The invention relates to medium-
carbon alloy cast steel shots and a manufacturing method thereof, which is characterized in that, each medium-
carbon alloy cast steel shot comprises the following chemical components in percentage by
mass: 0.35 percent of carbon, 0.11 percent of
silicon, 0.45 percent of
manganese, 1.2 percent of chrome, 0.015 percent of
sulfur, 0.020 percent of
phosphor and the balance of iron and inevitable impurities. The manufacturing process comprises the following steps of: mixing and
smelting, namely,
smelting the
raw material composition mixed proportionally into
liquid steel, pouring the
liquid steel into a
tundish and performing
deoxygenation by adopting an deoxidant; preparing shots by a centrifugally forming method, namely, pouring deoxygenized
liquid steel into a centrifugal disc which rotates at a high speed, throwing out the liquid steel under the action of a
centrifugal force to make the liquid steel fall into a cooling
water pool, and taking the liquid steel out and
drying the cooled steel to obtain formed cast steel shots; and performing heat treatment, namely, heating the formed cast steel shots until the temperature reaches 860 to 880 DEG C, performing cold
quenching after keeping the temperature for 20 to 40 minutes,
tempering for 40 to 80 minutes at the temperature of between 350 and 500 DEG C, and after
tempering, cooling rapidly by a steel plate vibrating screen
water cooling method to produce the medium-
carbon alloy cast steel shots. The medium-carbon
alloy cast steel shots and the manufacturing method thereof have the advantages of guaranteeing the high rigidity of the steel shots, avoiding crack generated in the centrifugally forming process and the heating
tempering process, improving the
toughness and the like.