| As one of the gray cast iron, boron gray cast iron is widely used in the department including automobile industry, mechanism industry and construction industry, etc. Aimed to develop the mechanical properties index, the content of this paper is mainly about boron gray cast iron, which melts with boron pig iron and is inoculated by the SiSr and SiFe compound inoculants. Following that, the mechanical properties is tested and the microstructure is observed. On this basis, the graphite, eutectic cell, boron carbide of boron gray cast iron is studied. At last, the shape factor is tested and the results of the mechanical properties and metallurgical quality index are obtained. This paper mainly studies the influence of the boron gray cast iron with its microstructure, mechanical properties and metallurgical quality index in different inoculating conditions.With the mass content of SiSr and SiFe increasing, results show that the tensile strength and hardness increase gradually with the increasing content of SiSr. When the ratio of SiSr is 0.12%, the maximum tensile strength is 325MPa. With the increase of SiSr from 0.18% to 0.36%, the tensile strength decreases from 325MPa to 305MPa. With the increase of SiSr from 0 to 0.18%, the hardness increases from 231HBS to 273HBS. The maximum data is 273HBS when the ratio of SiSr is 0.18%. With the increase of SiSr from 0.18% to 0.36%, the hardness decreases from 273MPa to 253MPa. Compared with the normal illustration, the results show that the shape of the graphite is A type and spread evenly. The finer eutectic cell is also obtained. The small block boron carbide is observed and they spread evenly in pearlite. The volume ratio of pearlite is more than 95%. According to the image analyzing techniques for quantitative metallography, the relative data is obtained and with this, the particular analysis can be carried out. When the ratio of SiSr is 0.12%, the ratio between length and width is 3.79...
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