scope:

This International Standard specifies the sampling and analytical procedure for the determination of diffusible and residual hydrogen in weld metal of martensitic, bainitic, and ferritic weld metal arising from the welding of such steels using arc welding processes with filler metal. The techniques described in this International Standard include collection of diffusible hydrogen via displacement of mercury or collection into a headspace filled with an inert gas such as argon. The amount of hydrogen collected is determined by measuring the displaced volume in the former and by thermal conductivity in the latter. The temperature for collection of diffusible hydrogen is controlled to avoid thermal activation of non-diffusible hydrogen. Furthermore, with application of a rapid method (short period of collection time), the measurement of the diffusible hydrogen amount can be carried out at elevated temperatures.