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为稳定获得高品质球墨铸铁,以牌号为QT450-15球墨铸铁件为研究对象,选用含镁、稀土不同的两种球化剂对原铁液在一定的球化处理温度范围内进行球化处理,并采用光学显微镜、扫描电镜、万能拉力试验机等方法对镁的吸收率、石墨球的大小、球化率、力学性能等进行了分析。研究了球化处理温度和低镁球化剂对球墨铸铁组织性能的影响。研究表明:在1450~1500℃内调整球化处理温度,选用低镁低稀土球化剂进行盖包法球化处理,球化反应平稳,Mg吸收率稳定在50%以上。铁素体含量大于95%,石墨球圆整细小。抗拉强度Rm大于450 MPa,伸长率A大于22%。
In order to obtain high-quality ductile iron steadily, taking the grade of QT450-15 ductile cast iron as the research object, two kinds of nodulizer with different contents of magnesium and rare earth were selected to treat the original molten iron in a certain balling treatment temperature range , And the absorption rate of magnesium, the size of graphite ball, spheroidization rate and mechanical properties were analyzed by optical microscope, scanning electron microscope and universal tensile testing machine. The effects of balling temperature and low-Mg nodularizer on the properties of ductile iron were investigated. The results show that the spheroidization temperature is adjusted within 1450 ~ 1500 ℃, the spheroidization of the low Mg / low rare earth nodularizer is adopted, the spheroidization reaction is steady, and the Mg absorption rate is stabilized at over 50%. Ferrite content greater than 95%, graphite ball round small. Tensile strength Rm is greater than 450 MPa, elongation A is greater than 22%.