BS ISO 15724:2001
$102.76
Metallic and other inorganic coatings. Electrochemical measurement of diffusible hydrogen in steels. Barnacle electrode method
| Published By | Publication Date | Number of Pages |
| BSI | 2001 | 20 |
This International Standard describes a method that uses an electronic hydrogen detection instrument for measuring relative, diffusible hydrogen concentrations in bare steels or in plated steels after the coating has been removed. It is assumed that the hydrogen is uniformly distributed throughout a part.
The method does not measure actual hydrogen concentration. However, oxidation current densities measured against time provide a useful indication of relative hydrogen concentrations and, therefore, the measurements can be used for comparison purposes. The method may be used as a quality control procedure as it does provide a quick means of measuring the effectiveness of pre- and/or post-plating heat treatments or of monitoring hydrogen uptake during plating or due to corrosion.
It is important to note that the absence of failure in a particular test does not provide confirmation of complete elimination of hydrogen embrittlement because no one test method can provide all the data necessary to evaluate the degree of hydrogen degradation.
For unplated parts the method is non-destructive; however, for plated parts the coating has to be removed prior to measurement by a means proven not to damage the steel or to introduce hydrogen.
This test method is limited to:
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carbon and alloy steels, excluding austenitic stainless steels (see note 1);
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flat specimens to which the cell can be attached (see note 2);
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measurements at room temperature (25 °C ± 1 °C).
NOTE 1 If this method is used for austenitic stainless steels and other face centred cubic (FCC) alloys, measurement times and interpretation of results will have to be determined because of the different kinetics involved.
NOTE 2 For slightly curved surfaces it is essential to define an area that is reproducible. The area calculation will be different from that described in this International Standard.
NOTE 3 The method can be applied to small parts, however, this necessitates some modification of the technique, procedure and interpretation of results.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 3 | Metallic and other inorganic coatings�— Electrochemical measurement of diffusible hydrogen in ste… |
| 5 | Contents Page |
| 6 | Foreword |
| 7 | Introduction |
| 9 | Metallic and other inorganic coatings�— Electrochemical measurement of diffusible hydrogen in ste… 1��� Scope 2��� Normative references |
| 10 | 3��� Principle 4��� Reagents 4.1��� Electrolyte 4.2��� Methyl alcohol 4.3��� Ethyl alcohol |
| 11 | 5��� Apparatus 5.1��� The barnacle electrode system 5.1.1��� cell 5.1.2��� gasket 5.1.3��� cell holder |
| 12 | 5.1.4��� anode 5.1.5��� cathode 5.1.6��� a current measuring device |
| 13 | 5.2��� Microscope 5.3��� Nylon cleaning pad 6��� Test specimens 7��� Calibration 7.1��� Calibrate the Ni/NiO electrode ( 7.2��� Charge the Ni/NiO electrode using a platinum, or similar, inert electrode as the cathode a… 7.3��� Calculate the cell contact area outlined by the gasket as follows. 7.4��� Measure the background current density by using uncoated specimens containing no hydrogen,… 8��� Procedure 8.1��� Specimen preparation 8.1.1��� The procedure for preparation of the specimen for testing depends on whether it is plate… |
| 14 | 8.1.2��� For unplated specimens, abrade the surface lightly with an aluminium oxide impregnated n… 8.1.3��� For plated specimens with post-plating heat treatment (see 8.2��� Cell assembly 8.2.1��� The time to assemble the cell and the commencement of measurement shall take no longer than 8.2.2��� Clamp the cell to the specimen just tightly enough to prevent leakage (see 8.2.3��� Insert the Ni/NiO electrode in the centre of the cell cavity. Ensure that there is no di… 8.2.4��� Connect the resistance and the switch between the Ni/NiO electrode and the specimen (see 8.2.5��� Connect the electrometer across the resistance so that the Ni/NiO electrode will measure… 8.2.6��� Connect the recorder ( 8.2.7��� Fill the cell with 8.3��� Current measurement 8.3.1��� Measurement of the current shall commence within 8.3.2��� Turn on the cell switch and activate the timer simultaneously. 8.3.3��� Record the current for 8.3.4��� Turn off the switch. 8.3.5��� Dismantle the cell, rinse and dry. 8.3.6��� Repeat the measurement ( 8.3.7��� If a series of measurements is to be made during the day, alternate Ni/NiO electrodes an… |
| 16 | 9��� Results 9.1��� Calculate the current from the voltage drop across the standard resistance using Ohm’s Law, 9.2��� Calculate the contact area from the diameter of the etched surface area (see 9.3��� Calculate the current density; e.g., if the 10��� Interpretation of results 10.1��� Irregular recorder tracings ( 10.2��� A measurement higher than the background current density indicates the presence of hydrog… 10.3��� Care shall be taken in inferring hydrogen levels over the whole part from limited measure… 10.4��� As the measurement is relatively rapid, it measures hydrogen that diffuses easily. It is,… 11��� Test report |
| 18 | Bibliography |
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