ASTM B850-98(2009)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: B850 − 98 (Reapproved2009)
Standard Guide for
Post-Coating Treatments of Steel for Reducing the Risk of
Hydrogen Embrittlement
This standard is issued under the fixed designation B850; 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 steel, 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.
1. Scope A919 Terminology Relating to Heat Treatment of Metals
(Withdrawn 1999)
1.1 This guide covers procedures for reducing the suscep-
B374 Terminology Relating to Electroplating
tibility in some steels to hydrogen embrittlement or degrada-
B851 Specification for Automated Controlled Shot Peening
tion that may arise in the finishing processes.
of Metallic Articles Prior to Nickel, Autocatalytic Nickel,
1.2 The heat treatment procedures established herein may
or Chromium Plating, or as Final Finish
be effective for reducing susceptibility to hydrogen embrittle-
2.2 ISO Standards:
ment. This heat-treatment procedure shall be used after plating
ISO 2080 Electroplating and Related Processes—
operations but prior to any secondary conversion coating 4
Vocabulary
operation.
ISO DIS 9588 Post-Coating Treatments of Iron or Steel for
1.3 ThisguidehasbeencoordinatedwithISO/DIS9588and Reducing the Risk of Hydrogen Embrittlement
is technically equivalent.
2.3 Federal Standard:
QQ-C-320 Chromium Plating (Electrodeposited)
NOTE1—Theheattreatmentdoesnotguaranteecompletefreedomfrom
the adverse effects of hydrogen degradation.
3. Terminology
1.4 The values stated in SI units are to be regarded as
3.1 Definitions—Manyofthetermsusedinthisguidecanbe
standard. No other units of measurement are included in this
found in Terminology B374, A919, or ISO 2080.
standard.
4. Requirements
2. Referenced Documents
4.1 Heat treatment may be performed on coated metals to
2.1 ASTM Standards:
reduce the risk of hydrogen embrittlement. The duration of
heat treatment in all cases shall commence from the time at
This specification is under the jurisdiction of ASTM Committee B08 on
which the whole of each part attains the specified temperature.
Metallic and Inorganic Coatingsand is the direct responsibility of Subcommittee
B08.02 on Pre Treatment.
Current edition approved Sept. 1, 2009. Published December 2009. Originally
approved in 1994. Last previous edition approved in 2004 as B850–98(2004). DOI: The last approved version of this historical standard is referenced on
10.1520/B0850-98R09. www.astm.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
Standards volume information, refer to the standard’s Document Summary page on Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
the ASTM website. Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B850 − 98 (2009)
4.2 Parts made from steel with actual tensile strengths manufacturing engineer, or other technically qualified indi-
≥1000 MPa (with corresponding hardness values of 300 vidual specify the treatment class on the part drawing or
HV , 303 HB, or 31 HR ) and surface-hardened parts may purchase order.
10kgf C
require heat treatment unless Class ER-0 is specified. Prepara-
5. Embrittlement Relief Treatment Classes
tion involving cathodic treatments in alkaline or acid solutions
5.1 With the exception of surface-hardened parts and parts
shall be avoided. Additionally, the selection of electroplating
that have been shot peened in accordance with Specification
solutions with high cathodic efficiencies is recommended for
B851,heattreatmentconditionsmaybeselectedonthebasisof
steel components with tensile strengths above 1400 MPa (with
actual tensile strength. When only the minimum tensile
corresponding hardness values of 425 HV , 401 HB, or 43
10kgf
strength is specified, or if the tensile strength is not known, the
HR ).
C
heat treatment condition may be selected by relating known or
4.3 Table 1 provides a list of embrittlement-relief heat-
measured hardness values to equivalent tensile strengths. It is
treatment classes from which the purchaser may specify the
recommended that the tensile strength be supplied by the
treatmentrequiredtotheelectroplater,supplier,orprocessoron
purchaser.
the part d
...