Study of the Effect of Composition and Thermal Deformation Treatment on Properties of Ferritic Steels Microalloyed with Titanium and Niobium. Part 1. Microstructure Characteristics

Low-Carbon Ti-Mo Microalloyed Hot Rolled Steels: Special Features of the Formation of the Structural State and Mechanical Properties

“…At the same rolling end temperatures (900 and 950 °C), the yield and tensile strengths of steels No. 12, 13 (Table 2) were higher in the case of using a coiling temperature of 650 °C compared to 600 °C [67]. In this case, the volume fraction of nanoscale interphase and "ferritic" carbide precipitates was also higher.…”

“…In addition, the ratio of titanium and molybdenum concentrations is important [1,69], and the maximum values of strength characteristics are achieved when atomic concentrations are equal. In [67] it was also found that steel with a higher titanium content (wt.%): 0.08C-0.21Mo-0.165Ti, has higher yield and tensile strengths than steel 0.08C-0.21Mo -0.092Ti (Table 2).…”

“…5 and No. 6 (Table 2), respectively, were carried out varying coiling temperatures after hot rolling from 500 to 700 • C. The maximum tensile and yield strengths were obtained in the case of T c = 600 • C due to the formation of the largest amount of precipitates, including interphase ones, and in [10,67]-in the case of T c = 650 • C. The authors of [41] demonstrated the opposite relationship. With a decrease in T c from 700 to 500 • C, the values of σ 0.2 and σ B for steel No.…”

“…Table 2 summarizes information on the mechanical properties of various studied Ti-Mo microalloyed steels and the corresponding parameters of hot rolling: finishing temperature of rolling (T f ) and coiling temperature (T c ), as well as the cooling rate from T f to T c (V c ). For the compositions studied in [9,10,39,[65][66][67], the values of T f and T c corresponding to the highest tensile and yield strengths were selected. It can be seen that the titanium content is from 0.09 to 0.233 wt.%, and molybdenum is usually 0.19-0.22 wt.%, in some cases up to 0.43 wt.%.…”

“…The cooling process after hot rolling and during coiling of the strip largely controls the main changes in the microstructure of the metal, the transformation of austenite into ferrite, and the formation of phase precipitates. The influence of T f , T c , and the cooling rate of rolled products from T f to T c on the structural state and mechanical properties has been studied in a number of works [9,10,39,41,65,67].…”