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采用膨胀法在Gleeble3800热模拟试验机上测试了耐候钢XG295NH钢的临界点Ac1、Ac3、Ms,及其变形后在不同冷却速度下连续冷却时的膨胀曲线和相变点;对该钢的组织进行分析,从而获得了该钢的动态CCT曲线。结果表明,当冷却速度小于3℃/s时,可得到铁素体+珠光体组织;当冷却速度达到3℃/s时,即出现贝氏体组织;当冷却速度达到10℃/s时,组织出现马氏体。在工业生产时,通过控制冷却速度,增加珠光体转变过冷度,同时延长在珠光体转变温度区间的停留时间,可获得晶粒大小合适的铁素体+珠光体组织。
The critical points Ac1, Ac3, Ms of weathering steel XG295NH were tested on Gleeble3800 thermal simulator by expansion method, and the expansion curves and transformation points of the quenched steel were continuously cooled at different cooling rates after deformation. The microstructure of the steel Analysis, which obtained the dynamic CCT curve of the steel. The results show that when the cooling rate is less than 3 ℃ / s, the ferrite + pearlite structure can be obtained. When the cooling rate reaches 3 ℃ / s, the bainite structure appears. When the cooling rate reaches 10 ℃ / s, Tissue martensite appears. In industrial production, ferrite + pearlite with appropriate grain size can be obtained by controlling the cooling rate, increasing the degree of undercooling of pearlite and prolonging the residence time in the pearlite transformation temperature range.