1、Designation: E2567 13aE2567 14Standard Test Method forDetermining Nodularity And Nodule Count In Ductile IronUsing Image Analysis1This standard is issued under the fixed designation E2567; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONDuctile cast iron, also known as nodular cast iron, and spherulitic or spheroidal graphitic iron, is
3、produced with graphite in a spherulitic form. Nodularizing elements, such as magnesium, cerium,lithium, sodium etc., are added to a molten metal bath of proper chemical composition to producediscrete particles of spheroidal-shaped graphite. The control of graphite shape is critical to nodulariron pr
4、operties.Areproducible measurement method is required for evaluation of the cast product andto control process variability. Shape is a difficult parameter to assess using standard chart methods,unless the shape is very close to well-recognized geometric shapes. Nodule density is also difficult toass
5、ess by chart methods as nodule size is also a variable and the chart cannot depict nodule densityvariations for nodules of all possible sizes. Stereological and metrological methods provide unbiasedtechniques for assessing structural variations. These procedures are best performed by image analysiss
6、ystems that eliminate operator subjectivity, bias and inaccuracies associated with manual applicationof stereological and metrological methods. The metallographic sectioning plane will cut through thenodules at random, producing images of graphite nodules with circular or near-circular peripherieswi
7、th a range of diameters.1. Scope1.1 This test method is used to determine the percent nodularity and the nodule count per unit area (that is, number of nodulesper mm2) using a light microscopical image of graphite in nodular cast iron. Images generated by other devices, such as a scanningelectron mi
8、croscope, are not specifically addressed, but can be utilized if the system is calibrated in both x and y directions.1.2 Measurement of secondary or temper carbon in other types of cast iron, for example, malleable cast iron or in graphitic toolsteels, is not specifically included in this standard b
9、ecause of the different graphite shapes and sizes inherent to such grades1.3 This standard deals only with the recommended test method and nothing in it should be construed as defining or establishinglimits of acceptability or fitness for purpose of the material tested.1.4 The values stated in SI un
10、its are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health p
11、ractices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A247 Test Method for Evaluating the Microstructure of Graphite in Iron CastingsE3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to Metallography1 This
12、test method is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct responsibility of Subcommittee E04.14 on QuantitativeMetallography.Current edition approved May 1, 2013Dec. 1, 2014. Published October 2013February 2015. Originally approved in 2011. Last previous edition
13、approved in 2013 asE256713.13a. DOI; 10.1520/E256713A.10.1520/E256714.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM
14、 website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult
15、prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsFor defini
16、tions of terms used in this test method, see Terminology E7.3.2 Definitions of Terms Specific to This Standard:3.2.1 MFDMaximum Feret Diameter3.2.2 minimum size requirementthe size threshold below which graphite particles are eliminated from the analysis.3.2.3 nodulea discrete graphite particle that
17、 exceeds both the required minimum size and shape factor as defined by thismethod.3.2.4 nodule counttotal number of graphite particles meeting the definition of a nodule in the area of interest (AOI).3.2.5 nodule density (Nodule count/unit area)number of nodules per mm2.3.2.6 nodularitydegree of rou
18、ndness, or closeness to a circular periphery, of a graphite particle in ductile iron based upon theshape factor.3.2.7 percent nodularity by areathe total area of particles defined as nodules which meet the minimum size requirementsdivided by the total area of all particles which meet the minimum siz
19、e requirements, expressed as a percentage. See 8.10.3.2.8 shape factora number between 0.00 and 1.0 resulting from formula (Eq 2) of this method.3.2.9 spherulitic graphitein cast iron, a small, spheroidal-shaped crystalline carbon body with a radial growth structure.4. Summary of Test Method4.1 This
20、 test method uses an image analyzer to measure the degree of roundness of graphite particles, viewed on ametallographic sectioning plane, that are above a minimum size in order to determine percent nodularity and nodule density. Themagnification used for the analysis is based on a Maximum Feret Diam
21、eter (MFD) 50 pixels and 125 pixels 50 pixels forthe average size graphite particle being measured. Particles having a MFD 300 per mm2, the results vary within 6 10 nodules per mm2, while for specimens with nodule counts 100, the agreementhas been within 6 10-15 nodules per mm2.11. Keywords11.1 grap
22、hite; image analysis; microstructure; nodule count; nodular iron; nodularity; shapeASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the
23、validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your c
24、omments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments ha
25、ve not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multipl
26、e copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 145
