Nucleation and growth process of sticking particle in ferritic stainless steels was investigated using a twodisk type hot rolling simulator. The sticking behavior was strongly dependent on the surface roughness of a high speed steel roll (HSS) and the oxidation resistance of the ferritic stainless steels. A sticking occurrence was more sensitive for the steels containing higher chromium. There was a critical value which was found to be 3mm of scale thickness in the suppression of the sticking phenomenon. It was also illustrated that the initial sticking particles were nucleated at the scratches formed on the roll surface and were served as the sticking growth sites. As rolling proceeded, the sticking particles grew by the process that the previous sticking particles provided the sticking growth sites.KEY WORDS: ferritic stainless steel; sticking behavior; hot rolling; high speed steel roll.

l.

Table 1. Experimental results of metal-nitride-gas equilibration in Fe-Cr melts.

No abstract

The equilibrium solubility of titanium and nitrogen in Fe-Ni melts was measured in the presence of pure solid TiN under various nitrogen pressures in the temperature range of 1843 to 1923 K. The activity coefficients of titanium and nitrogen relative to a 1 mass pct standard state in liquid iron were calculated from the experimental results for Fe-Ni alloys of nickel contents up to 30 mass pct. Nickel decreases the activity coefficient of titanium, but it increases the activity coefficient of nitrogen in an Fe-Ni-Ti-N melt. Therefore, the effect of nickel on the solubility product of TiN is not significant. The first-and second-order interaction parameters of nickel on titanium ( and , respectively) were determined to be Ϫ0.0115 and 0 at 1873 K, respectively. Similarly, the interaction parameters of nickel on nitrogen ( and , respectively) were determined to be 0.012 and 0, respectively, at 1873 K. The temperature dependence of these interaction parameters was also determined. r N Ni e N Ni r Ti Ni e Ti Ni