The typical solidification structure of hypoeutectic high chromium cast iron is primary austenite and reticular eutectic carbide (M23C6 or M3C type). This kind of low hardness carbide is distributed continuously in a reticular form, which separates the austenite matrix. Therefore, the hardness of hypoeutectic high chromium cast iron is not high. However, the eutectic high chromium cast iron obtains a kind of M7C3 carbide with better shape distribution and hardness than M23C6 and m3c due to the large amount of chromium. The castings made of this material have high hardness, impact toughness and wear resistance. In addition, the alloy with near eutectic composition has better fluidity and mold filling ability, its casting performance is better, and the casting defects are less. Therefore, the selected high chromium cast iron is of near eutectic composition, and its chemical composition is shown in Table 1.
| C | Si | Mn | S | P | Cr | Fe | |
| HCCI | 3.1 | 0.6 | 0.8 | 0.035 | 0.035 | 22 | allowance |
1.Test raw material composition
Pig iron, scrap steel, high-carbon ferrochromium and low-carbon ferrochromium used in the plant shall be used as furnace charge, and their chemical composition is shown in Table 2:
| C | Si | Mn | S | P | Cr | Fe | |
| Pig iron | 4.0 | 1.48 | 0.58 | 0.02 | 0.035 | — | allowance |
| Scrap steel | 0.18 | 0.29 | 0.4 | 0.035 | 0.03 | — | allowance |
| Low carbon iron complex | 0.18 | 1.5 | 1.11 | 0.038 | 0.035 | 50 | allowance |
| High carbon ferrochrome | 7.8 | 1.8 | 1.1 | 0.024 | 0.028 | 50 | allowance |
2.Batching calculation
The test takes the high chromium cast iron withCr22/C3 as the research object. The specific ingredients of this high chromium cast iron are as follows:
According to the chemical composition of raw materials pig iron, scrap steel, high carbon ferrochromium and low carbon ferrochromium, the mass fraction of fixed sum is and by adjusting the content of elements, mainly adjusting manganese, silicon and other elements, so that they are within their respective allowable range. The specific calculation method is as follows:
Where M1, M2, m3 and M4 respectively represent the quality of pig iron, scrap steel, low-carbon ferrochromium and high-carbon ferrochromium, which is 20kg in all ingredients. The calculation result is: mi=9.83kg; M2=2.28kg; M3=6.35kg; M4=2.45kg.