1、Designation: G73 10 (Reapproved 2017)Standard Test Method forLiquid Impingement Erosion Using Rotating Apparatus1This standard is issued under the fixed designation G73; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of l
2、ast 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 tests in which solid specimensare eroded or otherwise damaged by repeated discrete impactsof liquid
3、 drops or jets. Among the collateral forms of damageconsidered are degradation of optical properties of windowmaterials, and penetration, separation, or destruction of coat-ings. The objective of the tests may be to determine theresistance to erosion or other damage of the materials orcoatings under
4、 test, or to investigate the damage mechanismsand the effect of test variables. Because of the specializednature of these tests and the desire in many cases to simulate tosome degree the expected service environment, the specifica-tion of a standard apparatus is not deemed practicable. This testmeth
5、od gives guidance in setting up a test, and specifies testand analysis procedures and reporting requirements that can befollowed even with quite widely differing materials, testfacilities, and test conditions. It also provides a standardizedscale of erosion resistance numbers applicable to metals an
6、dother structural materials. It serves, to some degree, as atutorial on liquid impingement erosion.1.2 The values stated in SI units are to be regarded asstandard. The inch-pound units in parentheses are provided forinformation.1.3 This standard does not purport to address all of thesafety concerns,
7、 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 applica-bility of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recog
8、nized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1003 Test Method for
9、 Haze and Luminous Transmittanceof Transparent PlasticsE92 Test Methods for Vickers Hardness and Knoop Hard-ness of Metallic MaterialsE140 Hardness Conversion Tables for Metals RelationshipAmong Brinell Hardness, Vickers Hardness, RockwellHardness, Superficial Hardness, Knoop Hardness, Sclero-scope
10、Hardness, and Leeb HardnessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Propertiesof MaterialsG1 Practice for Preparing, Cleaning, and Evaluating Corro-sion Test SpecimensG32 Te
11、st Method for Cavitation Erosion Using VibratoryApparatusG40 Terminology Relating to Wear and ErosionG134 Test Method for Erosion of Solid Materials by Cavi-tating Liquid Jet2.2 Military Standards:3MIL-C-83231 Coatings, Polyurethane, Rain Erosion Resis-tance for Exterior Aircraft and Missile Plastic
12、 PartsMIL-P-8184 Plastic Sheet, Acrylic, Modified3. Terminology3.1 See Terminology G40 for definitions of terms that arenot defined below in either 3.2 or 3.3. Definitions appear in 3.2that are taken from Terminology G40 for important termsrelated to the title, Scope, or Summary of this test method.
13、Definitions of Terms Specific to this Test Method are given in3.3 that are not in Terminology G40.3.2 Definitions:1This test method 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 editi
14、on approved July 15, 2017. Published August 2017. Originallyapproved in 1982. Last previous edition approved in 2010 as G73 10. DOI:10.1520/G0073-10R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSta
15、ndards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.Copyright ASTM International, 100 Barr Harbor Drive, PO
16、 Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued b
17、y the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.1 All definitions listed below are quoted from Terminol-ogy G4005 (some modified).3.2.2 cumulative erosion-time curve, nin cavitation andimpingement erosion, a plot of cumulative erosion versuscumulative exposure duratio
18、n, usually determined by periodicinterruption of the test and weighing of the specimen. This isthe primary record of an erosion test. Most othercharacteristics, such as the incubation period, maximum ero-sion rate, terminal erosion rate, and erosion rate-time curve, arederived from it.3.2.3 damage,
19、nin cavitation or impingement, any effecton a solid body resulting from its exposure to these phenom-ena. This may include loss of material, surface deformation, orany other changes in microstructure, properties, or appearance.3.2.3.1 DiscussionThis term as here defined should nor-mally be used with
20、 the appropriate modifier, for example,“cavitation damage,” “liquid impingement damage,” “single-impact damage,” and so forth.3.2.4 incubation period, nin cavitation and impingementerosion, the initial stage of the erosion rate-time pattern duringwhich the erosion rate is zero or negligible compared
21、 to laterstages.3.2.4.1 DiscussionThe incubation period is usuallythought to represent the accumulation of plastic deformationand internal stresses under the surface that precedes significantmaterial loss. There is no exact measure of the duration of theincubation period. See related term, nominal i
22、ncubation periodin 3.3.9.3.2.5 liquid impingement erosion, nprogressive loss oforiginal material from a solid surface due to continued expo-sure to impacts by liquid drops or jets.3.2.6 maximum erosion rate, nin cavitation and liquidimpingement, the maximum instantaneous erosion rate in a testthat e
23、xhibits such a maximum followed by decreasing erosionrates. (See also erosion ratetime pattern.)3.2.6.1 DiscussionOccurrence of such a maximum istypical of many cavitation and liquid impingement tests. Insome instances it occurs as an instantaneous maximum, inothers as a steady-state maximum which p
24、ersists for sometime.3.2.7 normalized erosion resistance, Ne,na measure of theerosion resistance of a test material relative to that of aspecified reference material, calculated by dividing the volumeloss rate of the reference material by that of the test materialwhen both are similarly tested and s
25、imilarly analyzed. By“similarly analyzed,” it is meant that the two erosion rates mustbe determined for corresponding portions of the erosionrate-time pattern; for instance, the maximum erosion rate or theterminal erosion rate.3.2.7.1 DiscussionA recommended complete wording hasthe form, “The normal
26、ized erosion resistance of (test material)relative to (reference material) based on (criterion of dataanalysis) is (numerical value).”3.2.8 normalized incubation resistance, N0, nin cavitationand liquid impingement erosion, the nominal incubation periodof a test material, divided by the nominal incu
27、bation period ofa specified reference material similarly tested and similarlyanalyzed. (See also normalized erosion resistance.)3.3 Definitions of Terms Specific to This Standard:3.3.1 apparatus severity factor, Fan empirical factor thataccounts for the systematic differences between rationalizedero
28、sion rates (or rationalized incubation periods) as determinedfor the same material and impact velocity in different facilities.It reflects variations in test conditions not accounted for by thedata reduction procedures of this test method.3.3.2 erosion resistance number, NERthe normalized ero-sion r
29、esistance of a test material relative to a standardizedscale, calculated from test results with one or more designatedreference materials as described in this test method. See alsoreference erosion resistance (3.3.12).3.3.3 exposed surface (or area)that surface (or area) onthe specimen nominally sub
30、jected to liquid impingement.(1) For “distributed impact tests,” it is generally to be takenas the projected area of the exposed surface of the specimen ona plane perpendicular to the direction of impingement.However, if a plane specimen surface is deliberately orientedso as to obtain impingement at
31、 an oblique angle, then the actualplane area is used.(2) For “repetitive impact tests,” it is to be taken as theprojected area of the impinging liquid bodies on the specimen,the projection being taken in the direction of relative motion.3.3.3.1 DiscussionIn practice, it is usually found that thedama
32、ged area in repetitive impact tests is greater than theexposed area as defined above, but the above definition isadopted not only for simplicity but also for consistencybetween some of the other calculations for distributed andrepetitive tests.3.3.4 impingement rate, UiLT1the volume of liquidimpingi
33、ng per unit time on a unit area of exposed surface; fora plane target surface it is given by V cos .3.3.5 incubation impingement, H0Lthe mean cumula-tive impingement corresponding to the nominal incubationperiod; hence, impingement rate times nominal incubationtime.3.3.6 incubation resistance number
34、, NORthe normalizedincubation resistance of a test material relative to a standard-ized scale, calculated from test results with one or moredesignated reference materials as described in this test method.See also reference incubation resistance (3.3.13).3.3.7 incubation specific impacts, N0same as r
35、ationalizedincubation period.3.3.8 mean cumulative impingement, H Lthe cumulativevolume of liquid impinged per unit area of exposed surface;impingement rate times exposure time.3.3.9 nominal incubation period, t0the intercept on thetime or exposure axis of the straight-line extension of themaximum-s
36、lope portion of the cumulative erosion-time curve;while this is not a true measure of the incubation stage, itserves to locate the maximum erosion rate line on the cumu-lative erosion versus exposure coordinates.G73 10 (2017)23.3.10 rationalized erosion rate, Revolume of materiallost per unit volume
37、 of liquid impinged, both calculated for thesame area.3.3.11 rationalized incubation period, N0the duration ofthe nominal incubation period expressed in dimensionlessterms as the number of specific impacts; hence, the specificimpact frequency times nominal incubation time. (Also re-ferred to as incu
38、bation specific impacts.)3.3.12 reference erosion resistance, Sera normalized ero-sion resistance, based on interlaboratory test results, assignedto a specified reference material in this test method so as toconstitute a benchmark in the “erosion resistance number”scale. The value of unity is assign
39、ed to 316 stainless steel ofhardness 155 to 170 HV.3.3.13 reference incubation resistance, Sora normalizedincubation resistance, based on interlaboratory test results,assigned to a specific reference material in this test method soas to constitute a benchmark in the “incubation resistancenumber” sca
40、le. The value of unity is assigned to 316 stainlesssteel of hardness 155 to 170 HV.3.3.14 specific impacts, Nthe number of impact stresscycles of damaging magnitude experienced by a typical pointon the exposed surface, or an approximation thereof asestimated on the basis of simplified assumptions as
41、 describedin this test method. (This concept has sometimes been termed“impacts per site.”)3.3.15 specific impact frequency, fiT1the number ofspecific impacts experienced per unit time, given by (a/b) Ui.3.3.16 volume concentration, the ratio of the volume ofliquid to the total volume in the path tra
42、versed or swept out bythe exposed area of the specimen.3.3.17 volume mean diameter Lin a population of dropsof different sizes, the diameter of a sphere whose volumeequals the total volume of all drops divided by the total numberof drops.3.4 Symbols:A = exposed area of specimen, m2,a = projected are
43、a of impinging drop or jet, m2,b = volume of impinging drop or jet, m3,d = diameter of impinging drop or jet, m,F0= apparatus severity factor for incubation,Fe= apparatus severity factor for erosion rate,fi= specific impact frequency, s1,H = mean cumulative impingement, m,H0= incubation impingement,
44、 m,N0= number of specific impacts for incubation, or “ratio-nalized incubation period,” dimensionless,NER = erosion resistance number,NOR = incubation resistance number,n = number of jets or drops impacting on exposedsurface of specimen in one revolution,Qe= volumetric erosion rate, m3/s,Re= “ration
45、alized erosion rate,” (dY/dH), dimensionless,Se= normalized erosion resistance (relative to a specifiedreference material),Ser= reference erosion resistance,S0= normalized incubation resistance (relative to a speci-fied reference material),Sor= reference incubation resistance,t = exposure time, s,t0
46、= nominal incubation time, s,Ue= linear erosion rate (dY/dt), m/s = Qe/A,Ui= impingement rate (dH/dt), m/s,Ur= rainfall rate, m/s,Ut= terminal velocity of drops in falling rainfield, m/s,V = impact velocity of drop or jet relative to specimen,m/s,Vn= component of impact velocity normal to specimensu
47、rface, m/s,Y = mean depth of erosion, m, = angle of incidencethe angle between the directionof impacting drops and the normal to the solidsurface at point of impact, = volume concentration of liquid in rainfield or inspace swept through by specimen, and = rotational speed of specimens, rev/s.3.5 Exc
48、ept in equations where different units are expresslyspecified, the use of SI units listed in 3.4, or any other coherentsystem of units, will make equations correct without the needof additional numerical factors. When referring to quantities intext, tables, or figures, suitable multiples or submulti
49、ples ofthese units may, of course, be used.4. Summary of Test Method4.1 Liquid impingement tests are usually, but not always,conducted by attaching specimens to a rotating disk or arm,such that in their circular path they repeatedly pass through andimpact against liquid sprays or jets (Sections 6 and 7). Standardreference materials (Section 8) should be used to calibrate theapparatus and included in all test programs.4.2 Data analysis begins by establishing a cumulativeerosion-time curve from measurements of mass loss (or otherdam
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