1、Designation: B 850 98 (Reapproved 2004)Standard Guide forPost-Coating Treatments of Steel for Reducing Risk ofHydrogen Embrittlement1This standard is issued under the fixed designation B 850; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONWhen atomic hydrogen enters steel, it can cause a loss of ductility, load carrying ability, or c
3、racking(usually as submicroscopic cracks), as well as catastrophic brittle failures at applied stresses wellbelow the yield strength or even the normal design strength for the alloys. This phenomenon oftenoccurs in alloys that show no significant loss in ductility, when measured by conventional tens
4、ile tests,and is referred to frequently as hydrogen-induced delayed brittle failure, hydrogen stress cracking, orhydrogen embrittlement. The hydrogen can be introduced during cleaning, pickling, phosphating,electroplating, autocatalytic processes, porcelain enameling, and in the service environment
5、as a resultof cathodic protection reactions or corrosion reactions. Hydrogen can also be introduced duringfabrication, for example, during roll forming, machining, and drilling, due to the breakdown ofunsuitable lubricants, as well as during welding or brazing operations.1. Scope1.1 This guide cover
6、s procedures for reducing the suscep-tibility in some steels to hydrogen embrittlement or degrada-tion that may arise in the finishing processes.1.2 The heat treatment procedures established herein maybe effective for reducing susceptibility to hydrogen embrittle-ment. This heat-treatment procedure
7、shall be used after platingoperations but prior to any secondary conversion coatingoperation.1.3 This guide has been coordinated with ISO/DIS 9588 andis technically equivalent.NOTE 1The heat treatment does not guarantee complete freedomfrom the adverse effects of hydrogen degradation.2. Referenced D
8、ocuments2.1 ASTM Standards:2A 919 Terminology Relating to Heat Treatment of Metals3B 374 Terminology Relating to ElectroplatingB 851 Specification for Automated Controlled Shot Peeningof Metallic Articles Prior to Nickel, Autocatalytic Nickel,or Chromium Plating, or as Final Finish2.2 ISO Standards:
9、ISO 2080 Electroplating and Related ProcessesVocabulary4ISO DIS 9588 Post-Coating Treatments of Iron or Steel forReducing the Risk of Hydrogen Embrittlement42.3 Federal Standard:QQ-C-320 Chromium Plating (Electrodeposited)53. Terminology3.1 DefinitionsMany of the terms used in this guide canbe found
10、 in Terminology B 374, A 919, or ISO 2080.4. Requirements4.1 Heat treatment may be performed on coated metals toreduce the risk of hydrogen embrittlement. The duration ofheat treatment in all cases shall commence from the time atwhich the whole of each part attains the specified temperature.4.2 Part
11、s made from steel with actual tensile strengths$1000 MPa (with corresponding hardness values of 300HV10kgf, 303 HB, or 31 HRC) and surface-hardened parts mayrequire heat treatment unless Class ER-0 is specified. Prepara-tion involving cathodic treatments in alkaline or acid solutionsshall be avoided
12、. Additionally, the selection of electroplatingsolutions with high cathodic efficiencies is recommended for1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.02 on Pre Treatment.Current edition app
13、roved April 1, 2004. Published April 2004. Originallyapproved in 1994. Last previous edition approved in 1998 as B 85098.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refe
14、r to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.5Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-
15、50981Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.steel components with tensile strengths above 1400 MPa (withcorresponding hardness values of 425 HV10kgf, 401 HB, or 43HRC).4.3 Table 1 provides a list of embrittlement-relief heat-
16、treatment classes from which the purchaser may specify thetreatment required to the electroplater, supplier, or processor onthe part drawing or purchase order.NOTE 2The treatment class selected is based on experience with thepart, or similar parts, and the specific alloy used or with empirical testd
17、ata. Because of factors such as alloy composition and structure, type ofcoating, coating thickness, size, mass, or design parameters, some partsmay perform satisfactorily with no embrittlement-relief treatment. ClassER-0 treatment is therefore provided for parts that the purchaser wishes toexempt fr
18、om treatment.NOTE 3The use of inhibitors in acid pickling baths may not minimizehydrogen embrittlement.4.4 The electroplater, supplier, or processor is not normallyin possession of the necessary information, such as designconsiderations, operating stresses, etc., that must be consideredwhen selectin
19、g the correct embrittlement relief treatment. It isin the purchasers interest that his or her part designer,manufacturing engineer, or other technically qualified indi-vidual specify the treatment class on the part drawing orpurchase order.5. Embrittlement Relief Treatment Classes5.1 With the except
20、ion of surface-hardened parts and partsthat have been shot peened in accordance with SpecificationB 851, heat treatment conditions may be selected on the basisof actual tensile strength. When only the minimum tensilestrength is specified, or if the tensile strength is not known, theheat treatment co
21、ndition may be selected by relating known ormeasured hardness values to equivalent tensile strengths. It isrecommended that the tensile strength be supplied by thepurchaser.5.2 Steels that have been wholly or partly surface hardenedmay be considered as being in the category appropriate to thehardnes
22、s of the surface-hardened layer.5.3 If the purchaser requires any tests to be performed inorder to verify adequate embrittlement relief treatment, the testmethod and the sampling plan to be used shall be specified.6. Heat Treatment After Processing6.1 The heat treatment shall commence as soon as pos
23、sible,preferably within 1 h but not later than 3 h after plating andbefore commencement of any grinding or other mechanicaloperation. For cadmium, tin, zinc, their alloys, or any othercoating receiving a chromate treatment, heat treatment shall beconducted before chromate treatment.NOTE 4Chromate co
24、atings undergo change at temperatures above66C. The coating changes from an amorphous structure to a crystallinestructure and no longer exhibits self-healing properties. While the crys-tallized chromate coating will provide satisfactory corrosion protectionunder most natural environments, the chroma
25、te coating will no longer passaccelerated corrosion tests.NOTE 5The time period referred to is the length of time between theend of the plating operation and loading of the item concerned into theheat treatment processor.6.2 For high-strength steels, the conditions given in Table 1may be applied. Fo
26、r steels of actual tensile strength below 1000MPa, heat treatment after plating is not essential.6.3 Electroplated steel items having surface-hardened areasand through hardened or bearing steels, which would suffer anunacceptable reduction in hardness by treatment in accordancewith Table 1 shall be
27、heat treated at a lower temperature, butnot below 130C.6.4 Treatment at 440 to 480C will reduce the hardness ofchromium deposits. It shall not be applied to steels that may beaffected adversely by heat treatment at this temperature, andthe lower temperature range shall be applied. For temperedsteels
28、, items shall not be heat treated above a temperature thatshall be 50C below the tempering temperature.7. Keywords7.1 delayed brittle failure; heat treatment; hydrogen em-brittlement; hydrogen embrittlement relief; hydrogen inducedcracking; hydrogen stress cracking; post-treatments of steelTABLE 1 C
29、lasses of Embrittlement-Relief Heat Treatment (SeeSections 4-6 for details on the Use of Table 1)Hydrogen Embrittlement-Relief Treatment Classes for High-Strength SteelsClass Steels of Tensile Strength (Rm), MPaTemperature,CTime, hER-0 not applicableER-1 1701 to 1800 190220 min 22ER-2 1601 to 1700 1
30、90220 min 20ER-3 1501 to 1600 190220 min 18ER-4 1401 to 1500 190220 min 16ER-5 1301 to 1400 190220 min 14ER-6 1201 to 1300 190220 min 12ER-7A1525 or greater 177205 min 12ER-8 1101 to 1200 190220 min 10ER-9 1000 to 1100 190220 min 8ER-10A1250 to 1525 177205 min 8ER-11A1450 to 1800 190220 min 6ER-12A1
31、000 to 1500 177205 min 4ER-13 1000 to 1800 unpeened itemsand for engineering chromiumplated items440480 min 1ER-14Asurface-hardened parts 1401 130160 min 8ER-15Asurface-hardened parts 1401 to1800 plated with cadmium, tin,zinc, or their alloys130160 min 8ER-16 surface-hardened parts 1401plated with c
32、admium, tin, zinc,or their alloys130160 min 16AClasses ER-7, ER-10, ER-11, ER-12, ER-14, and ER-15 are traditionaltreatments used in Federal Standard QQ-C-320. They do not apply to any otherstandard.B 850 98 (2004)2ASTM International takes no position respecting the validity of any patent rights ass
33、erted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time b
34、y the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will rece
35、ive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Inte
36、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B 850 98 (2004)3
