CN-122016910-A - Method for measuring strain-induced precipitation kinetics of carbide based on thermal simulation experiment

CN122016910ACN 122016910 ACN122016910 ACN 122016910ACN-122016910-A

Abstract

The invention discloses a method for determining carbide strain-induced precipitation kinetics based on a thermal simulation experiment, which relates to the technical field of alloy steel thermal processing, and comprises the steps of obtaining stress and time change of alloy steel in a heat preservation process after deformation at different rolling temperatures in an austenitizing temperature interval; the method comprises the steps of generating stress and time curves at each rolling temperature according to the stress and time changes after rolling, measuring the start time and the end time of carbide strain induction precipitation in the heat preservation process of alloy steel, and generating a carbide precipitation dynamics curve based on the start time, the end time and the rolling temperature. Therefore, the carbide precipitation start-stop time can be extracted by continuously collecting stress and time in a single heat preservation process corresponding to each rolling temperature, heat preservation and sample replacement are not required to be interrupted, the operation is simple, the workload is small, a traceable and comparable time curve is convenient to form, and the whole strain induction precipitation process and the interaction relation between precipitation and static recrystallization are intuitively reflected.

Inventors

CHEN SONGJUN
ZOU LIMING
XU CHENGLIANG
WU JINCHEN
SU ZAIJUN
WANG PENGFEI
WANG MINGJIE
FENG JUN

Assignees

广州科技贸易职业学院

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (9)

1. A method for determining strain-induced precipitation kinetics of carbides based on thermal simulation experiments, the method comprising: Obtaining stress and time of an alloy steel sample in a heat preservation process after deformation at different rolling temperatures, wherein the rolling temperature is smaller than a preset solid solution temperature, and the preset solid solution temperature represents a critical temperature of solid solution of carbide in the alloy steel; Generating a stress time curve of the alloy steel sample during heat preservation after different rolling temperatures according to the stress and the time; determining the starting time and the ending time of carbide strain-induced precipitation of the alloy steel sample at different rolling temperatures according to the stress time curve; generating a carbide precipitation kinetics curve based on the start time, the end time, and the rolling temperature.
2. The method of claim 1, wherein the obtaining stress and time during the heat preservation after the rolling deformation of the alloy steel sample comprises: Welding thermocouple wires on the side wall of the alloy steel sample, and sequentially and respectively adhering a metal tantalum sheet and a graphite sheet on the two ends of the thermocouple wires to obtain the alloy steel sample; and in the environment with inert gas, carrying out heat preservation on the alloy steel sample after deformation at different rolling temperatures to obtain stress and time of the alloy steel sample in the heat preservation process after deformation at different rolling temperatures.
3. The method according to claim 2, wherein the step of maintaining the alloy steel sample after the deformation at different rolling temperatures in the environment with inert gas to obtain stress and time of the alloy steel sample during the maintaining process after the deformation at different rolling temperatures comprises: heating the alloy steel sample to a first preset temperature at a first preset speed in the environment with inert gas, and preserving heat for a first time to obtain an initial shape of the alloy steel sample; Cooling the initial shape to a second preset temperature at a second preset speed, and performing rolling at the second preset temperature after preserving heat for a second duration to obtain a first deformed shape; cooling the first deformed body to a third preset temperature at a third preset speed, preserving heat for a third duration, and rolling at the third preset temperature to obtain a second deformed body; In the process of preserving the second deformed body at the third preset temperature for a fourth time period, obtaining the stress and time of the alloy steel sample at the rolling temperature of the current third preset temperature; and changing a third preset temperature value, and repeating the process to obtain the stress and time of the alloy steel sample in the heat preservation process after rolling at different third preset temperatures.
4. The method according to claim 2, wherein the step of maintaining the alloy steel sample after deformation at different rolling temperatures in an environment with inert gas to obtain stress and time of the alloy steel sample during the maintaining process after deformation at different rolling temperatures comprises: heating the alloy steel sample to a first preset temperature at a first preset speed in the environment with inert gas, and preserving heat for a first time to obtain an initial shape of the alloy steel sample; Cooling the initial shape to a second preset temperature at a second preset speed, and preserving heat for a second time to obtain a first deformed shape; Cooling the first deformed body to a third preset temperature at the third preset speed, preserving heat for a third duration, and rolling at the third preset temperature to obtain a second deformed body; in the process of preserving the second deformed body at the third preset temperature for a fourth time period, obtaining stress and time of the heat preservation process of the alloy steel sample after rolling at the third preset temperature; and changing a third preset temperature value, and repeating the process to obtain the stress and time of the alloy steel sample in the heat preservation process after rolling at different third preset temperatures.
5. The method according to any one of claims 1 to 4, wherein the time for which the alloy steel sample is kept warm at different rolling temperatures is obtained by: taking the time from the beginning of heating to the end of rolling of the alloy steel sample as a first time; taking the time from the beginning of heating to the end of rolling of the alloy steel sample to the preset heat preservation time as second time; subtracting the first time from the second time to obtain the time.
6. The method of claim 1, wherein generating the stress-time profile corresponding to the different rolling temperature incubations from the stress and the time comprises: generating initial stress time curves corresponding to different rolling temperatures according to the stress and the time; and carrying out logarithmic transformation on the initial stress time curve to obtain stress time curves corresponding to the heat preservation at different rolling temperatures.
7. The method according to claim 1, wherein said deriving from said stress-time curve a start time and an end time of carbide precipitation of said alloy steel sample at different rolling temperatures comprises: Acquiring a first inflection point and a second inflection point which appear on the stress time curve, wherein the first inflection point is the first inflection point appearing on the stress time curve, and the second inflection point is the last inflection point appearing on the stress time curve; Taking the time corresponding to the first inflection point as the starting time of carbide precipitation; And taking the time corresponding to the second inflection point as the ending time of carbide precipitation.
8. A system for determining carbide strain induced precipitation kinetics based on thermal simulation experiments, the system comprising: The obtaining module is used for obtaining stress and time of a heat preservation process of the alloy steel sample after deformation at different rolling temperatures, the rolling temperature is smaller than a preset solid solution temperature, and the preset solid solution temperature represents the critical temperature of solid solution of carbide in the alloy steel; The processing module is used for generating a stress time curve of the alloy steel sample during the heat preservation period after different rolling temperatures according to the stress and the time, determining the starting time and the ending time of carbide strain induced precipitation of the alloy steel sample at different rolling temperatures according to the stress time curve, and generating a carbide precipitation dynamics curve based on the starting time, the ending time and the rolling temperatures.
9. An experimental machine, comprising a controller for clamping an alloy steel sample and applying pressure, a clamp for monitoring the temperature of the alloy steel sample, and a thermocouple wire for performing the method for determining carbide strain induced precipitation kinetics based on thermal simulation experiments according to any one of claims 1 to 7.

Description

Method for measuring strain-induced precipitation kinetics of carbide based on thermal simulation experiment Technical Field The invention relates to the technical field of alloy steel hot working, in particular to a method for measuring carbide strain-induced precipitation kinetics based on a thermal simulation experiment. Background In the process of controlling rolling of alloy steel, the rolling deformation increases the deformation energy storage and defect quantity of austenite of the alloy steel, and improves the precipitation chemical free energy in the austenite, thereby leading to carbide strain-induced precipitation. The improper amount of excessive strain-induced carbide precipitation inevitably consumes limited alloy elements dissolved in a matrix, reduces the precipitation of nanoscale carbide on a subsequent phase-change matrix, reduces the precipitation strengthening effect of the carbide, and is unfavorable for the improvement of the comprehensive performance of alloy steel, so that the measurement and control of the strain-induced precipitation of the carbide have important influence on the final structure and performance of the alloy steel. When researching the precipitation characteristics and the dynamics of alloy steel strain-induced precipitation carbide, a proper rolling process is required to be set so as to fully utilize the beneficial effects of alloy steel strain-induced precipitation carbide and improve the comprehensive performance of steel. And because the strain-induced precipitation kinetics of the carbide is mainly represented by a precipitation-temperature-time (PTT) curve, the strain-induced precipitation kinetics curve of the carbide in the alloy steel can be measured to provide data guidance for the setting of the controlled rolling process parameters, so that the structure and the performance of the steel are optimized. At present, the conventional methods for researching the strain-induced precipitation kinetics of alloy steel include a resistivity measurement method, a double-pass thermocompression method and an electrolytic dissolution method, but the methods are all experimental data obtained through a large number of independent individual experiments, the experimental operation is complex, the experimental amount is large, and the whole strain-induced precipitation process and the interaction relationship between precipitation and static recrystallization are difficult to intuitively reflect. Disclosure of Invention In view of the above, the present invention aims to provide a method for determining carbide strain-induced precipitation kinetics based on thermal simulation experiments, which only needs to analyze stress and corresponding time data continuously collected in a single isothermal heat preservation process corresponding to each rolling temperature for an alloy steel sample, so as to directly extract start time and end time of carbide strain-induced precipitation, and the whole determination process does not need to interrupt heat preservation and replace the sample, and has the advantages of simple experimental operation and small experimental quantity, so as to form a traceable, comparable and modelable time curve according to the start time and end time of precipitation, and simultaneously intuitively reflect the whole strain-induced precipitation process and interaction relation of precipitation and static recrystallization. In order to achieve the above object, according to a first aspect, an embodiment of the present invention provides a method for determining carbide precipitation kinetics based on a thermal simulation experiment, the method comprising obtaining stress and time of an alloy steel sample during a heat preservation process after deformation at different rolling temperatures, wherein the rolling temperatures are smaller than preset solid solution temperatures, the preset solid solution temperatures represent critical temperatures of solid solution of carbide in the alloy steel, generating a stress time curve of the alloy steel sample during the heat preservation process after the different rolling temperatures according to the stress and the time, determining start time and end time of carbide strain induced precipitation of the alloy steel sample at the different rolling temperatures according to the stress time curve, and generating a carbide precipitation kinetics curve based on the start time, the end time and the rolling temperatures. In the embodiment, the stress time curve of the alloy steel sample at different rolling temperatures is generated by acquiring the stress and time of the alloy steel sample in the heat preservation process after deformation at different rolling temperatures, so that the starting time and the ending time of carbide precipitation in the heat preservation process of the alloy steel sample are conveniently obtained according to the stress time curve, the dynamics curve of carbide precipitation is direc