Application of silicon-calcium inoculant: gray cast iron has good casting formability, processability, wear resistance, heat resistance, shock absorption and other properties. It is a traditional metal structural material and plays an important role in casting production. At present, gray iron castings account for the first weight (about 50-55%) among all kinds of castings. With the intensification of market competition, although gray cast iron is a traditional “large volume and wide range” metal structural material, it is also facing severe challenges in terms of material quality, performance and price. Especially in recent years, with the strengthening of Sino-foreign cooperation and exchanges, in many Sino-foreign joint venture production plants, two kinds of castings of the same brand at home and abroad are processed on the same line, and the tool wear of domestic gray castings is greater than that of imported castings. In many cases, this can seriously affect productivity.
For a long time, people have conducted a lot of systematic research on the solidification process of high-strength gray cast iron, the participation of silicon calcium inoculants in inoculation and modification, and the influence of alloying elements on the structure and properties. Gray cast iron. However, in order to ensure the high strength of the high-strength gray cast iron (σb≥300mpa) used in the research, the carbon equivalent is generally around 3.8%. However, gray cast iron with a high carbon equivalent will inevitably lead to increased cutting resistance, which will lead to increased tool wear.
Domestic researchers have found that after inoculation treatment with casi inoculants, the whitening tendency of castings can be minimized, the structure and performance of castings can be improved, and the grains can be refined. A machinability is a practical approach.
The calcium-silicon inoculant can improve the machinability of high-strength gray cast iron and the preparation method of gray cast iron. The calcium silicon inoculant reduces the fracture sensitivity and whitening tendency of gray cast iron and is beneficial to obtain fine and evenly distributed a-type graphite, and the obtained gray cast iron has higher strength and better machinability.
As the main component of silicon-calcium inoculant, Si can reduce the degree of supercooling, promote the nucleation of graphite, change the shape and refinement of graphite, promote graphitization, and reduce the tendency of whitening; it can make graphite and matrix in the gray cast iron structure obtain Significantly refined, and make a large amount of phosphorus eutectic hard phase in the as-cast structure form a dispersed distribution, improve the strength of gray cast iron, at the same time, this unique metallographic structure also makes the shearing of the leading edge of the cutting edge during turning The extrusion zone is narrowed and has good cutting performance; Ca is an important added element in the silicon-calcium inoculant, which has a decisive effect on the nucleation of eutectic graphite, can significantly promote graphitization, increase the number of graphite nodules, and reduce whiteness. Calcium-silicon inoculants have the functions of deoxidation, desulfurization, stabilizing austenite and refining pearlite, which can reduce the fracture sensitivity and whitening tendency of gray cast iron, and are beneficial to obtain fine and uniformly distributed a-type graphite.
The elements si and ca contained in the silicon-calcium inoculant not only utilize the inoculation ability of each element, but also have a synergistic effect among the elements, which can reduce the section sensitivity and whitening tendency of gray cast iron, and obtain excellent, curved and distributed cast iron. shape. The most uniform graphite; Finally, the gray cast iron inoculated with calcium-silicon inoculant, under the cutting action of a high-speed rotating tool, the fine and uniform graphite structure can improve the deformation of chips, reducing the friction and wear area of the tool, thereby improving Tool life.