经济型X80管线钢的CCT曲线

CCT curves of economical X80 pipeline steel

利用Formastor-FⅡ型热膨胀仪研究了两种不同成分的X80管线钢的连续冷却相变行为,绘制了连续冷却转变(CCT)曲线,并通过硬度试验,光学显微组织观察等手段分析了传统型和经济型X80管线钢的CCT曲线及两者在不同冷却条件下的相变规律。结果表明,经济型X80管线钢的CCT曲线比传统型的偏左移,但在实际生产冷速下,两条CCT曲线基本重合。随冷却速率的增加,两试验钢的组织转变规律基本相同,且硬度趋于一致;通过合理的控制相变,经济型X80钢可以获得与传统型X80钢相同的组织类型、细化程度以及硬度值。

Continuous cooling transformation behavior of two kinds of X80 pipeline steel with different compositions was simulated by using Formastor-F Ⅱ thermal dilatometer,and the continuous cooling transformation( CCT) curves were measured. The CCT curves and the rule of phase transformation at different cooling conditions were investigated by means of hardness test and OM observation. The results show that the CCT curves of economical X80 pipeline steel shift to the left compared with the traditional one,but two curves almost overlap at actual industrial production cooling rate. With cooling rate increasing,the microstructure transformation rules of the two tested steels are basically the same and the hardness tends to be equal. Economical X80 pipeline steel can obtain the same microstructure,structure refining degree and hardness as the traditional one by controlling the transformation reasonably.