ASTM G101-04(2015)

Standard Guide for Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels

SIGNIFICANCE AND USE
5.1 In the past, ASTM specifications for low-alloy weathering steels, such as Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M Grade 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M stated that the atmospheric corrosion resistance of these steels is “approximately two times that of carbon structural steel with copper.” A footnote in the specifications stated that “two times carbon structural steel with copper is equivalent to four times carbon structural steel without copper (Cu 0.02 maximum).” Because such statements relating the corrosion resistance of weathering steels to that of other steels are imprecise and, more importantly, lack significance to the user (1 and 2)4, the present guide was prepared to describe more meaningful methods of estimating the atmospheric corrosion resistance of weathering steels.  
5.2 The first method of this guide is intended for use in estimating the expected long-term atmospheric corrosion losses of specific grades of low-alloy steels in various environments, utilizing existing short-term atmospheric corrosion data for these grades of steel.  
5.3 The second method of this guide is intended for use in estimating the relative atmospheric corrosion resistance of a specific heat of low-alloy steel, based on its chemical composition.  
5.4 It is important to recognize that the methods presented here are based on calculations made from test data for flat, boldly exposed steel specimens. Atmospheric corrosion rates can be much higher when the weathering steel remains wet for prolonged periods of time, or is heavily contaminated with salt or other corrosive chemicals. Therefore, caution must be exercised in the application of these methods for prediction of long-term performance of actual structures.
SCOPE
1.1 This guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such as those described in Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

General Information

• Status: Historical
• Publication Date: 31-Oct-2015
• ICS: 77.060 - Corrosion of metals
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.04 - Corrosion of Metals in Natural Atmospheric and Aqueous Environments

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: G101 − 04 (Reapproved 2015)
Standard Guide for
Estimating the Atmospheric Corrosion Resistance of Low-
1
Alloy Steels
This standard is issued under the fixed designation G101; 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 Structural Steel Plate With Atmospheric Corrosion Resis-
tance
1.1 This guide presents two methods for estimating the
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
atmospheric corrosion resistance of low-alloy weathering
sion Test Specimens
steels, such as those described in Specifications A242/A242M,
G16 Guide for Applying Statistics to Analysis of Corrosion
A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS
Data
70W, and 100W, A852/A852M, and A871/A871M. One
G50 Practice for Conducting Atmospheric Corrosion Tests
method gives an estimate of the long-term thickness loss of a
on Metals
steel at a specific site based on results of short-term tests. The
other gives an estimate of relative corrosion resistance based
3. Terminology
on chemical composition.
3.1 Definitions of Terms Specific to This Standard:
1.2 The values stated in SI units are to be regarded as
3.1.1 low-alloy steels—iron-carbon alloys containing
standard. No other units of measurement are included in this
greater than 1.0 % but less than 5.0 %, by mass, total alloying
standard.
elements.
3.1.1.1 Discussion—Most “low-alloy weathering steels”
2. Referenced Documents
contain additions of both chromium and copper, and may also
2
2.1 ASTM Standards:
contain additions of silicon, nickel, phosphorus, or other
A242/A242M Specification for High-Strength Low-Alloy
alloying elements which enhance atmospheric corrosion resis-
Structural Steel
tance.
A588/A588M Specification for High-Strength Low-Alloy
Structural Steel, up to 50 ksi [345 MPa] Minimum Yield
4. Summary of Guide
Point, with Atmospheric Corrosion Resistance
4.1 In this guide, two general methods are presented for
A606 Specification for Steel, Sheet and Strip, High-
estimating the atmospheric corrosion resistance of low-alloy
Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, with
weathering steels. These are not alternative methods; each
Improved Atmospheric Corrosion Resistance
methodisintendedforaspecificpurpose,asoutlinedin5.2and
A709/A709M Specification for Structural Steel for Bridges
5.3.
A852/A852M Specification for Quenched and Tempered
4.1.1 The first method utilizes linear regression analysis of
Low-Alloy Structural Steel Plate with 70 ksi [485 MPa]
short-term atmospheric corrosion data to enable prediction of
Minimum Yield Strength to 4 in. [100 mm] Thick (With-
long-term performance by an extrapolation method.
3
drawn 2010)
4.1.2 Thesecondmethodutilizespredictiveequationsbased
A871/A871M Specification for High-Strength Low-Alloy
on the steel composition to calculate indices of atmospheric
corrosion resistance.
1
This guide is under the jurisdiction ofASTM Committee G01 on Corrosion of
5. Significance and Use
Metals and is the direct responsibility of Subcommittee G01.04 on Atmospheric
Corrosion.
5.1 In the past, ASTM specifications for low-alloy weath-
Current edition approved Nov. 1, 2015. Published December 2015. Originally
ering steels, such as Specifications A242/A242M, A588/
approvedin1989.Lastpreviouseditionapprovedin2010asG101–04(2010).DOI:
A588M, A606 Type 4, A709/A709M Grade 50W, HPS 70W,
10.1520/G0101-04R15.
2
and 100W, A852/A852M, and A871/A871M stated that the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
atmospheric corrosion resistance of these steels is “approxi-
Standards volume information, refer to the standard’s Document Summary page on
matelytwotimesthatofcarbonstructuralsteelwithcopper.”A
the ASTM website.
3
footnote in the specifications stated that “two times carbon
The last approved version of this historical standard is referenced on
www.astm.org. structural steel with copper is equivalent to four times carbon
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G101 − 04 (2015)
Differentiation of Eq 2 with respect to time gives the corrosion rate (R)
structural steel without copper (Cu 0.02 maximum).” Because
at any given time:
such statements relating the corrosion resistance of weathering
~B21!
steels to that of other steels are imprecise and, more
R 5 ABt (3)
4
Also, the time to a given corrosion loss can be calculated as follows:
importantly,lacksignificancetotheuser (1 and 2) ,theprese
...

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: G101 − 04 (Reapproved 2010) G101 − 04 (Reapproved 2015)
Standard Guide for
Estimating the Atmospheric Corrosion Resistance of Low-
1
Alloy Steels
This standard is issued under the fixed designation G101; 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 guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such
as those described in Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS 70W, and 100W,
A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based
on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
2
2.1 ASTM Standards:
A242/A242M Specification for High-Strength Low-Alloy Structural Steel
A588/A588M Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi [345 MPa] Minimum Yield Point, with
Atmospheric Corrosion Resistance
A606 Specification for Steel, Sheet and Strip, High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, with Improved
Atmospheric Corrosion Resistance
A709/A709M Specification for Structural Steel for Bridges
A852/A852M Specification for Quenched and Tempered Low-Alloy Structural Steel Plate with 70 ksi [485 MPa] Minimum
3
Yield Strength to 4 in. [100 mm] Thick (Withdrawn 2010)
A871/A871M Specification for High-Strength Low-Alloy Structural Steel Plate With Atmospheric Corrosion Resistance
G1 Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens
G16 Guide for Applying Statistics to Analysis of Corrosion Data
G50 Practice for Conducting Atmospheric Corrosion Tests on Metals
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 low-alloy steels—Iron-carboniron-carbon alloys containing greater than 1.0 % but less than 5.0 %, by mass, total alloying
elements.
1
This guide is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.04 on Atmospheric Corrosion.
Current edition approved May 1, 2010Nov. 1, 2015. Published May 2010December 2015. Originally approved in 1989. Last previous edition approved in 20042010 as
G101–04. –04 (2010). DOI: 10.1520/G0101-04R10.10.1520/G0101-04R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
3.1.1.1 Discussion—
Most “low-alloy weathering steels” contain additions of both chromium and copper, and may also contain additions of silicon,
nickel, phosphorus, or other alloying elements which enhance atmospheric corrosion resistance.
4. Summary of Guide
4.1 In this guide, two general methods are presented for estimating the atmospheric corrosion resistance of low-alloy weathering
steels. These are not alternative methods; each method is intended for a specific purpose, as outlined in 5.2 and 5.3.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G101 − 04 (2015)
4.1.1 The first method utilizes linear regression analysis of short-term atmospheric corrosion data to enable prediction of
long-term performance by an extrapolation method.
4.1.2 The second method utilizes predictive equations based on the steel composition to calculate indices of atmospheric
corrosion resistance.
5. Significance and Use
5.1 In the past, ASTM specifications for low-alloy weathering steels, such as Specifications A242/A242M, A588/A588M, A606
Type 4, A709/A709M Grade 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M stated that the atmospheric corrosion
resistance of these steels is “approximately two times that of carbon structural steel with copper.” A footnote in the specifications
stated that “two times carbon structural steel with copper is equivalent to four times carbon structural steel without c
...