Two-Roll Strip Casting Work Roll Replacement Method
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Solution Overview
Problem
The existing two-roll strip casting process with in-line rolling is limited by the wear of work rolls, leading to frequent roll changes and disruptions in the casting cycle, which results in defects and poor strip surface quality.
Innovation Solution
The method involves changing work rolls above and below the steel strip during casting, allowing continuous operation by adjusting the strip thickness and casting parameters, and using lifting devices to ensure contact-free passage and minimize damage, enabling indefinite casting cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If work rolls are changed regularly to prevent wear marks and maintain strip surface quality, then strip surface quality is improved, but casting cycle continuity is disrupted and productivity decreases
Solution Approach 1:
The rolling mill is divided into multiple rolling units (at least two), where one unit can continue operating while another undergoes roll changes. This segmentation allows the casting process to maintain continuity by switching between rolling units, thereby preventing casting cycle disruptions while ensuring strip surface quality through regular roll maintenance.
Solution Approach 2:
The invention enables continuous casting operation by having multiple rolling units available. When one rolling unit undergoes roll changes, the other rolling unit continues to process the strip, ensuring that the casting action never stops. This eliminates idle time and maintains productivity while still allowing for necessary roll maintenance.
2Reliability
If work rolls are changed between rolling operations in discontinuous operation, then roll wear is managed, but casting cycle is limited and production efficiency is reduced
Solution Approach 1:
The rolling mill is divided into multiple rolling units (at least two), where one unit can continue operating while another undergoes roll changes. This segmentation allows the casting process to maintain continuity by switching between rolling units, thereby preventing casting cycle disruptions while ensuring strip surface quality through regular roll maintenance.
Solution Approach 2:
Roll changes are performed in advance on standby rolling units before they are needed. This preliminary preparation ensures that when a rolling unit needs maintenance, a freshly maintained unit is already ready to take over, eliminating waiting time and extending the effective casting cycle duration.
3Manufacturing precision
If rolling is performed at high temperature (1,000-1,200°C) with low strip speed (0.5-2.0 m/s) to achieve casting, then casting quality is improved, but rolling speed is reduced compared to conventional hot-rolling
Solution Approach 1:
The rolling mill is divided into multiple rolling units (at least two), where one unit can continue operating while another undergoes roll changes. This segmentation allows the casting process to maintain continuity by switching between rolling units, thereby preventing casting cycle disruptions while ensuring strip surface quality through regular roll maintenance.
Solution Approach 2:
The process operates at high temperatures (1,000-1,200°C) with controlled low speeds (0.5-2.0 m/s) to achieve proper casting conditions. By maintaining these specific parameter ranges and using multiple rolling units, the system achieves high-quality casting while compensating for lower speeds through increased operational continuity and reduced idle time.
Data Source
AI summary
A method for extending the casting cycle for the two-roll strip casting of a steel strip, with inline rolling thereof, the steel strip being rolled in at least two successive rolling units of a rolling mill having replaceable working rolls. The casting process is carried out independently from the roll replacement by replacing the working rolls of one rolling unit during the casting, below or above the steel strip. An installation for carrying out the method includes a lifting devices for lifting the working rolls off the steel strip so as not to damage the strip during the replacement of the rolls.