Laser Ultrasonic Grain Size Estimation Without Reference Pieces
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Solution Overview
Problem
Existing methods for estimating grain size during hot rolling of steel require reference pieces or multiple echoes, which are inefficient and limited in measuring larger grain sizes, especially in high-temperature production environments.
Innovation Solution
A method using laser ultrasonic (LUS) measurement equipment that generates an ultrasonic pulse and measures the subsequent echo, utilizing the ultrasonic vibration immediately generated on the surface as a reference to estimate material properties, eliminating the need for reference pieces and enabling measurement of larger grain sizes by leveraging the generation event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference pieces or multiple echoes are used for grain size estimation, then measurement can be performed, but the method becomes inefficient and limited for larger grain sizes
Solution Approach 1:
The patent extracts the reference signal directly from the generation event (the initial ultrasonic vibration created by laser heating) rather than using separate reference pieces or multiple echoes. This extracted reference signal is then used to compare against subsequent echoes, eliminating the need for additional reference materials and improving measurement efficiency while maintaining accuracy for grain size estimation.
2Measurement precision
If reference pieces are used for measurement, then grain size can be estimated, but the device complexity and measurement process become more complicated
Solution Approach 1:
The measurement system uses itself to provide the reference signal. The generation event, which is inherently part of the measurement process, serves as the reference against which subsequent echoes are compared. This self-service approach eliminates the need for external reference pieces and simplifies the measurement setup while maintaining the capability to estimate grain size accurately.
3Adaptability or versatility
If conventional ultrasonic methods are used, then measurement is possible, but the method is limited for high-temperature production environments
Solution Approach 1:
The patent replaces conventional contact-based ultrasonic transducers with a non-contact laser-based system. The generation laser creates ultrasonic vibrations through optical heating, and the detection laser measures surface vibrations optically. This substitution of mechanical systems with optical systems enables measurement in high-temperature production environments where contact methods would fail, while maintaining grain size measurement precision.
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 efficient and precise estimation of grain size, particularly at elevated temperatures, improving the control of the steel rolling process and enabling the production of steel with desired grain size properties.
Implementation Method 1
providing a laser pulse onto a surface of the object by the generation laser such that an ultrasonic pulse is generated in the object and such that an ultrasonic vibration is immediately generated on the surface
Implementation Method 2
measuring at least a first subsequent ultrasonic echo from the object by use of the detection laser and the detector
Data Source
AI summary
Described is a method for estimating a material property of an object by means of a laser ultrasonic (LUS) measurement equipment comprising a generation laser, a detection laser and a detector. The method includes providing a laser pulse onto a surface of the object by the generation laser such that an ultrasonic pulse is generated in the object and such that an ultrasonic vibration is immediately generated on the surface, measuring at least a first subsequent ultrasonic echo from the object by use of the detection laser and the detector, which ultrasonic echo is an echo from the ultrasonic pulse generated in the object, measuring the ultrasonic vibration which is immediately generated on the surface, by use of the detection laser and the detector, and estimating the material property by use of an ultrasonic attenuation parameter based on the measured at least first subsequent ultrasonic echo, whereby the material property is estimated by using the measured ultrasonic vibration which is immediately generated on the surface as reference to the measured at least first subsequent ultrasonic echo.