LAUSR

Traditional thermo-mechanical controlled processing (TMCP) and microalloying technology are two major methods for refining microstructure and improving the mechanical properties of HSLA steels.1) The microstructure and mechanical properties of thermo-mechanically processed hot rolled strip steels are significantly influenced by the process parameters such as rolling ratio, rolling temperature, cooling pattern, cooling rate, and coiling temperature. Controlling the coiling temperature is the most economical and efficient way to improve the properties of steels.2,3) Zhang found that the microstructure of an X70 pipeline steel transformed form granular ferrite to bainite ferrite strip as the coiling temperature decreased.4) Xu et al. studied the influence of coiling temperature on the microalloying and properties of an (Nb, V, Ti)-containing HSLA steel, and concluded that the grain size was refined when coiling temperature dropped from 570°C to 450°C, which improved the yield strength of about 100 MPa.5) Microalloying elements such as Nb, Ti, and V have been Effects of Coiling Temperature on Microstructure and Precipitation Behavior in Nb–Ti Microalloyed Steels