Replacement method and maintenance operation of converter steelmaking taphole

Standards for replacing tapholes

(1) The tapping time is less than 3 minutes.

(2) The tapping hole is irregular in shape or has obvious pits inside, and the tapping steel is scattered.

(3) The tapping hole life is longer than the specified furnace life, which is pre-arranged according to the production plan.

How to replace the tapping hole

(1) The plan for replacing the tapping hole must be issued at least 4 hours in advance to facilitate production organization.

(2) After tapping out the steel and emptying residual slag, tilt the converter to an appropriate position on the large side and thoroughly clean residual steel from the tapping hole. Following slag splashing completion for this furnace charge, purge the vaporization flue with high-pressure nitrogen to remove adhered slag.

(3) Lower the converter to the appropriate position. Adjust the tapping hole drilling machine to align with the tapping hole angle, ensuring precise drilling angle, smooth hole walls, a round and uniform channel, and appropriate size to avoid damaging the tapping seat bricks.

(4) After drilling the tap hole, tilt the converter to a position convenient for installing the new tap hole. While drilling the tap hole, prepare the new tap hole, tap hole material, and tap hole material trough.

(5) Using a forklift and specialized tools, insert the new taphole into the drilled passageway and adjust its position. Secure the new taphole guard plate to the furnace shell’s taphole steel plate using electric welding for positioning (to facilitate positioning, fill the taphole passageway with an appropriate amount of taphole material before installing the new taphole).

(6) After positioning the taphole, cut open the upper section of the taphole guard plate to facilitate filling with taphole material.

(7)Using a forklift and taphole material trough, fill the taphole with an appropriate amount of prepared taphole material. Completely fill and compact the gap between the new taphole and the channel. Ensure sintering for 3–5 minutes to sinter the taphole while simultaneously preparing taphole material at the furnace rear.

(8) Tilt the converter to an appropriate position for pouring material into the taphole. Pour the prepared taphole material into the gap between the new taphole and the channel. During operation, avoid incomplete filling.

(9) Monitor the pouring process to prevent material leakage. After pouring, ensure a sintering time of at least 15 minutes.

(10) After each tap hole replacement, promptly adjust the slag-blocking car to ensure precise alignment of the slag-blocking cone.

Requirements for taphole maintenance and replacement

(1) The furnace master should pay attention to the condition of the tapping port for each batch of steel. After tapping, the inner and outer ports of the tapping port should be checked. If the inner port is not good, the master should pay attention to the condition of the rear large surface, and do a good job of final slag and post-slag pouring to maintain the rear large surface and the inner port of the tapping port. If the inner port is severely corroded, the furnace supervisor should be contacted in time to confirm on site, take measures, replace the tapping port, and maintain the rear large surface.

(2) If the outer port of the tapping port is severely corroded, it should be repaired in time. If the shaped steel plate is damaged, the converter foreman should be notified in time. If steel seepage is found at the tapping port, the furnace supervisor should be notified to confirm on site and arrange for replacement in time.

(3) As long as the tapping port is found to be broken or corroded, the furnace supervisor should be notified to confirm on site and arrange for replacement of the tapping port regardless of the number of times the tapping port is used.

(4) If the tapping time is less than 3 minutes, the furnace supervisor should be notified immediately to confirm on site, and the furnace supervisor should report to the dispatch room on site to coordinate the plan for replacing the tapping port.

(5) The furnace supervisor should always keep track of the taphole situation, determine the time to replace the taphole, and report to the planner. When replacing the taphole according to the plan, the foreman and the furnace master should arrange to replace the drill bit and clean the furnace mouth.

(6) When drilling the old taphole, the second assistant and the furnace master must confirm the correct angle of the drill rod and must not deviate.

(7) Before installing a new taphole, make sure there is no residual steel. If there is residual steel, use a coal oxygen gun to burn it clean to ensure that the inside of the inner mouth is uniform and smooth. When installing a new taphole and spraying the outer mouth, the furnace supervisor must ensure that the taphole is in the correct position before spraying the material. After spraying the outer mouth, use a coal oxygen gun to bake it for 3 to 5 minutes before shaking it to the back of the furnace.

(8) When spraying the back of the furnace, ensure that the material-water ratio is adjusted to the required level and the viscosity is appropriate before entering the furnace for spraying. Do not adjust the spray gun after inserting it into the furnace. If a dry self-flowing material is used at the tapping hole, the temperature must be appropriate and the self-flowing material must be fluid enough to fill the tapping hole completely.

(9) Before adding molten iron, make sure that the gunning material is completely dry before adding molten iron.

(10) Before production, make sure that the tapping hole is in good condition before adding molten iron. If flames are emitted from the tapping hole during blowing, it means that the tapping hole is unobstructed.

Measures to prolong the life of taphole

(1) Reduce the amount of slag discharged during the early and late stages of steel tapping, and use a slag blocking process to block the slag during the steel tapping process.

(2) If necessary, the slag can be reversed from the tapping port after adjusting the slag to reduce the erosion of the tapping port by the slag.

(3) Reduce the damage to the tapping port caused by high-temperature steel, over-oxidized steel, etc.

(4) Repair the tapping port in a timely manner to maintain its normal shape and size.

(5) Use high-quality materials. The material used for the tapping port is required to be resistant to high temperature, erosion, scouring, and rapid cooling and heating.