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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。
The phase transformation behavior of X80 pipeline steel during continuous cooling after two-stage rolling was studied on Gleeble-3800 thermal simulator. The CCT curve was established by thermal expansion and metallographic methods. The results show that the microstructures of X80 pipeline steel are mainly composed of ferrite and bainite at low cooling rate. When the cooling rate is more than 1 ℃ / s, the microstructure changes to bainite with different morphologies. With the increase of cooling rate , The organization significantly thinner, while the hardness of the material gradually increased. According to the CCT curve, in the actual production, the finishing temperature is controlled above 750 ℃ and the cooling rate after rolling is controlled at 20 ~ 30 ℃ / s, the high density dislocation and disperse MA component can be obtained. Body tissue, X80 pipeline steel to achieve high strength and high toughness.