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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This difference requires pattern recognition techniques which are beyond the scope of this method. As the degree of orientation or banding increases, the anisotropy index increases above one.
ASTM E1268 – 01(2016)
The accuracy of this conversion will become poorer as the test load decreases below gf. A minimum of ve measurements in each direction, generally more, were made on each micrograph by one or more persons. The load is adjusted so that the indent can be kept completely within the bands. Count only phase or constituent boundary intersections between unlike particles, grains, or patches. These conversions are for Knoop loads of gf or greater.
The degree of carbon segregation may be estimated by this method and reported for such specimens. However, depending on the alloy or material being examined, other illumination modes, such as polarized light or differential interference contrast illumination, may be used. If a line ends within a particle, patch or grain, count it as one half an interception.
Calculate the number of interceptions per unit length parallel to the deformation axis, N Lin accordance with: The deformation axis in each microstructure shown is horizontal.
However, an experienced operator can distinguish between the two forms of alignment, perhaps aided by the examples in Annex A1.
For small segregates, it may not be possible to obtain ve or more hardness tests values. Table 1 provides rules for counting while Fig. Because the degree of banding or orientation may vary through the product cross section, the test plane should sample the entire cross section. Each microstructure has been qualitatively described in accordance with the scheme outlined in Fig.
P’ PL’ 5 L t 3 where: The accuracy of this conversion will become poorer as the test load decreases below gf. A number in paren parenthese thesess indicates the year of last reappr reapproval. Alternatively, both phases may be aligned with neither appearing as a matrix phase.
Decide which phase or constituent is banded.
ASTM E 1268 2001(Reapproved 2016) Ferrite Banding Standard
Generally, it is best aetm count the banded phase present in least f1268. There are presently no absolute guides between the measured quantitative parameters and the qualitative terms used to describe the microstructure. 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: Current edition approved Dec.
This difference requires pattern recognition techniques which are beyond the scope of this method. The microindentation hardness test procedure should only be used to determine the difference in hardness in banded heat-treated metals, chiefly steels.
Summary of Practice 4. The Knoop indenter is particularly well suited for this work.
Conversion of HK values to HRC or other scales may involve considerable error particularly for test loads below gf. Link to Active This link will always route to the current Active version of e12268 standard. For fully martensitic sit ic car carbo bon n an and d al allo loy y ste steel elss 0 0.
Solid-state transformations may be inuenced by the resulting microsegregation pattern leading to development of a layered or banded microstructure. These conversions are for Knoop loads of gf or greater.
The load is adjusted so that the indent can be kept completely within the bands. Other examples of banding include carbide banding in hypereutectoid tool steels and martensite banding in heat-treated alloy steels. N’ NL’ 5 L t 1 with the sample length in the longitudinal direction at least 10 mm 0.
However, depending on adtm alloy or material being examined, other illumination modes, such as polarized light or differential interference contrast illumination, may be used. Qstm 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.
It is best if the wstm used does not reveal grain boundaries within a given phase. Count only phase or constituent boundary intersections between unlike particles, grains, or patches. As the degree of orientation or banding increases, the anisotropy index increases above one.
The anisotropy index for a randomly oriented, non-banded microstructure is one. Test Methods E list appropriate etchants for most metals and alloys. If the product form is too large to permit preparation of full cross sections, the samples prepared at the desired locations should have a minimum polished surface area of mm 2 0.
If both phases or constituents are banded, with no obvious matrix phase, choose one e12268 the phases constituents for counting. If a test line ends within a particle, count N as 12 and P as 1.
ASTM E (Reapproved ) Ferrite Banding Standard – PDF Free Download
The equations given in Annex A2 may be helpful for such conversions. Measurements are made with the test lines parallel and perpendicular to the deformation direction. Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm.
Both the matrix and the segregates must be fully martensitic except for normal minor amounts of retained austenite and in the as-quenched condition. If the sstm 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.
The length of full cross-section samples, in the deformation direction, should be at least 10 mm 0.