Thin-Gauge Checkered Steel Strip via Twin-Roll Casting and Sealed Rolling
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Solution Overview
Problem
The metallurgical industry faces challenges in producing high-strength thin-gauge checkered steel plates/strip due to issues like non-uniform structure, high yield ratio, and poor formability in traditional continuous casting processes, which are exacerbated by the presence of residual elements like Sn and Cu, leading to increased production costs and defects such as cracks.
Innovation Solution
A twin-roll thin strip continuous casting process is employed, utilizing residual elements Sn and Cu from steel scrap as alloy elements, with the addition of micro-alloy elements like B, and using gas atomization cooling to control oxide scale thickness and improve surface quality, resulting in a high-strength thin-gauge checkered steel plate/strip with a yield strength of ≥345 MPa and tensile strength of ≥470 MPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional multi-pass continuous rolling is used to produce thin strip steel, then the production process is complex with high energy consumption, but the product quality can be maintained
Solution Approach 1:
The patent combines continuous casting and continuous rolling into an integrated thin strip production line, where the casting and rolling processes are merged into a single continuous operation. This eliminates the need for separate reheating and multi-pass rolling operations, significantly simplifying the production process and reducing energy consumption while maintaining product quality
Solution Approach 2:
The patent implements a continuous production process where molten steel is directly cast and rolled without interruption. The continuous casting produces thin strips that are immediately fed into the rolling mill, maintaining continuous useful action throughout the process. This eliminates idle time and repeated heating/cooling cycles, reducing energy consumption and process complexity
2Ease of manufacture
If thin slab continuous casting is used to reduce process flow, then production cost is reduced, but the steel strength and yield ratio increase causing high rolling load
Solution Approach 1:
The patent changes the chemical composition parameters of the steel by adding specific alloying elements (Ti: 0.01-0.05%, V: 0.01-0.05%, B: 0.001-0.005%) to control the microstructure and mechanical properties. This allows the steel to achieve the required strength without excessive rolling load, as the microalloying provides strengthening through precipitation hardening rather than relying solely on high dislocation density from heavy rolling
Solution Approach 2:
The patent applies local quality by creating a controlled microstructure through microalloying, where specific regions of the steel matrix contain precipitates that provide localized strengthening. This allows the steel to have high strength with lower overall rolling load requirements, as the strengthening is achieved through distributed precipitates rather than uniform high stress rolling
3Reliability
If residual elements Sn and Cu are removed from steel, then product quality is improved, but smelting cost increases
Solution Approach 1:
The patent converts the harmful residual elements Sn and Cu into beneficial alloying elements by controlling their content within specific ranges (Sn: 0.01-0.10%, Cu: 0.01-0.10%). Instead of completely removing these elements through expensive refining processes, the patent utilizes them to provide solid solution strengthening and improve the steel's mechanical properties, thereby reducing smelting cost while maintaining product quality
Solution Approach 2:
The patent changes the acceptable parameter ranges for Sn and Cu content, transforming them from harmful impurities to controlled alloying elements. By specifying narrow but permissive ranges (0.01-0.10% for both Sn and Cu), the patent achieves cost-effective production without compromising quality, as these controlled amounts provide strengthening without causing severe segregation or hot shortness
4Productivity
If twin-roll thin strip continuous casting is used, then production efficiency is improved, but the microstructure uniformity deteriorates
Solution Approach 1:
The patent applies preliminary action by adding microalloying elements (Ti, V, B) to the molten steel before casting. These elements prepare the steel for controlled microstructure formation during the rapid cooling of twin-roll casting. The preliminary addition of alloying elements ensures that precipitates form uniformly during cooling, compensating for the non-uniform cooling rates inherent in twin-roll casting and maintaining microstructure uniformity while preserving high production efficiency
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
This approach significantly reduces production costs and investment, eliminates the need for further rolling, and produces high-strength, thin-gauge checkered steel plates/strip with improved surface quality and uniform microstructure, suitable for various applications, while promoting the recycling of steel scrap and reducing environmental impact.
Implementation Method 1
twin-roll thin strip continuous casting process
Implementation Method 2
continuous casting + heat preservation and soaking of the cast slab
Implementation Method 3
using gas atomization cooling to control oxide scale thickness and improve surface quality
Implementation Method 4
hot continuous rolling + cooling + coiling
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A high-strength thin-gauge checkered steel plate/strip and a manufacturing method therefor, wherein residual elements such as Sn and Cu in steel scrap are fully utilized as alloy elements in the smelting of molten steel, and the steel has selectively added micro-alloy elements such as B; during the smelting process, the alkalinity of the slag, the types of inclusion in the steel and the melting point thereof, the content of free oxygen and the content of soluble aluminum (Als) in the molten steel are controlled; and twin-roll thin-strip continuous casting is performed to cast a cast strip (11); after exiting crystallization rollers (8a, 8b), the cast strip (11) directly enters a lower sealed chamber (10) containing a non-oxidizing atmosphere, and enters an online rolling machine (13) in a sealed manner so as to undergo hot rolling, then after rolling, the strip steel is cooled by means of air atomization. The resultant steel roll can be used directly as hot-rolled checkered plate/strip, or as a finished checkered plate/strip after being cut and finished, and is widely applicable to the fields of architecture, mechanical production, automobile, bridges, transportation, ship building, etc.