Influence of Controlled Rolling on Microstructure and Performance of High-Manganese and High-Nitrogen Austenitic Steels

doi:10.12068/j.issn.1005-3026.2025.20240078

Abstract

Abstract:

To improve the yield strength of high-manganese and high-nitrogen austenitic steels， characterization methods such as scanning electron microscope （SEM） and electron backscatter diffraction （EBSD） were used， and the influence of the controlled rolling process on the microstructure evolution and mechanical properties of high-manganese and high-nitrogen austenitic steels in the Fe-Mn-Cr-N system was systematically investigated. The evolution characteristics of the microstructure and properties of the experimental steels were analyzed in two rolling processes at different temperatures： rolling in the recrystallization zone and the non-recrystallization zone. When the finish rolling temperature decreased from 1 040 ℃ to 973 ℃， the average grain size of the experimental steels decreased， and a small amount of deformation microstructures appeared. Accordingly， the strength， plasticity， and toughness were slightly improved. When the finish rolling temperature dropped to 849 ℃ in the non-recrystallization zone， the experimental steels were filled with deformed austenite grains with higher dislocation density， and the yield strength and tensile strength increased significantly. Low-temperature rolling in the non-recrystallization zone could overcome the limitations of insufficient yield strength of traditional high-manganese austenitic steels and obtain better comprehensive mechanical properties.

Key words: controlled rolling, finish rolling temperature, high-manganese and high-nitrogen austenitic steel, microstructure and performance, dislocation strengthening

CLC Number:

TG 335.5

Chu-heng ZHANG, Yan-mei LI, Xiang-tao DENG, Zhao-dong WANG. Influence of Controlled Rolling on Microstructure and Performance of High-Manganese and High-Nitrogen Austenitic Steels[J]. Journal of Northeastern University(Natural Science), 2025, 46(11): 58-65.

Figures/Tables 10

Table 1 Chemical composition of experimental

C	Mn	Si	Cr	Cu	N	Nb
0.01	25.00	0.23	13.5	1.04	0.35	0.08

Fig.1 Tensile specimen’s size(unit:mm)

Fig.2 EBSD crystallographic analysis of experimental steels at final rolling temperature

Fig.3 Curve showing local misorientation distribution of experimental steels

Fig.4 Statistical chart of grain size and distribution of experimental steels

Fig.5 Tensile curves and room-temperature impact energy of experimental steels

Table 2 Mechanical properties of experimental steels

终轧温度/℃	屈服强度/MPa	抗拉强度/MPa	延伸率/%	屈强比
1 040	435	744	55.0	0.58
973	452	758	56.7	0.60
849	770	893	35.9	0.86

Fig.6 Strain hardening rate curves of experimental steels

Fig.7 SEM morphologies of tensile fracture surface of experimental steels

Fig.8 SEM morphologies of impact fracture surface of experimental steels

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