Quenching Depth Measurement Using Electromagnetic Induction
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Solution Overview
Problem
Existing nondestructive inspection methods for quenching depth in workpieces are limited to axis-symmetrical shapes, require calibration curves obtained through extensive experimentation, and suffer from poor measurement accuracy and efficiency, especially when dealing with non-axis-symmetrical objects and varying workpiece sizes.
Innovation Solution
A quenching depth measurement method and apparatus that magnetizes the workpiece using an excitation coil, detects the induction magnetic field with a detection coil, and calculates the quenching depth based on known electromagnetic characteristic information of unquenched and completely quenched materials, utilizing finite element method analysis to estimate output voltage values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional nondestructive inspection methods using induction coils are used to measure quenching depth, then measurement can be performed on workpieces, but the workpieces are limited to axis-symmetrical shapes and the size of measurable workpieces is restricted by coil dimensions
Solution Approach 1:
The invention changes the measurement parameters by using multiple detection coils with different orientations (first detection coil for axial direction, second detection coil for radial direction) and different frequencies. This allows the system to adapt to various workpiece shapes and sizes while maintaining measurement precision through multi-parameter analysis of the induced voltages.
2Measurement precision
If calibration curves are obtained through extensive experimentation for each measurement position to ensure accurate quenching depth measurement, then measurement accuracy is improved, but a large number of man-hours are required for preparation and inspection
Solution Approach 1:
The invention replaces the mechanical experimentation process with computational simulation. By using finite element method or boundary element method to simulate the eddy current distribution and calculate expected voltages for various quenching depths, the system eliminates the need for extensive physical calibration experiments while maintaining measurement accuracy through virtual modeling.
Solution Approach 2:
The invention creates a virtual model (copy) of the workpiece and quenching process through numerical simulation. This virtual copy allows for rapid calculation of expected voltage values under different quenching conditions without requiring physical experimentation, thereby reducing preparation time while preserving measurement accuracy.
3Adaptability or versatility
If surface hardness testers are used in combination with eddy current measurement to specify quenching range, then quenching pattern inspection is supported, but the complexity of the inspection process increases
Solution Approach 1:
The invention makes the eddy current measurement system universal by enabling it to perform multiple functions: it can measure quenching depth, determine quenching patterns, and assess overall quenching quality all through electrical measurements. This eliminates the need for separate surface hardness testing equipment and procedures, reducing system complexity while maintaining comprehensive inspection capability.
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
Enables quick and accurate nondestructive inspection of quenching depth without the need for calibration curves, improving measurement efficiency and accuracy across various workpiece shapes and sizes, and reducing man-hours required for inspection.
Implementation Method 1
a low frequency AC magnetic field generated by an excitation coil magnetizes the steel material in a direction along the surface to generate eddy current
Implementation Method 2
a detection coil detects an induction magnetic field induced by the eddy current
Data Source
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AI summary
The purpose of the invention is to provide a nondestructive testing method capable of quickly and accurately measuring the quenching depth of a quenching processed material. To achieve this purpose, for example, the following quenching depth measuring method is employed. The quenching depth measuring method is used for measuring the quenching depth in a workpiece and comprises the steps of: magnetizing the workpiece by disposing, in the vicinity of the workpiece, a magnetizer equipped with an exciting coil; detecting, through a detection coil, an induced magnetic field generated by the magnetization; measuring the induced magnetic field as the output voltage of the detection coil; and specifying the thickness of the quenched hardened layer of the workpiece on the basis of known electromagnetic characteristic information of an unquenched material and a fully-quenched material and an output voltage value measured by the detection coil, the unquenched material being made of the same material as the constituent material of the workpiece and being a material on which a quenching process is not performed, the fully-quenched material being a material on which the quenching process is performed.