Scarfing is commonly employed to improve the surface quality of interstitial-free (IF) steel slabs used for automotive external panels, and usually steelworkers tend scarf deeper ensure even at cost losing yield. However, this may not work sometimes becomes worse. In present work, slab scarfing experiments were designed study effect depths on density sliver defects cold rolled sheets distribution nonmetallic macro inclusions (NMIs) in evaluated using automatic scanning electron microscopy...

The evolution of macro inclusions during continuous casting was investigated by large-area inclusion characterization using ASPEX and analysis nozzle blockage deposits. Six kinds over 5 μm were observed in samples taken from the tundish slabs: single alumina particles, dendrites, refractory-related alumina, associated with bubbles, clusters Al–Ti complex oxides. By examining morphology deposit, it concluded that slabs came decarburization layer washed away steel stream. Some deposit...

Full-scale water modelling studies combined with nail-dipping industrial trials at Shougang Jingtang (SGJT) Works were carried out in order to investigate the parameters that influence flow patterns continuous slab casting mould. The effects of speed/mould width combinations, argon bubbling rates, submerged entry nozzle (SEN) immersion depths and SEN geometries (port angle bottom shape) on examined. A CMI factor defined as ratio index is put forward describe effect these fluid results show...

The formation and characteristics of non-metallic inclusions in 316L stainless steel produced by the AOD (argon oxygen decarburization)–ladle furnace–continuous casting process were investigated. morphology composition changed significantly during refining processes. After de-oxidation with Si/Mn additions, spherical complex mainly consisting calcium silicates observed. contents MgO Al2O3 these continuously increased as moved from through ladle processing to tundish. As temperature decreased...

The number, morphology, size and composition of inclusions after deoxidation alloying in Ti-stabilised stainless steel were investigated. This was carried out by electrolytic extraction from matrix, followed microscopic examination. It found that the addition ferrosilicon manganese, later aluminium, changed manganese silicate-rich to alumina-rich inclusions. After tapping titanium wire feeding, three types TiN inclusion morphologies observed, single, twinned clusters. Both turbulence Stokes'...

Macro-inclusions in low carbon, aluminium-killed steel slabs were characterised by step-machining within a 10 mm zone from the slab surface using an ASPEX automatic inclusion analyzer. Dendritic structures cross-section of examined. The results show that alumina clusters and associated with bubbles are dominant macro-inclusions. Along width direction, macro-inclusions mostly found at centre because deeper hooks freezing meniscus surrounding submerged entry nozzle. In terms thickness,...

The characteristics of non-metallic inclusions in 347 stainless steel samples taken during a net-shape casting process after different holding times and melting temperatures were investigated using electrolytic extraction polished cross-sections. can be classified into three groups: oxides, composite sulphides. Within the first two groups subdivided based on their morphology following categories: spherical, irregular clusters. As temperature decreased, sulphide NbC precipitated within melt...

The inclusion behaviour during continuous casting were investigated in ultra low carbon (ULC) and high strength alloy (HSLA) steels. From tundish to cast slabs, the total oxygen (T.O) content decreased from 19 12 ppm, 11 ppm ULC steel HSLA steel, respectively. number density of inclusions by about 40%, while it kept almost constant casting. A simple calculation on T.O removal agreed well with measured value, which showed that was much larger through mould flux absorption than nozzle...

Based on the achievement of high speed continuous casting in SGJT, fluid flow, heat transfer, and lubrication behavior were analyzed elaborately. The results indicated that well-bottom SEN with angle −20° together FC mold could reduce level fluctuation effectively. When was applied at 1.9 m min−1, there an increase average flux about 0.06–0.1 MW m−2. During transfer analysis, empirical equation proposed solidification crater end validated by pin shooting method. Furthermore, a kind powder...

Deep-drawing steels are widely used in the automobile industry and macro-inclusions continuous casting slabs should be strictly controlled because they cause surface defects final products. In this paper, industrial tests with different speeds from 1.0 m.min-1 to 2.5 tundish superheats were carried out, then subsurface inclusions high-speed investigated a large detection area by ASPEX automatic inclusion analysis system, effect of speed superheat was studied. The results show that there six...

The deoxidation in Ti containing Al killed IF steels is a vital parameter that directly influences the steel cleanliness. In this study, evolution of compositions and inclusion characteristics during RH refining were investigated by industrial trials involving three Al-Ti modes, which adding Ti-Fe 2 min after Mode I, simultaneously II, alloys with two equal batches at 3.2 5 III. results showed nitrogen pickup several ppm was observed alloy addition. Therefore, content should be strictly...

With the thinner of automobile panel, press crack defects caused by large‐size calcium aluminate inclusions at automakers become obvious. Herein, in order to stabilize control molten steel, vortex slag entrainment (VSE) a 300 ton ladle is investigated numerical simulation. The effects steel throughput, cofferdam height close nozzle, and bottom structure on VSE are analyzed. Results demonstrate that residual (RMS) critical increase with increasing throughput. RMS increases when occurs. When...

The flow control devices (FCDs) in the tundish play an important role steel cleanliness and removal of macro-inclusions. To eliminate spot-like defects during deep-drawing process, liquid samples were taken from three industrial IF heats, effect weir structure on evaluated compared with aid ASPEX total detection area over 54 000 mm 2 . results showed that non-metallic inclusions 5 µm observed categorized into two types: type 1: alumina based 2: calcium aluminates. Compared to without weir,...

To the authors' best knowledge, unsteady period casting is detrimental for sound and good quality. On basis of mathematical model experimental observation, some typical phenomena including breakout shell, solidification, level hunching, steel cleanliness are discussed presently. The results show that solidification factor in mold within 22–28 mm min −1/2 superheat carried by impinging flow, about 300 below meniscus, enough to remelt thin solidified shell narrow face. After analysis crater...