Continuous Casting Nozzle Surface Roughness
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Solution Overview
Problem
Existing nozzle assemblies for continuous casting of non-ferrous pipes face issues with compound buildup and excessive grain size, leading to operational inefficiencies and reduced product quality, particularly in upward vertical casting.
Innovation Solution
A continuous casting nozzle assembly with a nozzle and mandrel design featuring a surface roughness of 1-8 Ra, angled and tangential melt feed openings, and a cooler made of graphite or ceramic materials, optimized to prevent compound buildup and improve crystal structure, along with a conical mandrel and press-on fit assembly for reduced material costs and improved casting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner surface of the nozzle is polished to a mirror surface by honing, then the building-up and depositing of compounds is reduced, but the production time and cost increase significantly
Solution Approach 1:
The invention changes the surface roughness parameter from a mirror finish (Ra < 0.8 μm) to a controlled rough surface (Ra 1.6-3.2 μm). This parameter change eliminates the need for time-consuming honing while preventing compound buildup through the optimized rough surface structure that inhibits deposition of separating metals, alloying elements, and oxygen compounds.
Solution Approach 2:
The invention uses a standard machined surface finish instead of expensive honing, accepting that the nozzle may need replacement after a certain service life. This approach trades the high initial cost and time of honing for a more economical standard manufacturing process, maintaining reliability through the optimized rough surface rather than ultra-fine polishing.
2Ease of manufacture
If graphite is used as refractory nozzle material, then the nozzle has excellent mold properties, but compound buildup and deposits occur more prominently on the inner surface
Solution Approach 1:
The invention changes the surface roughness parameter of the graphite nozzle from a polished state to a controlled rough state (Ra 1.6-3.2 μm). This parameter change modifies the surface properties to prevent compound deposition while maintaining the excellent mold characteristics of graphite, including its thermal conductivity and chemical resistance.
Solution Approach 2:
The invention applies a localized rough surface treatment specifically to the inner surface of the graphite nozzle where molten metal contacts. This local quality change prevents compound buildup at the critical interface between the graphite material and molten metal, while preserving the bulk graphite properties that provide excellent mold characteristics.
3Manufacturing precision
If the grain size of the internal structure is reduced for better shaping, then the internal composition becomes suitable for further shaping, but the casting process becomes more difficult to control
Solution Approach 1:
The invention changes the surface roughness parameter of the nozzle inner surface, which indirectly controls the grain size of the cast pipe's internal structure. The optimized rough surface (Ra 1.6-3.2 μm) promotes nucleation sites that refine grain structure, achieving suitable internal composition for further shaping without requiring complex process control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution prevents compound buildup, reduces grain size, and enhances the quality of cast pipes, improving further shaping properties and increasing the productivity of continuous casting facilities, suitable for non-ferrous materials like aluminum and copper alloys.
Implementation Method 1
a cooler (15) and a cooling liquid space (16) for removing heat from the molten metal
Implementation Method 2
cylindrical channels for cooling water extend between the concentric tubes
Implementation Method 3
a source of vacuum enables sucking melt into the cooling zone present within the nozzle
Data Source
AI summary
The invention relates to a continuous casting nozzle assembly (10) for casting, in particular for upward vertical casting, of a metallic, in particular a non-ferrous, pipe, which is suitable for uninterrupted casting, which nozzle assembly comprises a nozzle (11), a mandrel (12) and a cooler (15). Surface roughness of at least part, in particular of the dwindling area (Z), of inner surface of the nozzle (11) of the nozzle assembly (10) is 1-8.0 Ra, advantageously 3-5 Ra.