1、Designation: G76 07G76 13Standard Test Method forConducting Erosion Tests by Solid Particle ImpingementUsing Gas Jets1This standard is issued under the fixed designation G76; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year
2、 of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of material loss by gas-entrained solid particle impingement erosion withjet
3、nozzle type erosion equipment. This test method may be used in the laboratory to measure the solid particle erosion of differentmaterials and has been used as a screening test for ranking solid particle erosion rates of materials in simulated serviceenvironments (1, 2).2 Actual erosion service invol
4、ves particle sizes, velocities, attack angles, environments, and so forth, that willvary over a wide range (3-5). Hence, any single laboratory test may not be sufficient to evaluate expected service performance.This test method describes one well characterized procedure for solid particle impingemen
5、t erosion measurement for whichinterlaboratory test results are available.1.2 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard (exceptions below).1.2.1 Exceptions: Table 1 uses HRB hardness. Footnote 7 and 11.2 use abrasive
6、 grit designations.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to us
7、e.2. Referenced Documents2.1 ASTM Standards:3E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcessG40 Terminology Relating to Wear and Erosion2.2 American National Standard:ANSI B74.10 Grading of Abrasive Microgrits43. Te
8、rminology3.1 Definitions:1 This test method is under the jurisdiction of ASTM Committee G02 on Wear and Erosion and is the direct responsibility of Subcommittee G02.10 on Erosion by Solidsand Liquids.Current edition approved July 1, 2007July 1, 2013. Published July 2007July 2013. Originally approved
9、 in 1983. Last previous edition approved in 20052007 asG7605.07. DOI: 10.1520/G0076-07.10.1520/G0076-13.2 The boldface numbers in parentheses refer to a list of references at the end of this standard.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service
10、 at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.TABLE 1 Characteristics of Type 1020 Steel Reference
11、 MaterialAnnealed 15 min at 760C (1400F), air cooled.Annealed 900 s at 760C, air cooled.Hardness: HRB = 70 2.Chemical Composition:C = 0.20 0.01 wt %Mn = 0.45 0.10S = 0.03 0.01Si = 0.1 0.05P = 0.01 0.01This document is not an ASTM standard and is intended only to provide the user of an ASTM standard
12、an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is
13、to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 erosionprogressive loss of original material from a solid surface due to mechanical interaction between that surface anda fluid, a multicompo
14、nent fluid, or impinging liquid or solid particles.3.1.2 impingementa process resulting in a continuing succession of impacts between (liquid or solid) particles and a solidsurface.3.2 Definitions of Terms Specific to This Standard:3.2.1 erosion valuethe volume loss of specimen material divided by t
15、he total mass of abrasive particles that impacted thespecimen (mm3g1).3.2.2 Normalized Erosion Rateerosion value (mm3g1) of specimen material divided by erosion value (mm3g1) of referencematerial.4. Summary of Test Method4.1 This test method utilizes a repeated impact erosion approach involving a sm
16、all nozzle delivering a stream of gas containingabrasive particles which impacts the surface of a test specimen.Astandard set of test conditions is described. However, deviationsfrom some of the standard conditions are permitted if described thoroughly. This allows for laboratory scale erosion measu
17、rementsunder a range of conditions. Test methods are described for preparing the specimens, conducting the erosion exposure, andreporting the results.5. Significance and Use5.1 The significance of this test method in any overall measurements program to assess the erosion behavior of materials willde
18、pend on many factors concerning the conditions of service applications. The users of this test method should determine thedegree of correlation of the results obtained with those from field performance or results using other test systems and methods.This test method may be used to rank the erosion r
19、esistance of materials under the specified conditions of testing.6. Apparatus6.1 The apparatus is capable of eroding material from a test specimen under well controlled exposure conditions. A schematicdrawing of the exit nozzle and the particle-gas supply system is shown in Fig. 1. Deviations from t
20、his design are permitted;however, adequate system characterization and control of critical parameters are required. Deviations in nozzle design anddimensions must be documented. Nozzle length to diameter ratio should be 25:1 or greater in order to achieve an acceptableparticle velocity distribution
21、in the stream. The recommended nozzle5 consists of a tube about 1.5 mm inner diameter, 50 mm long,manufactured from an erosion resistant material such as WC, A12O3, and so forth. Erosion of the nozzle during service shall bemonitored and shall not exceed 10 % increase in the initial diameter.6.2 Nec
22、essary features of the apparatus shall include a means of controlling and adjusting the particle impact velocity, particleflux, and the specimen location and orientation relative to the impinging stream.6.3 Various means can be provided for introducing particles into the gas stream, including a vibr
23、ator-controlled hopper or ascrew-feed system. It is required that the system provide a uniform particle feed and that it be adjustable to accommodate desiredparticle flow values.5 The sole source of supply of the recommended nozzle (tungsten carbide) known to the committee at this time is Kennametal
24、 Inc., 1600 Technology Way, PO Box 231,Latrobe, PA 15650-0231. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee,1 which you may attend.FIG
25、. 1 Schematic Drawing of Solid Particle Erosion EquipmentG76 1326.4 Amethod to measure the particle velocity shall be available for use with the erosion equipment (6-9). Examples of acceptedmethods are high-speed photography (7), rotating double-disk (6),(8), and laser velocimeter (9). Particle velo
26、city shall be measuredat the location to be occupied by the specimen and under the conditions of the test.7. Test Materials and Sampling7.1 This test method can be used over a range of specimen sizes and configurations. One convenient specimen configurationis a rectangular strip approximately 10 by
27、30 by 2 mm thick. Larger specimens and other shapes can be used where necessary, butmust be documented.7.2 The abrasive material to be used shall be uniform in essential characteristics such as particle size, moisture, chemicalcomposition, and so forth.7.3 Sampling of material for the purpose of obt
28、aining representative test specimens shall be done in accordance with acceptablestatistical practice. Practice E122 shall be consulted.8. Calibration of Apparatus8.1 Specimens fabricated from Type 1020 steel (see Table 1 and Fig. 2) equivalent to that used in the interlaboratory test series6shall be
29、 tested periodically using specified (see Section 9) 50 m A12O3 particles to verify the satisfactory performance of theapparatus. It is recommended that performance be verified using this reference material every 50 tests during a measurement series,and also at the beginning of each new test series
30、whenever the apparatus has been idle for some time. The recommendedcomposition, heat treatment, and hardness range for this steel are listed in Table 1. The use of a steel of different composition maylead to different erosion results.Aphotomicrograph of the specifiedA12O3 particles is shown in Fig.
31、3. The range of erosion resultsto be expected for this steel under the standard test conditions specified in Section 9 is shown in Table 2 and is based oninterlaboratory test results.68.2 Calibration at standard test conditions is recommended even if the apparatus is operated at other test condition
32、s.8.3 In any test program the particle velocity and particle feed rate shall be measured at frequent intervals, typically every tentests, to ensure constancy of conditions.9. Standard Test Conditions9.1 This test method defines the following standard conditions.9.1.1 The nozzle tube shall be 1.5 mm
33、6 0.075 mm inner diameter at least 50 mm long.9.1.2 The test gas shall be nominally dry air. The test report shall indicate the amount of water present in the test gas, at whatpressure, and how the measurement was conducted.6 Supporting data have been filed at ASTM International Headquarters and may
34、 be obtained by requesting Research Report RR:G02-1003.FIG. 2 Microstructure of 1020 Steel Reference MaterialASTM Grain Size 9G76 133NOTE 1In the interlaboratory testing, one laboratory utilized cylinder-type compressed air having a water content amount described as “-50C dewpoint” by the manufactur
35、er. Whatever gas source is used in testing, a comparable level of dryness to that is recommended.9.1.3 The abrasive particles shall be nominal 50-m angular A12O3,7 equivalent to those used in the interlaboratory test series(see Fig. 3). Abrasive shall be used only once.NOTE 2Typical size distributio
36、n (determined by sedimentation): 100 % between 20 to 83 m, 50 % between 42 to 57 m, 50 % coarser than 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 flow ratewill be approximately 8 Lmin0.13 L/s1 and the system pressure will
37、be approximately 140 kPa (20 psig) although the pressurewill depend on the specific system design.9.1.5 The test time shall be 10 min600 s to achieve steady state conditions. Longer times are permissible so long as the finalerosion crater is no deeper than 1 mm.9.1.6 The angle between the nozzle axi
38、s and the specimen surface shall be 90 6 2.9.1.7 The test temperature shall be the normal ambient value (typically between 18C to 28C).9.1.8 The particle feed rate shall be 2.00.03360.5 gmin0.008 g/s.1.This corresponds to a particle flux at the specimen surfaceof about 2 mgmm2s1 under standard condi
39、tions. Particle flux determination requires measurement of the eroded area on thespecimen and is subject to considerable error. A measured width and depth profile of an erosion crater produced using statedconditions is shown in Fig. 4 and indicates a typical eroded width/depth relation.9.1.9 The dis
40、tance from specimen surface to nozzle end shall be 10 6 1 mm.10. Optional Test Conditions10.1 When test conditions or materials other than those given in Section 9 are used, reference to this test method shall clearlyspecify all test conditions and materials. It should be noted that other conditions
41、, for example, larger particle velocities, mayadversely affect measurement precision.11. Test Procedure11.1 Establish and measure the particle velocity and particle flow specified.Adjust equipment controls to obtain proper velocityand flow conditions before inserting test specimens. Particle flow ra
42、te values are determined by collecting (see Note 3) andsubsequently weighing the abrasive exiting from the nozzle for a measured time period.7 The sole source of supply of the aluminum oxide particlesobtained as grade 240-grit alundum powder known to the committee at this time is Norton Co., 1 NewBo
43、nd St, Worcester, MA 01606. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1 which you may attend.FIG. 3 Photomicrograph of 50 m A12O3 P
44、articles Used in Interlaboratory TestingG76 134NOTE 3Particles may be collected by directing the flow from the nozzle into a large vented container. Care must be taken to avoid causing anysignificant back pressure on the nozzle as this will disturb the system flow conditions.11.2 Prepare the specime
45、n surface if required to achieve uniformity and adequate finish. Grinding through a series of abrasivepapers to 400 grit is usually adequate so long as all surface scale is removed.Asurface roughness of 1 m (40 in.) rms or smalleris recommended. Clean the specimen surface carefully (see Note 4). Wei
46、gh on an analytical balance to 60.01 mg (see Note 5).NOTE 4Important considerations in cleaning include surface oils or greases, surface rust or corrosion, adhering abrasive particles, etc.NOTE 5Erosion weight loss determinations to 60.1 mg may be sufficient for particle velocities above 70 ms1 or s
47、ufficiently long exposure timeswhich lead to weight losses greater than 10 mg.11.3 Mount the specimen in proper location and orientation in the apparatus. Subject the specimen to particle impingement fora selected time interval, measured to an accuracy of 5 s. Remove the specimen, clean carefully (s
48、ee Note 4), reweigh and calculatethe mass loss.11.4 Repeat this process utilizing a new specimen each time to determine at least four points for a total time of at least 10min600 s and plot those values as mass loss versus elapsed time. Suitable times would be 2, 4, 8, and 16 min120, 240, 480, and96
49、0 s for a material such as Type 1020 steel. Steady state erosion should result after 160 to 2 min,120 s, depending on the material.Two examples of measured erosion versus time curves are shown in Fig. 5.11.5 The steady state erosion rate (see Terminology G40) is determined from the slope of the mass loss versus time plot. Theaverage erosion value is calculated by dividing erosion rate (mgmin(mg/s)1) by the abrasive flow rate (gmin(g/s)1) and thendividing by the specimen density (gcm3). Report the average erosion val
