Abstract
A new apparatus for determing the diffusible hydrogen in weld metals was developed, (Vacuum-extraction Method). This method is based on the principle that the diffusible hydrogen evolved from weld metals in a closed evacuated vessel is concentrated, by means of a Toepler pump, into the measuring unit and its gas volume is accurately measured.
Hydrogen evolution from JIS. type specimens was calculated by using the solution of one-dimensional diffusion model for the movement of hydrogen in uniform metals. Experimental results of hydrogen evolution by using the Vaccum-extraction method agree approximetely with the calculated values.
An apparent diffusion coefficient of hydrogen in the welded mild steel (SS41) at a room temperature of 20°C, D=1.06×10-6 cm2/sec was obtained from an analysis of the evolution curve of hydrogen from the weld metal.
