The invention discloses a gray
cast iron material for a
commercial vehicle brake drum and a preparation method of the gray
cast iron material. The gray
cast iron material comprises 3.7%-3.9% of C, 1.6%-2.0% of Si, 0.5%-0.7% of Mn, 0.05%-0.1% of S, 0.5%-0.7% of Cu, 0.1%-0.3% of Cr, 0.07%-0.1% of V, 0.05%-0.1% of Sn, 0.01%-0.04% of Zr, 0.007%-0.01% of La and the balance Fe and inevitable impurities. The preparation method comprises the following steps that raw materials are smelted to obtain a liquid
raw material, the temperature is increased to 1500 DEG C-1530 DEG C, a pretreating agent is added, cooling is conducted to 1480 DEG C-1500 DEG C to obtain base molten iron, the base molten iron is poured into a
casting ladle, an inoculant is added when the molten iron is discharged to obtain molten iron, the molten iron is poured at 1370 DEG C-1430 DEG C, and
stream inoculation is carried out simultaneously to obtain the gray cast iron material for the
commercial vehicle brake drum. According to the gray cast iron material for the
commercial vehicle brake drum and the preparation method of the gray cast iron material, the measures of molten iron pretreatment, secondary
inoculation and the like are adopted, the
graphite form is A type
graphite with the moderate size and a small amount of C type
graphite, a matrix structure with the fine sheet
pearlite larger than or equal to 95% is obtained, the tensile strength of a brake drum body is 210 Mpa-260 Mpa, the working face
hardness value is 180 HBW-220 HBW, the
thermal fatigue performance of the brake drum can be effectively improved, and the service life of the brake drum can be effectively prolonged.