ASTM B895-99
(Test Method)Standard Test Methods for Evaluating the Corrosion Resistance of Powder Metallurgy (P/M) Stainless Steel Parts/Specimens by Immersion in a Sodium Chloride Solution
Standard Test Methods for Evaluating the Corrosion Resistance of Powder Metallurgy (P/M) Stainless Steel Parts/Specimens by Immersion in a Sodium Chloride Solution
SCOPE
1.1 These test methods cover a procedure for evaluating the ability of sintered P/M 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 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B895–99
Standard Test Methods for
Evaluating the Corrosion Resistance of Powder Metallurgy
(P/M) Stainless Steel Parts/Specimens by Immersion in a
Sodium Chloride Solution
This standard is issued under the fixed designation B 895; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Ferric Chloride Solution
1.1 These test methods cover a procedure for evaluating the
3. Terminology
ability of sintered P/M stainless steel parts/specimens to resist
3.1 Definitions—Useful definitions of terms for metal pow-
corrosion when immersed in a sodium chloride (NaCl) solu-
ders and powder metallurgy are found in Terminology B 243.
tion.
1.2 Corrosion resistance is evaluated by one of two meth-
4. Summary of Test Method
ods. In Method 1, the stainless steel parts/specimens are
4.1 Method 1 is recommended for evaluating the corrosion
examined periodically and the time to the first appearance of
resistance of stainless steel powder metallurgy parts/specimens
staining or rust is used to indicate the end point. In Method 2,
and to verify that proper materials and processing conditions
continued exposure to the sodium chloride solution is used to
were used.
monitor the extent of corrosion as a function of time.
4.1.1 In this method, parts/specimens are immersed in 5 %
1.3 This standard does not purport to address the safety
(by mass) NaCl solution and examined periodically until the
concerns, if any, associated with its use. It is the responsibility
first appearance of staining or rust. A part or specimen is
of the user of this standard to establish appropriate safety and
considered to have reached the end point when the first sign of
health practices and determine the applicability of regulatory
corrosion occurs.
limitations prior to use.
4.2 Method 2 is recommended for evaluating the processing
variables used in producing parts/specimens.
2. Referenced Documents
4.2.1 In this method, parts/specimens are exposed further to
2.1 ASTM Standards:
the NaCL solution and periodically rated as either A, B, C, or
A 380 Practice for Cleaning and Descaling Stainless Steel
2 D (A-no corrosion; D-high or extreme corrosion) by compari-
Parts, Equipment and Systems
3 son with Fig. 1, a photograph of corroded specimens which
B 243 Terminology of Powder Metallurgy
serves as a standard. Method 2 has been found useful in alloy
B 528 Test Method for Transverse Rupture Strength of
3 screening and process optimization studies.
Sintered Metal Powder Specimens
D 1193 Specification for Reagent Water
5. Significance and Use
G 1 Practice for Preparing, Cleaning and Evaluating Corro-
5 5.1 The ability of sintered powder metallurgy stainless steel
sion Test Specimens
parts/specimens to resist corrosion when immersed in sodium
G 48 Test Method for Pitting and Crevice Corrosion Resis-
chloride solution is important to their end use. Causes of
tance of Stainless Steel and Related Alloys By the Use of
unacceptable corrosion may be incorrect alloy, contamination
ofthepartsbyironorsomeothercorrosion-promotingmaterial
or improper sintering of the parts (for example, undesirable
These test methods are under the jurisdiction of Committee B-9 on Metal
carbideandnitrideformationscausedbypoorlubricantburnoff
Powders and Metal Powder Products, and is the direct responsibility of Subcom-
or improper sintering atmosphere).
mittee B09.05on Structural Parts.
Current edition approved April 10, 1999. Published August 1999.
5.2 This standard may be part of a purchase agreement
Annual Book of ASTM Standards, Vol 01.01.
between the P/M parts producer (seller) and the user of the
Annual Book of ASTM Standards, Vol 02.05.
parts (purchaser) (Method 1). It may also be used to optimize
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 03.02. part or specimen production parameters (Method 2).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B895
FIG. 1 Rust or Stain (Immersion in Aqueous Solution of 5% NaCl)
6. Apparatus 8.1.2 The use of tongs or gloves, or both, to prevent
contamination in handling is suggested.
6.1 Sealable Glass or Plastic Jars, of suitable capacity for
specimens to be completely covered by the NaCl solution.
9. Preparation of Apparatus
6.2 Glass Beads (4 mm is recommended).
9.1 Soak previously used jars and glass beads in concen-
6.3 Glass Stirring Rods.
trated HCl for at least 12 h to remove rust stains; rinse with
6.4 Tongs (Stainless steel or plastic, nonmetallic plated).
distilled or deionized water, then rinse again and allow to dry.
7. Reagents
9.1.1 Place the glass beads in the bottom of the beaker. Use
a sufficient number of beads to keep the test specimen off the
7.1 Asodium chloride solution consisting of 5 6 0.1 % (by
bottom of the jar.
mass) NaCl shall be prepared using distilled or deionized water
conforming to Specification D 1193 (Type 4) andACS reagent
10. Procedure
grade NaCl solution. The 5 % NaCl solution shall be prepared
no less than 16 h before beginning the corrosion testing. 10.1 Method 1:
7.2 Concentrated HCl. 10.1.1 Place one part or specimen per jar on top of the glass
7.3 Distilled or deionized water. beads.Add the NaCl solution to each jar so that the volume of
solution, in millilitres, is at least five times the mass of the
8. Test Specimen
specimen in grams. The distance from the surface of the
8.1 Usuallytestpartsaresinteredparts,buttheymayalsobe part/specimen to the top of the solution should be at least 25
standard transverse rupture bars as defined in Test Method mm. The ratio of the volume of air to the volume of solution in
B 528.
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