ISO-1811-1-1988.pdf
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1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXAYHAPOjJHAR OPTAHM3AMR n0 CTAHAPTM3Al steel tools if used shall be made of magnetic material to assist in the sub- sequent removal of extraneous iron. 5.1.4 For alloys with magnetic
2、phases, carbide-tipped tools shall be used; magnetic cleaning shall not be used. Drillings, millings, sawings or clippings of alloys with no magnetic phases shall be treated carefully with a strong magnet to remove any particles of iron introduced during sampling. The drillings, mill- ings, sawings
3、or clippings shall be carefully examined, and any foreign material introduced in taking the sample shall be removed. 5.1.5 In certain cases a complete cross-section from a sam- pling unit may be required for spectrometric examination. Each cross-section shall be taken and properly marked before usin
4、g the remainder of the sampling unit for other sampling operations. 5.1.6 The gross sample shall be prepared by thoroughly mix- ing equal masses of drillings, millings, sawings or clippings taken from each sampling unit. The chips obtained by milling, drilling, etc., shall be uniformly small in size
5、. 5.1.7 The gross sample shall weigh at least four times the amount required for the total analysis, and shall be divided into four test samples of equal mass, each of which shall be placed in a container and sealed: one for the producer, one for the purchaser, one for reference purposes, if necessa
6、ry, and one as reserve. 5.1.6 In the event of the oxygen content of Cu-OFE (and CU-HCP if necessary) being determined, an additional group of test samples shall be taken from the selected sampling units. Each test sample shall consist of a single piece of adequate size, cut from the sampling unit by
7、 a method agreeable to both producer and purchaser at a mutually agreeable location in the sampling unit. Each test sample shall be cut into three test por- tions of approximately equal mass: one for the producer, one for the purchaser, and one for reference purposes, if necessary. Each party shall
8、determine oxygen on his test portion using an agreed procedure. 5.2 Horizontally cast unwrought products 5.2.1 Five holes shall be drilled through from the set surface at points equally spaced between the ends of the sampling unit. For billets, ingots and wire bars, these holes shall be along the mi
9、ddle line, and for cakes on a diagonal line between opposite corners. 5.2.2 Alternatively, any horizontally cast unwrought product may be milled at similar points through a section from side to centre or through an entire cross-section of the sampling unit. 5.3 Vertically cast unwrought products 5.3
10、.1 Five holes shall be drilled at points equally spaced be- tween the ends of the sampling unit. For billets and wire bars these holes shall be along the middle line, and for cakes on a diagonal line between opposite corners. 5.3.2 Alternatively, any vertically cast unwrought product may be milled a
11、t similar points through a section from side to centre or through an entire cross-section of the sampling unit. 5.4 Sampling units of mass greater than 450 kg Sampling of individual sampling units of mass greater than 450 kg shall be by agreement between the producer and the purchaser. 2 Copyright I
12、nternational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:49:21 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 1811-1 : 1988 (EI Annex A (normative) Sampling theory
13、A.1 Principles The theoretical aspects of sampling cast metal shapes and other metallurgical materials for chemical analysis are described in this annex. While it is recognized that cost, time and other practical considerations may necessitate substantial deviations, it is useful to outline the fund
14、amental theory of correct metallurgical sampling. Molten alloys will be homogeneous only when all com- ponents are completely dissolved and perfectly distributed by mixing, and when the temperature throughout the molten mass is above that of the liquidus. Castings, however, even solidified from such
15、 a homogeneous melt, will in most cases be heterogeneous. The degree of heterogeneity of the solid phase will depend mainly on the composition and rate of cooling of the melt. For example, a cylindrical casting of high-lead alloy may contain almost pure lead in its central core which solidified last
16、. Conversely, the cooled surface areas of copper-tin alloy castings often contain tin concentrations far above the average for the whole casting. Due to the almost ever-present problem of segregation, sampl- ing of cast metal shapes shall be adapted to the particular con- ditions of each separate ca
17、se. Continuously cast shapes may be sampled by removing material of uniform thickness from a complete cross-section. Such samples can be conveniently obtained by sawing, turning or milling. Although such samples provide correct representa- tion of the cast at the time of sampling, they would, of cou
18、rse, not be valid if the composition of the melt changed during the casting operation. A hypothetically correct but prohibitively expensive method of sampling horizontally and vertically cast metal shapes would be to cut complete segments from the top to the bottom of the casting. The minimum sample
19、 volume required for geometri- cally correct representation of all diffusion layers would be: - 25 % of the volume for shapes of rectangular horizon- tal section; - 12,5 % of the volume for shapes of square horizontal section; - a segment of any width for shapes of circular horizontal section A some
20、what simplified but still expensive compromise in sampling a cast metal shape is based on removing samples from two parallel diagonal planes. For a rectangular shape, the two diagonal planes are those which connect the centreline of the bottom with a parallel edge of the top and an edge of the botto
21、m with the parallel centreline of the top. For a cylindrical shape, the two parallel planes extend between the top diameter and the point at which a parallel tangent meets the bottom cir- cumference, and between the bottom diameter and the point at which a parallel tangent meets the top circumferenc
22、e. The samples might be produced by sawing, or by milling the ex- posed areas. It is recognized that, although a theoretically correct sample would result, the cost of this method is too high for practical consideration. It is presented only to indicate that simplification of the sampling geometry m
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