电脉冲对铸态高韧性球墨铸铁凝固组织及性能的影响

发布时间：2019-01-29 05:20

【摘要】：对铸态高韧性球墨铸铁QT400-18的凝固过程进行电脉冲处理,电脉冲参数为电压2 600 V,频率0.88 Hz,电容200μF,处理时间15min。通过对比试验可知:电脉冲处理可使铸铁的过冷度相比未处理的升高12K,改善了石墨形核和生长的动力学条件,从而使球状石墨的粒径减小,石墨球数量增加。铸铁经过电脉冲处理,球化率由未处理的平均80%提高到平均91%,石墨球数由平均172/mm~2提高到209/mm~2,石墨不易变态生长,圆整度得到改善。同时,球墨铸铁的凝固组织得到了改善,铁素体数量增加,达到83%,相比未电脉冲处理的试样提高了26.6%,铁素体晶粒小于未处理试样,基体中分布的珠光体数量和片层间距减少,在抗拉强度符合要求的条件下,伸长率提高了4.89%,-233K的冲击功Akv提高了3.56J。
[Abstract]:The solidification process of as-cast high toughness ductile iron (QT400-18) was treated with electric pulse. The parameters of electric pulse were voltage 2 600V, frequency 0.88 Hz, capacitance 200 渭 F, treatment time 15 min. The comparison experiment shows that the supercooling degree of cast iron can be increased by 12K compared with the untreated one, and the kinetic conditions of nucleation and growth of graphite can be improved. Thus, the particle size of nodular graphite is reduced and the number of graphite spheroids is increased. The spheroidization rate of cast iron was increased from 80% to 91%, and the graphite spheroidal number was increased from average 172/mm~2 to 209% / mm ~ (-2). The graphite was not easily metamorphosed and its roundness was improved. At the same time, the solidification structure of ductile iron was improved, and the number of ferrite increased to 833. Compared with the sample without electrical pulse treatment, the solidification structure of ductile iron was increased by 26.6. the ferrite grain was smaller than that of untreated sample. The number of pearlite distributed in the matrix and the lamellar spacing are reduced. Under the condition that the tensile strength meets the requirements, the impact energy Akv of 4.89- 233K is increased by 3.56J.
【作者单位】：西安建筑科技大学冶金工程学院;陕西省冶金工程技术研究中心;山西华翔集团;中冶集团陕西压延设备厂;
【基金】：西安市技术转移促进工程项目(CX1250(5))
【分类号】：TG143.5

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