Internal Oxide Thickness Estimation Using Cumulative Temperature
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Solution Overview
Problem
Existing methods fail to accurately estimate the thickness of the internal oxide layer in hot-rolled steel sheets, particularly in high-tensile strength steel, due to the complexity of internal oxidation processes and the difficulty in reflecting the internal oxidation starting temperature in existing models.
Innovation Solution
An internal oxide layer thickness estimation device and method that calculates cumulative temperature based on defined temperatures and time intervals, using correlation expressions to estimate the thickness of the internal oxide layer, incorporating the internal oxidation starting temperature and thermal history of the steel sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing estimation methods are used, then the estimation process is simple, but the measurement precision of internal oxide layer thickness is insufficient
Solution Approach 1:
The invention changes the parameter basis from simple time or Arrhenius integration to cumulative temperature (integral of temperature over time). This parameter transformation enables accurate reflection of the internal oxidation process that occurs at specific temperature ranges, thereby improving measurement precision without excessive complexity
Solution Approach 2:
The invention introduces cumulative temperature as an intermediary parameter that mediates between the complex thermal history and the internal oxide layer thickness. This intermediary captures the essential thermal exposure information needed for accurate estimation while simplifying the relationship between processing conditions and oxidation results
2Measurement precision
If integration is performed until room temperature is reached, then the estimation covers the entire cooling process, but the accuracy is reduced because the internal oxidation starting temperature is not reflected
Solution Approach 1:
The invention modifies the integration parameter by introducing the internal oxidation starting temperature as a threshold. The cumulative temperature calculation integrates only when the temperature exceeds this threshold, accurately reflecting that internal oxidation occurs only in specific temperature ranges during cooling, thereby improving estimation accuracy
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 allows for more accurate estimation of internal oxide layer thickness, improving the precision of predictions and enabling better control over the oxide layer formation, which is crucial for optimizing the pickling process.
Implementation Method 1
a cumulative temperature calculation unit that calculates a cumulative temperature on the basis of the temperatures defined by the first temperature definition unit and the second temperature definition unit and a predetermined period of time
Implementation Method 2
an internal oxide layer is formed in a base metal portion immediately below a scale layer. The internal oxide layer is a layer in which metal oxides are dispersed at grain boundaries and in crystal grains
Data Source
AI summary
This internal oxide layer thickness estimation device estimates a thickness of an internal oxide layer formed in a hot-rolled steel sheet. The internal oxide layer thickness estimation device includes: a first temperature definition unit that defines a temperature of a portion to be estimated, in which the thickness of the internal oxide layer is to be estimated, in the hot-rolled steel sheet; a second temperature definition unit that defines an internal oxidation starting temperature at which internal oxidation of the hot-rolled steel sheet starts; a cumulative temperature calculation unit that calculates a cumulative temperature on the basis of the temperatures defined by the first temperature definition unit and the second temperature definition unit and a predetermined period of time from an estimation start time at which estimation of the thickness of the internal oxide layer is started to an estimation evaluation time; a first correlation expression derivation unit that derives a first correlation expression indicating a correlation between the cumulative temperature calculated by the cumulative temperature calculation unit and an estimated value of the thickness of the internal oxide layer; and an internal oxide layer thickness estimation unit that estimates the thickness of the internal oxide layer on the basis of the first correlation expression.