In response to the decline in the qualification rate of inclusion internal control indices in 20CrMnTiH gear steel (sum of fine inclusion series categories ≤2.0, sum of coarse inclusion series categories ≤1.5, Ds≤1.0) at Ansteel Group Lingyuan Iron & Steel Co., Ltd., through data analysis and precise calcium treatment software analysis, the primary reason for the problem mentioned above was that the calcium content in the molten steel was too low, which caused the inclusion composition to deviate from the liquid phase region. After implementing measures such as optimizing the calcium addition process from"LF (calcium wire feeding)—RH"to"LF—RH (calcium wire feeding)"and reducing the calcium addition amount from 80~120 m/heat to 50~60 m/heat, the qualification rate of inclusion internal control indices for 20CrMnTiH improved from 74% to 90%. Meanwhile, the calcium yield in the molten steel in the continuous casting tundish increased from 2%~4% to 20%~25%, ensuring smooth production while improving the quality of the gear steel.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |