Mo含量对高等级管线钢相变行为及组织和性能的影响

通过调整一种高强韧管线钢中的Mo含量,研究Mo含量对动态相变规律的影响.在相同热机械控制轧制(TMCP)工艺下,比较Mo含量为0.2％和0.3％的两种钢的强度和韧性的差异,通过光学显微镜、EBSD、TEM等手段研究两种钢的复杂针状铁素体组织,并对组织和性能间的关系进行分析.结果表明:提高Mo含量有利于组织细化和针状铁素...

Effects of Mo content on phase transformation behavior,microstructure and mechanical properties of high grade pipeline steel

By adjusting the Mo content in a high-strength pipeline steel, the effect of Mo content on dynamic phase transformation was studied. Under the same TMCP condition, the strength and toughness of the steels with 0.2% Mo and 0.3% Mo were studied comparatively, and two different complex acicular ferrite (AF) microstructures were analyzed by optical microscope, EBSD, TEM and other means. The relationship between the microstructures and the mechanical properties was investigated. The results show that the increasce of Mo content is beneficial to refinement of the microstructure and formation of the acicular ferrite, and move the dynamic CCT curves to the lower right. Under the same rolling conditions, the strength of the steel with 0.3% Mo is higher, the increase of Mo content helps to improve the effects of precipitation strengthening and fine grain strengthening, at the same time, the volume fraction of bainitic ferrite (BF), the size and number density of MA islands are increased, and the strength is further increased. In the case of the same proportion of high angle grain boundaries, the impact property of the steel with 0.3% Mo is worse, the size and number density of MA islands as well as their degree of irregularity are the main factors to affect the impact property.