Effect of Nb Microalloying on Reversion and Grain Growth in a High-Mn 204Cu Austenitic Stainless Steel

Processing and Properties of Reversion-Treated Austenitic Stainless Steels

“…The value of the activation energy of grain growth was found by Rajasekhara et al [26] to be equal to that of conventional ASSs (~205 kJ/mol). Kisko et al [82] obtained much higher values for a Nb-microalloyed 204Cu grade, the value increasing from 363 to 458 kJ/mol with the increasing Nb content. Some experimental results for the growth of reversed fine grains in 201L, 204Cu, 301LN and 304 ASSs have been collected in Figure 7, revealing the trends at 800 and 900 • C. There is some difference between the data of 304L [17,70] and 304 [11] at 900 • C, but the processing of the structures was also different.…”

“…Tomimura et al [39] found that the reversion was diffusional at 652 • C in an 18Cr-9Ni alloy (Ni/Cr = 0.5) in spite of a high heating rate of 300 • C/s. Somani et al [23,80], Kisko et al [27,28,[81][82][83] and Järvenpää et al [84][85][86][87] have used a high heating rate of 200 • C/s in their experiments. They found that in 301LN (Ni/Cr ≈ 0.4), the diffusion-controlled reversion started, depending on prior cold rolling reduction, around 650-700 • C and was completed within few seconds at 750-800 • C. Examples of the influence of cold rolling degree on the reversion kinetics in a 301LN ASS are illustrated in Figure 4, where also the data of Takaki et al [40] for an 18Cr-8.5Ni steel is included.…”

“…The diffusional reversion is fast at 750 °C and above in both steels being completed within 100 s even after 45% cold rolling reduction. However, under certain conditions, both the shear and diffusional reversion mechanisms seem to be active in a 301LN [84,102] and also in a 204Cu [82,101]. Guy et al [35] found that in 18Cr-8Ni and 18Cr-12Ni ASSs the reverse transformation can proceed by both processes depending upon the heating time and temperature.…”

Microstructure, Mechanical Properties and Wear Resistance of Low Alloy Abrasion Resistant Martensitic Steel Reinforced with TiC Particles

“…And excessive nano-sized precipitation is disadvantageous to the ductility and toughness of steel. 31,32) The nano-sized TiC precipitation in 880Q, 550PT+880Q and 650PT + 880Q was observed using TEM, and its size distribution frequency was also counted. Figures 6(a)-6(c) show the TEM figures of TiC-reinforced steel plates under different treatments, previous works have shown that the spherical carbides in TEM figures had the FCC structure, which were nano-sized TiC precipitates.…”

On the microstructural-textural characterization and deformation analysis of a nano/ultrafine grained Fe-20Cr-8Mn-0.3N duplex alloy with superior mechanical properties

“…On the other hand, the annealing time and temperature should be sufficiently low that austenite grain growth is suppressed during reversion annealing. It is noted that microalloying has been also employed to inhibit grain growth of reversed austenite [30].…”