风电用QT400-18AL合成球墨铸铁的力学性能研究

Study on Mechanical Properties of QT400-18AL Synthetic Nodular Cast Iron for Wind Power

采用中频感应炉熔炼,制备了某型机用合成球墨铸铁和传统球墨铸铁,对比了两者的力学性能和断口特征,分析了两种铸铁的断裂机理。结果表明,用大量废钢加增碳剂制备的合成球墨铸铁球化率高,石墨球圆整,100%铁素体(F)基体。合成球墨铸铁冲击韧性显著提高,韧-脆转变温度为-40℃,相比传统球墨铸铁降低了60℃。合成球墨铸铁的基体塑性好,抵抗裂纹扩展能力强,拉伸试样断口上留下大量深韧窝和撕裂棱,属于韧性断裂。

The synthetic nodular cast iron and traditional nodular cast iron for a type of machine were prepared by using medium frequency induction furnace. The mechanical properties and fracture characteristics of the two nodular cast irons were compared, and the fracture mechanism of the nodular cast iron was analyzed. The results show that the synthetic nodular cast iron prepared with large quantifies of scrap and a small amount of recarburizer has high spheroidization rate, round shaped graphite and 100% ferrite matrix. The impact toughness of synthetic nodular cast iron increases significantly, and the ductile - brittle transition temperature is -40℃, which is 60℃ lower than that of traditional nodular cast iron. The matrix of synthetic nodular cast iron has good plasticity and strong ability to resist crack propagation. A large number of deep dimples and tearing edges are found on the fracture surface of the tensile specimens, which belongs to ductile fracture.