Behavior of hydrogen in steel in the steel-making and strand casting processes was studied.
The results are summarized as follows:
(1) The optimum procedure of sampling and analysis of hydrogen in liquid steel is determined.
(2) Diffusible and non-diffusible hydrogen in cast slabs can be analyzed separately by the methods of glycerine extraction and vacuum heating extraction respectively.
(3) Hydrogen content in liquid steel is about 2-4 ppm before tapping and increases abruptly during tapping. The amount of hydrogen increase is closely related to the humidity of atmosphere.
(4) Segregation of hydrogen is observed at the center of slabs, the amount of which is affected by the nondiffusible hydrogen content in cavitiees.
(5) Non-diffusible hydrogen content is confirmed to be proportional to the total volume of cavities which are formed during solidification.
(6) The degree of hydrogen segregation at the center of slabs decrease with an increase of the thickness of equiaxed structure zone in slabs, because cavities in the zone are scattered uniformly and finely.
