Steel material consumption is an important comprehensive technical and economic index of converter production, and it is also the main component of converter cost, accounting for 80% of the cost of steelmaking. The reasons affecting the consumption for magnesia brick of iron and steel materials are:
- Excessive blowing loss of converter
The hot metal condition is poor, its Si composition fluctuates greatly, and the splashing rate reaches 5%. Low silicon hot metal is easy to cause serious back blowing due to insufficient heat and improper operation, which greatly increases the iron oxide content in the slag and increases the iron loss.
- Low molten steel yield
During high temperature casting, the billet shell is thin, which is easy to cause production accidents. Due to frequent accidents, the amount of residual molten steel and continuous casting billet waste increases. At the same time, the cutting spacer is not replaced in time, and the oxygen pressure is unreasonable, resulting in a larger spacer, which reduces the yield of molten steel.
- High tapping temperature
High tapping temperature will increase continuous casting accidents and cause excessive hot metal loss.
Solution:
- Adjust furnace life structure
Some low-cost auxiliary materials are used to replace the amount of scrap into the furnace, so as to reduce the cost of iron and steel materials.
- Improve lime quality
Adopt good limestone to burn lime, and accurately control the amount of lime added.
- Reduce slag addition
When the steel slag volume increases by 10kg/t, the steel material consumption will increase by 2.5kg/t, and the operation of small slag volume shall be implemented.
- Increase high carbon yield
Increasing the high carbon drawing rate will greatly reduce the back blowing and reduce the metal oxidation loss.
- Reducing FeO content in slag
Reduce the process gun position on the premise of ensuring no gun burning and steel sticking, reduce the total iron content in low slag on the premise of meeting dephosphorization, and control the total iron content in slag below 16%.
- Reduce tapping temperature
The whole ladle capping process is adopted to reduce the tapping temperature.
- Improving metal yield of continuous casting
1) The operation idea of low-temperature rapid casting is adopted in the continuous casting process to optimize the physical and chemical properties of mold flux, ensure the stability of the casting process, eliminate the bonding phenomenon in the casting process and reduce the re casting.
2) The service life of tundish continuous casting is increased, the number of heat exchange tundish is reduced, and the rejection rate is reduced.
3) Strictly control the amount of residual steel for tundish casting, and control the height of tundish block below 200mm.
4) The appropriate cutting nozzle shall be selected according to the section size of the slab to reduce the weld joint and reduce the cutting slag.