ASTM B895-16(2020)e1
(Test Method)Standard Test Methods for Evaluating the Corrosion Resistance of Stainless Steel Powder Metallurgy (PM) Parts/Specimens by Immersion in a Sodium Chloride Solution
Standard Test Methods for Evaluating the Corrosion Resistance of Stainless Steel Powder Metallurgy (PM) Parts/Specimens by Immersion in a Sodium Chloride Solution
SIGNIFICANCE AND USE
5.1 The ability of sintered powder metallurgy stainless steel parts/specimens to resist corrosion when immersed in sodium chloride solution is important to their end use. Causes of unacceptable corrosion may be incorrect alloy, contamination of the parts by iron or some other corrosion-promoting material or improper sintering of the parts (for example, undesirable carbide and nitride formations caused by poor lubricant burnoff or improper sintering atmosphere).
5.2 This standard may be part of a purchase agreement between the PM parts producer and the purchaser of the parts (Method 1). It may also be used to optimize part or specimen production parameters (Method 2).
SCOPE
1.1 These test methods cover a procedure for evaluating the ability of sintered PM stainless steel parts/specimens to resist corrosion when immersed in a sodium chloride (NaCl) solution.
1.2 Corrosion resistance is evaluated by one of two methods. In Method 1, the stainless steel parts/specimens are examined periodically and the time to the first appearance of staining or rust is used to indicate the end point. In Method 2, continued exposure to the sodium chloride solution is used to monitor the extent of corrosion as a function of time.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
1.5 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
Relations
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.
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Designation: B895 − 16 (Reapproved 2020)
Standard Test Methods for
Evaluating the Corrosion Resistance of Stainless Steel
Powder Metallurgy (PM) Parts/Specimens by Immersion in a
Sodium Chloride Solution
This standard is issued under the fixed designation B895; 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.
ε NOTE—Editorial changes were made throughout in October 2020.
1. Scope* A380 Practice for Cleaning, Descaling, and Passivation of
Stainless Steel Parts, Equipment, and Systems
1.1 These test methods cover a procedure for evaluating the
B243 Terminology of Powder Metallurgy
ability of sintered PM stainless steel parts/specimens to resist
B528 Test Method for Transverse Rupture Strength of Pow-
corrosion when immersed in a sodium chloride (NaCl) solu-
der Metallurgy (PM) Specimens
tion.
D610 Practice for Evaluating Degree of Rusting on Painted
1.2 Corrosion resistance is evaluated by one of two meth-
Steel Surfaces
ods. In Method 1, the stainless steel parts/specimens are
D1193 Specification for Reagent Water
examined periodically and the time to the first appearance of
G1 Practice for Preparing, Cleaning, and Evaluating Corro-
staining or rust is used to indicate the end point. In Method 2,
sion Test Specimens
continued exposure to the sodium chloride solution is used to
G48 Test Methods for Pitting and Crevice Corrosion Resis-
monitor the extent of corrosion as a function of time.
tance of Stainless Steels and Related Alloys by Use of
1.3 The values stated in SI units are to be regarded as Ferric Chloride Solution
standard. No other units of measurement are included in this
standard. 3. Terminology
1.4 This standard does not purport to address all of the
3.1 Definitions—Useful definitions of terms for metal pow-
safety concerns, if any, associated with its use. It is the
ders and powder metallurgy are found in Terminology B243.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
4.1 Method 1 is recommended for evaluating the corrosion
1.5 This international standard was developed in accor-
resistance of stainless steel powder metallurgy parts/specimens
dance with internationally recognized principles on standard-
and to verify that proper materials and processing conditions
ization established in the Decision on Principles for the
were used.
Development of International Standards, Guides and Recom-
4.1.1 In this method, parts/specimens are immersed in 5 %
mendations issued by the World Trade Organization Technical
(by mass) NaCl solution and examined periodically until the
Barriers to Trade (TBT) Committee.
first appearance of staining or rust. A part or specimen is
considered to have reached the end point when the first sign of
2. Referenced Documents
corrosion occurs.
2.1 ASTM Standards:
4.2 Method 2 is recommended for evaluating the processing
variables used in producing parts/specimens.
These test methods are under the jurisdiction of ASTM Committee B09 on
4.2.1 In this method, parts/specimens are exposed further to
Metal Powders and Metal Powder Products and are the direct responsibility of
the NaCL solution and periodically rated as either A, B, C, or
Subcommittee B09.05 on Structural Parts.
D (A-no corrosion; D-high or extreme corrosion) by compari-
Current edition approved Oct. 1, 2020. Published October 2020. Originally
son with Fig. 1, a photograph of corroded specimens which
approved in 1999. Last previous edition approved in 2016 as B895 – 16. DOI:
10.1520/B0895-16R20E01.
serves as a standard. Additional examples of quantitative
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ratings may be found in Practice D610. Method 2 has been
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
found useful in alloy screening and process optimization
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. studies.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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B895 − 16 (2020)
FIG. 1 Examples of Ratings for Various Amounts of Rust or Stain (Immersion in Aqueous Solution of 5 % NaCl)
5. Significance and Use grade NaCl solution. The 5 % NaCl solution shall be prepared
no less than 16 h before beginning the corrosion testing.
5.1 The ability of sintered powder metallurgy stainless steel
parts/specimens to resist corrosion when immersed in sodium
7.2 Concentrated HCl.
chloride solution is important to their end use. Causes of
7.3 Distilled or deionized water.
unacceptable corrosion may be incorrect alloy, contamination
ofthepartsbyironorsomeothercorrosion-promotingmaterial
8. Test Specimen
or improper sintering of the parts (for example, undesirable
carbideandnitrideformationscausedbypoorlubricantburnoff
8.1 Usuallytestpartsaresinteredparts,buttheymayalsobe
or improper sintering atmosphere).
standard transverse rupture bars as defined in Test Method
5.2 This standard may be part of a purchase agreement
B528. A minimum of ten parts/specimens shall be used for
between the PM parts producer and the purchaser of the parts
each test except for routine testing of production parts, where
(Method 1). It may also be used to optimize part or specimen
the use of five parts is acceptable.
production parameters (Method 2).
8.1.1 The density of the parts or specimens, as well as any
post sintering treatments (that is, coining, repressing,
6. Apparatus
machining, etc.), shall be stated. Parts or specimens shall be
6.1 Sealable Glass or Plastic Jars, of suitable capacity for
free of oil, dirt, grease and fingerprints. If they have been
specimens to be completely covered by the NaCl solution.
cleaned, the cleaning method shall be stated. Refer to Practices
6.2 Glass Beads (4 mm is recommended).
A380 and G1 for recommended cleaning practices.
6.3 Glass Stirring Rods.
8.1.2 The use of tongs or gloves, or both, to prevent
6.4 Tongs (Stainless steel or plastic, nonmetallic plated). contamination in handling is suggested.
NOTE 1—Iron or low-alloy steel particles present on the surface of the
7. Reagents
sintered stainless steel parts/speciments can be revealed by placing the
7.1 Asodium chloride solution consisting of 5 6 0.1 % (by
parts/specimens in a concentrated solution of copper sulfate, CuSO . The
mass)NaClshallbepreparedusingdistilledordeionizedwater
dissolved copper plates out on the iron/low-alloy particles within minutes
conforming to Specification D1193 (Type 4) and ACS reagent and can be seen by using a low-magnification microscope.
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B895 − 16 (2020)
9. Preparation of Apparatus according to the following:
A—The part/specimen is free from stain or rust.
9.1 Soak previously used jars and glass beads in concen-
B—The first
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