工艺参数对X100管线钢中M-A岛和力学性能的影响

Effects of Process Parameters on Martensite-Austenite Island and Mechanical Properties of Pipeline Steel X100

利用光学显微镜、SEM、TEM及Image-plus 6.0图像分析软件等对X100管线钢中的M-A岛的形成机理、工艺影响因素及M-A岛的比例、尺寸、数量、分布对力学性能的影响进行了研究。结果表明:在10～60℃·s-1范围内,随轧后冷速的增加,M-A岛的尺寸、数量和比例均增加;终冷温度在350～500℃之间时,随温度的升高,M-A岛尺寸逐渐减小,而比例和数量则先增加后减小;M-A岛对强度和韧性的影响与其形态和分布有关,大量弥散分布的小尺寸M-A岛能在保证管线钢在具有较好强度的同时也具有优良的韧性。

The formation mechanism, processing-affection factors of M-A island and effects of ratio, size, quantity, distribution of M-A island on mechanical properties of the X100 pipeline steel were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy and image analysis software（Imageplus 6.0）. The results show that the ratio, size and quantity of M-A island increasd with the increase of cooling rate in the range of 10 -- 60℃·s^-1 ; the size of M-A island decreased with increasing the final cooling temperature in the range of 350--500℃,well ratio and quantity increased at first and then declined. Both strength and toughness were related to shape and distribution of M-A island. The steel in which M-A island dispersed distribution in small size had excellent performance on both strength and toughness.