鋼中のTiとSとの關係

Abstract

It has been recognized so far that titanium easily combines with nitrogen and carbon to form titanium-compounds, but there is another important relation between titanium and sulphur. Therefore, the author studied the general relationship between these elements, carbon, nitrogen, sulphur and titanium, when such elements co-exist in steel, as well as some experiments were performed on varions properties of titaninm-sulphide. Results of these tests were summarlized as follows:-1. When these elements, carbon, nitrogen and sulphur, which ba strong chemical affinity for titanium were contained in steel with titanium, it was found that nitrogen in steel preferentially combined with titanium to form titanium-nitride, and secondly sulphur and carbon combined with titanium to form TiS and TiC in this order. It was considered that the chemical affinity between titanium and such elements was in the following order, i.e. nitrogen, sulphur and carbon.2. The effect to reduce the sensibility in sulphur print was based on the stable charactor of TiS agamst acid. When TiS in steel was increased and FeS and MnS in steel was decreased, gradually the denseness of sulphur print decreased. When all sulphur in steel comhined to form TiS and there was left no FeS and MnS in steel, the arthor could not obtain the sulphur print of this steel. From the analytical results it was found that, when titanium content in steel was about as much as of sulphur, all sulphur in steel combined to form TiS and there was little sensibility for the sulphur print in this steel.3. TiS was present in steel in the state of microscopically small particles which had light violetgray colour, and it was discriminated clearly from fine particle TiC. TiS was not fluidtically deformed by hot working, but separated to fine particles and produced the lamination structure in steel.4. TiC could be soluble in γ at temperature above 1000°C and its solubility increased accordingly as temperature rose. But if these were large quantity of TiS with TiC in steel, the solubility and the precipitation of TiC decreased. It was considered that TiS in steel had such charactor as to obstruct the solution and the precipitation of TiC.5. TiS had remarkable effect to prevent the hot shortness by sulphur in steel. Hence titanium may be used as substitutional element for manganese.