Since we company set up. Based on years of practice, with our users carrying cooperate together to reduce electrode consumption in steel-making. Good effect has been obtained for the past several years. In order to let users better use of electrodes, we inductive analyzed the common abnormal problems that occur in the process of using electrodes for your reference.
Example 1:One company used RP and HP φ 300 mm electrode on a 70 mt LF furnace, and found the electrodes turns red and thin and can no longer use.
The problem is that the above electrode cannot bear 26 KA current
Example 2: The effect of AC Furnace phase sequence to electrode loose.
AC Furnace phase sequence has a great effect on electrode loose, which is happened on users from home and abroad.Among the15 units of domestic electric furnace that we measured: 10 of them need to change the phase sequence. 5 of them no longer get loose after take our advise to change their phase sequence. 1 of them don’t want to change, and 1 of them doesn’t change because the operator can not read English, and the electrode loose situation still the same; 3 of them is going to change. Recently, there are another plant who also face such problem. After our introduction, they are going to measure the sequence.
Example 3: One factory reflected electrode loose. According to our investigation: in addition to the phase sequence should change, only 4 teeth inside of the electrode upper hole are in good condition, other teeth have different degree of damage.There was one T3 iron lifting plug found mix-used to carry T4 electrodes on the spot. After corrected phase sequence and removed the T3 lifting plug, no loose were found till now.
Example 4: One plant’s electrodes always got broken, result from the large blocks of steel slag collapse or non-conductive factors. According to the statistics from their engineering department, 78% of electrodes breakage are caused by above reasons.
Example 5: Due to electrode hole wall on furnace cover slagging, electrodes were broken for many times handled by one team on LF furnace. After slag removal and keep the distance between electrode and wall of hole, no such breakage happened again.
Example 6: One factory used TOKAI φ 700 electrodes and happened more than 20 times of breakage. The manufacture came and checked their operation and found they connected the electrodes so tight that over the triangle mark. After justified, the breakage phenomenon eliminated.
Example 7: Every team of one factory has breakages on LF furnace. The reasons are: 1) one foot screw of the column was broken and one loosen among the four screws;2) The column verticality is 14 times larger than required. After adjustment, no more breakage.
Example 8: 16 pcs of nipples were broken in a factory. After check, we found they all broke at the point of pin. Pin hole φ 28mm, and deep（ 30 ～ 50mm ）× 2. We suggest them not to use pin.
Example 9:One plant reflect electrode breakage. We found that was caused by molten steel ladle-to-ladle, large temperature drop, and slag layer hardness increase, which not only often forced electrodes to breakage but also destroyed clamps causes electrode consumption increase.
Example 10: Electrode consumption increased when used in one plant’s LF furnace. After we compared the data of before, we found the electrode consumption rose 77.9%, power consumption rose by 15.8%, and 17.5% growth on production cycle. Then through calculation, there would be 170MT electrodes consumption increasing amount and their lost is about 5 million RMB. Through field investigation,we knew that in order to improve the environmental protection, the factory increased the height of small furnace cover about 1 meter; At the same time, suction dust removing valve from opening 45 ° to 90 °, that caused electrodes oxidation and heat dissipation increased. We wrote a report according to our findings and sent to the relevant leader of that factory and they approved.
Example 11: One factory reflected that their electrodes consumption has increased from 0.42kg /t to 0.52kg /t on LF furnace . The reason is VD ratio grew from 42.76% to 73%.
According to the memory of the leader in that factory, what they knew was same as our analysis.
Example 12: A plant said their electrodes have tripping phenomenon. Through on-the-spot investigation, we found that they used electrodes from several manufactures, and no loose will happen when they use separately but join two electrodes from different manufactures. This is mainly due to different manufacturers have different electrode machining tolerance and we recommend the user to reduce the changing times of electrodes from different manufactures to avoid mixing.
The above are some excerpts of electrode using problems we encountered and put forward suggestions of improvement through years of experience. Because the continuous and discontinuous consumption of electrodes involves the design of the electrode manufacture and design, equipment, raw materials, process, operation, and many other aspects, both sides and internal shall work together to find out the real reason as soon as possible when an exception occurs. The above instances are examples of honest fellowship solves practical problems. We are very appreciate the great help, cooperation and support from our customers during our investigation.We have a professional after-sales service team, and once you encounter electrodes use question, we will provide you with solutions in the first time.