阅读说明：本技术 一种通过声信号和介质温度预测淬火温度场组织场的方法 (Method for predicting quenching temperature field tissue field through acoustic signal and medium temperature ) 是由 盖登宇 王若琛 褚元召 王昊 庄主 梁科鹏 于 2020-11-19 设计创作，主要内容包括：本发明提供一种通过声信号和介质温度预测淬火温度场组织场的方法,1)使用淬火工件同种材料,加工制成圆柱形试样,在有机玻璃淬火槽中安装多个热电阻并编号；使用基于labview的淬火信号采集软件收集记录数据；2)使用编程软件对收集到的数据进行处理,区分淬火沸腾的不同阶段,计算试样不同位置的换热系数,并建立声信号与换热系数的联系；3)使用软件计算或实际测量得到材料的热力学参数,建立有限元模拟需要的材料模型；4)生产过程中,记录淬火时介质多点的温度和声信号并结合有限元模拟,建立淬火模型,得到全过程的温度场、组织场。本发明通过曲线拟合的方法计算得到的换热系数可以使淬火过程的数值模拟结果进一步提高精度。(The invention provides a method for predicting a quenching temperature field tissue field through acoustic signals and medium temperature, 1) quenching workpieces of the same material are processed into cylindrical samples, and a plurality of thermal resistors are arranged in an organic glass quenching tank and are numbered; collecting recording data by using quenching signal acquisition software based on labview; 2) processing the collected data by using programming software, distinguishing different stages of quenching boiling, calculating heat exchange coefficients of different positions of the sample, and establishing a relation between an acoustic signal and the heat exchange coefficients; 3) using software to calculate or actually measure thermodynamic parameters of the material, and establishing a material model required by finite element simulation; 4) in the production process, the temperature and the acoustic signals of multiple points of the medium during quenching are recorded and combined with finite element simulation to establish a quenching model, so that a temperature field and a tissue field of the whole process are obtained. The heat exchange coefficient calculated by the curve fitting method can further improve the accuracy of the numerical simulation result of the quenching process.)

1. A method for predicting a quenching temperature field tissue field through an acoustic signal and a medium temperature is characterized by comprising the following steps:

1) processing a quenching workpiece made of the same material into a cylindrical sample, installing a plurality of thermocouples in the cylindrical sample and numbering the thermocouples, and installing a plurality of thermal resistors in an organic glass quenching tank and numbering the thermal resistors; the sound sensor is fixed near the contact position of a sample and a medium by using a bracket, the thermocouple, the thermal resistor and the sound sensor are connected with the data acquisition instrument through the temperature transmitter, the quenching process in the organic glass water tank is shot by using a high-speed camera, the camera and the data acquisition instrument are connected with a computer through an industrial switch, and quenching signal acquisition software based on labview is used for collecting and recording data;

2) processing the collected data by using programming software, distinguishing different stages of quenching boiling, calculating heat exchange coefficients of different positions of the sample, and establishing a relation between an acoustic signal and the heat exchange coefficients;

3) using software to calculate or actually measure thermodynamic parameters of the material, and establishing a material model required by finite element simulation;

4) in the production process, the temperature and the acoustic signals of multiple points of the medium during quenching are recorded and combined with finite element simulation to establish a quenching model, so that a temperature field and a tissue field of the whole process are obtained.

2. The method for predicting the tissue field of the quenching temperature field through the acoustic signal and the medium temperature as claimed in claim 1, wherein the method uses equipment comprising a quenching part and a signal acquisition and processing part; the quenching section includes: the device comprises a lifting platform with a limiting device, a cylindrical heating furnace with a hole at the top end and capable of being opened and closed, a heating furnace base with a guide rail, an organic glass quenching tank and an iron wire frame for installing and fixing a thermal resistor; the signal acquisition processing part comprises: sound sensor, high-speed camera, thermocouple, thermal resistor, data collector, temp. transducer and power supply and computer for data processing.

Technical Field

The invention relates to a method for predicting a quenching temperature field tissue field through an acoustic signal and medium temperature, and belongs to the field of quenching result prediction.

Background

Quenching is often used as the final heat treatment for workpiece processing to generate martensite to improve the hardness and strength of the material. The measurement and prediction of the accurate temperature curve of the quenching and cooling process are always a research hotspot.

The actual measurement of a quenching temperature curve mostly uses a thermocouple for measuring temperature, a plurality of K-shaped armored thermocouples are inserted into a sample for recording the temperature, the obtained temperature curves are integrated, and the temperature field of a quenching part can be reflected to a certain extent.

The medium temperature is measured by using the thermal resistors which can measure the low temperature more accurately, the temperature of a fixed point in the quenching medium can be obtained, and the temperature distribution of the quenching medium in the whole process can be measured by arranging a plurality of thermal resistors.

At present, the temperature field in the whole quenching process is mostly obtained by calculating measured or calculated material thermodynamic parameters through finite element software, but the temperature field obtained by the method cannot accurately reflect the actual cooling process.

The main reasons are as follows: the simulation process generally does not consider the influence of the temperature rise of the medium along with quenching, and the common simulation mode in engineering can simplify the convective heat transfer of the medium and the workpiece during quenching into a fixed heat transfer coefficient and a fixed medium temperature.

The influence of the boiling of a quenching medium can be ignored in the simulation, the medium near the surface of the workpiece is boiled in the heat transfer process of the quenching, and the process is divided into three stages along with the reduction of the temperature difference: film boiling, transition boiling and nucleate boiling. The three stages have different heat exchange coefficient curves due to different heat insulation effects of the bubbles on the workpiece.

The energy of the acoustic signal is generated by bubble breakage and gas flow generated by quenching, the energy density of the acoustic signal can reflect the energy density of bubbles and gas, and further the quenching heat flow density is represented, and the heat exchange coefficient can be indirectly represented by combining the medium temperature.

The acoustic sensor can record the change of quenching sound, and the curve of the heat exchange coefficients at different positions along with the change of temperature can be obtained through the simultaneous analysis of the acoustic signal and the temperature curve measured by the thermocouples and the thermal resistors.

The special light source is used for polishing the quenching tank, so that bubbles in the quenching process are clear and easy to identify, and the sound insulation foam is used for reducing the influence of echo in the quenching tank.

Disclosure of Invention

Aiming at the problem that the quenching process cannot be accurately predicted at present, the invention provides a method for accurately predicting the temperature field organization field of a quenching piece.

The purpose of the invention is realized as follows:

a method for predicting a quench temperature field tissue field from an acoustic signal and a medium temperature, comprising the steps of:

1) processing a quenching workpiece made of the same material into a cylindrical sample, installing a plurality of thermocouples in the cylindrical sample and numbering the thermocouples, and installing a plurality of thermal resistors in an organic glass quenching tank and numbering the thermal resistors; the sound sensor is fixed near the contact position of a sample and a medium by using a bracket, the thermocouple, the thermal resistor and the sound sensor are connected with the data acquisition instrument through the temperature transmitter, the quenching process in the organic glass water tank is shot by using a high-speed camera, the camera and the data acquisition instrument are connected with a computer through an industrial switch, and quenching signal acquisition software based on labview is used for collecting and recording data;

2) processing the collected data by using programming software, distinguishing different stages of quenching boiling, calculating heat exchange coefficients of different positions of the sample, and establishing a relation between an acoustic signal and the heat exchange coefficients;

3) using software to calculate or actually measure thermodynamic parameters of the material, and establishing a material model required by finite element simulation;

4) in the production process, a quenching model can be established only by recording the temperature and sound signals of multiple points of the medium during quenching and combining finite element simulation, so as to obtain a temperature field and an organization field of the whole process.

The invention also includes such features:

the device used by the method comprises a quenching part and a signal acquisition and processing part; the quenching section includes: the device comprises a lifting platform with a limiting device, a cylindrical heating furnace with a hole at the top end and capable of being opened and closed, a heating furnace base with a guide rail, an organic glass quenching tank and an iron wire frame for installing and fixing a thermal resistor; the signal acquisition processing part comprises: sound sensor, high-speed camera, thermocouple, thermal resistor, data collector, temp. transducer and power supply and computer for data processing.

Compared with the prior art, the invention has the beneficial effects that:

for the quenching process which is difficult to directly measure the temperature field and is not accurate enough by the common numerical simulation technology, the precise prediction scheme of the temperature field tissue field, which can be used for various quenching media and various quenching temperatures, is provided. The quenching process is recorded and analyzed from multiple aspects by using various signal detection devices, and the bubble condition is accurately identified by using a high-speed camera to distinguish the boiling stage by considering the influence of the temperature rise of the medium. The heat exchange coefficient calculated by the curve fitting method can further improve the accuracy of the numerical simulation result of the quenching process.

Drawings

FIG. 1 is a schematic view of an experimental apparatus according to the present invention;

FIG. 2 is a schematic view of a sample;

FIG. 3 is an original picture;

FIG. 4 is a processed picture;

FIG. 5 is an original acoustic signal;

FIG. 6 is a processed acoustic signal;

FIG. 7 is a curve fit of the acoustic signal during entry into water;

FIG. 8 is a curve fit of acoustic signals during heat exchange in water;

FIG. 9 is a graph of measured temperatures of two thermocouples;

FIG. 10 is a temperature curve obtained by simulation at corresponding points;

fig. 11 is a temperature field obtained by simulation.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

The equipment requirements provided by the invention are shown in the figure

The quenching part comprises: the device comprises a lifting platform with a limiting device, a cylindrical heating furnace with a hole at the top end and capable of being opened and closed, a heating furnace base with a guide rail, an organic glass quenching tank and an iron wire frame for fixing a thermal resistor. The signal acquisition processing part comprises: sound sensor, high-speed camera, thermocouple, thermal resistor, data acquisition instrument, temperature transmitter and power supply, computer for data processing.

The technical scheme of the invention is as follows:

a method for predicting a quenching temperature field tissue field through an acoustic signal and a medium temperature is characterized by comprising the following steps:

1) the quenching workpiece made of the same material is processed into a cylindrical sample, a plurality of thermocouples are arranged in the cylindrical sample and numbered, and a plurality of thermal resistors are arranged in an organic glass quenching tank and numbered. The acoustic sensor is fixed near the position where the sample contacts the medium using a holder. The thermocouple, the thermal resistor and the acoustic sensor are connected with a data acquisition instrument through a temperature transmitter. A high speed camera was used to photograph the quenching process in the plexiglass flume. The camera and the data acquisition instrument are connected with a computer through an industrial exchanger. Recording data was collected using labview-based quench signal acquisition software. The special light source is used for polishing the quenching tank, so that bubbles in the quenching process are clear and easy to identify, and the sound insulation foam is used for reducing the influence of echo in the quenching tank.

2) And processing the collected data by using programming software, distinguishing different stages of quenching boiling, calculating the heat flux density of different positions of the sample, and establishing the relation between the acoustic signal and the heat exchange coefficient.

3) And (3) calculating or actually measuring thermodynamic parameters of the material by using software, and establishing a material model required by finite element simulation.

4) In the production process, a quenching model can be established only by recording the temperature and the acoustic signals of multiple points of the medium during quenching and combining finite element simulation, so as to obtain the temperature field of the whole process.

Further, the calculated temperature field can be combined with phase change data of the material to simulate and calculate a tissue field.

1. And installing a thermocouple on the processed sample, and welding a seal to prevent a quenching medium from entering the sample to influence the heat exchange boundary condition.

2. Fixing the sample at a position 5cm below the lifting platform clamp by using an iron wire, using the lifting platform to enable the sample to be lowered into water to determine that the sample can be completely submerged into the water, and enabling the clamp to be away from the water surface by a certain distance. Meanwhile, the camera is adjusted to clearly shoot the whole water entering process, and a limit block is set to record the descending distance. The clamp is then raised to the home position.

3. And pushing the heating furnace to the tail end of the slide rail, setting the quenching temperature, then starting to heat up, opening the front-pulling heating furnace after reaching the specified temperature, wrapping the sample into a hearth, locking the heating furnace, heating to the specified temperature, and then preserving heat for a specified time.

4. And opening a quenching temperature acquisition system, and starting to acquire the quenched sample temperature, the medium temperature, the acoustic signal and the image signal.

5. And opening the heating furnace, simultaneously lowering the sample to a specified position by using the lifting platform, and recording all signals by using the data acquisition system.

6. And processing the obtained data by using a data analysis system to establish the relation between the acoustic signal and the heat exchange coefficient.

7. And processing the picture shot by the high-speed camera by using programming software, and calculating to obtain the perimeter and the area of the bubble through binarization and contour filling processing. The degree of attachment of the bubbles was characterized using the ratio of the total area to the total perimeter to distinguish the three stages of boiling.

And 8, establishing the relation between the energy density and the heat exchange coefficient of the acoustic signal by respectively using curve fitting in the three stages to obtain a nonlinear regression equation.

9. After the mapping relation between the two is obtained, a thermocouple and a camera are not needed to be installed in actual production, only quenching sound signals are recorded, thermal resistors are arranged at reasonable positions in the quenching medium to measure the temperature of the medium, the heat exchange coefficient is calculated according to the mapping relation, and then the temperature field of the whole quenching process can be accurately calculated through finite element software by combining the temperature of the medium.

The overall process tissue field can then be calculated.