采用低Mo成分体系,研究超快冷工艺对厚规格X80微观组织和力学性能的影响规律。试验结果表明:随冷速的提高,屈服强度、抗拉强度均呈上升趋势,但屈服强度上升更明显,导致超快冷工艺下屈强比大幅提高;但由于冷速的提高导致晶粒细化析出物长大受到抑制,试验钢韧性不降反升,冲击和DWTT性能均有所提高。随冷速的增加,钢板沿厚度方向的冷速差异增大更明显,贝氏体板条的过度细化导致试验钢表层与心部硬度差异增大,表层硬度超标,冷成型开裂风险增大。 Low Mo component system was used to study the influence of ultra-fast cooling process on microstructure and mechanical properties of thick gauge X80. The experimental results show that with the increase of cooling rate, the yield strength and tensile strength all show an upward trend, but the yield strength increases more obviously, resulting in a sharp increase of yield ratio under ultra-fast cooling. However, due to the increase of cooling rate, The growth of precipitates was inhibited, the toughness of the test steel did not fall and rise, the impact and DWTT performance were improved. With the increase of cooling rate, the difference of cooling speed along the thickness direction increases more obviously. The excessive refinement of bainite slab results in the difference of hardness between the surface layer and the core of the test steel increases, the hardness of the surface layer exceeds the limit, and the risk of cold forming cracking increases .