Automated image analysis software for assessing banding or orientation of Microstructures in dual phase steel. For Annual Book of ASTM approved in Last previous edition approved in as E – 01(). Standards volume information, refer to the standard’s . ASTM E_ – Designation: E – 01 Standard Practice for Assessing the Degree of Bandin.
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For a highly banded microstructure, NL’ the bar above the quantity indicates an average value is a measure of the number 6 Not for Resale where: Stereological methods are not suitable for measuring individual features, instead use standard measurement procedures to dene the feature size.
Linear regression for this portion of the conversion reveals the following relationship: With this equation, the predicted HRC is within When a test line is tangent to the particle, grain, or patch of interest, N is counted as 12and P as 1.
The degree of orientation can vary from zero completely random distribution to 1. Tangent hits are counted as one intersection. NOTE 1—Although stereological measurement methods are used to assess the degree of banding or alignment, the measurements are only made on planes parallel to the deformation direction that is, a longitudinal plane and the three-dimensional characteristics of the banding or alignment are not evaluated.
Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. For plate or sheet products, a planar oriented that is, polished surface parallel to the surface of the plate or sheet test specimen, at subsurface, mid-thickness, or center locations, may also be prepared and tested depending on the nature of the product application.
Equivalent inch-pound values, when listed, are in parentheses and may be approximate. If the section size is too large to permit full cross sectioning, samples should be taken at standard locations, for example, subsurface, mid-radius or quarter-pointand center, or at specic locations based upon producer-purchaser agreements.
Link to Active This link will always route to the current Active version of the standard. If possible, a gf load should be used, particularly if the equivalent Rockwell C hardness HRC is to be estimated. The test grid is placed over the image projected onto the digitizing tablet and a cursor is used for counting.
Referenc Referenced ed Documents 1. The microindentation hardness test procedure should only be used to determine the difference in hardness in banded heat-treated metals, chiefly steels. All of the measurements were made using 23 enlargements of the photomicrographs presented. Either NL or PL, or both see For as-quenched hardnesses of 58—64 HRC 0. The Knoop indenter is particularly well suited for this work.
The experimental hardenability data lists an as-quenched hardness of 58 HRC for steels with carbon contents from 0. Last previous edition approved in as E — 01 If a test line ends within a particle, count N as 12 and P as 1.
ASTM E 1268 2001(Reapproved 2016) Ferrite Banding Standard
Calculate the number of boundary intersections per unit test length parallel to the deformation axis, PLin accordance with: Determine the nature of the banding present, for example, light versus dark etching martensite or bainite versus martensite. There are presently no absolute guides between the measured quantitative parameters and the qualitative terms used to describe the microstructure.
P Intersections—Count the asmt of unlike phase boundaries or constituent boundariesA crossed by the grid lines. Because the degree of banding or orientation may vary through the product cross section, the test plane should sample the entire cross section. If both phases or constituents are banded, with no obvious matrix phase, choose one of the phases constituents for counting. N Interceptions—Count the number of individual particles, grains, or patches of the constituent of interest crossed by the grid lines.
The accuracy of this conversion will become poorer as the test load decreases below gf. Sco Scope pe 1. The degree of carbon segregation may be estimated by this method and reported for such specimens. Th Thee st ster ereo eolo logi gica call me meth thod odss ma may y als also o be us used ed to ch char aract acter erize ize no nonn-ba band ast ed microst micr ostruc ructur tures es with seco second nd pha phase se con constit stituen uents ts ori oriente ented d elo elonga ngated ted in var varyin ying g deg degree reess in the deformation direction.
If both phases or constituents are banded, with no obvious matrix phase, choose one of the phases constituents for counting. Summary of Practice 4. NOTE 3—If the difference in Knoop hardness between the bands is not large, the statistical signicance of the difference can be determined using the t-test as described in most statistics textbooks.
The magnication must be high enough to permit accurate counting of feature interceptions or phase boundary intersections. For fully martensitic carbon and alloy steels 0. Equ Equiva ivalen lentt inc inch-p h-poun ound d val values ues, whe when n listed, are in parentheses and may be approximate. This problem occurs most commonly in NL and PL measurements in highly banded structures. A If possible, etch the specimens so that like phase or constituent boundaries are not revealed, only unlike boundaries.
This method is applicable only to steels with carbon contents from 0.
Calculate asttm number of interceptions per unit length parallel to the deformation axis, N Lin accordance with: Hardenability studies have demonstrated this relationship for fully martensitic microstructures in steels rapidly quenched from the prescribed austenitizing temperatures. Your consent to our cookies if you continue to use this website. The total length of the grid lines e126 be at least mm. This difference requires pattern recognition techniques which are beyond the scope of this method.
The experimental hardenability data lists an as-quenched hardness of 58 HRC for steels with carbon contents from 0.
ASTM E (Reapproved ) Ferrite Banding Standard – PDF Free Download
Stereological methods are not suitable for measuring individual features, instead use standard measurement procedures to define the feature size. Table 1 provides rules for counting while Fig. Decide which phase or constituent is banded. Originally published as E —