1、Designation: G 76 07Standard Test Method forConducting Erosion Tests by Solid Particle ImpingementUsing Gas Jets1This standard is issued under the fixed designation G 76; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of
2、last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of materialloss by gas-entrained solid particle impingement erosion withjetnozz
3、le type erosion equipment. This test method may beused in the laboratory to measure the solid particle erosion ofdifferent materials and has been used as a screening test forranking solid particle erosion rates of materials in simulatedservice environments (1, 2).2Actual erosion service involvespart
4、icle sizes, velocities, attack angles, environments, and soforth, that will vary over a wide range (3-5). Hence, any singlelaboratory test may not be sufficient to evaluate expectedservice performance. This test method describes one wellcharacterized procedure for solid particle impingement erosionm
5、easurement for which interlaboratory test results are avail-able.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appl
6、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 122 Practice for Calculating Sample Size to Estimate,With a Specified Tolerable Error, the Average for aCharacteristic of a Lot or ProcessG40 Terminology Relating to Wear and Erosion2.2 American National S
7、tandard:ANSI B74.10 Grading of Abrasive Microgrits43. Terminology3.1 Definitions:3.1.1 erosionprogressive loss of original material from asolid surface due to mechanical interaction between thatsurface and a fluid, a multicomponent fluid, or impinging liquidor solid particles.3.1.2 impingementa proc
8、ess resulting in a continuingsuccession of impacts between (liquid or solid) particles and asolid surface.3.2 Definitions of Terms Specific to This Standard:3.2.1 erosion valuethe volume loss of specimen materialdivided by the total mass of abrasive particles that impacted thespecimen (mm3g1).3.2.2
9、Normalized Erosion Rateerosion value (mm3g1)of specimen material divided by erosion value (mm3g1)ofreference material.4. Summary of Test Method4.1 This test method utilizes a repeated impact erosionapproach involving a small nozzle delivering a stream of gascontaining abrasive particles which impact
10、s the surface of atest specimen. A standard set of test conditions is described.However, deviations from some of the standard conditions arepermitted if described thoroughly. This allows for laboratoryscale erosion measurements under a range of conditions. Testmethods are described for preparing the
11、 specimens, conductingthe erosion exposure, and reporting the results.5. Significance and Use5.1 The significance of this test method in any overallmeasurements program to assess the erosion behavior ofmaterials will depend on many factors concerning the condi-tions of service applications. The user
12、s of this test methodshould determine the degree of correlation of the resultsobtained with those from field performance or results usingother test systems and methods. This test method may be usedto rank the erosion resistance of materials under the specifiedconditions of testing.1This test method
13、is under the jurisdiction of ASTM Committee G02 on Wearand Erosion and is the direct responsibility of Subcommittee G02.10 on Erosion bySolids and Liquids.Current edition approved July 1, 2007. Published July 2007. Originally approvedin 1983. Last previous edition approved in 2005 as G 7605.2The bol
14、dface numbers in parentheses refer to a list of references at the end ofthis standard.3For 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
15、 page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 The apparatus is capable of eroding m
16、aterial from a testspecimen under well controlled exposure conditions. A sche-matic drawing of the exit nozzle and the particle-gas supplysystem is shown in Fig. 1. Deviations from this design arepermitted; however, adequate system characterization andcontrol of critical parameters are required. Dev
17、iations in nozzledesign and dimensions must be documented. Nozzle length todiameter ratio should be 25:1 or greater in order to achieve anacceptable particle velocity distribution in the stream. Therecommended nozzle5consists of a tube about 1.5 mm innerdiameter, 50 mm long, manufactured from an ero
18、sion resistantmaterial such as WC, A12O3, and so forth. Erosion of thenozzle during service shall be monitored and shall not exceed10 % increase in the initial diameter.6.2 Necessary features of the apparatus shall include ameans of controlling and adjusting the particle impact velocity,particle flu
19、x, and the specimen location and orientation relativeto the impinging stream.6.3 Various means can be provided for introducing particlesinto the gas stream, including a vibrator-controlled hopper or ascrew-feed system. It is required that the system provide auniform particle feed and that it be adju
20、stable to accommodatedesired particle flow values.6.4 A method to measure the particle velocity shall beavailable for use with the erosion equipment (6-9). Examplesof accepted methods are high-speed photography (7), rotatingdouble-disk (6), (8), and laser velocimeter (9). Particle velocityshall be m
21、easured at the location to be occupied by thespecimen and under the conditions of the test.7. Test Materials and Sampling7.1 This test method can be used over a range of specimensizes and configurations. One convenient specimen configura-tion is a rectangular strip approximately 10 by 30 by 2 mmthic
22、k. Larger specimens and other shapes can be used wherenecessary, but must be documented.7.2 The abrasive material to be used shall be uniform inessential characteristics such as particle size, moisture, chemi-cal composition, and so forth.7.3 Sampling of material for the purpose of obtainingrepresen
23、tative test specimens shall be done in accordance withacceptable statistical practice. Practice E 122 shall be con-sulted.8. Calibration of Apparatus8.1 Specimens fabricated from Type 1020 steel (see Table 1and Fig. 2) equivalent to that used in the interlaboratory testseries6shall be tested periodi
24、cally using specified (see Section9)50mA12O3particles to verify the satisfactory performanceof the apparatus. It is recommended that performance beverified using this reference material every 50 tests during ameasurement series, and also at the beginning of each new testseries whenever the apparatus
25、 has been idle for some time. Therecommended composition, heat treatment, and hardness rangefor this steel are listed in Table 1. The use of a steel of differentcomposition may lead to different erosion results. A photomi-crograph of the specified A12O3particles is shown in Fig. 3.The range of erosi
26、on results to be expected for this steel underthe standard test conditions specified in Section 9 is shown inTable 2 and is based on interlaboratory test results.68.2 Calibration at standard test conditions is recommendedeven if the apparatus is operated at other test conditions.8.3 In any test prog
27、ram the particle velocity and particlefeed rate shall be measured at frequent intervals, typicallyevery ten tests, to ensure constancy of conditions.9. Standard Test Conditions9.1 This test method defines the following standard condi-tions.9.1.1 The nozzle tube shall be 1.5 mm 6 0.075 mm innerdiamet
28、er at least 50 mm long.9.1.2 The test gas shall be nominally dry air. The test reportshall indicate the amount of water present in the test gas, atwhat pressure, and how the measurement was conducted.NOTE 1In the interlaboratory testing, one laboratory utilized cylinder-type compressed air having a
29、water content amount described as “-50Cdew point” by the manufacturer. Whatever gas source is used in testing, acomparable level of dryness to that is recommended.5The sole source of supply of the recommended nozzle (tungsten carbide)known to the committee at this time is Kennametal Inc., 1600 Techn
30、ology Way, POBox 231, Latrobe, PA 15650-0231. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.6Supporting data have
31、been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: G021003.FIG. 1 Schematic Drawing of Solid Particle Erosion EquipmentTABLE 1 Characteristics of Type 1020 Steel Reference MaterialAnnealed 15 min at 760C (1400F), air cooled.Hardness: HRB = 70 6 2.Chemi
32、cal Composition:C=0.206 0.01 wt %Mn=0.456 0.10S=0.036 0.01Si = 0.16 0.05P=0.016 0.01G760729.1.3 The abrasive particles shall be nominal 50-m angularA12O3,7equivalent to those used in the interlaboratory testseries (see Fig. 3). Abrasive shall be used only once.NOTE 2Typical size distribution (determ
33、ined by sedimentation):100 % between 20 to 83 m, 50 % between 42 to 57 m, 50 % coarserthan 48 m.9.1.4 The abrasive particle velocity shall be 30 6 2 ms1,measured at the specimen location.At this velocity the gas flowrate will be approximately 8 Lmin1and the system pressurewill be approximately 140 k
34、Pa (20 psig) although the pressurewill depend on the specific system design.9.1.5 The test time shall be 10 min to achieve steady stateconditions. Longer times are permissible so long as the finalerosion crater is no deeper than 1 mm.9.1.6 The angle between the nozzle axis and the specimensurface sh
35、all be 90 6 2.9.1.7 The test temperature shall be the normal ambientvalue (typically between 18C to 28C).9.1.8 The particle feed rate shall be 2.0 6 0.5 gmin1. Thiscorresponds to a particle flux at the specimen surface of about2 mgmm2s1under standard conditions. Particle flux deter-mination requires
36、 measurement of the eroded area on thespecimen and is subject to considerable error. A measuredwidth and depth profile of an erosion crater produced usingstated conditions is shown in Fig. 4 and indicates a typicaleroded width/depth relation.9.1.9 The distance from specimen surface to nozzle endshal
37、l be 10 6 1 mm.10. Optional Test Conditions10.1 When test conditions or materials other than thosegiven in Section 9 are used, reference to this test method shallclearly specify all test conditions and materials. It should benoted that other conditions, for example, larger particle veloci-ties, may
38、adversely affect measurement precision.7The sole source of supply of the aluminum oxide particlesobtained as grade240-grit alundum powder known to the committee at this time is Norton Co., 1New Bond St, Worcester, MA 01606. If you are aware of alternative suppliers,please provide this information to
39、 ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.FIG. 2 Microstructure of 1020 Steel Reference MaterialASTM Grain Size 9FIG. 3 Photomicrograph of 50 m A12O3Particles Used inInterlaboratory Tes
40、tingFIG. 4 Example of Erosion Crater Profile for 1020 Steel Eroded at70 m/s Particle Velocity Using Standard Conditions OtherwiseG7607311. Test Procedure11.1 Establish and measure the particle velocity and particleflow specified. Adjust equipment controls to obtain propervelocity and flow conditions
41、 before inserting test specimens.Particle flow rate values are determined by collecting (see Note3) and subsequently weighing the abrasive exiting from thenozzle for a measured time period.NOTE 3Particles may be collected by directing the flow from thenozzle into a large vented container. Care must
42、be taken to avoid causingany significant back pressure on the nozzle as this will disturb the systemflow conditions.11.2 Prepare the specimen surface if required to achieveuniformity and adequate finish. Grinding through a series ofabrasive papers to 400 grit is usually adequate so long as allsurfac
43、e scale is removed.Asurface roughness of 1 m (40 in.)rms or smaller is recommended. Clean the specimen surfacecarefully (see Note 4). Weigh on an analytical balance to60.01 mg (see Note 5).NOTE 4Important considerations in cleaning include surface oils orgreases, surface rust or corrosion, adhering
44、abrasive particles, etc.NOTE 5Erosion weight loss determinations to 60.1 mg may besufficient for particle velocities above 70 ms1or sufficiently longexposure times which lead to weight losses greater than 10 mg.11.3 Mount the specimen in proper location and orientationin the apparatus. Subject the s
45、pecimen to particle impingementfor a selected time interval, measured to an accuracy of 5 s.Remove the specimen, clean carefully (see Note 4), reweighand calculate the mass loss.11.4 Repeat this process utilizing a new specimen each timeto determine at least four points for a total time of at least
46、10min and plot those values as mass loss versus elapsed time.Suitable times would be 2, 4, 8, and 16 min for a material suchas Type 1020 steel. Steady state erosion should result after 1 to2 min, depending on the material. Two examples of measurederosion versus time curves are shown in Fig. 5.11.5 T
47、he steady state erosion rate (see Terminology G40)isdetermined from the slope of the mass loss versus time plot.The average erosion value is calculated by dividing erosionrate (mgmin1) by the abrasive flow rate (gmin1) and thendividing by the specimen density (gcm3). Report the averageerosion value
48、as (mm3g1).11.6 Repeat 11.1 at the end of a series of tests (typicallyevery 10 tests) and more frequently if necessary.12. Report12.1 The test report shall include the following information:12.1.1 Material identification: type, chemical specification,heat and processing treatment, hardness, and dens
49、ity. Process-ing conditions shall include method of casting (such as chill orsand); method of forming (such as forging or pressing andsintering); and the percent of ideal density (important forceramics and powder metallurgy alloys).12.1.2 Specimens: method of preparing and cleaning speci-mens, initial surface roughness, and number tested.12.1.3 Eroding particle identification: size distribution,shape, composition, purity, source, and manufacturing method.Provide photograph of typical collection of particles. Refer-ence (10) can be co
