ISO 2738 pdf download.Sintered metal materials, excluding hardmetals — Permeable sintered metal materials — Determination of density, oil content and open porosity
1 Scope
This international Standard specifies methods of determining the density, oil content and open porosity of permeable sintered metal materials. It applies in particular to porous metal bearings and to structural parts produced by pressing and sintering metal powders.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 758, Liquid chemical products for industrial use — Determination of density at 20 °C. ISO 1 3944, Lubricated metal-powder mixes — Determination of lubricant content — Modified Soxhlet extraction method.
4 Terms and definitions
For the purposes of this International Standard the following terms and definitions apply. 4.1 density the density of the test piece may be expressed in two ways: 4.1.1 dry density the mass, after drying, divided by the volume 4.1.2 fully impregnated density (wet density) the fully impregnated mass divided by the volume 4.2 oil content the oil content of the test piece may be expressed in two ways: 4.2.1 percentage by volume the volume of the oil divided by the volume of the test piece and multiplied by 1 00 4.2.2 percentage of the volume of the open porosity the volume of the oil divided by the volume of the open porosity and multiplied by 1 00 4.3 open porosity (of the test piece) the oil content after full impregnation divided by the volume of the test piece and multiplied by 1 00 expressed as a percentage by volume 4.4 volume (of the test piece) total volume including the pores
5 Test procedures
Depending upon which of the properties is to be determined, some or all of the test procedures in clause 8 are carried out. Table 2 shows the test procedures that are carried out for the property to be determined. The values obtained for the various parameters are inserted in the respective formulae given in clause 9 to obtain the desired property.
6 Equipment
6.1 Analytical balance, of sufficient capacity and accurate to 0,01 %. 6.2 Soxhlet extractor, with oil solvent. 6.3 Device for weighing the test piece in air and in liquid NOTE The liquid is usually water (see Figures 1 , 2 and 3). 6.4 Vessel, large enough to accommodate the test piece and the device (6.3) for weighing it, containing distilled or deionized, and preferably degassed water, with 0,05 % (V/V) to 0,1 0 % (V/V) wetting agent added. 6.5 Apparatus for vacuum impregnation of the test piece with oil 6.6 Impregnation oil, of known density (see ISO 758 for the determination of the density of liquids). 6.7 Thermometer, accurate to ± 0,5 °C.
7 Test piece
7.1 Usually the test piece is tested whole. If this is not possible, the test piece may be cut or broken into smaller parts to facilitate the various operations. It is often most appropriate to test only a critical section of a component. 7.2 If the test piece has a mass less than 5 g a number of test pieces shall be tested together to obtain the average value. 7.3 The surface of the test piece shall be free of adhering dirt, grease or other foreign material. 7.4 The surface of the test piece shall be free from surplus oil. When removing any such surplus oil with an oil- absorbent material, care shall be taken to avoid removing oil contained in the pores. NOTE The presence of surplus oil on the surface of the test piece is most likely to occur after the full impregnation treatment.