Effect of Different Rolling Schedules on the Mechanical Properties and Microstructure of C Mn (V-Nb-Ti) Pipeline Steel

High strength low-alloy (HSLA) steels have been used for the production of welded pipes for more than 30 years. However, the alloy design of pipeline grades is being continuously modified and the process technology optimized because of increasing demand of high strength toughness combination requirement of pipeline steels. The HSLA steels have demonstrated superior mechanical properties through controlled rolling. In the present investigation, the effects of processing parameters, such as finish rolling temperature, rolling reduction and cooling rate, on the final microstructure and mechanical properties of a grade X70 type HSLA steel has been studied by tensile and charpy impact tests and optical microscopy. To yield better mechanical properties of X70 microalloyed steel grade, the optimization of the rolling process in the laboratory experiment and rolling mill has been carried out.