rp hp uhp graphite electrode

Pubdate: 08-13 2021

Twenty-three common questions about rp hp uhp graphite electrode in electric furnace steelmaking

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1 Twenty-three common questions about rp hp uhp graphite electrode in electric furnace steelmaking

rp hp uhp graphite electrode

Source: rp hp uhp graphite electrode-FAQ<hr /> Electric arc furnace steelmaking is in the ascendant in steel production enterprises. At present, among the three methods of open hearth, converter and electric arc furnace steelmaking, the proportion of electric furnace steel reaches 3% About ten. Electric arc furnace steelmaking uses rp hp uhp graphite electrode as a conductive material.

The consumption of rp hp uhp graphite electrode in electric arc furnace steelmaking depends on the quality of rp hp uhp graphite electrode, as well as the level of steelmaking operation and management. Now, we analyze the usage problems accumulated by our factory’s rp hp uhp graphite electrode user service over the years, in order to benefit the use and operation of rp hp uhp graphite electrode in electric arc furnace steelmaking.

01. What are the main factors affecting the consumption of rp hp uhp graphite electrode in electric arc furnace steelmaking?

Mainly include:

(1) Filling amount and feeding method.

(2) Feeding time and power-off time.

(3) Smelting cycle.

(4) Exhaust gas emission and dust removal system.

(5) rp hp uhp graphite electrode adjustment quality.

(6) Load regulation quality.

(7) Oxygen blowing operation.

(8) Connection quality of rp hp uhp graphite electrode.

(9) rp hp uhp graphite electrode joint body mass.

(10) rp hp uhp graphite electrode joint hole and joint machining accuracy.

02. What matters should be paid attention to in the storage of rp hp uhp graphite electrode in steel mills?

The rp hp uhp graphite electrode and joints should be stored on a clean concrete floor to prevent the rp hp uhp graphite electrode from being damaged or sticking to dirt; for the rp hp uhp graphite electrode that is not used temporarily, do not remove the packaging to prevent dust and debris from falling To the thread of the joint or the end face of the rp hp uhp graphite electrode and the inner thread of the hole of the rp hp uhp graphite electrode. The rp hp uhp graphite electrode should be neatly stored in the warehouse, and the two ends of the rp hp uhp graphite electrode should be padded to prevent slipping. The stack height of the rp hp uhp graphite electrode should generally not exceed two meters. The stored rp hp uhp graphite electrode should be protected from rain and moisture to avoid cracks and accelerated oxidation of the rp hp uhp graphite electrode during steelmaking. Store the rp hp uhp graphite electrode joint away from high temperature to prevent the joint plug from melting and overflowing.

rp hp uhp graphite electrode

03. How to avoid breaking and tripping of rp hp uhp graphite electrode during steelmaking?

The following measures are taken during the steelmaking process to effectively avoid breaking and tripping of the rp hp uhp graphite electrode:

(1) The phase sequence of the rp hp uhp graphite electrode is correct, counterclockwise.

(2) The scrap steel is evenly distributed in the steel furnace, and large pieces of scrap steel should be placed at the bottom of the furnace as much as possible.

(3) Avoid non-conductive materials in scrap steel.

(4) The rp hp uhp graphite electrode column is aligned with the furnace top hole, and the rp hp uhp graphite electrode column is parallel. The furnace top hole wall should be cleaned frequently to avoid the accumulation of residual steel slag and force the rp hp uhp graphite electrode to be broken.

(5) Keep the electric furnace tilting system in good condition and keep the electric furnace tilting stable.

(6) Avoid clamping the rp hp uhp graphite electrode holder at the joint of the rp hp uhp graphite electrode and the joint hole of the rp hp uhp graphite electrode. (7) Choose joints with high strength and high processing accuracy.

(8) The torque applied when connecting the rp hp uhp graphite electrode should be appropriate.

(9) Before and during the connection of the rp hp uhp graphite electrode, prevent the rp hp uhp graphite electrode hole thread and joint thread from mechanical damage.

(10) rp hp uhp graphite electrode holes and joints prevent steel slag or foreign objects from being embedded and affecting the screw connection.

04. When steel mills use rp hp uhp graphite electrode, what should be paid attention to during crane lifting?

Regardless of whether the rp hp uhp graphite electrode is transported by a forklift or a crane, it must be carefully operated. During the lifting and transportation of the rp hp uhp graphite electrode, damage to the end and threads of the rp hp uhp graphite electrode will cause serious damage to the use of the rp hp uhp graphite electrode The problem is especially important to protect the thread of the threaded hole and the joint. When lifting the rp hp uhp graphite electrode, there must be a pad to prevent damage to the end face and joint thread of the rp hp uhp graphite electrode.

rp hp uhp graphite electrode

05. How to connect rp hp uhp graphite electrode correctly?

When connecting, use compressed air to blow the rp hp uhp graphite electrode hole, the end face of the rp hp uhp graphite electrode, and the joints. There should be no dust and foreign objects embedded. The joints should be kept clean and flat. When the two rp hp uhp graphite electrodes are rotated After entering to a certain extent (the gap is about 10mm), blow it with compressed air again, and then tighten the rp hp uhp graphite electrode with torque pliers. The torque applied during tightening should be appropriate. If there is a gap in the connection after tightening, it must be Exit and reconnect until there is no gap.

06. Regarding the correct clamping position of the rp hp uhp graphite electrode holder.

The rp hp uhp graphite electrode holder cannot be clamped at the junction of the rp hp uhp graphite electrode and the threaded hole of the rp hp uhp graphite electrode. It should be clamped at the rp hp The area between the two white wires of the uhp graphite electrode. At the same time, before the rp hp uhp graphite electrode is clamped by the holder, the surface of the rp hp uhp graphite electrode and the holder should be blown off with compressed air to ensure that the current and heat flow are in the rp hp uhp graphite electrode. The conduction between the hp uhp graphite electrode and the holder is good to prevent arcing from causing damage to the holder, thereby prolonging the life of the holder.

07. What are the measures to reduce the oxidation consumption of rp hp uhp graphite electrode during steelmaking in an electric arc furnace?

The main reduction measures are:

(1) Reduce the oxidation consumption of the periphery of the rp hp uhp graphite electrode, strengthen the sealing of the furnace, and reduce the intrusion of air into the furnace; minimize the exposure time of the red heat rp hp uhp graphite electrode outside the furnace, and standardize the oxygen blowing operation.

(2) For the smelting furnace, if conditions permit, the rp hp uhp graphite electrode adopts spray cooling technology, which can effectively reduce the side oxidation consumption of the rp hp uhp graphite electrode.

(3) The steel plant sprays anti-oxidant substances on the surface of the rp hp uhp graphite electrode, or the manufacturer of the rp hp uhp graphite electrode adopts antioxidant dipping treatment technology before the rp hp uhp graphite electrode leaves the factory to improve the oxidation resistance of the rp hp uhp graphite electrode body performance.

rp hp uhp graphite electrode

08. How does the phase sequence of rp hp uhp graphite electrode affect the use of rp hp uhp graphite electrode?

The phase sequence of the rp hp uhp graphite electrode during electric arc furnace steelmaking is opposed to the tripping and breaking of the rp hp uhp graphite electrode during use. If the phase sequence of the rp hp uhp graphite electrode is clockwise, rp hp uhp graphite electrode When the electrode is energized for a period of time, it will loosen, which will easily cause the rp hp uhp graphite electrode to loosen or the joint to break. The correct phase sequence of the rp hp uhp graphite electrode should be counterclockwise. In this way, the rp hp uhp graphite electrode will be spliced during use. Getting closer.

09. Why is the phase rp hp uhp graphite electrode required to be parallel and aligned with the top hole of the furnace cover during electric arc furnace steelmaking?

When the rp hp uhp graphite electrode column and the top hole of the furnace cover are dealt with, the rp hp uhp graphite electrode column should avoid friction with the furnace cover. For AC furnace, the three-phase rp hp uhp graphite electrode column should be kept parallel as much as possible.

10. How to apply torque when screwing rp hp uhp graphite electrode?

The torque applied during screwing of the rp hp uhp graphite electrode should be appropriate, and the operation should be inertial. Too small a torque will cause the joint to loosen thermally, and too much torque will cause the rp hp uhp graphite electrode to crack in the joint hole. Use a special one when screwing. rp hp uhp graphite electrode screwing tool, do not overtighten or loosen it. If there is a gap in the end face contact after tightening, it must be removed and cleaned before re-spinning.

11. Why is graphite spreader better than metal spreader?

Although the metal spreader is durable and not easy to be damaged, the thermal expansion of the metal spreader will easily crack the hole of the rp hp uhp graphite electrode when it is heated during use. At the same time, it is easy to damage the thread in the hole of the rp hp uhp graphite electrode when the metal spreader is taken. , Causing the thread in the hole to be scraped off a large area, making the rp hp uhp graphite electrode prone to tripping. The graphite spreader has the same thermal expansion performance and hardness as the rp hp uhp graphite electrode, so the above-mentioned poor use will not occur, but the graphite The spreader has a short service life and is easily damaged. If serious damage is found, it should be replaced in time.

rp hp uhp graphite electrode

12. How to correctly choose rp hp uhp graphite electrode in electric arc furnace steelmaking?

According to the design characteristics of the electric arc furnace, the rp hp uhp graphite electrode that meets the production of the electric arc furnace is reasonably selected, and the product with the best cost performance is selected. It is very necessary to carefully select the rp hp uhp graphite electrode suitable for each furnace, the special performance of the steelmaking furnace, the feeding method, the maximum current intensity, the length of the rp hp uhp graphite electrode column under the holder, the furnace side wall and the rp The distance between the circumference of the hp uhp graphite electrode and so on are all factors that must be considered when the electric arc furnace chooses to use the rp hp uhp graphite electrode.

13. What impact does the resistivity performance have on the use of rp hp uhp graphite electrode in steelmaking?

The resistivity of the rp hp uhp graphite electrode is a physical indicator that reflects the electrical conductivity of the rp hp uhp graphite electrode. It is related to the manufacturing process of the rp hp uhp graphite electrode. The country has qualitative resistivity of the rp hp uhp graphite electrode of different specifications. Generally speaking, when a steel plant chooses a certain specification of rp hp uhp graphite electrode, it must be within the resistivity range specified by the national metallurgical standard. Too high resistivity will cause the rp hp uhp graphite electrode to be energized. Red heat, increase oxidation consumption of rp hp uhp graphite electrode.

14. What effect does the volume density performance have on the use of rp hp uhp graphite electrode in steelmaking?

The volume density of the rp hp uhp graphite electrode reflects the compact state of the rp hp uhp graphite electrode, and is closely related to the manufacturing process of the rp hp uhp graphite electrode. The country has specified values for the volume density of rp hp uhp graphite electrode of different specifications. Products with low bulk density indicate that the overall structure of the product has higher porosity, and the oxidation rate of the product is faster at high temperatures, which easily causes the consumption of rp hp uhp graphite electrode to increase. Generally speaking, when steel mills choose rp hp uhp graphite electrode, rp hp uhp graphite electrode The bulk density of graphite electrode is better within the specified value, but the higher the bulk density is not, the better, because some rp hp uhp graphite electrodes with too high bulk density sometimes have poor thermal shock resistance and are prone to surface spalling during steelmaking. Loss of blocks and cracks will affect steelmaking.

rp hp uhp graphite electrode

15. When steel mills use rp hp uhp graphite electrode, why should they prevent multiple products from mixing?

The rp hp uhp graphite electrode used in steel mills is often supplied by multiple manufacturing companies. When multiple products are used in steelmaking, it will not only make it difficult for the steel mill to calculate the consumption of a single product, but also due to the raw materials and manufacturing used by each manufacturer. Depending on the process, the physical and chemical properties and machining tolerances of the rp hp uhp graphite electrode and joints of various manufacturers have certain differences. Therefore, the matching tolerances generated during the mixed use can easily cause the rp hp uhp graphite electrode to fall off and break. The correct way to use is to use the product of a certain manufacturer alone, and then connect to the product of another manufacturer after the end. It is necessary to reduce the use of different manufacturers. rp hp uhp graphite electrode replacement times, the rp hp uhp graphite electrode of the same manufacturer should use the matching connector of the same manufacturer to prevent mixing.

16. What are the characteristics of needle coke?

Needle coke is a high-quality carbon raw material, divided into coal-based and oil-based. Its surface has obvious strip lines. When broken, most of them are long needle-shaped fragments. The fibrous structure can be observed under a microscope. Hence it is called needle coke. Needle coke is easy to graphitize at a high temperature above 2000 degrees. The rp hp uhp graphite electrode manufactured by it has low electrical resistivity, high bulk density, and low thermal expansion coefficient. Essential material for ultra-high-power rp hp uhp graphite electrode and high-power rp hp uhp graphite electrode. The price of needle coke is much more expensive than that of ordinary coke, and is currently about 5-8 times higher.

17. Will the dust collection system on the electric arc furnace affect the consumption of rp hp uhp graphite electrode?

The fan used in the dust collection system generates a certain negative pressure during work, which increases the air flow rate around the red hot rp hp uhp graphite electrode during steelmaking, which also increases the oxidation consumption of the rp hp uhp graphite electrode. A well-adjusted dust collection system not only maintains a good working environment, but also stabilizes the consumption of the rp hp uhp graphite electrode.

rp hp uhp graphite electrode

18. How to avoid increased consumption of rp hp uhp graphite electrode during steelmaking?

To avoid increased consumption of rp hp uhp graphite electrode during steelmaking, the following should be done:

(1) Maintain a good power supply status, and transmit power within the allowable current intensity range of the rp hp uhp graphite electrode according to the design requirements of the electric furnace.

(2) Prevent the arc starting point from being immersed in the molten pool.

(3) Prevent the rp hp uhp graphite electrode from being immersed in molten steel to increase carbon.

(4) If conditions permit, rp hp uhp graphite electrode adopts spray cooling technology.

(5) Set up the correct exhaust emission system.

(6) Use the correct oxygen blowing system.

19. How long is the production cycle of rp hp uhp graphite electrode?

The production process and corresponding time of a batch of ultra-high power or high power rp hp uhp graphite electrode are as follows: rp hp uhp graphite electrode pressing (3 days)-roasting (25 days)-immersion (4 days) ——Re-roasting (15 days)——Graphitization (10 days)——Machining, quality inspection (2 days)——Finished product packaging and delivery (1 day), that is, from feeding to product shipment, there is no stop in production The fastest cycle time is 60 days, and the production of rp hp uhp graphite electrode joints requires more two immersion and three baking processes than rp hp uhp graphite electrode, so the production cycle takes 90 days at the fastest.

20. What are the characteristics of the rp hp uhp graphite electrode produced by the tandem graphitization furnace?

The development direction of graphitization furnace is internal heat tandem graphitization furnace. Because the current density of the series connection column is the same, the resistivity difference of the rp hp uhp graphite electrode is very small; secondly, the resistivity at both ends of the inner string graphitized product is slightly lower than that of the middle part (the Acheson furnace graphitized product has high resistivity at both ends In the middle), it is beneficial to reduce the resistance of the connection when users use it, and alleviate the overheating and redness of the joint connection. Therefore, the quality uniformity of the rp hp uhp graphite electrode produced by the tandem graphitization furnace is better than that of the Acheson furnace. It is suitable for the production requirements of electric arc furnace steelmaking.

21. Why does the quality of the rp hp uhp graphite electrode joint play an important role in electric arc furnace steelmaking?

The joint plays a key role in the connection when the rp hp uhp graphite electrode is steelmaking. The quality of the joint is directly related to the use of the rp hp uhp graphite electrode in the electric furnace steelmaking. No matter how good the quality of the rp hp uhp graphite electrode is, if not A reasonable combination of high-quality joints can also cause problems in steelmaking. According to relevant data, in electric furnace steelmaking, more than 80% of rp hp uhp graphite electrode accidents are caused by joint breakage and loosening. Therefore, the choice of high-quality rp hp uhp graphite electrode joint is electric arc furnace steelmaking rp Guarantee conditions for normal use of hp uhp graphite electrode.

22. Which quality indicators of rp hp uhp graphite electrode (joint) products have an impact on electric furnace steelmaking?

(1) Quality indicators such as bulk density, resistivity, strength, elastic modulus and thermal expansion coefficient of rp hp uhp graphite electrode.

(2) Quality indicators such as bulk density, resistivity, strength, elastic modulus and thermal expansion coefficient of the joint.

(3) The machining accuracy of rp hp uhp graphite electrode and joints, no matter how good the quality of rp hp uhp graphite electrode and joints is, there is no good machining accuracy (mainly refers to the cooperation of rp hp uhp graphite electrode and joints), and the use effect is not good.

(4) The quality of the internal structure of the rp hp uhp graphite electrode and the joint requires no cracks that cause hidden dangers in use.

23. What will happen if the end face of the rp hp uhp graphite electrode on the upper end of the rp hp uhp graphite electrode holder is severely oxidized?

When steel is made in the smelting furnace, the scrap is burned in the furnace. At the same time, due to the oxygen blowing in the furnace, the height of the flame column is often higher than the end face of the rp hp uhp graphite electrode at the upper end of the holder, which is easy to oxidize the end face of the rp hp uhp graphite electrode. Severe oxidation will cause the end face of the rp hp uhp graphite electrode to deform from a flat surface to a bevel. When the new rp hp uhp graphite electrode is connected to the upper end, the oxidized deformation of the end face of the lower rp hp uhp graphite electrode cannot make good contact with the new rp hp uhp graphite electrode. , Rp hp uhp graphite electrode has a large gap, which is easy to cause oxidation and fracture of internal joints. Without changing the steelmaking conditions, the best preventive measure is to add a protective cover on the end face of the rp hp uhp graphite electrode at the upper end of the holder to block flame and air, so as to protect the end face of the rp hp uhp graphite electrode.


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