ISO/TC 119/SC 2 - Sampling and testing methods for powders (including powders for hardmetals)

This document specifies a method of determining the particle size distribution of metallic powders by dry sieving into size fractions. The method is applicable to dry, unlubricated metallic powders, but not applicable to powders in which the morphology differs markedly from being equiaxial, for example flake-type powders. The method is not applicable to metallic powders having a particle size wholly or mostly under 45 µm.

This document specifies a method for determining the flow rate of metallic powders, including powders for hardmetals and mixes of metallic powders and organic additives such as lubricants, by means of a calibrated funnel (Gustavsson flowmeter). The method is applicable only to powders which flow freely through the specified test orifice.

This document specifies a method of measuring the air permeability and the porosity of a packed bed of metal powder, and of deriving therefrom the value of the envelope-specific surface area. The permeability is determined under steady-state flow conditions, using a laminar flow of air at a pressure near atmospheric. This document does not include the measurement of permeability by a constant volume method. Several different methods have been proposed for this determination, and several test devices are available commercially. They give similar, reproducible results, provided that the general instructions given in this document are respected, and the test parameters are identical. This document does not specify a particular commercial test device and corresponding test procedure. However, for the convenience of the user, an informative annex has been included (see Annex A) which is intended to give some practical information on three specific methods: — the Lea and Nurse method, involving a test device which can be built in a laboratory (see A.1); — the Zhang Ruifu method, using a similar test device (see A.2); — the Gooden and Smith method, involving a test device which can be built in a laboratory but for which a commercial test device also exists. (Two types of commercial test device exist; one of these is no longer available for purchase, but is still being used, see A.3.) These methods are given as examples only. Other test devices available in various countries are acceptable within the scope of this document. This testing method is applicable to all metallic powders, including powders for hardmetals, up to 1 000 µm in diameter, but it is generally used for particles having diameters between 0,2 µm and 75,0 µm. It is not intended to be used for powders composed of particles whose shape is far from equiaxial, i.e. flakes or fibres, unless specifically agreed upon between the parties concerned. This testing method is not applicable to mixtures of different metallic powders or powders containing binders or lubricant. If the powder contains agglomerates, the measured surface area can be affected by the degree of agglomeration. If the powder is subjected to a de-agglomeration treatment (see Annex B), the method used is to be agreed upon between the parties concerned.

This document specifies a method for the determination of the total oxygen content of metallic powders by reduction-extraction at high temperature. By agreement, this method is also applicable to the determination of the total oxygen content of sintered metal materials. The method is applicable to all powders of metals, alloys, carbides, and mixtures thereof which are non-volatile under the test conditions. The sample can be in powder or compact form. The analysis is carried out on the powder as supplied, but the method is not applicable if the powder contains a lubricant or binder. If such substances are present, the method may be used only if they can first be completely removed by a method not affecting the oxygen content of the powder. This document is to be read in conjunction with ISO 4491-1.

This document specifies the funnel method for the determination of the apparent density of metallic powders under standardized conditions. The method is intended for metallic powders that flow freely through a 2,5 mm diameter orifice. It can, however, be used for powders that flow with difficulty through a 2,5 mm diameter orifice but flow through a 5 mm diameter orifice. Methods for the determination of the apparent density of powders that will not flow through a 5 mm diameter orifice are specified in ISO 3923‑2[1].

ISO 4490:2018 specifies a method for determining the flow rate of metallic powders, including powders for hard metals, by means of a calibrated funnel (Hall flowmeter). The method is applicable only to powders which flow freely through the specified test orifice.

ISO 4492 specifies a method by which the dimensional changes associated with compacting and sintering of metallic powders are compared with those of a reference powder when processed under similar conditions (see Clause 4). The method applies to the determination of three types of dimensional changes involved with the processing of metallic powders, excluding powders for hardmetals.

ISO 3927:2017 specifies methods for measuring the extent to which a metallic powder is compacted when subjected to uniaxial compressive loading in a confining die under specified conditions. The method is not applicable to powders for hardmetals.

ISO 4496:2017 specifies methods for determining, in iron, copper, tin and bronze powders, the approximate content of non-metallic materials which are insoluble in the ordinary mineral acids. The insoluble matter referred to is generally considered to be acid-insoluble silica and silicates, carbides, alumina, clays or other refractory oxides which are either present in the raw material from which the powders are manufactured or introduced during the manufacturing process.

ISO 13944:2012 specifies a method for the determination of the lubricant content of a powder mix. The method is also suitable for preparing samples for measuring the content of elements, e.g. graphite and oxygen, the determination of which is interfered with by the presence of a lubricant. A condition of the application of the method is that a suitable solvent for the lubricant concerned is known and available.

ISO 13947:2011 specifies a metallographic method for determining the non-metallic inclusion level in metal powders using a powder-forged specimen. The test method covers repress powder-forged test specimens in which there has been minimal lateral flow ( This test method can also be used to determine the non-metallic inclusion content of powder-forged steel parts. However, in parts where there has been a significant amount of material flow, the near-neighbour separation distance needs to be changed, or the inclusion sizes agreed between the parties need to be adjusted. This test method is not suitable for determining the non-metallic inclusion level of parts that have been forged such that the core region contains porosity. At the magnification used for this test method, residual porosity is hard to distinguish from inclusions. Too much residual porosity makes a meaningful assessment of the inclusion population impossible. This test method can be applied to materials that contain manganese suifide (admixed or prealloyed), provided the near-neighbour separation distance is changed from 30 µm to 15 µm.

ISO 14168:2011 specifies a method for determining the performance characteristics of copper-base infiltrating powders.

ISO 3953:2011 specifies a method for the determination of tap density, i.e. the density of a powder that has been tapped into a container under specified conditions.

ISO 18549-2:2009 describes two methods for the determination of the time (flow rate) it takes for a given quantity of a heated powder mix, based on iron or steel powders and to be used for warm compaction, to pass through a funnel with a given orifice diameter. Method A uses a funnel with an orifice of 2,5 mm and a test portion of 50 g and is, to a large extent, based on the method standardized in ISO 4490:2008. The method can only be used for powder mixes that flow freely through the 2,5 mm orifice in the heated condition. Method B uses a funnel with an orifice of 5 mm and a test portion with a size of 150 g. Both methods cover a testing temperature range of 60 °C to 180 °C and either of them can be selected after agreement between the parties involved.

ISO 18549-1:2009 describes a method for the determination of apparent density at elevated temperatures for powder mixes, based on iron or steel powders and intended for warm compaction. The method is, to a large extent, based on the apparent density method (funnel method) standardized in ISO 3923-1:2008, but either of the two funnels that are mentioned can be selected after agreement between the parties involved.

ISO 3954:2007 specifies procedures for the sampling of powders for powder metallurgical purposes. lt also covers the splitting of the sample into the quantity required for testing.

Gives some recommendations for the correct interpretation of the results obtained. The test methods are applicable generally to all powders of metals, alloys, carbides and mixtures thereof. The constituents of the powder shall be non-volatile and free of lubricant or organic binder. The limitations of the methods which depend upon the nature of the analysed metal are discussed in clause 4.

This second edition cancels and replaces the first edition (i. e. ISO 3995:1977). The method subjects a compact pressed form metallic powder to a uniformly increasing transverse force under controlled conditions until fracture occurs. the green strength is determined on compacts either having a particular density or after compaction at a specific compacting pressure.

IS applicable to powders that will not flow freely through a 5 mm orifice. The oscillating funnel method (part 3) gives better precision, but it cannot be used in cases where the powder may change its properties due to the vibration action applied to the powder during testing. Gives principle, symbols and designations, apparatus, sampling, procedure, expression of results and test report.

ISO 4490:2014 specifies a method for determining the flow rate of metallic powders, including powders for hard metals, by means of a calibrated funnel (Hall flowmeter). The method is applicable only to powders which flow freely through the specified test orifice.

ISO 4491-4:2013 specifies a method for the determination of the total oxygen content of metallic powders by reduction-extraction at high temperature. By agreement, this method is also applicable to the determination of the total oxygen content of sintered metal materials. The method is applicable to all powders of metals, alloys, carbides, and mixtures thereof which are non-volatile under the test conditions. The sample may be in powder or compact form. The analysis is carried out on the powder as supplied, but the method is not applicable if the powder contains a lubricant or binder. If such substances are present, the method may be used only if they can first be completely removed by a method not affecting the oxygen content of the powder. ISO 4491-4:2013 is to be read in conjunction with ISO 4491-1.

ISO 13517:2013 specifies a method for determining the flow rate of metallic powders, including powders for hardmetals and mixes of metallic powders and organic additives such as lubricants, by means of a calibrated funnel (Gustavsson flowmeter). The method is applicable only to powders which flow freely through the specified test orifice.

ISO 4492:2013 specifies a method by which the dimensional changes associated with compacting and sintering of metallic powders are compared with those of a reference powder when processed under similar conditions. The method applies to the determination of three types of dimensional changes involved with the processing of metallic powders, excluding powders for hardmetals.

ISO 3927:2011 specifies methods for measuring the extent to which a metallic powder is compacted when subjected to uniaxial compressive loading in a confining die under specified conditions. The method is not applicable to powders for hardmetals.

ISO 4490:2008 specifies a method for determining the flow rate of metallic powders, including powders for hardmetals, by means of a calibrated funnel (Hall flowmeter). The method is applicable only to powders which flow freely through the specified test orifice.

ISO 3923-1:2008 specifies the funnel method for the determination of the apparent density of metallic powders under standardized conditions. The method is intended for metallic powders that flow freely through a 2,5 mm diameter orifice. It may, however, be used for powders that flow with difficulty through a 2,5 mm diameter orifice but flow through a 5 mm diameter orifice. Methods for the determination of the apparent density of powders that will not flow through a 5 mm diameter orifice are specified in ISO 3923-2.

ISO 13947:2007 specifies a metallographic method for determining the non-metallic inclusion level in metal powders using a powder-forged specimen. The test method covers repress powder-forged test specimens in which there has been minimal lateral flow ( This test method can also be used to determine the non-metallic inclusion content of powder-forged steel parts. However, in parts where there has been a significant amount of material flow, the near-neighbour separation distance needs to be changed, or the inclusion sizes agreed between the parties need to be adjusted. This test method is not suitable for determining the non-metallic inclusion level of parts that have been forged such that the core region contains porosity. At the magnification used for this test method, residual porosity is hard to distinguish from inclusions. Too much residual porosity makes a meaningful assessment of the inclusion population impossible.

ISO 14168:2003 specifies a method for determining the performance characteristics of copper-base infiltrating powders.

Method for the determination of the lubricant content of a powder mix. The method is also suitable for measuring the content of elements such as graphite and oxygen, the determination of which is interfered with the presence of a lubricant.

The principle of the method specified is tapping a specified amount of powder in a container by means of a tapping apparatus until no further decrease in the volume of the powder takes place. The mass of the powder divided by its volume after the test gives its tap density. By agreement, the tapping may be carried out by hand.

Specifies a method of measuring the air permeability and the porosity of a packed bed of metal powder, and of deriving therefrom the value of the envelope-specific surface area. Annexes A and B are for information only.

Specifies methods which are suitable only where Stokes' equation is applicable. They are suitable for all metallic powders containing particles in the size range 1 µm to 100 µm. Does not apply to powders: containing particles whose shape is far from equiaxial; which are mixtures; containing lubricant or binder; which cannot be dispersed in a liquid.

The test method is applicable to all powders of metals, alloys, carbides and mixtures thereof which are non-volatile under the test conditions. The sample may be in powder or compact form. The test is not applicable if the powder contains a lubricant or binder. This part of ISO 4491 shall be read in conjunction with ISO 4491-1.

This second edition cancels and replaces the first edition (i. e. ISO 3927:1977). Specifies methods to measure the extent to which a metallic powder is compacted when subjected to uniaxial compressive loading in a confining die under specified conditions. The method is not applicable to powders for hardmetals.

This second edition cancels and replaces the first edition (i. e. ISO 4492:1978). The method is applicable to the determination of three types of dimensional changes involved with the processing of metallic powders. Gives principle, test parameters, symbols and designations, apparatus, sampling, procedure, expression of results and test report. An annex contains information on demensional change behaviour.

The method is applicable to dry, unlubricated powders, but not applicable to powders in which the morphology differs markedly from being equiaxial, for example flake-type powders. Is not applicable to metallic powders having a particle size wholly or mostly unter 45 /u. Specifies principle, apparatus, preparation of test portion, procedure, expression of results and test report.

This second edition cancels and replaces the first edition (i. e. ISO 3923:1977). The method is intended for metallic powders that flow freely through a 2,5 mm diameter orifice. It may, however, be used for powders that flow with difficulty through a 2,5 mm diameter orifice but flow freely through a 5 mm diameter orifice. Methods for powders that will not flow through a 5 mm diameter orifice are specified in parts 2 and 3.

The insoluble matter is generally considered to be acid-insoluble silica and silicates, carbides, alumina, and clays. The methods are applicable to lubricant-free powders. ISO 4496 specifies apparatus and reagents, sampling, procedure, expression of results and test report.

The method is applicable only to powders which flow freely through the specified test orifice. It measures the time required for 50 g of a metallic powder to flow through the orifice of a calibrated funnel. Specifies apparatus, calibration of the funnel, sampling, procedure, expression of results and test report.

Specifies procedures for the sampling of powders for powder metallurgical purposes. It also covers the splitting of the sample into the quantity required for testing. Defines lot, increment, gross sample, composite sample, test sample, test portion and test piece.