材料期刊网

通过热模拟连续冷却及实验室轧制实验，研究了不同冷却制度下X100管线钢显微组织特征及力学性能变化规律。研究结果表明：随冷却速度升高及终冷温度降低，实验钢显微组织由针状铁素体过渡至板条贝氏体及马氏体，非淬火条件实验钢中马氏体岛或M-A岛为微孪晶马氏体；轧制后直接以约30℃/s冷却至450℃左右时，实验钢具有良好强韧性，采用弛豫及超快冷工艺时，需控制弛豫时间以及超快冷结束温度并与随后的冷却工艺相结合，方可获得理想的显微组织及良好强韧性。

A lab designed pipeline steel was used to study the continuous cooling transformation (CCT) and the microstructure characteristic and mechanical properties in different cooling schedules. It was shown that with cooling rate increasing and finish cooling temperature decreasing, the microstructure evolved from acicular ferrite to lath bainite and martensite, martensite islands or M-A islands were micro-twining martensite in non-quenched steel, the comprehensive mechanical properties was the optimum in the steel that cooled to about 450℃ at the rate of about 30℃/s without relaxation. When relaxation and super-fast cooling process is used, it is essential to well control the relaxation time and finish cooling temperature of super-fast cooling process and combine with the following cooling process for obtaining the perfect microstructure and strength and toughness.