ASTM A604-93(2003)
(Test Method)Standard Test Method for Macroetch Testing of Consumable Electrode Remelted Steel Bars and Billets
Standard Test Method for Macroetch Testing of Consumable Electrode Remelted Steel Bars and Billets
SCOPE
1.1 This test method covers testing and inspection and is applicable to bars, billets, and blooms of carbon, alloy, and stainless steel which have been consumable electrode remelted.
1.2 For the purpose of this test method, the consumable electrode remelting process is defined as a steel refining method wherein single or multiple electrodes are remelted into a crucible producing an ingot which is superior to the original electrode by virtue of improved cleanliness or lower gas content or reduced chemical or nonmetallic segregation. See Appendix X1 and Appendix X2 for descriptions of applicable remelting processes.
1.3 This test method and the accompanying comparison macrographs are generally applicable to steel bar and billet sizes up to 225 in.2 in transverse cross section.
1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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.
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Designation:A 604–93 (Reapproved 2003)
Standard Test Method for
Macroetch Testing of Consumable Electrode Remelted Steel
Bars and Billets
This standard is issued under the fixed designation A 604; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (ε) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2.2 ASTM Adjuncts:
2 ADJA0604
1.1 This test method covers testing and inspection and is
Adjunct to A604 Test Method for Macroetch Testing of
applicable to bars, billets, and blooms of carbon, alloy, and
Consumable Electrode Remelted Steel Bars and Billet
stainlesssteelwhichhavebeenconsumableelectroderemelted.
1.2 For the purpose of this test method, the consumable
3. Description of Macroetch Testing
electrode remelting process is defined as a steel refining
3.1 Macroetch testing, as described herein, is a method for
method wherein single or multiple electrodes are remelted into
examining and rating transverse sections of bars and billets to
a crucible producing an ingot which is superior to the original
describe certain conditions of macro segregation which are
electrode by virtue of improved cleanliness or lower gas
often characteristic of consumable electrode remelted materi-
content or reduced chemical or nonmetallic segregation. See
als. This test method is not intended to define major defects
Appendix X1 and Appendix X2 for descriptions of applicable
such as those described by Method E 381.
remelting processes.
3.2 This test method employs the action of an acid or other
1.3 This test method and the accompanying comparison
corrosive agent to develop the characteristics of a suitably
macrographs are generally applicable to steel bar and billet
prepared specimen. After etching, the sections are compared
sizes up to 225 in. in transverse cross section.
visually, or at a very low magnification, if necessary for
1.4 The values stated in inch-pound units are to be regarded
clarification of conditions, to standard plates describing the
as the standard. The values given in parentheses are for
various conditions which may be found. Materials react differ-
information only.
ently to etching reagents because of variations in chemical
1.5 This standard does not purport to address all of the
composition,methodofmanufacture,heattreatment,andmany
safety concerns, if any, associated with its use. It is the
other variables.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 4. Application
bility of regulatory limitations prior to use.
4.1 When material is furnished subject to macroetch testing
and inspection under this test method, the manufacturer and
2. Referenced Documents
purchaser should be in agreement concerning the following:
2.1 ASTM Standards:
4.1.1 The stage of manufacture at which the test shall be
E 381 Method of Macroetch Testing Steel Bars, Billets,
conducted,
Blooms, and Forgings
4.1.2 The number and location of the sections to be tested,
4.1.3 The condition and preparation of the surface to be
This test method is under the jurisdiction of ASTM Committee A01 on Steel, macroetched,
Stainless Steel, and RelatedAlloys and is the direct responsibility of Subcommittee
4.1.4 The etching reagent, temperature and time of etching,
A01.06 on Steel Forgings and Billets.
or degree of etching including any special techniques which
Current edition approved April 10, 2003. Published July 2003. Originally
must be used, and
approved in 1970. Last previous edition approved in 1998 as A 604 – 93(1998).
ASTM CommitteeA01 gratefully acknowledges the help of theAISI Commit-
4.1.5 The type and degree of conditions or combinations
tee on General Metallurgy in preparing the appendix, assembling the macroetch
thereof that shall be considered acceptable or subject to
photographs, and assisting with the text of this test method.
3 metallurgical review.
A complete set of the 20 macrographs on glossy paper is available at nominal
cost from ASTM Headquarters, 100 Barr Harbor Drive, W. Conshohocken, PA
19428. Request Adjunct ADJA0604.
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 604–93 (2003)
5. Sample Preparation 7. Etching Containers
5.1 Unless otherwise specified, the test shall be performed 7.1 Macroetching must be done in containers that are
resistant to attack from the etching reagents. Caution must be
on specimens, usually ⁄4 to 1 in. thick, cut to reveal a
transverse surface. exerted to prevent the occurrence of electrolytic couples which
can cause uneven attacks and misleading results.
5.2 Disks for macroetch inspection may be removed from
billets by a variety of methods including torch cutting, sawing,
8. Preparation of Etched Surface and Examination
machining, or high-speed abrasive wheels. Adequate prepara-
8.1 Upon completion of etching, surfaces of disks should be
tion of the surface for macroetching must completely remove
cleaned by either chemical or mechanical methods that do not
the effects of torch cutting or high-speed abrasive wheels.
affect the macroetch quality. Care should be taken to prevent
5.3 Due to the nature of the conditions to be detected,
rusting of the etched surface.
further surface preparation is usually required.
5.4 When such further preparation is performed, grinding,
9. Interpretation of Conditions Found by Macroetching
machining, or sanding should be carried out in such a manner
9.1 Four distinct classes of conditions are defined and
as not to mask the structure.
described under this method:
5.5 The surface of the disk to be etched must be free of dirt,
9.1.1 Class 1: Freckles—Circular or near-circular dark
grease, or other foreign material which might impair the result
etching areas generally enriched with carbides and carbide-
of the test.
forming elements.
9.1.2 Class 2: White Spots—Light etching areas, having no
6. Etching Reagents
definitive configuration or orientation which are generally
6.1 The etching response and appearance is dependent upon reduced in carbide or carbide-forming elements.
the type and temperature of the etching reagent and the time of 9.1.3 Class 3: Radial Segregation—Radially or spirally
immersion. These details must be established by agreement oriented dark etching elongated areas occurring most fre-
between manufacturer and purchaser. quently at mid-radius which are generally carbide enriched.
6.2 For illustrative purposes some of the commonly used This condition may be easily confused with freckles in some
materials.
etching reagents are as follows:
9.1.4 Class 4: Ring Pattern—One or more concentric rings
6.2.1 Hydrochloric Acid—A solution of 1 part commercial
evidenced by a differential in etch texture associated with
concentrated hydrochloric acid (HCl, sp gr 1.19) and 1 part
minor composition gradients and ingot solidification.
water is more generally used than any other macroetching
9.2 Macroetch photographs show examples of each of the
reagent. This solution may be heated without significant
conditions revealed by macroetch testing, with five degrees of
change in concentration, and may be reused if it has not
severity, identified as A, B, C, D, and E for each condition.
become excessively contaminated or weakened. Etching is
generally done with the solution at a temperature of approxi- Degree A exhibits the minimum occurrence of each condition
detectable by visual examination of the etched surface, while
mately 160°F.
degrees B, C, D, and E represent increasing severity of
6.2.2 Hydrochloric Acid-Sulfuric Acid Mixture—A mixture
occurrence.
containing 50 % water, 38 % commercial concentrated HCl,
9.3 For each condition, or combination of conditions, rat-
and12 %commercialconcentratedsulfuricacid(H SO ,spgr
2 4
ings shall be obtained by comparing each macroetched section
1.84) is sometimes used in place of the previously mentioned
with the standard photographs. Bar or billet sections to 225 in.
50 % HCl solution. The statements in the previous paragraph
cross-sectional area may be rated against these standards.
regarding reuse and temperature of etchant are applicable to
Larger sizes may be rated by agreement between manufacturer
this reagent.
and purchaser, but caution must be exercised in interpretation
6.2.3 Aqua Regia—A solution consisting of 1 part concen-
ofsuchresults.Figs.1-20havebeenreduced44%inareafrom
trated nitric acid (HNO , sp gr 1.42) and 2 parts concentrated
the
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