Four kinds of inoculants were selected in the experiment, which were 75sife, SRSI, basi, sisR (80%) and 75fesi (20%) composite inoculants. The inoculants were inoculated in the bag with the addition amount of 0.6 wt.%. The results of liquid iron composition measured by direct reading spectrum analyzer are shown in Table 1.
The changes of mechanical properties of Gray Cast Iron Inoculated with different inoculants are shown in Table 2. It can be seen from table 2 that the tensile strength of the sample is between 356 MPa and 385 MPa, which meets the requirements of ht350. The tensile strength inoculated with 75sife is the largest, reaching 385 MPa; The tensile strength of the samples inoculated with basi and SRSI inoculants is the same; The tensile strength of the sample inoculated with composite inoculant is the lowest. The hardness of gray cast iron treated with four inoculants is basically the same, but the section sensitivity of gray cast iron is quite different. Among them, the gray cast iron sample treated with composite inoculation is most affected by the change of wall thickness, and the section sensitivity of Gray Cast Iron Inoculated with SRSI inoculant is less. The Vickers hardness and Brinell hardness of the four groups of samples have a certain mirror relationship, and their variation range is between 384 HV and 398 HV. Different inoculants have their own advantages in improving the strength of gray cast iron, improving the hardness of matrix and reducing the sensitivity of casting section.