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1.1 These practices include procedures for the sampling of the various ferroalloys and steel additives, either before or after shipment from the plants of the manufacturers. They are designed to give results representative of each lot that will be comparable with the manufacturer''s guaranteed analysis for the same lot. For check analysis, the purchaser may use any sampling procedure he desires, but the analytical results obtained on such samples shall not be a basis for complaint or rejection, unless the procedure followed is of an accuracy equivalent to that prescribed in these methods.
1.2 In sampling ferroalloys and steel additives, serious errors often occur from contamination of the samples by iron from the sampling appliances. Therefore, special precautions should be observed to avoid this source of error. Metallic iron may be removed with a magnet from nonmagnetic alloys; its estimation in other alloys requires special analytical procedures ( ). To avoid this error, parts of crushers and pulverizing equipment contacting the samples shall be of steel or other material showing a high resistance to abrasion of the type involved.
Note 1: Metallic iron in ferrochromium and ferrosilicon may be determined as follows: Transfer 5 g of the sample of alloy to a 150-mL beaker, add 25 mL of HNO3 (1 + 3), cover, boil 5 min, filter into a 250-mL beaker, and wash with hot water. Add NH4OH in slight excess, heat to boiling, filter, and wash with hot water. Dissolve the precipitate on the paper with a minimum quantity of hot HCl (1 + 2), wash the filter with hot water, and titrate the iron by a standard procedure such as that described in Test Method .
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound values in parenthesis are given for information only.
1.4 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.
|Engelse titel||Standard Practices for Sampling Ferroalloys and Steel Additives for Determination of Chemical Composition|