Solutions to Graphiteelectrode Breakage

Some of the reasons for the breakage of the graphiteelectrode are operation and control, but the quality of the graphite electrode itself is also the decisive factor for the breakage of the graphiteelectrode.

GraphiteElectrode quality reasons

(1) The reason why the nipple is broken: The nipple plays a key role in the connection during the graphiteelectrode in steelmaking, and the quality of the nipple is directly related to the use of the graphiteelectrode in the electric furnace steelmaking. The connection area formed by the graphite electrode and the nipple is a place with large and complex electrical, thermal and mechanical loads, and it is also a common fracture site. According to relevant data, in electric furnace steelmaking, more than 80% of electrode use accidents are caused by broken nipples or loose tripping. As far as the nipple quality itself is concerned, there are mainly the following reasons for the breakage: if the nipple bulk density is low, the strength is?low, and it is easy to cause breakage during use;The high thermal stress of the nipple at the graphiteelectrode connection increases the probability of fracture; The flexural strength of the nipple is not enough; The internal crack nipple is mixed into the finished joint to cause a hidden danger in use; The nipple and the electrode processing accuracy index do not match reasonably to cause the?breakage.

(2) The probability of GraphiteElectrode breakage is low, and the main reasons for GraphiteElectrode breakage are as follows: the electrode nipple hole has quality defects; the density and strength of the electrode are not enough; the electrode and nipple specification, processing accuracy does not match; the cracks at the end of the?GraphiteElectrode are caused by the poor thermal shock resistance of the electrode; in addition, the GraphiteElectrode with internal transverse cracks is mixed into the finished product without detection, and there is a great risk of breaking.

Precautionary Measures and Operational Suggestions

1 Preventive measures against breakage during smelting operations

(1) The distribution of various steel scraps in the basket and the conditions of feeding into the furnace need to be reasonably configured to prevent light and thin steel materials from forming a ball on the top of the furnace and making it difficult to descend, and to avoid large pieces of steel scrap from collapsing and breaking the electrodes.

(2) When smelting, especially when it is close to melting, it is necessary to carefully observe the distribution of unmelted furnace materials. If a bridging structure has been formed, oxygen blowing or physical swinging or shaking must be used first to allow the charge to slump in the event of a power failure and the electrode has been raised to a high level, so as to prevent the electrode from being broken by the slump.

(3) The strength of electrode should suitable for the process requirements. The electrode Nipple should use a nut of appropriate strength, and keep it clean, and use a special clamping device. Before replacing the electrode and hoisting, the lifting ring must be tightened to ensure that the lifting ring is in close contact with the electrode. In order to keep the interface clean, it is required to keep the end cap of the new electrode until the lifting ring is installed.

(4) The electrode holder should avoid being caught in the white line between the electrode connections. The electrode connection cannot be above the electrode holder. The electrode holder cannot be clamped on an open sleeve or a sleeve with a ring.

2 Preventive measures during the control process

(1) After high-voltage power transmission, it is necessary to observe whether the three-phase no-load voltage of the secondary short network is balanced (determined by the insulation resistance of the three-phase short network to the ground, and the unbalanced voltage should be within 10%).

(2) Before the electrode is automatically lowered, make sure that there is no non-conductive object in the scrap steel layer directly below the electrode.

(3) After the electrode of the first phase drops and touches the scrap steel, observe whether the secondary voltage of the electrode of this phase drops immediately.

(4) When an arc occurs on an electrode of a certain phase, whether the secondary current display of the electrode of this phase can be seen (the pointer of the ammeter has a large swing).

(5) Regularly detect whether the braking force of the electrode hydraulic drive mechanism and the system delay coefficient have changed.