作者:武鹏海 ，姜文勇 ，冯义成 ，郭二军 ，王丽萍
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Authors:WU Peng-hai ,JIANG Wen-yong ,FENG Yi-cheng ,GUO Er-jun ,WANG Li-ping
摘要:摘要:针对厚大断面耐热Si-Mo球墨铸铁石墨畸变和球化孕育衰退问题，通过SiC预处理铁水，浇注不同壁厚的标准Y型试块，采用金相显微镜、扫描电镜和电子万能拉伸试验机，对比研究了SiC预处理工艺对厚大断面耐热Si-Mo球墨铸铁显微组织和力学性能影响规律。结果表明，进行SiC炉前预处理后，壁厚为25mm和75mm试样边缘位置的球化率均达到了90%以上，球化等级为2级；壁厚75mm试样的中间位置，球化等级也达到了3级，球化率为80%-90%；壁厚75mm边缘位置试样的抗拉强度为526MPa，延伸率为14.3%，中间位置则为515MPa和13.0%；壁厚25mm的试样的抗拉强度为550MPa，延伸率为18.5%。随着高温拉伸温度升高，壁厚75mm试样的抗拉强度逐渐降低。在350℃时，试样的抗拉强度数值高达490MPa，500℃时，其抗拉强度数值仍可达到267MPa。
Abstract:Abstract:To solve the problem of nodularization and graphite degeneration of thick section heat-resistant Si-Mo ductile iron, standard Y-type test blocks with different wall thickness were poured, and the effects of the SiC pretreatment process on the microstructure and mechanical properties of thick heavy section heat-resistant Si-Mo ductile iron were studied by metallographic microscopy, scanning electron microscopy and electronic universal tensile testing machines. The results show that after furnace pretreatment by SiC, the spheroidization percentage on the edge positions of the specimens with wall thicknesses of 25mm and 75mm reach more than 90%, and the spheroidization level is grade 2. In the middle position of the specimen with a wall thickness of 75mm, the spheroidization grade also reached grade 3, and the spheroidization percentage was 80-90%; the tensile strength of the sample on the edge of the sample with 75mm wall thickness was 526MPa, the elongation was 14.3%, and in the middle position, which was 515MPa and 13%, respectively. The tensile strength of the specimen with a 25mm wall thickness is 550MPa, and the elongation is 18.5%. With increasing tensile temperature, the tensile strength of the specimen with a 75 mm wall thickness gradually decreases. At 350℃, the tensile strength of the sample is as high as 490MPa, and at 500℃, the tensile strength can still reach 267MPa.

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