BS ISO 16573‑1:2020 Steel — Measurement method for the evaluation of hydrogen embrittlement resistance of high strength steels Part 1: Constant load test.
7.3 Electroplating conditions
An electrochemical reaction is used for Cd plating. Immerse the metal platinum (Pt) anode into the prepared Cd solution, and immerse the specimen in order for it to work as a cathode. After hydrogen pre-charging, clean the specimens by mechanical grinding (polishing) or with 0,1 N HCI and 0,1 N NaOH by ultrasonic cleaner for 30 s, respectively. Then, immerse the specimens in Cd plating solution and apply a constant current of 0,5 A for 300 s. Other conditions of current and time may also be used for Cd plating. Using the potential difference, Cd is adhered to the surface of the specimen.
The thickness of Cd plating should be at least 15 im or higher to prevent hydrogen release. Extreme care is needed to handle the solutions containing Cd during the entire Cd plating procedures.
8 Constant loading test
8.1 Constant loading test procedures
The suggested methods for the constant loading test are the following.
a) Use adequate jig to apply uniaxial loading to the specimens.
b) Specimens containing various diffusible hydrogen contents shall be used to measure the time to failure. In the case of hydrogen continuous charging, various current densities shall be applied to measure the time to failure of a specimen.
c) Unless otherwise specified, stress ratio (applied stress/tensile stress shall be 0,8. Other stress ratio may be agreed between manufacturer and purchaser.
NOTE Tensile strength is measured in evaluated type of specimen without hydrogen charge in advance.
d) If the specimens are not fractured after up to 100 h (up to 200 h, if necessary), one can conclude that these specimens do not fracture under these conditions and discontinue the test.
eJ To ensure reliability, it is recommended that at least three specimens be tested at the same stress ratio.
1) After the constant loading test, diffusible hydrogen contents of the specimen should be immediately measured. If it is impossible to measure diffusible hydrogen content immediately following the test, specimens shall he preserved below —SO °C, preferably in liquid nitrogen, to prevent hydrogen release from the fractured surface.
BS ISO 16573‑1 pdf download.