0000003103 00000 n
0000054526 00000 n
0000374877 00000 n
There appears to be a general bias in that comparisongrain size ratings claim that the grain size is somewhat coarser12 to 1 G number lower than it actually is see X1.3.5.Repeatability and reproducibility of comparison chart ratingsare generally 61 grain size number.4.1.2 Planimetric ProcedureThe planimetric in-volves an actual count of the number of grains within a knownarea. Significance and Use4.1 These test s cover procedures for estimating andrules for expressing the average grain size of all metalsconsisting entirely, or principally, of a single phase. 0001618831 00000 n
0000012449 00000 n
4.1.2 Planimetric Procedure—The planimetric method in-volves an actual count of the number of grains within a known area. The term may also be applied to other granular materials. The tests may also be used for any structures having appear-ances similar to those of the metallic structures shown in thecomparison charts. 0000003294 00000 n
0000004685 00000 n
Terminology3.1 DefinitionsFor definitions of terms used in these tests, see Terminology E7.3.2 Definitions of Terms Specific to This Standard3.2.1 ASTM grain size numberthe ASTM grain sizenumber, G, was originally defined asNAE5 2G211where NAEis the number of grains per square inch at100X magnification.
Vacuum grooving Preferentially evaporates austenite grain boundaries ASTM grain size in terms of the number of grains ASTM grain size number Number of grains/in.
0000354410 00000 n
is used to determine the ASTMgrain size number, G. The precision of the is a functionof the number of intercepts or intersections counted. (1970), are widely used for sand and mud, and are essential for the objective de- scription of clastic sediment. 1.5 These test methods deal only with the recommended test methods and nothing in them should be construed as defining or establishing limits of acceptability or fitness of purpose of the materials tested.1.6 The measured values are stated in SI units, which are regarded as standard. The reports can also be generated in excel.
0000374916 00000 n
0000024209 00000 n
The ASTM grain size equation is: n = 2G-1 (Eq 12) where n is the number of grains per square inch at 100×.
0000365982 00000 n
These charts wereconstructed to reflect the typical log-normal distribution ofgrain sizes that result when a plane is passed through aE112 133three-dimensional array of grains. 0001074415 00000 n
0001581523 00000 n
0000018475 00000 n
0000005455 00000 n
To obtain the number per square milli-metre at 1X, multiply by 15.50.3.2.2 grainan individual crystal with the same atomicconfiguration throughout in a polycrystalline material; thegrain may or may not contain twinned regions within it orsub-grains.3.2.3 grain boundarya very narrow region in a polycrys-talline material corresponding to the transition from onecrystallographic orientation to another, thus separating oneadjacent grain from another; on a two-dimensional planethrough three-dimensional polycrystalline materials, the grainedges between adjacent grains surrounding a single grain makeup the outline of the two-dimensional grains that are observedin the light microscope and are measured or counted by theprocedures in this test .3.2.4 grain boundary intersection count, Pdeterminationof the number of times a test line cuts across, or is tangent totangent hits are counted as one 1 intersection grain bound-aries triple point intersections are considered as 1-12 intersec-tions.3.2.5 grain intercept count, Ndetermination of the numberof times a test line cuts through individual grains on the planeof polish tangent hits are considered as one half an intercep-tion; test lines that end within a grain are considered as one halfan interception.3.2.6 intercept lengththe distance between two opposed,adjacent grain boundary intersection points on a test linesegment that crosses the grain at any location due to randomplacement of the test line.3.3 Symbols matrix grains in a two phase constituentmicrostructure.A test area.A mean grain cross sectional area.AI grain elongation ratio or anisotropy index for alongitudinally oriented plane.d mean planar grain diameter Plate III.D mean spatial volumetric grain diameter.f Jeffries multiplier for planimetric .G ASTM grain size number.
0000025298 00000 n
0000016801 00000 n
These test methods apply chiefly to single phase grain structures but they can be applied to determine the average size of a particular type of grain structure in a multiphase or multiconstituent specimen.1.2 These test methods are used to determine the average grain size of specimens with a unimodal distribution of grain areas, diameters, or intercept lengths.
0000025010 00000 n
0000374154 00000 n
0000005695 00000 n
planimetric methods are always applicable for determining average grain size.
0000021084 00000 n
English: Wentworth grain size chart from United States Geological Survey Open-File Report 2006-1195, “Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation” by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins Only certain grades/carbon levels work, and there is an art to the etching and rating. This method results in an ASTM grain size number for the photomicrograph.
Scope1.1 These test s cover the measurement of averagegrain size and include the comparison procedure, the planim-etric or Jeffries procedure, and the intercept procedures.These test s may also be applied to nonmetallicmaterials with structures having appearances similar to those ofthe metallic structures shown in the comparison charts.
For higher degrees of accuracy in determiningaverage grain size, the intercept or planimetric procedures maybe used. 0000008798 00000 n
0000365658 00000 n
Scope 1.1 These test methods cover the measurement of average grain size and include the comparison procedure, the planimet- ric (or Jeffries) procedure, and the intercept procedures.