Abstract: The tangential and axial impact toughness of steel S355NL for wind power tower flange (/% : 0.14C, 0.22Si, 1.35Mn, 0.010P, 0.002S, 0.06Cr, 0.01Mo, 0.l0Ni, 0.03Cu, 0.40Ceq) at -20~-80℃ has been tested and analyzed. The results show that with decreasing test temperature the V-type impact energy of steel S355NL decreases, the ductile-brittle transition temperature of tangential specimen is lower than -80℃ ( average impact energy at -80℃ is 76.89 J) and the ductile-brittle transition temperature of axial specimen is about —65℃ (average impact energy at -60℃ is 96.10 J and that at -70℃ is 13.28 J ) , the morphology of impact fracture transfers from ductile shear fracture to quasi cleavage fracture and until to complete cleavage fracture with "fan-shaped" cleavage pattern.

Key words: Steel S355NL for Wind Power Tower Flange, Low Temperature Impact Toughness, Ductile-Brittle Transition Temperature, Morphology of Impact Fracture

摘要： 试验和分析了风电塔筒法兰S355NL钢（/%:0.14C，0.22Si，1.35Mn，0.010P，0.002S，0.06Cr，0.01Mo，0.10Ni，0.03Cu，0.40Ceq）-20~-80℃切向和轴向冲击韧性。结果表明,S355NL钢V-型冲击功随试验温度降低而下降,切向试样的韧脆转变温度低于-80℃（-80℃平均冲击功76.89 J）,轴向试样的韧脆转变温度在-65℃左右（-60℃平均冲击功96.10 J,-70℃13.28 J）,冲击断口形貌由韧性剪切断口转变为准解理断口,直至具有"扇形"解理花样的完全解理断口。

关键词: 风电塔筒法兰钢S355NL, 低温冲击韧性, 韧脆转变温度, 冲击断口形貌