Inoculation treatment of grey cast iron

1. Characteristics of inoculation treatment

Up to now, there is no agreement on the mechanism of inoculation treatment at home and abroad, but the inoculation treatment of cast iron has the following commonness [4-5]:

(1) Furnace front performance and fluidity. Inoculation treatment is generally to add inoculant into molten iron flow when tapping in front of furnace, and (or) to add inoculant into molten iron flow when pouring (called “flow inoculation”); the shorter the time from the end of inoculation treatment to casting pouring, the better the effect.

(2) A small amount or a small amount. The addition of inoculant can improve the mechanical and physical properties of cast iron significantly.

(3) Nucleation. The main function of inoculant addition is to produce a large number of graphite core during solidification, so as to change the eutectic structure of cast iron.

2. Function of inoculation treatment

(1) Promote graphitization, effectively reduce the tendency of white mouth of molten iron, and eliminate the white mouth at the thin wall.

(2) The medium-sized A-type graphite can be obtained by refining eutectic group and graphite, reducing the formation of supercooled graphite and its associated ferrite.

(3) It can promote the formation of ferrite and refine pearlite, that is to say, the structure that should be white mouth or hemp mouth is changed into the ash mouth structure with finer eutectic group.

(4) Improve section sensitivity of castings.

(5) Improve the mechanical properties of castings, improve the processing properties of cast iron.