Norm

ASTM E975-13

Standard Practice for X-Ray Determination of Retained Austenite in Steel with Near Random Crystallographic Orientation

54,27

Over deze norm

Status Definitief
Aantal pagina's 7
Commissie E04.11
Gepubliceerd op 15-02-2013
Taal Engels

1.1 This practice covers the determination of retained austenite phase in steel using integrated intensities (area under peak above background) of X-ray diffraction peaks using chromium Kα or molybdenum Kα X-radiation.

1.2 The method applies to carbon and alloy steels with near random crystallographic orientations of both ferrite and austenite phases.

1.3 This practice is valid for retained austenite contents from 1 % by volume and above.

1.4 If possible, X-ray diffraction peak interference from other crystalline phases such as carbides should be eliminated from the ferrite and austenite peak intensities.

1.5 Substantial alloy contents in steel cause some change in peak intensities which have not been considered in this method. Application of this method to steels with total alloy contents exceeding 15 weight % should be done with care. If necessary, the users can calculate the theoretical correction factors to account for changes in volume of the unit cells for austenite and ferrite resulting from variations in chemical composition.

1.6 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

TABLE 1 Calculated Theoretical Intensities Using Chromium Kα RadiationA

hkl

Sinθ/λ

θ

f

Δf′

Δf"

/F/2

LP

P

TB

N2

R

(α iron, body-centered cubic, unit-cell dimension ao  = 2.8664Å):

110

0.24669

34.41

18.474

−1.6

0.9

1142.2

4.290

12

0.9577

0.001803B

101.5C

200

0.34887

53.06

15.218

−1.6

0.9

 745.0

2.805

 6

0.9172

0.001803B

 20.73C

211

0.42728

78.20

13.133

−1.6

0.8

 534.6

9.388

24

0.8784

0.001803B

190.8C

(γ iron, face-centered cubic, unit-cell dimension a o  = 3.60Å):

111

0.24056

33.44

18.687

−1.6

0.9

4684.4

4.554

 8

0.9597

0.0004594B

 75.24C

200

0.27778

39.52

17.422

−1.6

0.9

4018.3

3.317

 6

0.9467

0.0004594B

 34.78C

220

0.39284

64.15

14.004

−1.6

0.8

2472.0

3.920

12

0.8962

0.0004594B

 47.88C

A  Data from “International Tables for X-Ray Crystallography,” Physical and Chemical Tables , Vol III, Kynoch Press, Birmingham, England, 1962, pp. 60, 61, 210, 213; Weighted Kα1 and Kα2 value used (λ = 2.29092Å).
B  Temperature factor (T = e−2M) where M = B(sin 2 θ)/λ2 and 2B = 0.71. Also N is the reciprocal of the unit-cell volume.
C  Calculated intensity includes the variables listed that change with X-ray diffraction peak position.

Details

ICS-code 77.080.20
Nederlandse titel Standard Practice for X-Ray Determination of Retained Austenite in Steel with Near Random Crystallographic Orientation
Engelse titel Standard Practice for X-Ray Determination of Retained Austenite in Steel with Near Random Crystallographic Orientation

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