Baking is an important process for producing ultra-high […]
Baking is an important process for producing ultra-high power graphite electrodes with excellent performance. Ultra high power graphite electrode are widely used in electric arc steelmaking furnaces with high current density and harsh working conditions due to their low electrical resistivity, good oxidation resistance, and low thermal expansion coefficient, and their bulk density and flexural strength are also required To reach a higher level, at the same time, its elastic modulus must be appropriate, and it needs to match the performance of the supporting electrode joints to show good thermal shock resistance during the electric furnace steelmaking process, and it is not easy to break. Therefore, it is necessary to strictly control the process parameters of each process of ultra-high power graphite electrode production to ensure that the product quality of each process is qualified and the internal structure of the product is uniform and stable. Therefore, continuously optimizing each link of process control is an effective means to obtain better quality products. This article focuses on the discussion and analysis of the main factors affecting product quality in the roasting process.
Roasting concept and process content
1. The concept of roasting
Roasting refers to the pressure-type green product (green body) surrounded by air-isolated fillers, by continuously receiving external heat, the asphalt in the product becomes pitch coke, and at the same time it combines with the carbon aggregate particles to become firm The integrated heat treatment process.
2 Several important steps in the roasting process
1) Preparation before installing the furnace: check the furnace condition and perform preventive maintenance within the specified time period to meet the furnace installation requirements.
2) Filler preparation: Process qualified fillers and fill the voids around the raw product by machinery to avoid deformation of the product when the asphalt in the raw product becomes liquid during the heating cycle.
3) Furnace loading: The raw products are mechanically loaded into the designated position in the roaster box.
4) Heating: The heat generated by the fuel is indirectly transferred to the product itself through the combustion of the fuel, so that it is continuously heated.
5) Cooling: gradually reduce the fuel supply as required to reduce the heat supply in the furnace; when the roasting process is over, the temperature in the furnace is gradually reduced to 400 ℃ through forced air cooling, and then naturally cooled to ambient temperature .
6) Out of the oven: Use machinery to remove and remove the filler around the product in the furnace box, and then move the product out of the furnace box to the cleaning site to clean the surface of the product.
7) Inspection: Inspect the surface of the product with naked eyes, and judge the internal structural defects by hammering echo method.