Large-Cross-Section Ingot Casting With Moving Electromagnetic Stirring
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Solution Overview
Problem
Current methods for producing large cross-section ingots face issues such as mold sticking, insufficient solidification, segregations, and high investment costs, limiting the quality and economic viability of producing blocks with diameters over 300mm and lengths over 5m.
Innovation Solution
A method involving continuous movement of an electromagnetic stirrer from the bottom to the top of the cast block during post-casting, combined with secondary cooling and electroslag remelting using a consumable electrode to maintain heating and compensate for shrinkage, allowing for controlled solidification and improved quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If gray cast iron molds are used for casting large cylindrical blocks, then blocks with diameters of 600mm and lengths of 5m can be produced, but the cast block gets stuck in the mold during stripping and the solidification structure is insufficient with segregations and blowholes
Solution Approach 1:
The patent replaces the conventional gray cast iron mold system with a water-cooled copper mold system. The copper mold uses forced water circulation through internal channels to actively control heat extraction and solidification, replacing the passive thermal properties of gray cast iron molds. This substitution enables precise temperature control during casting, ensuring complete solidification and eliminating defects while accommodating large block dimensions.
Solution Approach 2:
The patent changes the thermal parameters of the mold system by using copper with high thermal conductivity instead of gray cast iron. The water cooling system adjusts the heat extraction rate by controlling water flow rate and temperature, transforming the solidification process from uncontrolled to precisely regulated, thereby achieving uniform solidification structure without segregations or blowholes.
2Speed
If continuous casting plants with large cross-sections are used, then casting speeds of 0.15-0.30m/min can be achieved, but arched systems with large construction heights are required and strand solidification is incomplete
Solution Approach 1:
The patent replaces the arched continuous casting system with a vertical directional solidification system. The water-cooled copper mold is positioned vertically with the long axis aligned to gravity, eliminating the need for large-radius arches. The active water cooling enables rapid heat extraction that compensates for the reduced solidification time at higher casting speeds, achieving complete solidification without requiring extended construction heights.
Solution Approach 2:
The patent applies preliminary cooling action by establishing water circulation through the copper mold before and during the casting process. The mold is pre-cooled and maintains optimal temperature distribution throughout casting, ensuring that even at increased speeds, the solidification front progresses uniformly and completely through the entire strand length.
3Productivity
If casting times are extended to produce longer strands, then more material can be produced, but deep-reaching primary shrinkage cavities form and yield decreases
Solution Approach 1:
The patent maintains continuous water circulation through the copper mold throughout the entire casting process, ensuring uninterrupted heat extraction. This continuous active cooling prevents temperature gradients that would lead to shrinkage cavities, allowing longer strands to be produced without compromising structural integrity or yield.
Solution Approach 2:
The patent adjusts the water flow rate and temperature parameters dynamically during casting to maintain optimal heat extraction rates. By controlling these parameters, the solidification velocity is optimized to match the casting speed, preventing liquid metal shrinkage and cavity formation even during extended casting operations for longer strands.
4Productivity
If single-strand plants with 600mm cross-section are used, then casting capacity of 33t/h is achieved, but investment costs cannot be amortized due to low market demand
Solution Approach 1:
The water-cooled copper mold system is designed with universal applicability to various casting configurations. The same basic mold design can be adapted for single-strand, multi-strand, continuous, or batch casting operations with different cross-sections and speeds. This versatility allows a single plant installation to serve multiple market demands and product specifications, improving economic viability.
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
Enables economical production of high-quality blocks with diameters over 300mm and lengths over 5m, reducing defects and investment costs by ensuring complete solidification and maintaining quality throughout the process.
Implementation Method 1
a movable stirrer, in this case an electromagnetic stirrer 10, 13 is used
Implementation Method 2
by melting a consumable electrode 18
Implementation Method 3
by melting a consumable electrode 18
Data Source
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AI summary
The invention relates to a method and a plant for the production of blocks with a large cross-section, different cross-sectional shapes and lengths of more than 5 m by casting in a short, water-cooled mold (4) and drawing off the solidifying block (6) until the desired block length is reached and subsequent heating of the metal sump by an electroslag process with consumable electrodes (18) or re-casting from a heated intermediate vessel (3) or a heatable hood (22) and influencing the solidification structure by using electromagnetic stirrers (10, 11, 13) during casting and after the end of casting until solidification is complete.