【摘要】 在Gleeble-3800热模拟机上研究了X80管线钢经两阶段轧制后连续冷却过程中的相变行为,用热膨胀法和金相法建立了连续冷却转变(CCT)曲线。结果表明,在低冷速下,X80管线钢组织主要由铁素体+贝氏体组成,当冷速大于1℃/s时,组织全部转变为不同形貌的贝氏体,随冷速增加,组织明显变细,同时材料的硬度逐步增高。根据CCT曲线,在实际生产中,终轧温度控制在750℃以上且轧后冷却速率控制在20~30℃/s最好,此时可获得含高密度位错和弥散MA组元的贝氏体组织,使X80管线钢同时达到高强度高韧性。更多还原

【Abstract】 The continuous cooling transformation behavior was studied after two steps deformation by Gleeble-3800 thermal mechanical simulator for X80 pipeline steel,and the continuous cooling transformation(CCT) curve was set up by thermal dilation method and metallographic method.The results show that,ferrite and bainite in the X80 steel are mainly obtained at low cooling rate,microstructure is entirely composed of bainite with different shapes when the cooling rate is higher than 1 ℃/s,as the cooling rate goes up,microstructure is refined and the hardness enhanced gradually.According to the CCT curve,when the final rolling temperature is higher than 750 ℃ and cooling rate is between 20-30 ℃/s,bainite with high-density dislocation and disperse MA constituents can be acquired in actual production,which ensures the X80 steel possess of high strength and toughness simultaneously.更多还原