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将Mn-Ti型低碳低合金高强钢连铸坯热送至2250热连轧生产线上,设定终轧温度为860℃,终轧至8 mm,然后分别控冷至320、280、240、170和100℃卷取,观察并研究了试验钢的微观组织对冲击性能的影响,分析了不同卷取温度下多种形态铁素体、位错、M-A岛对钢材冲击性能的控制机制。结果表明,随着试验钢卷取温度由320℃降到100℃,试验钢微观组织中位错结构和细小M-A岛的多边形铁素体最有利于冲击吸收能量的增加;当板条状铁素体和大尺寸M-A岛出现时,冲击吸收能量下降;特别是当卷取温度为240℃时,有较大长度的板条状铁素体形成,试验钢的冲击吸收能量下降至最小。
Mn-Ti low-carbon low-alloy high-strength steel slab billet heat delivery to the 2250 hot rolling production line, set the finishing temperature of 860 ℃, and finally rolled to 8 mm, and then were controlled cooling to 320,280,240, 170 and 100 ℃. The influence of the microstructure of the test steel on the impact property was observed and studied. The control mechanism of the impact properties of various forms of ferrite, dislocation and MA island on the steel under different coiling temperatures was analyzed. The results show that as the coiling temperature of the test steel decreases from 320 ℃ to 100 ℃, the polygonal ferrite in the microstructure of the test steel and the fine MA island are most conducive to the increase of the impact absorption energy. When the strip-shaped ferrite The impact absorption energy decreased when the body and the large-size MA island appeared. Especially when the coiling temperature was 240 ℃, the lamellar ferrite with larger length was formed, and the impact absorption energy of the test steel was reduced to a minimum.