The breakage of the graphite electrode is partly due to its handling and control, but the quality of the electrode itself is also a determining factor.
(1) Causes of nipple fracture of graphite electrode:
The nipple of graphite electrode plays a key role in the connection of electrode in steelmaking. The quality of nipple is directly related to the application of electrode in steelmaking.The connection area formed by graphite electrode and nipple is a complex part with large electrical, thermal and mechanical loads, and is also a common part of fracture.According to relevant data, more than 80% electrode accidents in electric furnace steelmaking are caused by nipple breakage or loosening.In terms of the quality of the nipple itself, the main reasons for nipple fracture are: small volume density, low strength, easy to fracture when using;High resistivity, the joint temperature rises quickly when energized, resulting in large thermal stress at the electrode nipple.Increased risk of nipple breakage;Fracture strength is not enough;Internal crack joint mixed with finished nipple, forming a major hidden trouble;Nipple and electrode machining accuracy index is not reasonable match, easy to fracture.
(2) Causes of electrode fracture
In general, the probability of electrode fracture is low.The main causes of electrode fracture are: screw hole quality defects;Insufficient electrode volume density and strength;The index of electrode and nipple do not match, and the machining accuracy is not high.The deep crack at the electrical end is caused by the unqualified quality of the threaded hole.Thermal shock resistance of electrode.In addition, electrodes with no internal transverse cracks detected in the finished product pose a significant risk of breakage.