1、Designation: C1495 07 (Reapproved 2012)C1495 16Standard Test Method forEffect of Surface Grinding on Flexure Strength of AdvancedCeramics1This standard is issued under the fixed designation C1495; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the effect of surface grinding on the flexure s
3、trength of advanced ceramics.Surface grinding of an advanced ceramic material can introduce microcracks and other changes in the near surface layer, generallyreferred to as damage (See(see Fig. 1 and Ref. (1).2 Such damage can result in a changemost often a decreasein flexurestrength of the material
4、. The degree of change in flexure strength is determined by both the grinding process and the responsecharacteristics of the specific ceramic material. This method compares the flexure strength of an advanced ceramic material afterapplication of a user-specified surface grinding process with the bas
5、eline flexure strength of the same material. The baseline flexurestrength is obtained after application of a surface grinding process specified in this standard. The baseline flexure strength isexpected to approximate closely the inherent strength of the material.The flexure strength is measured by
6、means ofASTM standardflexure test methods.1.2 Flexure test methods used to determine the effect of surface grinding are C1161 Test Method for Flexure Strength ofAdvanced Ceramics at Ambient Temperatures and C1211 Test Method for Flexure Strength of Advanced Ceramics at ElevatedTemperatures.1.3 Mater
7、ials covered in this standard are those advanced ceramics that meet criteria specified in flexure testing standards C1161and C1211.1.4 The flexure test methods supporting this standard (C1161 and C1211) require test specimens that have a rectangular crosssection, flat surfaces, and that are fabricat
8、ed with specific dimensions and tolerances. Only grinding processes that are capable ofgenerating the specified flat surfaces, i.e. that is, planar grinding modes, are suitable for evaluation by this method. Among the1 This test method is under the jurisdiction of ASTM Committee C28 on Advanced Cera
9、mics and is the direct responsibility of Subcommittee C28.01 on MechanicalProperties and Performance.Current edition approved Aug. 1, 2012Sept. 1, 2016. Published November 2012October 2016. Originally approved in 2001. Last previous edition approved in 20072012as C1495 07.C1495 07 (2012). DOI: 10.15
10、20/C1495-07R12.10.1520/C1495-16.2 The boldface numbers in parentheses refer to a list of references at the end of this standard.FIG. 1 Microcracks Associated with Grinding (Ref. (1)2This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of wh
11、at 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 to be considered th
12、e official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1applicable machine types are horizontal and vertical spindle reciprocating surface grinders, horizontal and vertical spindle rotarysurface grinders, double disk grind
13、ers, and tool-and-cutter grinders. Incremental cross-feed, plunge, and creep-feed grindingmethods may be used.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety
14、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 use.2. Referenced Documents2.1 ASTM Standards:3C1145 Terminology of Advanced Ceramics
15、C1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient TemperatureC1211 Test Method for Flexural Strength of Advanced Ceramics at Elevated TemperaturesC1239 Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters for Advanced CeramicsC1322 Practi
16、ce for Fractography and Characterization of Fracture Origins in Advanced CeramicsC1341 Test Method for Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramic Composites3. Terminology3.1 Materials Related:3.1.1 advanced ceramic, na highly engineered, high-performance, predominately nonme
17、tallic, inorganic, ceramic materialhaving specific functional attributes. C11453.1.2 baseline flexure strength, nin the context of this standard, refers to the flexure strength value obtained after applicationof a grinding procedure specified in this standard.3.1.2.1 DiscussionFor the advanced ceram
18、ics to which this this standard is applicable, the baseline flexure strength is expected to be a closeapproximation to the inherent flexure strength.3.1.3 ceramic matrix composite, na material consisting of two or more materials (insoluble in one another) in which the major,continuous component (mat
19、rix component) is a ceramic, while the secondary component(s) (reinforcing component) may beceramic, glass-ceramic, glass, metal, or organic in nature. These components are combined on a macroscale to form a usefulengineering material possessing certain properties or behavior not possessed by the in
20、dividual constituents. C13413.1.4 grinding damage, nany change in a material that is a result of the application of a surface grinding process. Among thetypes of damage are microcracks (Fig. 1), dislocations, twins, stacking faults, voids, and transformed phases.3.1.4.1 DiscussionAlthough they do no
21、t represent internal changes in microstructure, chips and surface pits, which are a manifestation ofmicrofracture, and abnormally large grinding striations are often referred to as grinding damage. Residual stresses that result frommicrostructural changes may also be referred to as grinding damage.3
22、.1.5 inherent flexure strength, nthe flexure strength of a material in the absence of any effects of surface grinding or othersurface finishing process, or of extraneous damage that may be present. The measured inherent flexure strength may depend onthe flexure test method, test conditions, and test
23、 specimen size.3.1.5.1 DiscussionFlaws due to surface finishing or extraneous damage may be present but their effect on flexure strength is negligible compared tothat of “inherent” flaws in the material.3.1.6 materials lot or batch, na single billet or several billets prepared from defined homogeneo
24、us quantities of raw materialspassing simultaneously through each processing step to the end product is often referred to as belonging to a single lot or batch.3.1.6.1 Discussion3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. F
25、or Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.C1495 162There is no assurance that a single billet is internally homogenous or that billets belonging to the same lot or batch isare identical.3.2 Grinding Process RelatedDefinitions
26、 in this section apply to grinding machines and modes that generate planar surfaces.Applicable grinding machines types are identified in (1.4). Some definitions may not be applicable when used in connection withnon-planar grinding modes such as centerless and cylindrical modes which are outside of t
27、he scope of this standard.3.2.1 blanchard grinding, na type of rotary grinding in which the workpiece is held on a rotating table with an axis of rotationthat is parallel to the (vertical) spindle axis.3.2.2 coolant, nusually a liquid that is applied to the workpiece and/or wheel or wheel, or both,
28、during grinding for cooling,removal of grinding swarf, and for lubrication.3.2.3 coolant flow rate, nvolume of coolant per unit time delivered to the wheel and workpiece during grinding.3.2.4 creep-feed grinding, na mode of grinding characterized by a relatively large wheel depth-of-cut and correspo
29、ndinglylow rate of feed.3.2.5 cross-feed, nincrement of displacement or feed in the cross-feed direction.3.2.6 cross-feed direction, ndirection in the plane of grinding which is perpendicular to the principleprincipal direction ofgrinding. (Fig. 2)3.2.7 down-feed, nincrement of displacement or feed
30、in the down feed direction. (Fig. 2)3.2.8 down-feed direction, ndirection perpendicular to the plane of grinding for a machine configuration in which the grindingwheel is located above the workpiece. (Fig. 2)3.2.9 down-grinding, nA condition of down-grinding is said to hold when the velocity vector
31、tangent to the surface of thewheel at points of first entry into the grinding zone has a component normal to and directed into the ground surface of theworkpiece. (Fig. 3a)3.2.10 dressing, na conditioning process applied to the abrasive surface of a grinding wheel to improve the efficiency ofgrindin
32、g.3.2.10.1 DiscussionFIG. 2 Machine Axes for Horizontal Spindle Reciprocating Surface GrinderC1495 163Dressing may accomplish one or more of the following: (1) removal of bond material from around the grit on the surface of thegrinding wheel causing the grit to protrude a greater distance from the s
33、urrounding bond, (2) removal of adhered workpiecematerial which interferes with the grinding process, removal of worn grit, (3) removal of bond material thereby exposingunderlying unworn grit, and (4) fracture of worn grit thereby generating sharp edges.3.2.11 grinding axis, nany reference line alon
34、g which the workpiece is translated or about which it is rotated to effect theremoval of material during grinding.3.2.12 grinding direction, nwhen used in reference to flexure test bars, refers to the angle between the long (tensile) axis ofthe flexure bar and the path followed by grit in the grindi
35、ng wheel as they move across the ground surface. See longitudinalgrinding direction and transverse grinding direction. (Fig. 4)3.2.13 grit depth-of-cut, nnominal maximum depth that individual grit on the grinding wheel penetrate the workpiece surfaceduring grinding. Synonymous with undeformed chip t
36、hickness.3.2.14 in-feed, nsynonymous with wheel depth-of-cut and down feed.3.2.15 longitudinal grinding direction, ngrinding direction parallel to the long axis of the flexure bar. (Fig. 4a)3.2.16 machine axes, nreference line along which translation or about which rotation of a grinding machine com
37、ponent (table,stage, spindle.) takes place. (Fig. 2)3.2.17 planar grinding, na grinding process which generates a nominally flat (plane) surface.3.2.18 reciprocating grinding, nmode of grinding in which the grinding path consists of a series of linear bi-directionaltraverses across the workpiece sur
38、face.3.2.19 rotary grinding, nmodes of planar grinding in which the grinding path in the plane of grinding is an arc, effected eitherby rotary motion of the workpiece or of the grinding wheel.3.2.19.1 DiscussionGrinding striations left on the workpiece surfaces are arcs.3.2.20 surface grinding, na g
39、rinding process used to generate a flat surface by means of an abrasive tool (grinding wheel)having circular symmetry with respect to an axes about which it is caused to rotate. (Fig. 2)3.2.21 table speed, nspeed of the grinding machine table carrying the workpiece usually measured with respect to t
40、he machineframe.3.2.22 transverse grinding direction, ngrinding direction perpendicular to the long axis of the flexure bar. (Fig. 4b)3.2.23 truing, nprocess by which the abrasive surface of a grinding wheel is brought to the desired shape and is madeconcentric with the machine spindle axis of rotat
41、ion.FIG. 3 Relative Wheel and Workpiece Directions of Motion for Down Grinding and Up GrindingFIG. 4 Grinding Directions with Respect to Flexure Bar Orienta-tionC1495 1643.2.24 undeformed chip thickness, nmaximum thickness of a chip removed during grinding, assuming that the chip isdisplaced from th
42、e surface without deformation or change in shape.3.2.24.1 DiscussionEquivalent in size to grit depth-of-cut.3.2.25 up-grinding, na condition of up-grinding is said to hold when the velocity vector tangent to the surface of the wheelat points of first entry into the grinding zone has a component norm
43、al to and directed out of the ground surface of the workpiece.(Fig. 3b)3.2.26 wheel depth-of-cut, ndepth of penetration of the grinding wheel into the workpiece surface as it moves parallel to thesurface to remove a layer of material. (Fig. 3)3.2.26.1 DiscussionOften abbreviated to depth-of-cut.3.2.
44、27 wheel specifications, ndescription of the grinding wheel dimensions, grit type, grit size, grit concentration, bond type,and any other properties provided by the wheel manufacturer that characterize the grinding wheel.3.2.28 wheel surface speed, ncircumferential speed of the grinding wheel surfac
45、e at points which engage the workpiece duringthe process of grinding.3.3 Surface Finish Related:3.3.1 lay, nrefers to the direction a non-random pattern of surface roughness in the plane of the surface, e.g. for example, thedirection of abrasive striations on a surface prepared by grinding. (Fig. 2)
46、3.3.2 roughness, nthree-dimensional variations in surface topography characterized by wavelengths in the plane of the surfacethat are small compared to the design dimensions of the workpiece.3.3.3 waviness, nsurface topographic variations characterized by wavelengths in the plane of the surface that
47、 are largecompared to the roughness but smaller than the design dimensions of the workpiece.3.4 Flexure Test Related:3.4.1 break force, nforce at which a test specimen fractures (fails) in a flexure test.3.4.2 flexural strength, na measure of the ultimate strength of a specified beam in bending. C11
48、453.4.3 tensile face, nside of a flexure test specimen that is stressed in tension in a flexure test.Other terms related to flexure testing can be found in C1161.Other terms related to flexure testing can be found in C1161.3.5 Fractography Related:3.5.1 crack, nas used in fractography, a plane of fr
49、acture without complete separation. C13223.5.2 flaw, na structural discontinuity in an advanced ceramic body which acts as a highly localized stress riser. C13223.5.3 fractography, nmeans and methods for characterizing a fractured test specimen or component. C11453.5.4 fracture origin, nthe source from which brittle fracture commences. C11453.5.5 fracture mirror, nas used in fractography of brittle materials, a relatively smooth region in the immediate vicinity ofand surrounding the fracture origin. C1322Other terms
