Method for analyzing post-dynamic recrystallization process of high-strength steel

Abstract

The invention discloses a method for analyzing the post-dynamic recrystallization process of high-strength steel and belongs to the field of plastic forming. The method comprises the following steps that 1, a cylindrical sample is prepared; 2, a single-pass compression experiment is conducted at different deformation temperatures, strain states and deformation, and after the deformation of the sample reaches a preset value, the sample is quenched immediately; 3, the quenched sample is sliced in the axis direction of the sample; 4, slices are subjected to infrared heating to the target temperature in a high-temperature laser confocal in-situ observation experiment and then subjected to heat preservation, real-time in-situ observation is conducted, and metallograph in the metallographic structure changing process is shot; and 5, the grain sizes and dynamic recrystallization volume fractions at different time are obtained through the metallograph, and then the influence of different parameters on the post-dynamic recrystallization process is analyzed. According to the method for analyzing the post-dynamic recrystallization process of the high-strength steel, a thermocompression experiment method and an in-situ observation experiment method are combined, real-time dynamic observation can be achieved, experiment precision is improved, materials are saved, the period is shortened, and the cost is lowered.

Description

technical field [0001] The invention belongs to the field of plastic forming, and more specifically relates to an analysis method for the post-dynamic recrystallization process of high-strength steel. Background technique [0002] With the rapid development of my country's aerospace, ship, submarine and other large-scale equipment industries in recent years, the demand for large and complex components continues to increase, and the requirements for product quality are also getting higher and higher. In order to be able to produce large and complex components that can serve in extreme environments such as high loads and high impacts, multi-pass hot forging methods are often used for integral forming. However, during multi-pass overall hot forging, during the heat treatment process between passes, the grains will undergo static and sub-dynamic recrystallization, which is collectively referred to as the post-dynamic recrystallization process. These two mechanisms have an impor...

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Problems solved by technology

[0003] However, the grain size model and kinetic model of post-dynamic recrystallization are relatively rare, because building an accurate model requires a large number of double-pass compression tests to check the influence of process parameters on recrystallization volume fraction, which not only leads to experimental The cost is high, and it will take up a lot of time for scientific researchers

In addition, the double-pass compression test also has the following problems: Due to the influence of the precision of the thermocompression forming equipment, different samples are repeated under the same process conditions, and the measured results are not the same. This is the later data. The analysis has a greater impact; the object of the study is the evolution of the average austenite grain size, not the change law of the average size of a certain grain, and the results obtained are inaccurate; the conventional experimental method needs to be quenched with water to retain For the microstructure of the material, only the data of metallographic corrosion at room temperature can be counted. It is difficult to directly observe the evolution process of the austenite grain structure during the post-dynamic recrystallization process under high temperature conditions, and it is impossible to directly and accurately study the post-dynamic recrystallization process of the material. Mechanism of microstructure evolution; due to the rapid metadynamic recrystallization process, traditional experimental methods are difficult to accurately observe and distinguish between metadynamic and static recrystallization processes, and it is difficult to quantitatively analyze the microstructure change kinetics of the two processes and the recrystallization process

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