ISO/TC 17/SC 7 - Methods of testing (other than mechanical tests and chemical analysis)

This document specifies a method (Baumann) for the macrographic examination of steel by means of contact printing using silver salts and acid. The method is applicable to steels of which the sulphur content is less than 0,40 %. This method can also be applied to cast irons.

This document provides an evaluation method of the resistance of high-strength steels to hydrogen embrittlement (i.e. hydrogen delayed fracture) using slow strain rate test with hydrogen pre-charged specimens. The amount of hydrogen absorbed in the specimens is analysed quantitatively by thermal desorption analysis such as gas chromatography, mass spectrometry and so on. This document includes testing methods for either smooth or notched specimens. It is applicable to ferritic base steels.

This document provides a method for the evaluation of the resistance to hydrogen embrittlement (i.e. hydrogen delayed fracture) using constant loading test with hydrogen pre-charged specimens. The amount of hydrogen content absorbed in the specimens is analysed quantitatively by thermal desorption analysis such as gas chromatography, mass spectrometry and so on. In the case of hydrogen continuous charging such as hydrogen absorption in aqueous solution at free corrosion potential, hydrogen absorption in atmospheric corrosion environments and hydrogen absorption in high pressure hydrogen gas, the evaluation method is also briefly described. This method is mainly applicable to the evaluation of hydrogen embrittlement resistance of high strength steel bolts.

This document specifies a micrographic method of determining apparent ferritic or austenitic grain size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a perfectly consistent grain size.

ISO 3887:2017 defines the decarburization and specifies three methods of measuring the depth of decarburization of steel products.

ISO 18203:2016 specifies a method of measuring the case hardening depth, surface hardening depth, nitriding hardness depth and total thickness of surface hardening depth obtained, e.g. thermal (flame and induction hardening, electron beam hardening, laser beam hardening, etc.) or thermochemical (carbonitriding, carburizing and hardening, hardening and nitriding, etc.) treatment.

ISO 17577:2016 specifies a method for the automated and/or manual ultrasonic testing of uncoated steel flat products for internal discontinuities by the pulse echo technique. It is applicable to non-alloyed or alloyed steel flat products, in a nominal thickness range of 6 mm to 200 mm. However, this International Standard may be applied to austenitic and austenitic-ferritic steels, provided that the difference between the amplitude of the noise signal and that of the echo detection threshold is sufficient for the limit fixed. Unless otherwise agreed, for testing of steel flat products for welded steel tubes, ISO 10893‑9 applies. Other techniques of testing (e.g. by transmission) or other test equipment may be used at the manufacturer's discretion, provided that they give identical results to those obtained under the conditions of this International Standard. In the event of a dispute, only the method defined in this International Standard will prevail. Testing of flat products, of thickness less than 6 mm and over 200 mm, may be the subject of special agreements between the parties concerned. Testing is normally carried out in the place of production or on the premises of the supplier.

ISO 16574:2015 defines resolvable pearlite and specifies two methods of determining the percentage of resolvable pearlite. The methods are applicable for wire rod made from control cooling steel with carbon content greater than 0,65 % C.

ISO 4969:2015 establishes guidelines for the macroscopic examination of steel by hot etching, room temperature etching and electrolytic etching. The method has very wide application. Selection of the type, concentration and temperature of the reagent, the etching apparatus and the conditions of surface preparation of the test piece make it possible to achieve the required aim. NOTE It might be difficult to see fine voids and cracks and discriminate between them and determine their nature by macroetching.

ISO 4967:2013 specifies a micrographic method of determining the non-metallic inclusions in rolled or forged steel products having a reduction ratio of at least 3 using standard diagrams. This method is widely used to assess the suitability of a steel for a given use. However, since it is difficult to achieve reproducible results owing to the influence of the test operator, even with a large number of specimens, precautions should be taken when using the method. ISO 4967:2013 also provides for the determination of non-metallic inclusions by image analysis technologies.

This International Standard specifies a micrographic method of determining the duplex grain size of rolled or forged steel products using standard diagrams or by the point count procedure.

Applies to constituents (a phase as well as a micrographic constituent composed of two or more phases) which are clearly identifiable. The point grid is superimposed a given number of fields of the observed surface. By counting the number of points the volume fraction is calculated.

Specifies a method for assessing steels with C levels between 0,1 % and 1,5 % and a total content of alloy elements less than or equal to 5 %. The use of this method for other steels shall be subject to special agreement. Contains principles, sampling, preparation of samples, assessment of the distribution of carbides, expression of results and test report. An annex gives reference photomicrographs.

Macroscopic methods deal with non-metallic inclusions visible to the naked eye or with the aid of a magnifying glass with a magnification of not more than X 10. Only inclusions equal to or greater than 1 mm long are taken into consideration. Covers the blue fracture test method, the step machined test method, the magnetic particle inspection method.

ISO 16573:2015 provides a method for the evaluation of the resistance to hydrogen embrittlement (i.e. hydrogen delayed fracture) using constant loading test with hydrogen pre-charged specimens. The amount of hydrogen content absorbed in the specimens is analysed quantitatively by thermal desorption analysis such as gas chromatography, mass spectrometry and so on. In the case of hydrogen continuous charging such as hydrogen absorption in aqueous solution at free corrosion potential, hydrogen absorption in atmospheric corrosion environments and hydrogen absorption in high pressure hydrogen gas, the evaluation method is also briefly described. This method is mainly applicable to the evaluation of hydrogen embrittlement resistance of high strength steel bolts.

ISO 643:2012 specifies a micrographic method of determining apparent ferritic or austenitic grain size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a perfectly consistent grain size.

ISO 17577:2006 specifies a method for the automated and/or manual ultrasonic testing of uncoated steel flat products for internal discontinuities by the reflection method. It is applicable to non-alloyed or alloyed steel flat products, in a nominal thickness range of 6 mm to 200 mm. However, this standard may be applied to austenitic and austenitic-ferritic steels, provided that the difference between the amplitude of the noise signal and that of the echo detection threshold is sufficient for the limit fixed. Unless otherwise agreed, for testing of steel flat products for welded steel tubes, ISO 12094 applies.

ISO 3887:2003 defines decarburization and specifies three methods of measuring the depth of decarburization of non-alloy and low-alloy steels.

ISO 643 specifies a micrographic method of determining apparent ferritic or austenitic grain size in steels. It describes the methods of revealing grain boundaries and of estimating the mean grain size of specimens with unimodal size distribution. Although grains are three-dimensional in shape, the metallographic sectioning plane can cut through a grain at any point from a grain corner, to the maximum diameter of the grain, thus producing a range of apparent grain sizes on the two-dimensional plane, even in a sample with a perfectly consistent grain size.

ISO 2639 defines the case-hardened depth, and specifies methods for the determination of this depth, in steel. It is applicable to carburized cases and carbonitrided cases; parts that, when heat treated to final hardness, have a hardness of less than 450 HV 1 at a distance of three times the case-hardened depth, from the surface. The case-hardened depth is defined by special agreement where these conditions are not met.

Specifies the methods for revealing the grain and for estimating the mean size of the grain revealed. Includes a counting method (annex A) and determination of grain size by using of standard charts (annnexes B and C) taken from an AFNOR Standard and an ASTM document, respectively.

Defines the effective case depth, and specifies methods for the determination of this depth, in steel. Is applicable to carburized cases and carbo-nitrided cases, the depth of which is greater than 0,3 mm, and parts which have a hardness of less than 450 HV at a distance of 3 X the effective case depth from the surface.

This macroscopic method has very wide application. Selection of the type and concentration of the reagent, the temperature of the reaction and the conditions of surface preparation of the test piece make it possible to achieve the required aim. Specifies general, principle, reagents, test piece, procedure, preservation of test pieces and test report.

Specifies the micrographic method and the microhardness measurement method. Applies to thin surface layers, with thicknesses of less than or equal to 0.3 mm, obtained, for example, by mechanical (shot blasting, shot peening, etc), thermal (flame or induction hardening, etc) or thermochemical (carbonitriding, carburizing and hardening, etc) treatment. It is not applicable to thin surface layer which are not continuous with the basis metal.

The Baumann method uses contact printing using silver salts and sulphuric acid. It is applicable to non-alloy and alloy steels and to cast irons of which the sulphur content is less than 0.1 %. Specifies general, principle, products and reagents, test pieces, procedure and test report.

Defines carburization and specifies three methods of measuring the depth of decarburization of non-alloy and low-alloy steels (micrographic method, method of measuring the micro-hardness and methods of determination of carbon content).

Defines the effective depth of hardening and specifies a measuring method. Applies to hardened layers with a depth greater than 0,3 mm, and parts which have at a distance 3 x depth of hardening from the surface a hardness less than hardness limit - 100.