ASTM grain size

There are two commonly used ways of characterizing the grain size of a crystalline solid. One is the ASTM grain size number, N, defined by... 

EXAMPLE 1.1. Figure 1.1 is a micrograph taken at 200X. What is the ASTM grain size number ... 

For random microstructures, and the ASTM grain size are related. An approximate relationship can be found by assuming that the grains can be approximated by circles of radius, r. The area of a circular grain, nr2, can be expressed as the average linear intercept, , times its width, 2r, as shown in Figure 1.3, so 2r = nr2. Therefore,... 

Count the number of triple points in Figure 1.10 and deduce the ASTM grain size from this count. Compare with your answer to Problem 2A. 

What is the linear intercept grain size (in millimeters) corresponding to an ASTM grain size number of 8 ... 

If the ASTM grain size number is increased by one, by what factor is the number of grains per volume changed ... 

Temperature dependence of pearlite nucleation and growth rates in a 0.78% C, 0.63% Mn steel of ASTM grain size 5.25. Data from R. F. Mehl and A. Dube, Phase Transformations in Solids (New York Wiley, 1951), 545. Reprinted with permission of John Wiley Sons, Inc. 

Figure 12a. Normal ASTM grain size microstructure. Reproduced with permission from Ref, 7. Copyright 1972 American Society for Metals.

Fig. 10.2. Representative examples of ASTM grain sizes in low-carbon steel (a) grain size 2 180 im), (b) grain size 5 60 iim), (c) grain size 7 ( 30 (xm), (d) grain size 10 10 xm). Mean...

Chemical compositions plus processing and heat treatment schedules relative to Inconel 718 and Udimet 718 are presented in Tables I and II. Hardness and ASTM grain size (average numbers) are included in Table II. Both the Inconel 718 and Udimet 718 superalloys were obtained as large-diameter (29 cm and 26 cm, respectively) hot-finished forging billets, vacuum-induction-melted and vacuum-arc-remelted (VIM-VAR). The two alloys have comparable chemical compositions, but the Inconel 718 has a significantly higher silicon content. 

Little difference was observed in the hardness values between the two cold-worked plus solution-treated and double-aged (STDA) Inconel 718 materials, although a significant difference in ASTM grain size numbers was apparent. 

Table II. Heat Treatment, Hardness, and ASTM Grain Size Number Relative to VIM-VAR Inconel 718 and Udimet 718...

GS = the ASTM grain size in accordance with ASTM E 112, Test Methods for Determining the Average Grain Size. 

GBA = A, [5.09544 x lO exp (0.34696 X)] where A, = the specimen area and X = the ASTM grain size in accordance with ASTM E 112, Test Methods for Determining Average Grain Size. 

Figure 2.5 Visual description of various grain ASTM grain sizes.

Relationship between ASTM grain size nnmber and nnmber of grains per sqnare inch (at 100 x)... 

Relationships have been developed that relate mean intercept length to ASTM grain-size number these are as follows ... 

For an ASTM grain size of 6, approximately how O many grains would there be per square inch under... 

Determine the ASTM grain-size number if O 30 grains per square inch are measured at a magnification of 250 X. 

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