Microstructure Evolution and Tensile Properties of Cold-Rolled and Annealed Fe-30Mn-0.14C-7Cr-0.26Ni Steel

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2021-09, Vol.52 (9), p.3839-3848
• Main Authors: Chen, Xiaoman, Zhang, Jiaxin, Xiong, Jianchao, Wang, Yuhui, Zhang, Yubin, Wang, Tiansheng, Peng, Yan
• Format: Article
• Language: English
• Subjects: Annealing; Carbides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium steels; Cold rolling; Cold working; Deformation; Elongation; Evolution; Grain refinement; Grain size; Heat treating; Materials Science; Metallic Materials; Microstructure; Nanotechnology; Original Research Article; Precipitation hardening; Solution strengthening; Structural Materials; Surfaces and Interfaces; Temperature; Tensile properties; Thin Films; Ultrafines; Yield strength; Yield stress
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-021-06345-y

The carbide precipitation, microstructure evolution, and tensile properties of Fe - 30Mn - 0.14C - 7Cr - 0.26Ni (in wt pct) steel after cold rolling to 95 pct reduction followed by annealing at temperatures ranging from 600 °C to 900 °C for 1 hour were investigated. The results show that, when the annealing temperature is increased from 600 °C to 900 °C, the grain size increases from 0.65 ± 0.30 to 5.75 ± 3.87 μ m. When the annealing temperature is 600 °C, Cr 23 C 6 carbides begin to precipitate. When the annealing temperature is increased from 600 °C to 800 °C, the average size of carbides increases from 39 to 69 nm. When the annealing temperature is increased to 900 °C, no carbides are produced due to the increased solubility of C in the austenite matrix. Ultrafine grains (~ 0.8 ± 0.58 μ m) with a large amount of nanoscale carbides (~ 53 ± 21.8 nm) were obtained after annealing at 700 °C, resulting in a good combination of yield strength (679 MPa) and total elongation (38.4 pct). The fraction of deformation twins within the samples under different tensile strains was calculated, and it was revealed that grain refinement can seriously inhibit the generation of deformation twins. In addition, it has been found that grain refinement strengthening, precipitation strengthening, and dislocation strengthening have significant effects on yield strength, while the effects of solution strengthening and lattice friction are relatively weaker.