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Supplement to A.S.T. M. Methods of Chemical Analysis of Metals.—These methods are a revision of and supersede the former Tentative Methods of Chemical Analysis of Ferro-Alloys (A 104-36 T) which latter methods appear on pages 60 to 94 of the Society's publication '"A.S.T. M. Methods of Chemical Analysis of Metals (1936)." Since these methods replace the former Tentative Methods A 104- 36 T, this copy should be substituted in the compilation of the Methods of Chemical Analysis of Metals.
Tentative Methods of
CHEMICAL ANALYSIS OF
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A.S.T. M. Designation: E 31
This Tentative Standard of the American Society for Testing Materials is, under its Regulations, subject to annual revision. Suggestions for revision should be addressed to the Society, 260 S. Broad St., Philadelphia, Pa.
The following methods have been compiled as standard procedures for use in referee analyses. These methods, however, are not intended to preclude the use of other methods (or apparatus) that give results within permissible variations. In any case, the analyst should check the method and technique that is used by means of a National Bureau of Standards' standard sample that has a composition comparable with that of the material under test. A list of these standard samples is given in the Bureau's supplement to circular C 398.
Concentration of Acids.—Throughout these methods, the use of concentrated acids is intended, unless otherwise specified. For example, hydrochloric acid, or HCl, refers to the concentrated acid (sp. gr. as furnished by the manu-
facturers. Diluted acids will be designated as in the following example: "diluted HCl (2:98)" will mean 2
1 Under the standardizatio:: procedure of the Socio!, these methods are under the Jurisdiction of the A.S.T. M. Committee E-3 on Chemical Analysis of Metals.
2 These methods are in effect a revision of and replace the former Tentative Methods of Chemical Analvsis of Ferro-Allovs (A 1(14-36 T) which were published as tentative from 1925 to 1927, adopted as standard in 1927, revised in 1934, but withdrawn and republished as tentative from 1936 to 1938.
Accepted for publication as tentative 1a Committee E-10 on Standards, August 25, 1938.
volumes of the concentrated acid of sp. gr. 1.19, diluted with 98 volumes of distilled water.
Water.—The term "water" as used in these methods refers only to distilled water.
Attention is directed to certain precautions to be observed in the use of the reagents employed in the analytical procedures described in these methods.
Perchloric acid has become a valuable reagent in the analysis of ferrous alloys. While perchloric acid of 70 per cent strength may be boiled with impunity at approximately 200 C, it cannot be too strongly emphasized that contact of the boiling undiluted arid or hot vapor of perchloric acid, with organic matter, or even easily oxidized inorganic matter such as compounds of trivalent anti-money, will lead to serious explosions. If oxidizable substances are present, nitric acid must always be added as a precautionary measure before the addition of perchloric acid and evaporation to fumes of the acid. Do not use rubber thumb stalls around fuming perchloric acid. Handle with beaker tongs. Perchloric