: Determination of Corrosion Attack in Indoor Atmospheres
ISO 11844-3 Corrosion of Metals and Alloys — Classification of Low Corrosivity of Indoor Atmospheres — Part 3: Measurement of Environmental Parameters Affecting Indoor Corrosivity
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
3.1
corrosivity of atmosphere
ability of the atmosphere to cause corrosion in a given corrosion system
3.2
category of corrosivity of atmosphere
standardized rating of corrosivity of atmosphere in relation to the one-year corrosion effect
3.3
type of atmosphere
characterization of the atmosphere on the basis of appropriate classification criteria other than corrosivity or of complementary operation factors, such as rural, urban, industrial, marine, chemical, etc.
3.4
temperature-humidity complex
combined effect of temperature and relative humidity on the corrosivity of the atmosphere
3.5
time of wetness
period when a metallic surface is covered by adsorptive and/or liquid films of electrolyte to be capable of causing atmospheric corrosion
3.6
pollution level
numbered rank based on quantitative measurements of specific chemically active substances, corrosive gases or suspended particles in the air (both natural and the result of human activity) that are different from the normal components of the air
3.7
category of location
conventionally defined typical exposure conditions of a component or structure; for example, exposure in the open air, under shelter, in a closed space, etc.
3.8
dose-response function
relationship derived from results of field tests for calculation of corrosion loss from average values of environmental parameters
4 Symbols and Abbreviated Terms
4.1 Symbols
For the purposes of this document, the following symbols apply.
rcorr: Corrosion rate for the first year of atmospheric exposure.
T: Air temperature.
Pd: SO2 deposition rate.
Pc: SO2 concentration.
Sd: Cl- deposition rate.
τ: Time of wetness.
4.2 Abbreviation terms
For the purposes of this document, the following abbreviation terms apply.
C: Atmospheric corrosivity category.
RH: Relative humidity.
5 Category of Corrosivity of the Atmosphere
The corrosivity of the atmosphere is divided into six categories (see Table 1).
Table 1 Categories of Corrosivity of the Atmosphere
Category Corrosivity
C1 Very low
C2 Low
C3 Medium
C4 High
C5 Very high
CX Extreme
6 Classification of Corrosivity of the Atmosphere
The corrosivity of atmospheric environments shall be classified either by determination of the corrosivity in accordance with Clause 7 or, where this is not possible, by estimation of the corrosivity in accordance with Clause 8. Both methods of the corrosivity evaluation represent a generalized approach and are characterized by some uncertainties and limitations.
A corrosivity category determined from the first-year corrosion loss reflects the specific environmental situation of the year of exposure.
A corrosivity category estimated from the dose-response function reflects the statistical uncertainty of the given function.
A corrosivity category estimated using the informative procedure based on the comparison of the local environmental conditions with the description of typical atmospheric environments can lead to misinterpretations. This approach is to be used if experimental data are not available.
Annex A defines uncertainties related to the determination and normative estimation of atmospheric corrosivity categories.
Detailed classification of low corrosivity of indoor atmospheres covering the corrosivity categories C1 and C2 in terms of this part is specified in ISO 11844-1, ISO 11844-2 and ISO 11844-3.
Contents of GB/T 19292.1-2018
Foreword II
Introduction IV
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and Abbreviated Terms
5 Category of Corrosivity of the Atmosphere
6 Classification of Corrosivity of the Atmosphere
7 Corrosivity Determination Based on Corrosion Rate Measurement of Standard Specimens
8 Corrosivity Estimation Based on Environmental Information
Annex A (Informative) Sources of Uncertainty Associated with the Determination and Estimation of Atmospheric Corrosivity
Appendix B (Informative) Characterization of the Atmosphere in Relation to Its Corrosivity
Annex C (Informative) Description of Typical Atmospheric Environments Related to the Estimation of Corrosivity Categories
Bibliography
