大断面低温铁素体球墨铸铁的试验研究

Experimental Study on Heavy Section Low Temperature Ferrite Nodular Cast Iron

以QT400-18L大断面低温铁素体球墨铸铁为研究对象,通过合理选择原材料,严格控制铁液化学成分,选用低镁球化剂进行盖包法球化处理,采用多次孕育和含Sb孕育剂进行随流孕育的复合孕育方式,控制合适的浇注温度等工艺措施,生产出各项指标合格的铸件。试样的抗拉强度不低于370 MPa,屈服强度不低于230 MPa,伸长率不低于24%,硬度约为140 HB,-20℃冲击功平均值不低于为13 J。

Taking the heavy section low temperature ferrite nodular cast iron QT400-18L as the research object, the heavy section nodular cast iron was produced with good external and internal quality by performing a series of quality control measures such as the reasonable choice of the raw materials, strictly controlling the chemical composition of the melt, the use of tundish-cover process with low magnesium nodulizers, stream multi-inoculation with the trace elements Sb, the proper control of pouring temperature etc. The tensile strength and the yield strength of samples are more than 370 MPa and 230 MPa, respectively, its elongation is more than 24%, hardness is 140 HB ,and its -20℃ low temperature impact toughness is more than 13 J.