The breakage of graphite electrode is partly due to operation and control, but the quality problem of electrode itself is also the decisive factor of electrode breakage.

1. Reasons for internal quality of electrode

(1) The reason why the joint breaks is that the joint plays a key role in electrode steelmaking. The quality of the joint is directly related to the use of the electrode in electric furnace steelmaking. The connection area formed by graphite electrode and joint is not only a large and complex part of electrical, thermal and mechanical load, but also a common fracture part.

(2)Generally, the probability of electrode breaking is low. The main reasons for electrode breaking are as follows: there are quality defects in electrode screw holes; The bulk density and strength of the electrode are not enough; The electrode does not match with the joint index and machining accuracy; The deep crack at the end of the electrode is caused by the poor thermal shock resistance of the electrode; In addition, the electrode with internal transverse crack is mixed into the finished product and is not detected, so there is a great risk of breaking.

2. Preventive measures for breaking during smelting operation

(1) Reasonable distribution structure: the distribution of various scrap steel in the material basket and the situation of adding into the furnace shall be reasonably configured to avoid that the light and thin steel materials form a group on the top of the furnace and are difficult to go down, and to prevent the electrode from being broken by the collapse of large scrap steel.

(2) The electrode shall adopt the strength suitable for the process requirements. The connecting electrode shall adopt nuts with appropriate strength, clean them, and use special clamping tools. Before replacing the electrode and lifting, the lifting ring must be fastened to ensure close contact between the lifting ring and the electrode. In order to ensure the cleanness of the interface, it is required to keep the protective end cap of the new electrode until the lifting ring is installed.

(3)The electrode holder shall avoid being clamped in the white line between the electrode connections. The electrode connection shall not be above the electrode holder. The electrode holder shall not be clamped on the open socket or the socket with lifting ring.

3. Conclusion

(1) The electrode of electric furnace can be broken due to material collapse, resonance, non-standard clamping operation, abnormal condition of electrode regulator, hydraulic driving mechanism of electrode regulator, improper control measures of electrode internal quality and other factors.

(2) By taking corresponding technical and management measures for the factors such as distribution structure, electrode clamping, no-load voltage of secondary short network, non-conductive object, secondary current, braking force of electrode hydraulic driving mechanism and system delay coefficient, the phenomenon of electrode breaking can be significantly improved.

(4)There is a certain one sidedness in judging the quality of electrode (joint) by virtue of the physical and chemical indexes of electrode (joint). The matching of our products with the smelting process, furnace structure and smelting steel grade of different customers should be fully considered, and a set of scientific and reasonable electrode production and technical application scheme should be established