Effect of Ti on Impact Resistance of N80-1 Tubing

The 36Mn2V steel is a commonly-used material for producing the N80-1 tubing and casing. Generally the online normalization or the offline normalization processes are used to ensure the strength and toughness of the 36Mn2V steel.The mechanical properties and microstructures of the N80-1 tubings with different chemical compositions are analyzed.And the undercooled austenite continuous cooling transitional curve is obtained via the thermodynamics software simulation, and thus the effect of Ti on the impact resistance of the N80-1 tubing is studied. The results show that the addition of micro-alloying element Ti shifts the CCT curve to the right side and reduces the transition-starting cooling rate of bainite and martensite so as to get more bainite and martensite existing in the post hot-rolling microstructure, resulting in increases of both the strength and the hardness, and decrease of the impact energy.