Characteristics of Non-metallic Inclusions in Steel Obtained from Different-Sized Samplers
- PDF / 1,195,250 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 27 Downloads / 158 Views
RODUCTION
IN steel production, analysis of molten steel is essential for identifying sources of problems that occur during the refining process or for determining its elemental composition; however, there are many sizes of samplers, the choice of which directly influences the cooling rate of steel solidification.[1–7] The solidification and cooling rates, in turn, affect the size and chemistry of non-metallic inclusions and the accuracy of the inclusion analysis. Selection of an appropriately sized sampler is therefore vital to performing an accurate study of inclusion characteristics. Several previous studies have investigated the influence of sampler type on inclusion behavior during the sampling process. Some studies found that the filling velocity and solidification of liquid steel were dependent on the sampler geometry and that the steel composition affected the distribution and size of inclusions.[8,9] Compared with inclusions obtained by metal-cap-protected lollipop-shaped samplers, most inclusions in argon-protected lollipop-shaped samplers were distributed more homogeneously which resulted in lower and more even filling velocities.[8] Zhang et al.[10] found
HANG LIAO, SHUFENG YANG, JINGSHE LI, and JIE FENG are with the School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China. Contact e-mail: [email protected] Manuscript submitted August 30, 2016.
METALLURGICAL AND MATERIALS TRANSACTIONS B
that the predicted inclusion collisions due to turbulence during sampling were much higher than those that occurred in a ladle furnace during steelmaking. In lollipop-shaped samplers, the bottom half is preferred region for analysis, except for areas close to the bottom surface.[11] Barrel-type samplers are also used in industrial experiments; these are not prone to the formation of shrinkage voids in the sample because of a steady filling velocity during the sampling process.[12,13] Using current technologies, direct observation of changes in inclusions during the solidification process is impossible; factors affecting the characteristics of inclusions during the solidification have therefore been investigated using various analysis methods. Ma et al.[14–17] used a segregation model and nucleation theory to investigate the precipitation and growth of inclusions during the solidification process. Goto et al.[18–20] determined the characteristics of inclusions during solidification by comparing the oxygen content and cooling rate of different types of steels. In laboratory experiments, Ohta[21] used the change in Ni content of different regions of the steel sample to identify different stages of solidification; in this way, the effects of various elements on inclusion characteristics during solidification were determined. In summary, most of the aforementioned studies were based on laboratory experiments and theoretical analyses to study the characteristics of inclusions during solidification. Few studies of the effects of different-sized samplers have been performed on an indu
Data Loading...
