高强高韧合成球墨铸铁的组织及力学性能
Microstructures and Mechanical Properties of Synthetic Ductile Cast Iron with High Strength and Ductility
贺 焱1， 郭学锋2， 林 浩1， 杨小健3
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作者单位：1. 西安理工大学 材料科学与工程学院，陕西 西安 710048； 2.河南理工大学 材料科学与工程学院，河南 焦作 454000；3. 陕柴重工 铸造事业部，陕西 兴平 713105
中文关键字：合成球墨铸铁； 球化率； 奥氏体枝晶； 力学性能
英文关键字：synthetic ductile iron; spheroidization rate; austenite dendrites; mechanical property
中文摘要：以废钢为主要原材料（20%生铁+20%回炉料+60%废钢），使用中频感应电炉熔炼，采用中间加入和镜面加入联合增碳方式， 制备了合成球墨铸铁QT 450-23铸件。合成铸铁球化级别1级，球化率95%，石墨圆整，球径10～20 μm，基体为100%铁素体。合成铸铁抗拉强度为450 MPa， 伸长率为23.3%。在高温组织中，奥氏体枝晶发达，显著提高材料的冲击韧性，V型缺口冲击试样常温冲击韧性为18.4 J/cm2，是相同成分和工艺条件下，传统生铁为主配方球铁的2倍。
英文摘要：High strength and ductility synthetic ductile cast iron was prepared using scrap steel as the mainly raw material (20% pig iron+20% scrap returns+60% scrap steel). The carbon content of the melt was modulated with recarburization process during melting and regulated just before finishing melting process by adding powder carbon on the melt surface. The microstructure with first class spheroidizing grade, 95% spheroidization rate, round shaped graphite with 10 μm to 20 μm diameter and 100% ferrite matrix was checked in the high strength and ductility synthetic ductile cast iron. The produced synthetic ductile cast iron castings had tensile strength of 450 MPa, tensile elongation of 23.3% and impact toughness of 18.4 J/cm2 with a standard V-notched impact specimen. It is found the large percentage of austenite dendrites is formed in synthetic ductile iron at high temperature. the impact toughness with a standard V-notched impact specimen of the prepared castings doubles the impact toughness value of other specimens prepared by traditional method using pig iron as mainly materials.