ASTM B975-18e1

Standard Test Method for Measurement of Internal Stress of Metallic Coatings by Split Strip Evaluation (Deposit Stress Analyzer Method)

SIGNIFICANCE AND USE
5.1 Internal stress in applied coatings exhibits potential to cause a breakdown of resistance to corrosion and erosion as a result of the formation of fractures from micro-cracking and macro-cracking within the applied coating. This phenomenon can also cause blistering, peeling, reduction of fatigue strength, and loss. The resulting stress can be tensile in nature, causing the deposit to contract, or compressive in nature, causing the deposit to expand.  
5.2 To maintain quality assurance by the bent strip method, it is necessary to monitor production processes for acceptable levels of internal deposit stress in applied coatings. Note that the highest value of the internal deposit stress as obtained on a stress-versus-plating-thickness curve is usually the truest value of the internal deposit stress. Most low values are false. Initial values tend to be lower than the actual value because of the effect of stock material edge burrs and the resistance of the stock material to bending. Excessive deposit thickness causes lower-than-true value since the coating overpowers and changes the initial modulus of elasticity of the test piece, which becomes more difficult to bend as the coating continues to build upon it. This phenomenon can be corrected considerably by use of a formula that compensates for modulus of elasticity differences between the deposit and the substrate materials, but it does remain a factor. See Eq 2.
SCOPE
1.1 This test method for determining the internal tensile or compressive stress in applied coatings is quantitative. It is applicable to metallic layers that are applied by the processes of electroplating or chemical deposition that exhibit internal tensile or compressive stress values from 200 to 145 000 psi (1.38 to 1000 MPa).  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Historical
• Publication Date: 30-Nov-2018
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.10 - Test Methods

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
´1
Designation: B975 − 18
Standard Test Method for
Measurement of Internal Stress of Metallic Coatings by Split
1
Strip Evaluation (Deposit Stress Analyzer Method)
This standard is issued under the fixed designation B975; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Footnote 5 was editorially corrected in February 2020.
INTRODUCTION
The deposit stress analyzer method provides a rapid, accurate, and economical means for the
determination of the internal tensile and compressive stress in metallic and nonmetallic coatings.
Internal stress is expressed in pounds per square inch or megapascals. This procedure for measuring
internal stress offers the advantages of test specimens that are pre-calibrated by the manufacturer, a
small test specimen coating surface area, and rapid determination of the internal stress in the applied
coating.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method for determining the internal tensile or
B636Test Method for Measurement of Internal Stress of
compressive stress in applied coatings is quantitative. It is
Plated Metallic Coatings with the Spiral Contractometer
applicable to metallic layers that are applied by the processes
E177Practice for Use of the Terms Precision and Bias in
of electroplating or chemical deposition that exhibit internal
ASTM Test Methods
tensile or compressive stress values from 200 to 145 000 psi
E691Practice for Conducting an Interlaboratory Study to
(1.38 to 1000 MPa).
Determine the Precision of a Test Method
1.2 The values stated in either SI units or inch-pound units
3
2.2 IEC Standard:
are to be regarded separately as standard. The values stated in
IEC 61010Safety Requirements for Electrical Equipment
eachsystemarenotnecessarilyexactequivalents;therefore,to
for Measurement, Control, and Laboratory Use
ensure conformance with the standard, each system shall be
used independently of the other, and values from the two
3. Terminology
systems shall not be combined.
3.1 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.1.1 average deposit thickness, n—average deposit thick-
safety concerns, if any, associated with its use. It is the
nessequalsthedepositweightingramsdividedbythespecific
responsibility of the user of this standard to establish appro-
gravity of the deposit in grams per cubic centimetre multiplied
priate safety, health, and environmental practices and deter-
by the plated deposit surface area per test strip (see Eq 3).
mine the applicability of regulatory limitations prior to use.
3.1.2 constant K, n—this certifiable calibrated number is
1.4 This international standard was developed in accor-
determined experimentally for each material lot of test strips
dance with internationally recognized principles on standard-
manufactured to enable simple mathematical calculation of the
ization established in the Decision on Principles for the
internal deposit stress while factoring the influence of the
Development of International Standards, Guides and Recom-
percent elongation difference between the deposit and the
mendations issued by the World Trade Organization Technical
substrate without the use of complicated bent strip formulas.
Barriers to Trade (TBT) Committee.
See Note 4 in Section 8.
1 2
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Test Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2018. Published January 2019. Originally the ASTM website.
3
approved in 2015. Last previous edition approved in 2015 as B975–15. DOI: Available from International Electrotechnical Commission (IEC), 3, rue de
10.1520/B0975-18E01. Varembé, P.O. Box 131, 1211 Geneva 20, Switzerland, http://www.iec.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
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B975 − 18
3.1.3 helix, n—metal strip approximately 0.01 to 0.013in. 4.3 The deposit stress analyzer method for determining the
(0.025 to 0.033 cm) thick formed as a helix approximately internal stress value of a given plating uses bent strip technol-
0.9in. (2.3 cm) in diameter and 6.1in. (15.5 cm) long with or ogy and the formulas devised for calculation of results appli-
withoutapolyt
...

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.
´1
Designation: B975 − 18 B975 − 18
Standard Test Method for
Measurement of Internal Stress of Metallic Coatings by Split
1
Strip Evaluation (Deposit Stress Analyzer Method)
This standard is issued under the fixed designation B975; 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
ε NOTE—Footnote 5 was editorially corrected in February 2020.
INTRODUCTION
The deposit stress analyzer method provides a rapid, accurate, and economical means for the
determination of the internal tensile and compressive stress in metallic and nonmetallic coatings.
Internal stress is expressed in pounds per square inch or megapascals. This procedure for measuring
internal stress offers the advantages of test specimens that are pre-calibrated by the manufacturer, a
small test specimen coating surface area, and rapid determination of the internal stress in the applied
coating.
1. Scope
1.1 This test method for determining the internal tensile or compressive stress in applied coatings is quantitative. It is applicable
to metallic layers that are applied by the processes of electroplating or chemical deposition that exhibit internal tensile or
compressive stress values from 200 to 145 000 psi (1.38 to 1000 MPa).
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
1.3 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 appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
B636 Test Method for Measurement of Internal Stress of Plated Metallic Coatings with the Spiral Contractometer
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 IEC Standard:
IEC 61010 Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
1
This test method is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 on Test
Methods.
Current edition approved Dec. 1, 2018. Published January 2019. Originally approved in 2015. Last previous edition approved in 2015 as B975 – 15. DOI:
10.1520/B0975-18.10.1520/B0975-18E01.
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
Available from International Electrotechnical Commission (IEC), 3, rue de Varembé, P.O. Box 131, 1211 Geneva 20, Switzerland, http://www.iec.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
´1
B975 − 18
3.1.1 average deposit thickness, n—average deposit thickness equals the deposit weight in grams divided by the specific gravity
of the deposit in grams per cubic centimetre multiplied by the plated deposit surface area per test strip (see Eq 3).
3.1.2 constant K, n—this certifiable calibrated number is determined experimentally for each material lot of test strips
manufactured to enable simple mathematical calculation of the internal deposit stress while factoring the influence of the percent
elongation difference between the deposit and the substrate without the use of complicated bent strip formulas. See Note 4 in
Section 8.
3.1.3 helix, n—metal strip approximately 0.01
...