The use of acoustic methods to investigate the dynamics of recrystallization and phase transitions in Armco iron and structural steel

Abstract

This paper is devoted to development of acoustic methods for the investigation of the dynamics of structural changes in iron-based alloys, which are associated with phase transitions, processes of recrystallization and relaxation, and physical stimulation of various types. Samples of Armco iron are used to obtain the temperature dependences of the velocity and attenuation of ultrasound in the range from 20 to 1040 °C. The acoustic properties of 08Kh14AN4MDB high-strength corrosion-resistant martensitic steel are measured in the same temperature range. The obtained data on the propagation velocity of sound are used to calculate the values of the elastic modulus of Armco iron and 08Kh14AN4MDB steel in the range from 20 to 950 °C.

An investigation of acoustic emission in Armco iron and structural steel in the process of recrystallization and phase transitions

“…3, the magnetic phase transition begins at 670 °C and ends at 770 °C, and the α → γ transition begins at 870 °C and ends at 915 °C, which agrees with the data of [8,11]. In 08Kh14AN4MDB steel, the magnetic transition occurs in the range from 630 to 720 °C, which agrees with the data of [8], and the α → γ transition -at 755-825 °C; compared to the data of [8] obtained by the curves of temperature distribution of the acoustic parameters of this steel, the α → γ transition is shifted towards higher temperatures by 25-45 °C. The AE activity in the region of 900 °C is apparently associated with the presence of alloying additions and presents a subject of further investigations.…”

“…The AE method was used in this study, which is a continuation of the investigations of the acoustic properties of materials [4,7,8], to investigate the dynamics of structural changes in metal materials. The AE was investigated in Armco iron and 08Kh14AN4MDB (chrome-nitrogen-nickel-molybdenum-copper-niobium) structural steel in the process of annealing and of heating from 20 to 1000 °C in the vicinity of the Curie point and α → γ phase transition.…”

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…Then, based on the information about the phase transformations taking place in the tested material, the AE signals were assigned to specific phase transformations. Acoustic emission offers us new opportunities to track changes in the material during thermal processes [10,[29][30][31][32]. This method also creates the possibility of obtaining the correlation of recorded EA signals with the microstructure [30].…”