1、SAE-J439ADOPTION NOTICESAE-J439, “TOOLS, SINTERED CARBIDE“, was adopted on 12-JUN-92 foruse by the Department of Defense (DoD). Proposed changes byDoD activities must be submitted to the DoD Adopting Activity:Commander, Atlantic Division, Naval Facilities EngineeringCommand, Criteria Office, 1510 Gi
2、lbert St, Norfolk, VA 23511-2699. Copies of this document may be purchased from theSociety of Automotive Engineers 400 Commonwealth DriveWarrendale, Pennsylvania, United States, 15096-0001. http:/www.sae.org/_Custodians: Adopting Activity:Navy - YDArmy - MRNavy - YDAir Force - 99Reviewer Activities:
3、DLA - ISFSC 9510DISTRIBUTION STATEMENT A: Approved for public release; distributionis unlimited.SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicab
4、ility and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and sugg
5、estions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1991 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, W
6、arrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National StandardJ439aREV.FEB77Issued 1956-04Revised 1977-02Superseding J439SINTERED CARBIDE TOOLSForewordThis Document has also changed to comply with the new SAE Technical Standards Board format.1. ScopeThis recomm
7、ended practice covers methods for measuring or evaluating five properties orcharacteristics of sintered carbide which contribute significantly to the performance of sintered carbide tools.These properties are: hardness, specific gravity, apparent porosity, structure, and grain size. They are covered
8、under separate headings below.2. ReferencesThere are no referenced publications specified herein.3. Hardness3.1 GeneralThe Rockwell hardness tester provides a simple, rapid, and reliable means of measuring thehardness of sintered carbide tools. A hardness value is easily obtained, but is subject to
9、error if precautionarymeasures are not taken in making this test. Hardness determinations, therefore, shall be made according tothe requirements outlined below and in ASTM E 18, Methods of Test for Rockwell Hardness and RockwellSuperficial Hardness of Metallic Materials.3.2 Apparatusa. Rockwell hard
10、ness testing machine with 60 kg load and diamond brale penetrator for use with the Ascale1.b. Two tungsten carbide test blocks with a hardness of 90.0 and 92.0 Rockwell A (RA) respectively.3.3 Material - SamplePreparation of the surface of the specimen prior to making the hardness test is of majorim
11、portance. It is recommended that a finish equivalent to that produced with a 220 grit diamond grindingwheel be obtained on the surface which is to be checked for hardness. Because of the shallow penetration ofthe diamond penetrator used in making this test, the surface being tested for hardness must
12、 be parallel to thesurface opposite of that being tested. Both surfaces must be smooth and devoid of any bulge or otherirregularity affecting parallelism. If these two surfaces are only slightly out of parallel, an error will be obtainedin the hardness reading.1. It is recommended that a diamond bra
13、le especially selected for use with the Rockwell “A“ scale be used for this type of testing. This type of penetrator is of higher quality, free from chips and other imperfections, and should be specified for Rockwell “A“ scale use. Slowing down of the rate of speed at which the major load is applied
14、 during testing will aid in increasing the life of the diamond brale. This change in load application does not affect the accuracy of the hardness reading. The use of the superficial scale is not recommended for hardness testing of sintered car-bides unless extreme care is exercised with regard to p
15、arallelism and smoothness during surface preparation of the specimen.SAE J439a Revised FEB77-2-It is important that the Rockwell hardness testing machine is located in such a manner and area that it is freefrom vibration while hardness tests are being performed. Vibration is detected by the bounding
16、 effecttransmitted through the needle of the indicator after the major load has been applied.3.4 ProcedureThe hardness test shall be made using the RA scale. This reading is obtained by observing thedeflection of the needle pointer on the black scale with a 60 kg load and the diamond brale penetrato
17、r.2Before making the hardness test on the carbide material, the Rockwell testing machine shall be checked foraccuracy, using a tungsten carbide test block of known hardness. Two check blocks of different hardnessvalues are recommended to assure accurate hardness readings over the general range of ha
18、rdness of thecommon grades of sintered carbides. The check blocks should have a hardness of 90.0 and 92.0 RArespectively. The check block having the hardness closest to the expected hardness of the carbide material tobe checked shall be selected for calibrating the Rockwell tester. The average of fi
19、ve readings should checkwithin 0.2 of a hardness number. If the Rockwell tester varies appreciably from the hardness number of thetest block, the dial of the machine must be adjusted so that the correct reading is obtained. The amount ofvariation is noted and this correction plus or minus is applied
20、 when taking the hardness reading on thespecimens of sintered carbide being tested. This dial adjustment will be made just before the major load isapplied. With careful manipulations, hardness readings can be accurately duplicated when the hardness testeris calibrated in this manner.4. Specific Grav
21、ity4.1 GeneralThe specific gravity of sintered carbide tool materials shall be determined by the immersion method,using as a basis the difference in weight of the carbide in air and in water.4.2 Apparatusa. A standard analytical balance of 200 g capacity and 0.1 mg sensitivity at full load.b. A 150-
22、 or 250-ml beaker, depending upon the size of the carbide specimen.c. Small diameter nonferrous wire.d. Thermometer 0100 C for room temperatures capable of being read to nearest 0.5 C.4.3 Materialsa. The specimen shall be surface ground all over with a 100 grit diamond wheel before testing.b. Distil
23、led water.4.4 Procedurea. Weigh the specimen, to the nearest 0.5 mg.b. Support a beaker of distilled water3 over the pan of the balance by a suitable bridge. Water levelshould be high enough to cover the specimen by at least 1/4 in.c. Suspend the specimen and the wire from the beam hook, placing the
24、 specimen in the water, and weighto the nearest 0.5 mg.d. Remover the specimen from the wire and weigh the wire alone in water. Subtract this weight from thetotal weight found in step c.e. Observe the temperature of the water to the nearest 1.0 C.2. See Footnote 1.3. Care should be used to see that
25、no air bubbles are present on the sample after immersion, and that the wire twist on the sample is completely submerged. Several drops of a suitable wetting agent will aid in eliminating air bubbles.SAE J439a Revised FEB77-3-4.5 CalculationsWa = Weight of Specimen in AirWw = Weight of Specimen in Wa
26、terD = Relative Density of Water at Test Temperature (Density relative to that of Water at 4 C)(Eq. 1)5. Apparent Porosity, Structure, And Grain Size5.1 GeneralApparent porosity, structure, and grain size shall be evaluated by metallographic examination, asoutlined below.Apparent porosity is the ter
27、m applied to the inherent porosity, non-metallic inclusions, and uncombined carbonas observed in the microstructure of the properly prepared surface of sintered carbides.Structure refers to the type and distribution of the metal carbides and binder material observed in themicrostructure of the prope
28、rly prepared surface of sintered carbides.Grain size is the term applied to the predominating particle sizes, in microns, of the metal carbides observed inthe microstructure.5.2 Sample PreparationSelect a specimen approximately 1/2 in. square from the area of particular interest ofthe sample to be t
29、ested. Sectioning should be done with a diamond cutoff wheel. Mount unwieldy specimensin hard bakelite or its equivalent, then grind as follows:a. Rough grind using a green silicon carbide wheel.b. Fine grind using a 320 grit diamond wheel running at a speed of approximately 5500 surface fpm.Samples
30、 should be polished using the ordinary metallographic polishing equipment. Impregnate a paperpolishing disc, properly attached to the bronze disc of the polishing lap, with a light (SAE 10) oil. Applydiamond paste to the oiled paper and work it in with the fingertip. At least two polishing laps shou
31、ld be used inthe following order:a. A diamond lap using a 10 m maximum diamond powder.b. A diamond lap using a 1 m maximum diamond powder.Hold the specimen 1-3 in. from the center of the lap running at approximately 1150 rpm. Considerablepressure should be exerted on the specimen while polishing in
32、intervals of approximately 10 sec. Rotating thespecimen 90 deg between each interval is recommended. (CAUTION: Light pressure and too much polishingmay cause pitting of the specimen.)Polishing is ineffective when the specimen is above approximately 150 F; therefore, polishing time should becarefully
33、 watched to keep the temperature of the specimen below this point. Extreme cleanliness is necessaryto prevent contamination of the diamond laps. The specimen should be washed thoroughly with a suitablesolvent after each polishing operation.Specific GravityWa DWa Ww-=SAE J439a Revised FEB77-4-5.3 App
34、arent Porosity EvaluationAfter the prescribed sample preparation, the sample shall be examined inthe unetched condition at a magnification of 200X.A porosity rating shall be made by comparing the observed field with the porosity charts of Figures 13.The rating charts depict both the type of porosity
35、, designated alphabetically, and the quantity of porosity,designated numerically. Type A classifies porosity sizes under 10 m in diameter; Type B classifies porositysizes between 10 and 40 m in diameter; Type C classifies cluster porosity or that developed by the presenceof uncombined carbon, and is
36、 considered the type most detrimental to tool performance.5.4 Structure EvaluationAfter the prescribed sample preparation the sample shall be etched and examined at amagnification of 1500X. The etchant shall consist of a fresh solution having equal parts of 10% potassiumhydroxide and 10% potassium f
37、erricyanide. The sample shall be immersed in the etchant for 2 minutes, thenrinsed with water and the polished surface swabbed with wet cotton. A second immersion for approximatelyanother 2 minutes shall be made to delineate the structure. The sample shall then be washed with water anddried with alc
38、ohol and air to prevent staining. Examination of the prepared surface shall be made with ametallographic microscope utilizing an oil immersion objective. Figures 4A and 4B are typicalphotomicrographs of tungsten carbide (WC) with 6% cobalt and 13% cobalt, respectively. Figures 4C and 4Dare typical p
39、hotomicrographs of tungsten carbide (WC) plus solid solution carbide (WC-TiC-TaC) with 4.5%cobalt and 11% cobalt, respectively. The tungsten carbide particles are angular and gray in appearance, thesolid solution particles, where present, are rounded and usually darker gray, and the cobalt binder ap
40、pearswhite. The abnormal “eta phase“ carbide is not depicted by the photomicrographs. It is a brittle, carbondeficient carbide detrimental to tool performance but is readily detected as a very rapid etching, blackconstituent.The data provided by this test are an excellent indicator for identifying a
41、 particular producers product and itsuniformity.5.5 Grain Size EvaluationSample preparation, etching technique, and equipment shall be the same asdescribed for structure evaluation.The grain size shall be determined by comparing representative areas of the observed sample field with thecarbide grain
42、 size chart (Figure 5). This chart illustrates the relationship of particle sizes from 1 to 10 m asobserved at a magnification of 1500X.The grain size rating shall consist of a sequence of numbers such as 231. Each number refers to a carbideparticle size range; that is a “1“ includes all particles w
43、hich are 1 m or finer, a “2“ includes all particles over 1through 2 m, a “3“ includes all particles over 2 through 3 m, etc., as illustrated by the carbide grain sizechart. The sequence of the numbers shall be in the order of the sample area they represent, with the firstnumber representing the grea
44、test area. A minimum of 80% of the representative sample area shall beincluded in the rating.Grain size and distribution has considerable influence on the mechanical properties of sintered carbide. Thus,materials having similar composition but different grain size and distribution may have very diff
45、erentperformance characteristics.SAE J439a Revised FEB77-5-FIGURE 1TYPE A - APPARENT POROSITY MICROSTRUCTURE OF CEMENTED CARBIDES (X200) (B 276)SAE J439a Revised FEB77-6-FIGURE 2TYPE B - APPARENT POROSITY MICROSTRUCTURE OF CEMENTED CARBIDES (X200) (B 276)SAE J439a Revised FEB77-7-FIGURE 3TYPE C - AP
46、PARENT POROSITY MICROSTRUCTURE OF CEMENTED CARBIDS (X200) (B 276)SAE J439a Revised FEB77-8-FIGURE 4TYPICAL MICROSTRUCTURES OF SINTERED CARBIDS (1500X, MURAKAMIS REAGENT)6. Notes6.1 Marginal IndiciaThe change bar (l) located in the left margin is for the convenience of the user in locatingareas where
47、 technical revisions have been made to the previous issue of the report. An (R) symbol to the leftof the document title indicates a complete revision of the report.PREPARED BY THE SAE IRON AND STEEL TECHNICAL COMMITTEESAE J439a Revised FEB77RationaleNot applicable.Relationship of SAE Standard to ISO
48、 StandardNot applicable.ApplicationThis recommended practice covers methods for measuring or evaluating five properties orcharacteristics of sintered carbide which contribute significantly to the performance of sintered carbidetools. These properties are: hardness, specific gravity, apparent porosity, structure, and grain size. Theyare covered under separate headings below.Reference SectionThere are no referenced publications specified herein.Developed by the SAE Iron and Steel Technical Committee
