ASTM_B_895_-_16.pdf

Designation:B89516Standard Test Methods forEvaluating the Corrosion Resistance of Stainless SteelPowder Metallurgy(PM)Parts/Specimens by Immersion in aSodium Chloride Solution1This standard is issued under the fixed designation B895;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 These test methods cover a procedure for evaluating theability of sintered PM stainless steel parts/specimens to resistcorrosion when immersed in a sodium chloride(NaCl)solu-tion.1.2 Corrosion resistance is evaluated by one of two meth-ods.In Method 1,the stainless steel parts/specimens areexamined periodically and the time to the first appearance ofstaining or rust is used to indicate the end point.In Method 2,continued exposure to the sodium chloride solution is used tomonitor the extent of corrosion as a function of time.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A380 Practice for Cleaning,Descaling,and Passivation ofStainless Steel Parts,Equipment,and SystemsB243 Terminology of Powder MetallurgyB528 Test Method for Transverse Rupture Strength of Pow-der Metallurgy(PM)SpecimensD610 Practice for Evaluating Degree of Rusting on PaintedSteel SurfacesD1193 Specification for Reagent WaterG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG48 Test Methods for Pitting and Crevice Corrosion Resis-tance of Stainless Steels and Related Alloys by Use ofFerric Chloride Solution3.Terminology3.1 DefinitionsUseful definitions of terms for metal pow-ders and powder metallurgy are found in Terminology B243.4.Summary of Test Method4.1 Method 1 is recommended for evaluating the corrosionresistance of stainless steel powder metallurgy parts/specimensand to verify that proper materials and processing conditionswere used.4.1.1 In this method,parts/specimens are immersed in 5%(by mass)NaCl solution and examined periodically until thefirst appearance of staining or rust.A part or specimen isconsidered to have reached the end point when the first sign ofcorrosion occurs.4.2 Method 2 is recommended for evaluating the processingvariables used in producing parts/specimens.4.2.1 In this method,parts/specimens are exposed further tothe NaCL solution and periodically rated as either A,B,C,orD(A-no corrosion;D-high or extreme corrosion)by compari-son with Fig.1,a photograph of corroded specimens whichserves as a standard.Additional examples of quantitativeratings may be found in Test Method D610.Method 2 has beenfound useful in alloy screening and process optimizationstudies.5.Significance and Use5.1 The ability of sintered powder metallurgy stainless steelparts/specimens to resist corrosion when immersed in sodiumchloride solution is important to their end use.Causes ofunacceptable corrosion may be incorrect alloy,contaminationof the parts by iron or some other corrosion-promoting materialor improper sintering of the parts(for example,undesirablecarbide and nitride formations caused by poor lubricant burnoffor improper sintering atmosphere).1These test methods are under the jurisdiction of Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.05 on Structural Parts.Current edition approved April 1,2016.Published April 2016.Originallyapproved in 1999.Last previous edition approved in 2015 as B895 15.DOI:10.1520/B0895-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 This standard may be part of a purchase agreementbetween the PM parts producer(seller)and the user of the parts(purchaser)(Method 1).It may also be used to optimize part orspecimen production parameters(Method 2).6.Apparatus6.1 Sealable Glass or Plastic Jars,of suitable capacity forspecimens to be completely covered by the NaCl solution.6.2 Glass Beads(4 mm is recommended).6.3 Glass Stirring Rods.6.4 Tongs(Stainless steel or plastic,nonmetallic plated).7.Reagents7.1 A sodium chloride solution consisting of 5 6 0.1%(bymass)NaCl shall be prepared using distilled or deionized waterconforming to Specification D1193(Type 4)and A