Ti添加量对球墨铸铁组织及力学性能的影响

Effect of Ti addition on microstructure and mechanical properties of ductile iron

将Ti-C-Fe预制块添加到球墨铸铁中,考察了不同Ti含量对球墨铸铁组织及力学性能的影响。结果表明:Ti添加后,在铁液中主要以TiC和Ti(C,N)的形式存在,并使珠光体和铁素体组织得到细化;Ti的质量分数为0.023%时,石墨数目、球化率以及铁素体含量提高;随着Ti含量的升高,生成的TiC颗粒会阻碍C原子的扩散,使石墨球出现畸变,球化率下降,铁素体含量降低。力学性能测试表明:Ti的质量分数为0.023%的试样具有良好的综合力学性能,其屈服强度和抗拉强度分别提高了5.43%、3.73%,延伸率提高了10.64%;当Ti的质量分数为0.054%~0.072%时,试样有较高的抗拉强度;Ti质量分数达到最高0.135%时,试样的屈服强度和布氏硬度达到最大。

The effects of different Ti contents on the microstructure and mechanical properties of ductile cast iron were investigated by adding Ti-C-Fe pre-forms. The results show that Ti mainly exists in the form of TiC and Ti(C,N)in molten iron,and the structures of pearlite and ferrite are refined. Ti content of 0.023 wt.% can increase the spheroidization rate,graphite number and ferrite content. With the increase of Ti content,The generated TiC particles will hinder the diffusion of C atoms,resulting in distortion of the graphite spheres,a decrease in the spheroidization rate and ferrite content. The mechanical properties of the specimens were tested and found that the ductile iron specimen with Ti content of 0.023 wt.%possessed good comprehensive mechanical properties,and its yield strength and tensile strength were increased by 5.43% and 3.73% respectively,and the elongation percentage was increased by 10.64%.When the Ti content was between 0.054 wt.% and 0.072 wt.%,the tensile strength of the sample was higher. The yield strength and brinell hardness of the sample with Ti content of 0.135 wt.% reached the maximum.