Precipitation behavior of Ti in high strength steels

• Published in: Journal of Central South University Vol. 24; no. 12; pp. 2767 - 2772
• Main Authors: Wu, Si-wei, Liu, Zhen-yu, Zhou, Xiao-guang, Yang, Hao, Wang, Guo-dong
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.12.2017; Springer Nature B.V
• Subjects: Chemical precipitation; Engineering; Heat treating; High strength low alloy steels; Hot rolling; Mathematical analysis; Mechanical properties; Metallic Materials; Microalloying; Precipitates; Solid solubility; Stability; Titanium carbide; Yield strength; Yield stress; Ti(C, N); precipitation strengthening; solid solubility; yield strength; high strength steel
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-017-3690-7

Precipitation behavior of Ti in high strength steels was investigated by means of the equilibrium solid solubility theory. The contributions of Ti content to yield strength were calculated. The calculated results were verified by the hot rolling experiment for C–Mn steel and C–Mn–Ti micro alloyed steel, respectively. The research results show that the precipitates are mainly TiN at the higher temperature. With the decreasing temperature, the proportion of TiC in precipitates increases gradually. When the temperature drops to 800 °C, TiC will become predominant for the precipitation of Ti. When Ti content is less than 0.014% (mass fraction), Ti has little influence on the yield strength. When Ti content is in the range of 0.014%–0.03% (mass fraction), the yield strength of Ti micro alloyed steel is greatly increased, which leads to instability of the mechanical properties of the steel. Therefore, the design of Ti content in high strength steels should avoid this Ti content range. When Ti content is higher than 0.03%, the yield strength increases stably. In this experiment, when added Ti content was controlled in the range of 0.03%–0.05%, the contribution to the yield strength of Ti micro alloyed steel can reach about 92.44 MPa.