Hot-Dip Coated Steel Strip Thickness Control

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Solution Overview

Problem

Current methods for processing hot-dip coated hot-rolled steel strips lack the ability to achieve controlled and precise thickness reduction directly in the processing line, leading to variations in surface quality and dimensional accuracy.

Innovation Solution

A method and installation that includes a steel strip passing through a pickling station, rinsing station, drying station, heating furnace, and melting bath, with a rolling-mill stand equipped with a thickness gauge for controlled thickness reduction, allowing for adjustments based on real-time measurements to maintain precise final thickness and tolerance, and optionally featuring special roll finishes and rolling fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional temper-pass rolling is used for thickness reduction, then the process is simple and quick, but the thickness control precision and uniformity are poor

Engineering Contradiction:
Improvethickness control precisionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A feedback control system is implemented where thickness measurements are continuously taken during the rolling process, and the results are used to adjust rolling parameters in real-time. This closed-loop control ensures precise thickness management while maintaining process efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The rolling process transitions from static, fixed-parameter temper-pass rolling to a dynamic system where rolling forces, speeds, and gaps are continuously adjusted based on real-time thickness measurements and material properties, enabling precise control adaptability.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If controlled thickness reduction is implemented with real-time measurement and feedback, then thickness precision and uniformity improve, but the device complexity and measurement requirements increase

Engineering Contradiction:
Improvethickness uniformityVSAvoidmeasurement and control complexity
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

Traditional mechanical contact-based thickness measurement is replaced with non-contact measurement systems (such as laser or optical sensors), eliminating mechanical complexity while achieving high-precision thickness detection and control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system monitors and dynamically adjusts multiple process parameters (rolling force, strip speed, temperature) to maintain optimal thickness control, transforming a single-parameter process into a multi-parameter coordinated control system that improves precision without proportionally increasing complexity.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If thickness reduction is performed to achieve final dimensions, then dimensional accuracy improves, but surface quality may deteriorate due to cold working effects

Engineering Contradiction:
Improvedimensional accuracyVSAvoidsurface quality degradation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The rolling process is conducted at controlled temperatures that prevent excessive cold working, and rolling parameters (speed, force, pass distribution) are optimized to minimize surface degradation while achieving the required dimensional accuracy through precise thickness control.

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 approach enables a controlled thickness reduction of up to 30% with improved uniformity and reduced tolerances, enhancing the mechanical properties of the steel strip, such as yield point and tensile strength, while maintaining smaller thickness variations along the strip length compared to traditional temper-pass rolling methods.

Implementation Method 1

at least one thickness gauge located in the exit of the rolling-mill stand checks whether the final thickness has been achieved

Methodology Applied
Scientific EffectRadiation: Radiation

Implementation Method 2

the final thickness and the thickness tolerance of the hot-dip coated steel strip are achieved by a controlled thickness reduction in a rolling-mill stand

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

the steel strip passes through a pickling station, a rinsing station, a drying station, a heating furnace and then a melting bath

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

the steel strip passes through a pickling station, a rinsing station, a drying station, a heating furnace and then a melting bath

Methodology Applied
Scientific EffectHeat: Heating

Data Source

PatentUS8163348B2Controlled thickness reduction for hot-dip coated, hot-rolled steel strip and installation used in this process
Publication Date: 2012.04.24 SMS GROUP GMBH

AI summary

The invention relates to a method for hot-dip coating hot-rolled steel strip, during which the steel strip passes through a pickling station, a rinsing station, a drying station, a heating furnace and then through a molten bath. The final thickness and the thickness tolerance of the hot-dip coated steel strip are achieved by a controlled thickness reduction in a roll stand in the process line. The achievement of the finished thickness is controlled by at least one thickness measuring unit at the outlet of the roll stand, and deviations upward or downward therefrom are fed back in the form of an actuating signal for actuating the roll stand in order to appropriately increase or decrease the thickness reduction. The invention also relates to an installation for producing a steel strip of the aforementioned type.