ASTM A – Designation: A /A M – 01 An American National Standard Standard Practice f. This standard is issued under the constant designation a /a m; the number right away following the designation suggests the yr. according to the guidelines of ASTM E, “Standard Guide for ASTM A, “Standard Practice for Steel Casting, Austenitic Alloy.
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ASTM D e1. A number in parentheses indicates the year of last reapproval. A a8800 epsilon e indicates an editorial change since the last revision or reapproval. Methods are described for estimating ferrite content by chemical, magnetic, and metallographic means. Within the text, the SI units are shown in brackets.
The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the practice. 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.
This may be formed upon solidication from the molten metal delta ferrite or by transformation from austenite or sigma phase on cooling in the solid state alpha ferrite.
BoxN. Current edition approved Mar.
Originally published as A — Signicance and Use 4. The ferrite content may be limited by purchase order requirements or by the design construction codes governing the equipment in which the castings will be used. The quantity of ferrite in the structure is fundamentally a function of the chemical composition of the alloy and its thermal history.
Because of segregation, the chemical composition, and, therefore, the ferrite content, may differ from point to point on xstm casting. Determination of the ferrite content by any of the procedures described in the following practice is subject to varying degrees of imprecision which must be recognized in setting realistic limits on the range of ferrite content specied.
Sources of error include the following: Therefore, the precision of the ferrite content estimated from chemical composition depends on the accuracy of the chemical analysis procedure. These may so alter the magnetic response of the alloy that the indicated ferrite content is quite different from that of the same chemical composition that has undergone different thermal treatment.
Also, because the magnets or probes of the various measuring instruments are small, different degrees of surface roughness or surface curvature will vary the magnetic linkage with the material being measured.
NOTE 1—There may be a substantial decrease awtm the ferrite content of weld deposits after solution heat treatment in comparison with the as-deposited value. Estimation of Ferrite Content 7. If a comparison is made of ferrite content estimated from a product analysis performed by the purchaser, with that estimated from the heat analysis see 7.
Z800 estimates of ferrite content from magnetic measurements Qstm or from point counts S2or both, if ordered by the purchaser, also shall be reported. They shall not apply unless specied in the order, in which event the specied methods of ferrite content estimation shall be employed by the manufacturer before shipment of the castings. Asym measurements shall be made on material after the solution heat treatment required by the applicable product specication, or, if any subsequent solution heat treatment is employed, then after the nal solution heat treatment.
Measurements may be made either before or after performance of the tension test.
ASTM International – Standard References for ASTM A / AM – 14
If a tension test is not required by the applicable product specication, measurements may be made on a specimen cut from a keel block of a design in Fig. All measurements shall be made on weld deposits as deposited. When measurements are made on a curved surface the asttm of curvature must be greater than 0. Because of errors in chemical analyses, the calculated ratio may differ from the actual composition ratio and, as a result, the ferrite content may be higher or lower than indicated by the central X1.
Accordingly, if additional estimates of ferrite content are made by magnetic or metallographic methods, they can be expected to differ from the diagram value. The possible extent of this difference is shown by the broken lines. If the composition ratio is 1. Similar axtm is available in Table X1. The gures immediately above and below on the lines U and L indicate the probable upper and lower bounds of the ferrite range that may be expected.
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This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ve years and if not revised, either reapproved or withdrawn. Your comments are invited adtm for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.
Standard Practice for Steel Casting, Austenitic Alloy, Estimating Ferrite Content Thereof
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