HYDROGEN IN MOLTEN STEEL (I)
Behavior of Hydrogen in Molten Steel in Electric Furnace Steel Making Process
1955 Volume 41 Issue 4 Pages 416-424
Details
1955 Volume 41 Issue 4 Pages 416-424
Variations of hydrogen in liquid steel on steelmaking process of hundreds of heat molten by basic electric arc furnace or acid high-frequency furnace during 1952 fiscal year were statistically studied. The amount of hydrogen as well as oxygen in steel were determined by a rapid method, by means of vacuum fusion of the specimen and subsequent measurment of the extracted gas by thermoconductivity method. The following conclusions were obtained.
1. Hydrogen in molten steel seemed to have a tendency of reaching some steady values with a given damp pressure in atmosphere. Those values varied with working conditions, especially the state of slag, such as, acid, basic, oxidizing or teducing, and they became highest when steel was molten under basic reducing slag. [H] and √PH2O had linear relations when they were statistically observed, where [H] was hydrogen content in molten steel, and PH2O was damp pressure in the atmosphere.
2. [H] was partially removed by boiling the steel bath in oxidizing condition of b sic electric arc furnace. Δ[H] had linear relation to Δ[C]×[H]2, where Δ[H] was amount of hydrogen removed, Δ[C] was amount of carbon removed and [H] was mean value of hydrogen in steel at the beginning and at the end of oxidation.
3. Rapid increase of hydrogen in steel during earlier stage of reduction in basic electric hearth, in residual oxidizing slag as well as in added meterials, such as, lime, deoxidizer and carburizing meterials, was considered to easily enter into steel.
Oxigen and hydrogen in molten steel on the stage, were found to vary with intimate corelations. Ratios of [H]2×[O] at the end of oxidation and that at the earlier stage of reduction of the same heat had almost constant values, although the values [H]2×[O] had wide range according to the melting conditions.
4. Researches were also made on the relations of [H] at tapping of basic electric arc furnace to PH2O on various specificatons of the steel. The lower carbon the steel had, the higher effect of PH2O on [H] at tapping were in the average recognized.
