Ti对N80-1油管冲击性能的影响

Effect of Ti on Impact Resistance of N80-1 Tubing

36Mn2V是生产N80-1钢级油管的常用材料,一般采用在线常化或离线正火的生产工艺保证其强韧性。分析了不同化学成分N80-1钢级油管的力学性能和显微组织,用热力学软件模拟得到了过冷奥氏体连续冷却转变曲线,研究了Ti对N80-1油管冲击性能的影响。结果表明:由于微合金元素Ti的添加使过冷奥氏体连续冷却转变曲线右移,降低了贝氏体和马氏体开始转变的冷却速度,使热轧后的组织中有较多的贝氏体和马氏体,从而造成强度和硬度升高及冲击功降低。

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.