ASTM B849-02(2023)
(Specification)Standard Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement
Standard Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement
ABSTRACT
This specification covers the pre-treatment procedures of iron or steel for reducing the susceptibility or degree thereof to hydrogen embrittlement or degradation that may arise in electroplating, autocatalytic plating, porcelain enameling, chemical conversion coating, and phosphating.
SCOPE
1.1 This specification covers procedures for reducing the susceptibility or degree of susceptibility to hydrogen embrittlement or degradation that may arise in electroplating, autocatalytic plating, porcelain enameling, chemical conversion coating, and phosphating and the associated pretreatment processes. This specification is applicable to those steels whose properties are not affected adversely by baking at 190 °C to 230 °C or higher (see 6.1.1).
1.2 The heat treatment procedures established herein have been shown to be effective for reducing the susceptibility of steel parts of tensile strength 1000 MPa or greater that have been machined, ground, cold-formed, or cold-straightened subsequent to heat treatment. This heat-treatment procedure is used prior to any operation capable of hydrogen charging the parts, such as the cleaning procedures prior to electroplating, autocatalytic plating, porcelain enameling, and other chemical coating operations.
Note 1: 1 MPa = 145.1 psi.
1.3 This specification has been coordinated with ISO/DIS 9587 and is technically equivalent.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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.
1.6 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
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Standards Content (Sample)
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.
Designation: B849 − 02 (Reapproved 2023)
Standard Specification for
Pre-Treatments of Iron or Steel for Reducing Risk of
Hydrogen Embrittlement
This standard is issued under the fixed designation B849; 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.
INTRODUCTION
When atomic hydrogen enters steels and certain other metals, for example, aluminum and titanium
alloys, it can cause a loss of ductility, load carrying ability, or cracking (usually as submicroscopic
cracks) as well as catastrophic brittle failures at applied stresses well below the yield strength or even
the normal design strength for the alloys. This phenomenon often occurs in alloys that show no
significant loss in ductility, when measured by conventional tensile tests, and is referred to frequently
as hydrogen-induced delayed brittle failure, hydrogen stress cracking, or hydrogen embrittlement. The
hydrogen can be introduced during cleaning, pickling, phosphating, electroplating, autocatalytic
processes, porcelain enameling, and in the service environment as a result of cathodic protection
reactions or corrosion reactions. Hydrogen can also be introduced during fabrication, for example,
during roll forming, machining, and drilling, due to the breakdown of unsuitable lubricants as well as
during welding or brazing operations. Parts that have been machined, ground, cold-formed, or
cold-straightened subsequent to hardening heat treatment are especially susceptible to hydrogen
embrittlement damage.
The results of research work indicate that the susceptibility of any material to hydrogen
embrittlement in a given test is related directly to its trap population. The time-temperature
relationship of the heat treatment is therefore dependent on the composition and structure of steels as
well as plating metals and plating procedures. Additionally, for most high-strength steels, the
effectiveness of the heat treatment falls off rapidly with a reduction of time and temperature.
1. Scope parts, such as the cleaning procedures prior to electroplating,
autocatalytic plating, porcelain enameling, and other chemical
1.1 This specification covers procedures for reducing the
coating operations.
susceptibility or degree of susceptibility to hydrogen embrittle-
ment or degradation that may arise in electroplating, autocata-
NOTE 1—1 MPa = 145.1 psi.
lytic plating, porcelain enameling, chemical conversion
1.3 This specification has been coordinated with ISO/DIS
coating, and phosphating and the associated pretreatment
processes. This specification is applicable to those steels whose 9587 and is technically equivalent.
properties are not affected adversely by baking at 190 °C to
1.4 The values stated in SI units are to be regarded as the
230 °C or higher (see 6.1.1).
standard.
1.2 The heat treatment procedures established herein have
1.5 This standard does not purport to address all of the
been shown to be effective for reducing the susceptibility of
safety concerns, if any, associated with its use. It is the
steel parts of tensile strength 1000 MPa or greater that have
responsibility of the user of this standard to establish appro-
been machined, ground, cold-formed, or cold-straightened
priate safety, health, and environmental practices and deter-
subsequent to heat treatment. This heat-treatment procedure is
mine the applicability of regulatory limitations prior to use.
used prior to any operation capable of hydrogen charging the
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
This specification is under the jurisdiction of ASTM Committee B08 on
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee ization established in the Decision on Principles for the
B08.02 on Pre Treatment.
Development of International Standards, Guides and Recom-
Current edition approved Nov. 1, 2023. Published November 2023. Originally
mendations issued by the World Trade Organization Technical
approved in 1994. Last previous edition approved in 2019 as B849 – 02 (2019).
DOI: 10.1520/B0849-02R23. Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B849 − 02 (2023)
2. Referenced Documents 4.2 Parts made from steel with actual tensile strengths
2 ≥1000 MPa (with corresponding hardness values of
2.1 ASTM Standards:
300 HV , 303 HB, or 31 HR ) and surface-hardened parts
10kgf c
A919 Terminology Relating to Heat Treatment of Metals
3 shall require heat treatment unless Class SR-0 is specified.
(Withdrawn 1999)
Preparation involving cathodic treatments in alkaline or acid
B242 Guide for Preparation of High-Carbon Steel for Elec-
solutions shall be avoided.
troplating
B322 Guide for Cleaning Metals Prior to Electroplating
4.3 Table 1 lists the stress-relief heat-treatment classes to be
B374 Terminology Relating to Electroplating
specified by the purchaser to the electroplater, supplier, or
B851 Specification for Automated Controlled Shot Peening
processor on the part drawing or purchase order. When no
of Metallic Articles Prior to Nickel, Autocatalytic Nickel,
stress relief treatment class is specified by the purchaser, Class
or Chromium Plating, or as Final Finish
SR-1 shall be applied (see Note 4).
2.2 ISO Standards:
NOTE 2—The treatment class selected is based on experience with the
ISO 2080 Electroplating and Related Processes—
part, or similar parts, and the specific alloy used or with empirical test
Vocabulary
data. Because of factors such as alloy composition and structure, size,
mass, or design parameters, some parts may perform satisfactorily with no
ISO/DIS 9587 Pre-Treatments of Iron or Steel for Reducing
stress relief treatment. Class SR-0 treatment is therefore provided for parts
the Risk of Hydrogen
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