阅读说明：本技术 一种多频率自动扫描的材料硬度检测装置及方法 (Multi-frequency automatic scanning material hardness detection device and method ) 是由 张凌雪 胡茂海 胡肇烜 于 2018-08-03 设计创作，主要内容包括：本发明公开了一种多频率自动扫描的材料硬度检测装置及方法。该装置包括励磁线圈、待检材料、感应线圈和检测电路,其中检测电路包括频率合成电路、频率信号放大电路、感应信号放大电路和模数转换电路、控制器；所述励磁线圈与检测电路中的频率信号放大电路相连,感应线圈与检测电路中的感应信号放大电路相连；检测电路通过串行接口连接到PC机。方法为：将待检材料放入励磁线圈和感应线圈之间,改变励磁线圈激励信号频率和功率,检测电路检测励磁线圈和感应线圈中感应电动势的变化,并将数据返回至PC机可视化,以此检测材料的硬度是否合格。本发明能够简单快速、精确无损地检测材料的硬度,具有精度高、实用性好的优点。(The invention discloses a material hardness detection device and method with multi-frequency automatic scanning. The device comprises an excitation coil, a material to be detected, an induction coil and a detection circuit, wherein the detection circuit comprises a frequency synthesis circuit, a frequency signal amplification circuit, an induction signal amplification circuit, an analog-to-digital conversion circuit and a controller; the excitation coil is connected with a frequency signal amplifying circuit in the detection circuit, and the induction coil is connected with an induction signal amplifying circuit in the detection circuit; the detection circuit is connected to the PC through a serial interface. The method comprises the following steps: the material to be detected is placed between the excitation coil and the induction coil, the excitation signal frequency and power of the excitation coil are changed, the detection circuit detects the change of induced electromotive force in the excitation coil and the induction coil, and data are returned to a PC for visualization, so that whether the hardness of the material is qualified or not is detected. The invention can simply, rapidly and accurately detect the hardness of the material without damage, and has the advantages of high precision and good practicability.)

1. The material hardness detection device with the multi-frequency automatic scanning function is characterized by comprising an excitation coil (1), a material to be detected (2), an induction coil (3) and a detection circuit (4), wherein the detection circuit (4) comprises a frequency synthesis circuit, a frequency signal amplification circuit, an induction signal amplification circuit, an analog-to-digital conversion circuit and a controller;

the excitation coil (1) is connected with a frequency signal amplifying circuit in the detection circuit (4), and the induction coil (3) is connected with an induction signal amplifying circuit in the detection circuit (4); the detection circuit (4) is connected to the PC through a serial interface;

the material (2) to be detected is placed between the excitation coil (1) and the induction coil (3), the detection circuit (4) detects the change of induced electromotive force in the induction coil (3), the induced electromotive force is subjected to digital-to-analog conversion and is returned to the PC to be displayed, and whether the hardness of the material (2) to be detected is qualified or not is determined according to data of the induced electromotive force.

2. The apparatus for detecting hardness of material according to claim 1, wherein the induction coil (3) is composed of a pair of coils with the same impedance and opposite winding directions.

3. The apparatus for detecting hardness of material according to claim 1, wherein the frequency synthesis circuit in the detection circuit (4) is composed of a DDS and a single chip, and the DDS employs a chip AD 9850.

4. A multi-frequency automatic scanning material hardness detection method is characterized by comprising the following steps:

step 1, a DDS in a frequency synthesis circuit is controlled by a PC to generate a sinusoidal signal with a fixed amplitude of 1V, and the signal is input into an excitation coil (1) through a frequency signal amplification circuit to generate an excitation magnetic field;

step 2, putting the material to be detected (2) between the excitation coil (1) and the induction coil (3) to generate corresponding induced electromotive force, sending the induced electromotive force to an analog-to-digital conversion circuit through an induction signal amplification circuit, processing the induced electromotive force by the analog-to-digital conversion circuit to obtain a digital signal of the induced electromotive force, and returning the digital signal to the PC;

and 3, determining whether the hardness of the material (2) to be detected is qualified or not by the PC according to the digital signal of the induced electromotive force: if the induced electromotive force value is within the designated threshold value, the workpiece is qualified, otherwise, the workpiece is unqualified.

5. The method for detecting hardness of material with multiple frequency auto-scanning as claimed in claim 4, wherein the PC of step 3 determines whether the hardness of the material to be detected (2) is qualified according to the digital signal of the induced electromotive force, specifically:

and designating a DDS (direct digital synthesizer) to output a signal with the frequency range of 0-4 MHz by a PC (personal computer), detecting induced electromotive force of the material (2) to be detected under different magnetic fields, and carrying out weighted average on the detection results to obtain a final result.

Technical Field

The invention belongs to the technical field of automatic scanning detection, and particularly relates to a multi-frequency automatic scanning material hardness detection device and method.

Background

The hardness of a material can be considered as an ability of the surface of the material to resist plastic deformation under compressive stress. The hardness test can give a quantitative concept of the hardness of a material, namely, a hardness indicator is used for expressing the hardness of the material. Conventional methods for measuring the hardness of materials are classified into three types, i.e., spring rebound (e.g., Shore hardness), indentation (e.g., Brinell hardness, Rockwell hardness, Vickers hardness), and scratch (e.g., Mohs hardness). The detection results of the three detection methods are extremely easy to interfere, errors are easy to cause, and the detection on finished products cannot be carried out.

Disclosure of Invention

The invention aims to provide a device and a method for detecting the hardness of a nondestructive material by multi-frequency automatic scanning, which are convenient, rapid, accurate and efficient, so that the accuracy of the hardness detection of the material is improved.

The technical solution for realizing the purpose of the invention is as follows: a material hardness detection device with multi-frequency automatic scanning comprises an excitation coil, a material to be detected, an induction coil and a detection circuit, wherein the detection circuit comprises a frequency synthesis circuit, a frequency signal amplification circuit, an induction signal amplification circuit, an analog-to-digital conversion circuit and a controller;

the excitation coil is connected with a frequency signal amplifying circuit in the detection circuit, and the induction coil is connected with an induction signal amplifying circuit in the detection circuit; the detection circuit is connected to the PC through a serial interface;

the material to be detected is placed between the excitation coil and the induction coil, the detection circuit detects the change of induced electromotive force in the induction coil, the induced electromotive force is subjected to digital-to-analog conversion and is returned to the PC for displaying, and whether the hardness of the material to be detected is qualified or not is determined according to data of the induced electromotive force.

As a specific example, the induction coil is composed of a pair of coils with the same impedance and opposite winding directions.

As a specific example, a frequency synthesis circuit in the detection circuit is composed of a DDS and a single chip microcomputer, and the DDS adopts a chip AD 9850.

A multi-frequency automatic scanning material hardness detection method comprises the following steps:

step 1, controlling a DDS in a frequency synthesis circuit to generate a sinusoidal signal with a fixed amplitude of 1V by a PC (personal computer), and inputting the signal into an excitation coil through a frequency signal amplification circuit to generate an excitation magnetic field;

step 2, putting the material to be detected between the excitation coil and the induction coil to generate corresponding induced electromotive force, sending the induced electromotive force to an analog-to-digital conversion circuit through an induced signal amplification circuit, processing the induced electromotive force by the analog-to-digital conversion circuit to obtain a digital signal of the induced electromotive force, and returning the digital signal to the PC;

and 3, determining whether the hardness of the material to be detected is qualified or not by the PC according to the digital signal of the induced electromotive force: if the induced electromotive force value is within the designated threshold value, the workpiece is qualified, otherwise, the workpiece is unqualified.

As a specific example, the PC in step 3 determines whether the hardness of the material to be detected is qualified according to the digital signal of the induced electromotive force, specifically:

and designating a DDS (direct digital synthesizer) to output a signal with the frequency range of 0-4 MHz by a PC (personal computer), detecting induced electromotive force of the material to be detected under different magnetic fields, and carrying out weighted average on the detection result to obtain a final result.

Compared with the prior art, the invention has the remarkable advantages that: (1) the material to be detected is placed in the excitation coil and the induction coil, so that the hardness of the material can be detected only through the induction coil, and nondestructive detection is successfully realized; (2) the material is detected under different frequencies generated by the frequency synthesis circuit, and the detection results are weighted and averaged, so that the accuracy of the detection results is improved; (3) the induced electromotive force generated in the induction coil by the material to be detected is detected, and the result is returned to the PC, so that the hardness of the material can be simply, quickly, accurately and efficiently measured, and the detection efficiency is improved.

Drawings

Fig. 1 is a basic structure diagram of a multi-frequency auto-scanning material hardness testing apparatus according to the present invention.

Fig. 2 is a schematic diagram of an internal structure of the detection circuit of the present invention.

Fig. 3 is an external structural diagram of the detection circuit of the present invention.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

The invention relates to a multi-frequency automatic scanning nondestructive material hardness detection device, which detects the hardness of a material to be detected by detecting induced electromotive force generated by the material in a magnetic field.

With reference to fig. 1-2, the device for detecting hardness of a material with multi-frequency automatic scanning of the present invention comprises an excitation coil 1, a material to be detected 2, an induction coil 3 and a detection circuit 4, wherein the detection circuit 4 comprises a frequency synthesis circuit, a frequency signal amplification circuit, an induction signal amplification circuit, an analog-to-digital conversion circuit and a controller;

the excitation coil 1 is connected with a frequency signal amplifying circuit in the detection circuit 4, and the induction coil 3 is connected with an induction signal amplifying circuit in the detection circuit 4; the detection circuit 4 is connected to a PC through a serial interface;

the material 2 to be detected is placed between the excitation coil 1 and the induction coil 3, the detection circuit 4 detects the change of induced electromotive force in the induction coil 3, the induced electromotive force is subjected to digital-to-analog conversion and is returned to a PC for displaying, and whether the hardness of the material 2 to be detected is qualified or not is determined according to data of the induced electromotive force.

Referring to fig. 3, the exciting coil 1 and the induction coil 3 are respectively connected to the detection circuit 4, and are connected to the PC through the interface serial interface 43 of the detection circuit 4. The excitation coil 1 is connected with the frequency signal amplifying circuit through an interface 41 of the detection circuit, and the induction coil is connected with the induction signal amplifying circuit through an interface 42 of the detection circuit.

As a specific example, the induction coil 3 is composed of a pair of coils with the same impedance and opposite winding directions.

As a specific example, the frequency synthesis circuit in the detection circuit 4 is composed of a DDS and a single chip, and the DDS employs a chip AD 9850.

As a specific example, the digital-to-analog conversion circuit is constituted by one a/D converter.

The invention discloses a material hardness detection method with multi-frequency automatic scanning, which is characterized by comprising the following steps:

step 1, controlling a DDS in a frequency synthesis circuit to generate a sinusoidal signal with a fixed amplitude of 1V by a PC (personal computer), and inputting the signal into an excitation coil 1 through a frequency signal amplification circuit to generate an excitation magnetic field;

step 2, putting the material 2 to be detected between the excitation coil 1 and the induction coil 3 to generate corresponding induced electromotive force, sending the induced electromotive force to an analog-to-digital conversion circuit through an induced signal amplification circuit, processing the induced electromotive force by the analog-to-digital conversion circuit to obtain a digital signal of the induced electromotive force, and returning the digital signal to the PC;

and 3, determining whether the hardness of the material to be detected 2 is qualified or not by the PC according to the digital signal of the induced electromotive force: if the induced electromotive force value is within the designated threshold value, the workpiece is qualified, otherwise, the workpiece is unqualified.

Further, step 3 the PC determines whether the hardness of the material to be inspected 2 is qualified according to the digital signal of the induced electromotive force, specifically:

and designating a DDS (direct digital synthesizer) to output a signal with the frequency range of 0-4 MHz by a PC (personal computer), detecting induced electromotive force of the material to be detected 2 under different magnetic fields, and carrying out weighted average on the detection results to obtain a final result so as to improve the accuracy of judgment.

The present invention will be described in further detail with reference to specific examples.