When designing a steel plant, the type of Continuous Casting Machine (CCM) must be carefully selected, taking into full consideration the production process, product quality, and economic aspects of the project. When the CCM operates alongside an electric furnace or converter, several key points must be addressed.
Key Points to Consider
Multi-Furnace Continuous Casting
To maximize the production capacity of the CCM, a multi-furnace continuous casting method is generally employed. This approach helps improve steel yield and reduce costs.
Orderly Process Coordination
The casting time of the CCM and the converter should be well-coordinated to ensure seamless process flow.
CCM Capacity
The capacity of the CCM should exceed that of the steelmaking furnace by approximately 10–20% to maintain smooth operation and prevent bottlenecks.
Appropriate Refining Equipment
The use of suitable refining equipment is crucial for ensuring the quality of the molten steel.
CCM and Rolling Mill Matching
Steel Grades
Modern CCMs can produce over 100 types of steel grades. The next processing step should be selected based on product quality and steel grade requirements.
Billet Section Compatibility
The billet section’s size and shape must match the requirements of the rolling mill. Small-billet CCMs typically supply 650, 500, or 400-type mills for the production of bars, profiles, and wire rods. Generally, a 140–220 mm billet is used for a 650 mill, while a 120–140 mm billet is suitable for 500/300 mills. 400/300 mills can process 90–120 mm billets. A 160 mm billet is primarily used for producing steel sections such as rails, I-beams, and channel steel. Slabs are generally used for thick plate mills or broad strip mills to produce medium-thick plates or hot-rolled strip coils.
Compression Ratio
Generally, smaller billet sections reduce heating times and rolling passes, leading to improved mill productivity and energy savings. The compression ratio—the ratio of the cast billet’s cross-sectional area to that of the rolled material—must meet product quality requirements: A compression ratio of 3 ensures the required mechanical properties for standard products; A compression ratio of 4 provides enhanced physical properties and material density.
Shape Tolerance Requirements
Square billets must be regular in shape, with diagonal deviations not exceeding 2.5–3% and corner angles maintained at 90° ± 2°. Severe diamond-shaped distortion can cause pile-ups during rolling or prevent smooth feeding into the mill’s hole pattern. For slabs, excessive bulging should be avoided, with a maximum warping allowance of 10 mm/m.
