The design of the steel casting dross pan affects its efficiency in collecting and filtering the dross, and if the dross is brought into the ladle or casting mold, it will become an impurity, reducing the purity and quality of the casting, leading to scrapping. The dross also corrodes ladle, conveyor and furnace refractories, raising costs. Therefore, regular inspection and maintenance help prevent accumulation and blockage of the drainage outlet, and is also a very necessary procedure.
Dross Pan Design Factors That Enhance Collection
The job of steel casting dross pan is to effectively capture and hold the dross so it doesn't re-enter the metal stream. Here are key dross pan design factors that enhance dross collection and improve metal yield:
Size: Larger dross pan surface area and capacity improves the probability and quantity of dross capture. Pans should be sized based on expected dross volumes.
Shape: Rectangular pans provide a more uniform dross spread compared to square designs. Uniform coverage ensures full dross capture.
Slope: Angled pans cause dross to flow downhill into a collection zone for easy removal. 30-45° slopes are optimal.
Lip: Extended lip length or flared shapes maximize dross capture area. Lips project directly beneath or around the pour stream.
Coating: Anti-stick coatings like titanium nitride prevent dross from adhering to pan surfaces for easy removal.
Drainage: Drain holes allow molten steel to flow back to the furnace preventing loss. Dross is left behind.
y incorporating appropriate sizing, angling, and key design features, steel casting dross pan plays a vital role in enhancing the efficient separation and collection of floating slag and oxides, ultimately maximizing metal yield and process effectiveness.
How Improved Dross Removal Increases Metal Yield?
When dross pans are designed for maximum dross capture, it directly translates into higher casting yields and productivity:
Scrap reduction: Less dross carryover means fewer castings rejected for impurities and defects. This reduces costly rework and scrap.
Furnace yield: As dross is removed rather than reabsorbed, more clean steel can be poured out of each furnace heat.
Ladle life: Preventing dross entry into transfer ladles reduces erosion lengthening their usable life.
Trough/launder wear: Captured dross causes less abrasive wear of pouring troughs, extending maintenance cycles.
Refractory life: Stopping dross carryback into the furnace protects linings from dissolution. This extends campaigns between re-linings.
Energy savings: As heat loss is reduced by keeping dross separate from hot metal, energy costs are decreased.
Melt loss: Drainage holes prevent the holdback of any residual steel, recovering it for casting instead of loss.
Enhanced dross removal from pans leads to increased metal yield and productivity by minimizing scrap, improving furnace yield, extending ladle and trough life, preserving refractory, and reducing energy costs. This optimization ensures that clean steel is poured, minimizing rejections and maximizing the overall yield of the casting process.
Alternative Dross Pan Designs
While fixed rectangular pans are most common, some other steel casting dross pan designs include:
Articulating pans: Pans pivot to tilt dross into a collection bucket. Servo motors provide precise tilt control.
Rotating pans: Motor-driven pans rotate along the pour stream to continually expose the clean collection area.
Traveling pans: Pans on actuators transverse across the stream for dynamic dross removal.
Magnetic pans: Electromagnets underneath the pan apply upward force to hold captured dross until dumped.
Belt pans: Continuous belt pans rotate dross away from the lip while exposing the new collection surface.
While alternative dross pan designs such as articulating, rotating, traveling, magnetic, and belt pans offer specific benefits, standard fixed rectangular pans are generally preferred due to their simplicity, reliability, and cost-effectiveness. These designs adequately meet the needs of most foundries, making them a suitable choice for dross removal.
Conclusion
Steel casting dross pan design is critical for maximizing the removal of impurities in steel casting production. By considering key factors like pan size, shape, slope, coatings, and drainage - dross pans can be designed to efficiently collect and hold slag. Effective dross capture keeps yields high by preventing oxides and non-metallics from contaminating the casting stream or eroding furnaces and ladles. Both productivity and profitability are increased by proper dross pan selection and design. If you want a suitable slag tray, Huan-tai will be a good choice, please contact at tech@huan-tai.org.
References:
1. Xu, W., Liu, X., Liu, B., Tang, H. and Jiang, H. (2018). Improving steel casting surface quality by removing surface oxide layers before mold pouring. AFS Transactions, 26, pp.545-552.
2. Sahai, Y. and Askheda, A. (2007). Unbonded dross - Formation mechanisms and methods of prevention. AFS Transactions, 89, pp.463-476.
3. Garat, M. and Arana, J.L. (2002). A contribution to the understanding of different types of dross formed in aluminium melting processes. Journal of Materials Science, 37(18), pp.3883-3887.
4. Piepel, G.F., Visnapuu, A., Oja, A. and Kolats, M. (2009). Evaluation of various dross-collection systems. AFS Transactions, 26, pp.487-494.
5. Sahai, Y. and Emi, T. (1996). Effect of mold flux dross on steel quality and productivity. Iron and Steelmaker, 23(1), pp.43-50.
6. Zhang, L., Thomas, B.G. and Sussman, R.C. (1994). Effect of mold flux dross on properties of steels. Iron and Steelmaker, 21(12), pp.41-46.
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