Alloyed Position Determination in Hot Dip Galvanizing

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Solution Overview

Problem

Existing methods for determining the alloyed position in hot dip galvanizing processes, particularly those using induction heating, face challenges due to stray radiation noise and temperature variations in the heat holding zone, leading to imprecise measurements.

Innovation Solution

A method and apparatus that acquire radiance information from multiple radiation thermometers, estimate steel sheet temperatures based on temperature decreasing patterns, and calculate emissivity to precisely determine the alloyed position, accounting for temperature changes and stray radiation noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiation thermometers are used to measure alloyed position in conventional furnaces with flame heating, then the measurement can be performed, but stray radiation noise from the heat source mixes into the measurement value causing imprecise emissivity measurement

Engineering Contradiction:

Improveemissivity measurement precisionVSAvoidstray radiation noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes the harmful stray radiation component from the measurement system. By using multiple radiation thermometers at different positions and applying mathematical processing, the system separates the stray radiation noise from the true target emission, eliminating its harmful effect on emissivity measurement precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary mathematical processing step that acts as a mediator between the raw radiation measurements and the final emissivity calculation. Through calculations involving multiple measurement points and temperature corrections, the system mediates the measurement process to compensate for stray radiation effects and achieve precise emissivity values.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If conventional alloyed position determination methods are applied to induction heating processes with gradual cooling, then the existing measurement system can be used, but the alloyed position cannot be determined precisely due to temperature decrease in the heat holding zone

Engineering Contradiction:

Improvealloyed position determination precisionVSAvoidsteel sheet temperature stability

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The invention performs preliminary temperature measurement and correction actions before the final alloyed position determination. By measuring temperatures at multiple points along the conveying direction and calculating the temperature distribution pattern in advance, the system prepares correction data that compensates for temperature decreases, enabling precise alloyed position determination despite thermal transients.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention adapts the measurement system to dynamic temperature conditions by continuously tracking temperature changes along the steel sheet path. The system dynamically adjusts measurements and calculations based on the actual temperature distribution, which varies with position and time, allowing accurate alloyed position determination in non-stationary thermal fields.

Inventive Principle:

Principle #15Dynamics

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 more accurate determination of the alloyed position, reducing the likelihood of defective layers and improving quality control in hot dip galvanizing processes by considering temperature changes and minimizing the impact of stray radiation noise.

Implementation Method 1

information regarding a result of measurement of radiance from each of a plurality of radiation thermometers installed in a vicinity of a heat holding zone

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS9459220B2Alloyed position determining method, alloyed position determining apparatus, and recording medium

Publication Date: 2016.10.04 NIPPON STEEL CORPORATION

AI summary

[Object] To determine an alloyed position more precisely even in processes in which induction heating is used in a previous section of alloying, which have been becoming more common in recent years, and a steel sheet is alloyed by being gradually cooled in a heat holding zone.[Solution] An alloyed position determining method includes a step for acquiring information regarding a result of measurement of radiance from each of a plurality of radiation thermometers installed in a vicinity of a heat holding zone in a hot dip galvanizing line of a steel sheet and along a conveying direction of the steel sheet in the heat holding zone, the radiation thermometers measuring radiance of the steel sheet conveyed, a step for estimating steel sheet temperatures at installation positions of the radiation thermometers by use of information regarding a temperature decreasing pattern of the steel sheet, accompanied by a position change in the conveying direction in the heat holding zone, and information regarding the installation positions of the radiation thermometers, a step for calculating emissivity at the installation positions of the radiation thermometers by use of the estimated steel sheet temperatures at the installation positions of the radiation thermometers and the information regarding the result of measurement of radiance, and a step for determining an alloyed position based on the calculated emissivity.