Endless Thin Slab Rolling Without Intermediate Heating

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Solution Overview

Problem

Current casting-rolling composite systems are not compact or cost-effective enough for small-scale production of high-quality hot strips, particularly for annual production volumes of 1 million tons or less, and struggle with reliably producing medium to high alloy steel grades without requiring intermediate heating, which increases operating costs.

Innovation Solution

A method for producing a wound hot strip in a compact casting-rolling composite system involving a continuous casting system that forms a thin slab strand with a liquid core, which is then hot rolled exclusively from its casting heat through multiple passes without intermediate heating, achieving a thickness of 2.5 to 10 mm in the austenitic temperature range, and wound into coils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional casting-rolling composite systems are used, then production capacity is sufficient for large volumes, but the systems are not compact and have high capital expenditure for small production volumes

Engineering Contradiction:
Improveplant compactnessVSAvoidproduction volume
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The plant is divided into compact, integrated modules: continuous casting unit directly connected to rolling mill, with in-line cooling and coil winding. This segmentation allows the system to maintain full production functionality while occupying minimal space, making it ideal for small steel mills with annual production of 1 million tons or less

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple functions are merged into a single continuous process line: casting, rolling, cooling, and winding are integrated without intermediate storage or handling. The casting-rolling composite system combines these operations in-line, eliminating the need for separate furnaces and reducing overall plant footprint while maintaining productivity

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If intermediate heating is applied before finish rolling, then hot rolling can be performed, but operating costs increase

Engineering Contradiction:
Improvehot rolling capabilityVSAvoidoperating cost
Core Design Contradiction:
Ease of operationVSUse of energy by stationary object

Solution Approach 1:

The system uses the heat generated during the rolling process itself and the ambient temperature of the incoming slab to maintain rolling conditions. The continuous casting produces slabs at temperatures suitable for direct rolling, and the rolling mill recycles heat through the process, eliminating the need for external heating facilities and reducing operating costs

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The continuous casting-rolling process maintains thermal continuity without interruption. The slab moves continuously from casting to rolling, preserving heat throughout the process. This continuous action eliminates the need for intermittent heating cycles and associated energy costs

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If high casting speeds are used to achieve required throughput, then productivity increases, but reliability of continuous casting mill decreases

Engineering Contradiction:
ImprovethroughputVSAvoidcasting mill reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system optimizes casting parameters including speed, temperature, and slab thickness to achieve the required throughput of 0.487 m²/min while maintaining reliable operation. By carefully controlling these parameters within optimal ranges, the plant achieves both high productivity and casting mill reliability simultaneously

Inventive Principle:
Principle #35Parameter changes

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 method enables the reliable and cost-effective production of high-quality hot strips from a wide range of steel grades with low operating costs, reducing capital and operational expenses while maintaining high production efficiency.

Implementation Method 1

continuous casting of molten steel in a continuous mold to form a thin slab strand with a liquid core

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

hot rolling of the thin slab strand in the rolling mill to the hot strip by three to five rolling passes

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

cooling of the hot strip in the cooling section

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3558563B1Method for the endless manufacture of a coiled hot rolled sheet in a combined casting and rolling installation, and a combined casting and rolling installation
Publication Date: 2024.08.21 PRIMETALS TECH AUSTRIA GMBH
  • EP3558563B1 patent drawingFigure 1
  • EP3558563B1 patent drawingFigure 2~3
  • EP3558563B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for endless production of a coiled hot strip (15) in a casting-rolling integrated plant. The problem to be solved is that of specifying a method by which high-quality hot strip (15) of varying steel qualities can be cost-effectively produced. The method should also be reliable and cause extremely low operating costs. Said problem is solved by a method according to claim 1.