材料期刊网

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％.

Stably high quality nodular cast iron was prepared by spheroidized treatment at a special temperature using original melted iron as raw materials and two kinds of containing different RE and Mg as nodulizers.Absorptivity of Mg in melted iron,the graphite sizes and spheroidization rate,and the mechanical properties of the ductile iron at different temperatures were analyzed by means of optical microscope,scanning electron microscopy and universal tensile testing machine.The effects of nodulizer and spheroidizing temperature on the microstructure and mechanical properties of the nodular cast iron were studied.The results show that when spheroidizing temperature is between 1450 and 1500 ℃ and using low-Mg nodularizer,the reaction of the spheroidize is stable,and the absorptivity of Mg is stable at more than 50％.The ferrite content is greater than 95％,and the graphite ball after spheroidization treatment with low-Mg nodularizer is more rounded and smaller.The tensile strength and the elongation of the nodular cast iron are greater than 450 MPa and 20％,respectively.