Effect of V–Ti Addition on Microstructure Evolution and Mechanical Properties of Hot-Rolled Transformation-Induced Plasticity Steel

Abstract

In order to reveal the effect of V-Ti addition on the microstructure evolution and the mechanical properties of hot-rolled transformation-induced plasticity (TRIP) steel, two steels with 0.072V-0.051Ti steel (Bear-V-Ti steel) and 0.001V-0.001Ti steel (Free-V-Ti steel) were designed, respectively, and the comparison analyses were carried out by performing thermodynamic calculation and an experiment. With the thermodynamic calculation, the critical annealing temperature of a large fraction of retained austenite (* 51%) obtained via solute enrichment was determined, and an optimized quenching at 650°C and tempering at 200°C adopted on the as-hot-rolled steel. The results show that the V-Ti TRIP steel displays more optimum mechanical stability during the tensile deformation, since the fraction and the mechanical stability of retained austenite are improved and the microstructure is also ultrarefined by V-Ti alloy precipitation. The yield strength of Bear-V-Ti steel increases from 650 to 800 MPa, and the ductility reaches 37%, showing that the comprehensive mechanical properties are greatly improved.

Deformation-Induced Strengthening Mechanism in a Newly Designed L-40 Tool Steel Manufactured by Laser Powder Bed Fusion

“…Although the tempering heat treatment is expected to reduce the inherent dislocations of martensite (which can soften the material), the measured tensile strength is higher. This difference is due to a lower amount of softer retained austenite in the heat-treated condition (compared to the as-printed state), leading to a higher tensile strength [30,31]. The tensile data reveal that the softening caused by tempering cannot overcome the effect of hardening as a result of reduced MS1 maraging steel, aged [10] 2121 ± 8 8 ± 2 M789 steel, aged [20] 1784 ± 2 11 ± 1 FeCrMoVC tool steel, as-printed [14] 3796 ± 163 14.7 ± 2 H11 tool steel, tempered [12] 2148 ± 16 8.8 ± 1 Heatvar, aged [3] 1980 ± 20 2 ± 1 L-40, tempered (present work) 1720 ± 14 10 ± 2 retained austenite and carbide precipitation.…”

Effect of heat treatment process on precipitation of V microalloyed steel

“…V has a relatively strong grain refinement effect, which can improve the strength and toughness of steel, as well as improve the thermal stability of the steel. Like Nb, V can combine with C and N to form precipitated V(C, N) phases, which when dispersed, have a strengthening effect and improve the performance of steel [26][27][28][29]. In previous reports, the nucleation sequence of vanadium carbonitride homogeneous precipitates, the composition of vanadium precipitates, and the nucleation mechanism of interphase precipitation have been extensively studied [30].…”

First-Principle Study on the Stability of Lightly Doped (Nb1–xTix)C Complex Carbides and Their Verification in 1045 Steel

“…Faced with global warming and environmental issues, there is an urgent need for steel materials to develop in a green direction, which requires steel materials to have better comprehensive mechanical properties and service life. 1,2 For as-cast steel materials, adding grain refiners to the melt is one of the most effective strengthening methods. 3 By dispersing the particles uniformly in the melt, the concentration fluctuations and the overcooling of the composition formed by the surface melting of the particles make the particles become the nucleation core to refine the grains, 4 which greatly improves the strength, 5 toughness, 6 and fatigue strength 7 of the material.…”

“…Faced with global warming and environmental issues, there is an urgent need for steel materials to develop in a green direction, which requires steel materials to have better comprehensive mechanical properties and service life. , For as-cast steel materials, adding grain refiners to the melt is one of the most effective strengthening methods …”