Strengthening of Low Carbon Steel by Nano-sized Vanadium Carbide in Ferrite and Tempered Martensite

Abstract

The precipitation of nano-sized alloy carbides in steels with a large amount of strengthening can be obtained by conventional tempering of martensite or interphase precipitation occurring during isothermal ferrite transformation. In this study, a vanadium-microalloyed low carbon steel with a composition of Fe-0.1C-0.4V-1.5Mn-0.05Si (mass%) was either isothermally transformed or quenched and tempered at 923 K for various periods, to comparatively investigate the precipitation behaviors of vanadium carbide and the resultant strengthening effects in ferrite and tempered martensite. When compared under the same conditions, tempered martensite is characterized by a higher yield strength and a smaller uniform elongation than that of ferrite. The quantification of microstructural features via multiple characterization techniques demonstrates a finer crystallographic grain size, a higher dislocation density of tempered martensite compared with that of ferrite, together with a relatively coarser dispersion of nano-sized precipitates due to its lower nucleation rate and higher growth rate than interphase precipitation. The strengthening amounts of all these factors are estimated using the theoretical models, the summation of which can well reproduce the yield strength of both ferrite and tempered martensite in the microalloyed low carbon steel.

Impact of material selection on the efficiency of the crushing unit low-medium carbon steel

“…Additionally, any alloying elements other than cobalt can be used to improve the hardenability of low-carbon steel According to studies, low-carbon steel's mechanical qualities benefit from finer grain sizes, however, the ferrite grain size mostly determines how well low-carbon steel performs mechanically. The importance of the grain boundary mechanism in carbon diffusion in carbon iron and discovered a linear relationship between the polycrystalline border volume fractions and the carbon diffusion barrier [30]. Temperature increases the dynamics, which also enhances carbon diffusion.…”

Influence of Silicon Contents on the Microstructure and Tensile Properties of Quenching and Partitioning (Q&P) Processed Low Carbon Steel

“…The yield strength of martensite and bainite was known to be controlled by the following parameters; solid solution, grain size, precipitate, and dislocation. 37,[39][40][41] Among the parameters, the solute carbon content is known to play a major role in the strengthening of martensite or bainite in low carbon steels. 36) Indeed, the solute carbon content in martensite and bainite is affected by the precipitation of carbide and the partitioning of carbon into the austenite; both processes act as a sink of carbon regarding to the amount of solute carbon in martensite or bainite.…”

Online Prediction of Mechanical Properties of the Hot Rolled Steel Plate Using Time-series Deep Neural Network

“…According to the differences in chemical composition, production process and final organization, the contributions of various strengthening mechanisms are different. 33) The contribution of grain boundary and precipitation strengthening to yield strength is greater than that of solution strengthening. The contribution of solution strengthening to tensile strength is more significant than that of the other three strengthening methods.…”