Effect of Sulfur Content and Solidification Variables on Morphology and Distribution of Sulfide in Steel Ingots
1976 Volume 62 Issue 10 Pages 1319-1328
Details
1976 Volume 62 Issue 10 Pages 1319-1328
The morphology and distribution of sulfide in steel ingot have a close connection with chemical composition of steel and solidification variables. Using steels containing 0.004, 0.01, 0.05, 0.10, and 0.63%S, the authors have investigated the effects of sulfur content and solidification variables on the morphology and distribution of sulfide.
The results obtained are summarized as follows: 1) Morphologies of sulfides are dependent on sulfur content. In the range of sulfur content up to 0.01%, type I sulfide is found and with more than 0.05% sulfur, type II sulfide is observed. The higher the sulfur content, the larger the area of type II sulfide.
2) Large dendritic sulfide (type D) as a primary phase is observed in the specimens containing 0.63% S and 2.88% Mn, and its size is dependent on the cooling rate.
3) From the observation of three dimensional morphology of sulfide using a scanning electron micro scope, it is found that type II sulfide is dendritic and type II and Type D sulfides are occasionally inter connected.
4) The size arid spacing are expressed as a function of the cooling rate, Vin°C /min.
i) Average size of type I sulfide, d in μm; d=13.9 V-0.30ii) Average spacing of rod-like (type II) sulfide, λ in μm; λ=10.7 V-0.30iii) Average size of rod-like (type II) sulfide, d′ in μm; d′=2.9 V-0.22 The average size of rod-like (type II) sulfide is smaller than that of type I at the same cooling rate.
5) Type I and type II sulfides are located in interdendritic spaces, on the other hand, type D sulfides are distributed randomly.
