1、Designation: G40 15G40 17Standard Terminology Relating toWear and Erosion1This standard is issued under the fixed designation G40; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.Anumber in parentheses ind
2、icates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The terms and their definitions given herein represent terminology relating to wear and erosion of solid bodies due tomechanical interactions such as occur with c
3、avitation, impingement by liquid jets or drops or by solid particles, or relative motionagainst contacting solid surfaces or fluids. This scope interfaces with but generally excludes those processes where material lossis wholly or principally due to chemical action and other related technical fields
4、 as, for instance, lubrication.1.2 This terminology is not exhaustive; the absence of any particular term from this collection does not necessarily imply thatits use within this scope is discouraged. However, the terms given herein are the recommended terms for the concepts theyrepresent unless othe
5、rwise noted.1.3 Certain general terms and definitions may be restricted and interpreted, if necessary, to make them particularly applicableto the scope as defined herein.1.4 The purpose of this terminology is to encourage uniformity and accuracy in the description of test methods and devices andin t
6、he reporting of test results in relation to wear and erosion.NOTE 1All terms are listed alphabetically. When a subsidiary term is defined in conjunction with the definition of a more generic term, analphabetically-listed cross-reference is provided.1.5 This international standard was developed in ac
7、cordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM
8、 Standards:2C242 Terminology of Ceramic Whitewares and Related Products3. Terminologyabradant, na material that is producing, or has produced, abrasive wear.abrasion, nin tribology, the process by which relative motion between a surface and hard particles or protuberances on anopposing surface produ
9、ces abrasive wear of that surface. (See also abrasive wear.)abrasive wear, nwear due to hard particles or hard protuberances forced against and moving along a solid surface.abrasion-corrosion, na synergistic process involving both abrasive wear and corrosion in which each of these processes isaffect
10、ed by the simultaneous action of the other and, in many cases, is thereby accelerated.abrasivity, nthe ability of a material or substance to cause abrasive wear.absolute impact velocitySee impact velocity.acceleration period, nin cavitation and liquid impingement erosion, the stage following the inc
11、ubation period during which theerosion rate increases from near zero to a maximum value. (See also erosion rate-time pattern.)accumulation period, nin cavitation and liquid impingement erosion, a less-preferred term for acceleration period.1 This terminology is under the jurisdiction of ASTM Committ
12、ee G02 on Wear and Erosion and is the direct responsibility of Subcommittee G02.91 on Terminology.Current edition approved Nov. 1, 2015Aug. 15, 2017. Published November 2015December 2017. Originally approved in 1973. Last previous edition approved in 20132015as G40 13.G40 15. DOI: 10.1520/G0040-15.1
13、0.1520/G0040-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is
14、intended only to provide the user of an ASTM standard 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 c
15、urrent versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1adhesive wear, nwear due to localized bonding between contacting solid surfaces leading to ma
16、terial transfer between the twosurfaces or loss from either surface.angle of attack, nin impingement erosion, the angle between the direction of motion of an impinging liquid or solid particle andthe tangent to the surface at the point of impact.angle of incidence, nin impingement erosion, the angle
17、 between the direction of motion of an impinging liquid or solid particleand the normal to the surface at the point of impact.apparent area of contact, nin tribology, the area of contact between two solid surfaces defined by the boundaries of theirmacroscopic interface. (Contrast with real area of c
18、ontact.)asperity, nin tribology, a protuberance in the small-scale topographical irregularities of a solid surface.attenuation period, nin cavitation and liquid impingement erosion, a less-preferred term for deceleration period.average erosion rate, na less preferred term for cumulative erosion rate
19、. (See also interval erosion rate.)Beilby layer, nan altered surface layer of supposedly amorphous material formed on a crystalline solid during mechanicalpolishing, whose existence was proposed in Sir George Beilbys writings. The existence of such a layer is not supported byrecent research, and the
20、 use of this term is therefore considered archaic and is strongly discouraged.bio-tribocorrosion, nin the field of medical devices and dental restoratives, a form of tribocorrosion in which biologicalsubstances make up one or more of the triboelements or are present in the contact region between the
21、m.break-in,nSee run-in.break in,vSee run in.brinelling, ndamage to a solid bearing surface characterized by one or more plastically formed indentations caused by static orimpulsive overloads, especially as found in rolling contact bearings. (See also false brinelling.)brittle erosion behavior, neros
22、ion behavior having characteristic properties that can be associated with brittle fracture of theexposed surface; that is, little or no plastic flow occurs, but cracks form that eventually intersect to create erosion fragments.(See also ductile erosion behavior.)DISCUSSIONIn solid impingement an eas
23、ily observable aspect of erosion helps to distinguish brittle from ductile behavior. This is the manner in which volumeremoval varies with the angle of attack. With brittle erosion the maximum volume removal occurs at an angle near 90, in contrast to approximately25 for ductile erosion behavior.carr
24、ier fluid, nin impingement or slurry erosion, fluid medium that transports impinging solid or liquid particles and that givesthe particles their momentum relative to the solid surface on which they are impinging.catastrophic period, nin cavitation or liquid impingement erosion, a stage during which
25、the erosion rate increases so drasticallythat continued exposure threatens or causes gross disintegration of the exposed surface.This stage is not inevitable; it is observedmost commonly with some brittle materials. When it does occur, it may begin during any stage of the more common erosionrate-tim
26、e pattern.catastrophic wear, nrapidly occurring or accelerating surface damage, deterioration, or change of shape caused by wear to sucha degree that the service life of a part is appreciably shortened or its function is destroyed.cavitating disk device (or apparatus), na flow cavitation test device
27、 in which cavitating wakes are produced by holes in, orprotuberances on, a disk rotating within a liquid-filled chamber. Erosion test specimens are attached flush with the surface ofthe disk, at the location where the bubbles are presumed to collapse.cavitating jet, na continuous liquid jet (sometim
28、es submerged) in which cavitation is induced by the nozzle design, or sometimesby an obstruction placed in the center of the flow passage.cavitating wake,nSee flow cavitation.cavitation, nthe formation and subsequent collapse, within a liquid, of cavities or bubbles that contain vapor or a mixture o
29、fvapor and gas.DISCUSSIONCavitation originates from a local decrease in hydrostatic pressure in the liquid, usually produced by motion of the liquid (see flow cavitation) or ofa solid boundary (see vibratory cavitation). It is distinguished in this way from boiling, which originates from an increase
30、 in liquid temperature.G40 172DISCUSSIONThe term cavitation, by itself, should not be used to denote the damage or erosion of a solid surface that can be caused by it; this effect of cavitationis termed cavitation damage or cavitation erosion. To erode a solid surface, bubbles or cavities must colla
31、pse on or near that surface.cavitation cloud, na collection of a large number of cavitation bubbles. The bubbles in a cloud are small, typically less than 1mm (0.04 in.) in cross section. A surface that is being eroded by cavitation is usually obscured by a cavitation cloud.cavitation damage,nSee da
32、mage.cavitation erosion, nprogressive loss of original material from a solid surface due to continued exposure to cavitation.cavitation erosion test, na procedure whereby the surface of a solid is subjected to cavitation attack under specified, ormeasurable, or at least repeatable conditions.DISCUSS
33、IONSuch tests can be divided into two major classes depending on whether flow cavitation or vibratory cavitation is generated.cavitation number, , na dimensionless number that measures the tendency for cavitation to occur in a flowing stream of liquid,and that is computed from the equation:5Po 2 P v
34、!/12V o2 (1)where:Pv = vapor pressure,Po = static pressure in the stream in an undisturbed state,Vo = undisturbed stream velocity, and = liquid density.DISCUSSIONThe cavitation number and the net positive suction head (NPSH) are related by the equation:NPSH511!Vo 2/2g (2)where g is the acceleration
35、due to gravity.cavitation tunnel, na flow cavitation test facility in which liquid is pumped through a pipe or tunnel, and cavitation is inducedin a test section by conducting the flow through a constriction, or around an obstacle, or a combination of these.coefficient of friction or f,nin tribology
36、, the dimensionless ratio of the friction force (F) between two bodies to the normalforce (N) pressing these bodies together. (See also static coefficient of friction and kinetic coefficient of friction.) 5F/N! (3)collection efficiency, nin impingement erosion and particulate flows, the cross-sectio
37、nal area of undisturbed fluid containingparticles that will all ultimately impinge on a given solid surface, divided by the projected area of the solid surface, where thesetwo areas are perpendicular to the direction of relative motion between the solid surface and the particles in the undisturbed f
38、luid.DISCUSSION“Undisturbed fluid” means fluid that is sufficiently ahead of the solid surface to be undisturbed by the flow around the solid surface. For example, theparticles could be carried in a stream of fluid moving toward a solid surface that is stationary, or the solid surface could be movin
39、g through a suspensionof particles. Not all of the particles that move in the direction of the solid surface or lie in its path will impinge upon it, since some will be carriedaway in the fluid as it flows around the surface.DISCUSSIONA variety of terms having the same meaning can be found in the li
40、terature. These include “collision efficiency,” “capture efficiency,” “catchmentefficiency,” “impaction ratio,” and others. The term “collection efficiency,” being perhaps the most widely used, is preferred.continuous jet,nSee liquid jet.corrosive wear, nwear in which chemical or electrochemical rea
41、ction with the environment is significant.G40 173cumulative erosion, nin cavitation and impingement erosion, the total amount of material lost from a solid surface during allexposure periods since it was first exposed to cavitation or impingement as a newly-finished surface. (More specific terms tha
42、tmay be used are cumulative mass loss, cumulative volume loss, or cumulative mean depth of erosion. See also cumulativeerosion-time curve.)DISCUSSIONUnless otherwise indicated by the context, it is implied that the conditions of cavitation or impingement have remained the same throughout allexposure
43、 periods, with no intermediate refinishing of the surface.cumulative erosion rate, nthe cumulative erosion at a specified point in an erosion test divided by the corresponding cumulativeexposure duration; that is, the slope of a line from the origin to the specified point on the cumulative erosion-t
44、ime curve.(Synonym:average erosion rate)cumulative erosion-time curve, nin cavitation and impingement erosion, a plot of cumulative erosion versus cumulativeexposure duration, usually determined by periodic interruption of the test and weighing of the specimen. This is the primaryrecord of an erosio
45、n test. Most other characteristics, such as the incubation period, maximum erosion rate, terminal erosion rate,and erosion rate-time curve, are derived from it.cutting wear, nin solid impingement erosion, the erosive wear associated with the dissipation of kinetic energy of impact arisingfrom the ta
46、ngential component of the velocity of the impacting particles.DISCUSSIONSince erosion due to oblique particle impact inevitably involves deformation wear as well as cutting wear, the magnitude of the cutting wear can beexperimentally determined by conducting a separate test at normal impact to deter
47、mine the deformation wear, and subtracting that from the total wearat any angle of impact, where both tests are conducted with the same normal component of impact velocity and both results are normalized to the massof impacting particles. See also related terms deformation wear, ductile erosion beha
48、vior, and brittle erosion behavior.damage, nin cavitation or impingement, any effect on a solid body resulting from its exposure to these phenomena. This mayinclude loss of material, surface deformation, or any other changes in microstructure, properties, or appearance.DISCUSSIONThis term as here de
49、fined should normally be used with the appropriate modifier, for example, “cavitation damage,” “liquid impingement damage,”“single-impact damage,” and so forth.debris, nin tribology, particles that have become detached in a wear or erosion process.deceleration period, nin cavitation or liquid impingement erosion, the stage following the acceleration period or the maximumrate period (if any) during which the erosion rate has an overall decreasing trend although fluctuations may be superimposedon it. (See also
