Microstructural characterization and strengthening behavior of nanometer sized carbides in Ti–Mo microalloyed steels during continuous cooling process

Investigating nano-precipitation in a V-containing HSLA steel using small angle neutron scattering

“…In response to this need, Funakawa et al [10] reported the development of a new type of hot rolled steel that is based on a composition which gives rise to a ferrite matrix with nanometre-sized microalloy carbides. The latter are formed via the well-known interphase precipitation mechanism in which rows and sheets of nanometre scale MX precipitates form at a moving / interface during either isothermal transformation or continuous cooling and their very fine scale leads to a large precipitation hardening effect [2,[10][11][12][13][14][15][16][17][18][19]. The steel composition and processing conditions need to be carefully selected to avoid the formation of pearlite or cementite which would degrade formability [10].…”

“…Previous studies of IPP have included topics such as the effect of transformation temperature [11,15,26], time [27], cooling rate [16,[28][29][30], orientation relationship [15,[31][32][33][34][35], hot deformation [17,36] as well as the addition of Mo [10,14,[21][22][23][24][25] on precipitate composition, size, morphology and number density. The majority of these prior studies have used transmission electron microscopy (TEM) to characterise the precipitates [14,18,19,22,37,38].…”

Metallurgical and Process Strategy for the Production of 700 Mpa Hot Rolled Structural Steel Coil

“…Interphase TiC precipitation creates a higher volume fraction but the precipitates tend to be slightly larger, while random TiC precipitation creates less volume fraction but finer TiC precipitates. Figure 9 shows temperature/time where TiC interphase and random precipitation occur [11] and illustration of volume fraction/size relationship of each. The optimum TiC relationship would have the volume fraction created by interphase precipitation and the size/diameter created by random precipitation.…”

Influence of rolling temperature and cooling rate on nano-size carbides in a Ti-Mo microalloyed steel

“…Since the rolling temperature can affect the austenite grain boundaries, which function as nucleation sites for ferrite transformation via dynamic and/or non-dynamic recrystallization, the characteristics of nano-sized precipitation with respect to ferrite transformation should be closely related to the rolling temperature. In addition, the cooling rate after isothermal holding in ferrite transformation regions can affect interphase or random precipitation; for example, continuous interphase precipitation is expected if ferrite transformation is incomplete, or supersaturation precipitation can occur due to incomplete precipitation after isothermal holding [13,14]. To our knowledge, there is currently no consensus on this process due to its complexity.…”