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研究了冷却工艺和化学成分对一种经济型X100钢的组织与力学性能的影响。结果表明,随着终冷温度从500~550℃降低至200~300℃,同时冷速从20℃/s提高至45℃/s,规定总延伸强度Rt0.5和抗拉强度提高,可以达到X100强度级别制管的性能要求。随着终冷温度的降低和冷速的提高,组织中板条贝氏体含量的增加是强度提高的原因。高终冷温度、低冷速时,钢中加入Mo、Cr可以增加板条贝氏体从而提高规定总延伸强度;低终冷温度、高冷速时,Mo、Cr对屈服强度的影响不明显。另外,低终冷温度、高冷速下获得的X100试验钢具有优异的冲击性能和DWTT性能,-40℃冲击吸收能量大于240 J,-30℃全壁厚试样DWTT剪切面积比大于85%。
The effects of cooling process and chemical composition on the microstructure and mechanical properties of an economical X100 steel were investigated. The results show that with the final cooling temperature from 500 ~ 550 ℃ to 200 ~ 300 ℃, while the cooling rate from 20 ℃ / s to 45 ℃ / s, the provisions of the total tensile strength Rt0.5 and tensile strength can be achieved X100 strength level tube performance requirements. With the decrease of the final cooling temperature and the increase of the cooling rate, the increase of the bainite content in the structure is the reason for the increase of the strength. High final cold temperature, low cooling rate, the addition of Mo, Cr steel can increase the bainite lath so as to improve the provisions of the total extension strength; low final cooling temperature, high cooling rate, Mo, Cr yield strength is not obvious . In addition, the X100 test steel obtained at low final cooling temperature and high cooling speed has excellent impact performance and DWTT performance, the impact absorption energy at -40 ° C is greater than 240 J, and the shear wall area ratio at DWTT at -30 ° C is greater than 85 %.