Experimental Study On Acoustic Emission Of S30408 Steel During Strain Strengthening

Austenitic stainless steel due to its excellent mechanical properties and corrosion resistance is widely used in the field of pressure equipment,people through the strain hardening process to make austenitic stainless steel pressure equipment thinner,lighter while at the same time to ensure its safety,While the strain hardening process directly affects the bearing capacity of the pressure equipment.Strain-enhanced loading rate is an important control parameter of the strain hardening process.Therefore,it is very important to understand the plastic deformation of the internal structure of the strain hardening process at different loading rates.In this paper,acoustic emission technique is used to monitor the strain enhancement process at different loading rates.The acoustic emission characteristics of the S30408 standard specimen are studied.The main contents of this paper are summarized as follows:(1)The S30408 steel strain stabilized acoustic emission monitoring scheme was developed.The experimental data show that there is a significant correlation between the material loading stage and the acoustic emission characteristic parameters.(2)The acoustic emission monitoring scheme of S30408 steel tensile test was developed.The experimental data show that there is a significant correlation between the material loading stage and the acoustic emission characteristic parameters.The strain intensification process at different loading rates is analyzed by using the normalization of the acoustic emission parameters and the correlation acoustic emission characteristic parameter analysis.The trends of the acoustic emission parameters under different loading rates are described.At the same time,the difference of the amplitude distribution of acoustic emission in different strain range is obtained.(3)The acoustic emission monitoring scheme of S30408 steel cyclic loading tensile test was developed,and the Kaiser effect of S30408 steel acoustic emission at different loading rates was used to determine the memory capacity of the material.The results show that when the loading rate is 2mm/min,the specimen used in this paper shows a good Kaiser effect,and the material can accurately record the loading history,indicating that the plastic deformation of the material is sufficient at the loading rate.(4)On the basis of the above research,the correlation analysis is carried out on the amplitude,rise time and duration of the acoustic emission signal at different loading rates.The acoustic emission signals were classified according to the distribution characteristics of amplitude,rise time and duration,and finally achieved the use of acoustic emission technology to monitor the S30408 specimen used in the strain hardening effect.