01 Tundish preparation
- Check the wall, bottom and baking conditions of the tundish;
- The middle contractor shall determine the middle contract number used on duty according to the middle contract situation, write it on the blackboard and explain and sign on the “Tundish Packaging Safety Use Record Sheet” in the duty room (such as: normal, spare, new package and baking status, Out of service);
- The continuous caster (installing the nozzle for the tundish) shall use the “normal” tundish hoisting described by the contractor, and check whether the hoisting chain is normal before hoisting;
- Two people cooperate when installing the tundish, and pay attention to the position of the hand when directing the driving down;
- Tundish nozzle installation
①Clean up the debris in the middle bag;
②Fill high temperature agent around the nozzle of the tundish;
③Smear refractory mud around the bottom of the nozzle. The refractory mud shall be applied sufficiently and no gaps shall be left. Then use a wooden block to lightly drive into the tundish nozzle hole;
④ Bake at the nozzle and roast with an oxygen lance until the refractory mud is dry;
- Tundish centering: Use a crowbar to adjust lightly so that the nozzle of the tundish is aligned with the center of the crystallizer. Method: Insert the drainage tube into the water port of the tundish, and the drainage tube rotates 360° to fall on the mouth of the mold;
- When driving the middle chartered car, pay attention to observe whether anyone has feet on the track to prevent crushing;
- Do a good job of swinging
① The residual steel on the pendulum trough should be cleaned;
②Fill the pendulum trough with quartz sand, which is required to be strong and flat;
③Put double-layer asbestos at the place facing the nozzle. If the pendulum channel sticks to too much steel during production, the residual steel should be disposed of in time, and the quartz sand should be refilled to avoid piercing the pendulum channel due to the number of pendulum channels.
02Second cold room cleaning
- Clean the residual steel on the nozzle, and all the nozzles are blocked and replaced to ensure that the water volume and angle are normal when spraying water;
- Clean the residual steel on the spray frame and wrap it with glass fiber; protect the spray pipe to avoid deformation;
- Clean the cold steel on the cylinder and small roller to ensure normal operation.
03Initiator head installation
- Use a small wooden block to block the starter head and the hook head. The gap hook head must be welded firmly to prevent it from being pulled off due to weak welding;
- Use asbestos cloth to pave the other end of the hook head to cover the hook head and the starter head;
- Operate the starter switch to send the starter head to the lower port of the copper tube of the crystallizer;
- Observe the gap between the starter bar and the spray pipe to see if the spray trap is deformed and the arc is normal to ensure uniform cooling;
- Fill the starter head with cold steel and drainage sand. The cold steel must be tightly arranged and not inclined to prevent scratching the copper pipe when pulling the steel;
- Use a plug to block the nozzle of the tundish package, and move the swing groove under the nozzle.
04 Safe operation of unpacking
- After the bale containing molten steel is hoisted on the bale rack, tap the bale switch to open the bale to the middle of the tundish, and measure the temperature of the ladle molten steel. The temperature of the first bale is 1650°C-1660°C, and open The large package mechanism allows the molten steel to flow automatically into the tundish;
- If the molten steel cannot be drawn out automatically, the steel puller should be notified to burn oxygen and drain; the method of oxygen burn and drainage:
① Use a cutting torch to burn the oxygen tube;
②One person opens the oxygen valve;
③The person who blows oxygen and drains must wear long leather gloves and pull the mask;
④ Insert the oxygen tube into the water port of the large bag to blow oxygen and drain;
⑤The large contractor drives the large chartered car to cooperate with the drainer to lead out the molten steel;
⑥After the drainage is successful, the valve must be closed immediately, and the drainage person should withdraw to a safe area;
- Tundish liquid level and temperature control
①When the liquid level of the tundish reaches 150mm, notify the steel puller to start pouring;
②The temperature of the tundish should be controlled above 1530℃;
③Control the large package mechanism to control the amount of molten steel injected into the tundish, threatening to control the liquid level of the tundish according to the amount of molten steel and the pulling speed;
④When the amount of molten steel is insufficient, the liquid level and temperature of the tundish should be controlled to ensure the molten steel connection;
⑤The temperature of the molten steel in the tundish is lower than 153. ℃ and the temperature must be increased by blowing oxygen. A small amount of manganese should be added to the molten steel during the oxygen blowing;
⑥ Open the mechanism and observe the molten steel in the ladle when the steel is flowing. If there is any turning, you should avoid it in time and notify the steel puller;
⑦After replenishing the water port, after opening the package, pay attention to observe whether the molten steel in the large ladle is turning, and if there is turning, avoid it in time and notify the steel puller;
⑧After the casting is normal, ensure that the temperature of the tundish is around 1530℃;
⑨ Observe the underwater flow of the ladle steel, and find that the molten steel flow is twisted and close the mechanism in time to prevent slagging;
⑩If it is found that the organization cannot be closed, the dispatcher or the operator should be notified in time, and the large package should be lifted away;
⑪The ladle of molten steel must be completely discharged, and the mechanism must not be closed in advance.
05 Safe operation of pouring steel
- After receiving the notice of contract opening, adjust the switch to the “pouring steel” position, remove the plug and swing slot, use a drainage gun to drain, and inject molten steel into the mold copper tube;
- Observe whether the column flow is in the middle of the mold copper tube. If there is a deviation, schedule the package position until the column flow is in the middle of the mold copper tube;
- Turn on the vibration switch. When the molten steel in the copper tube of the mold is close to the upper mouth 5cm, adjust the pull speed switch to start pulling the steel;
- Pouring steel requires a balance of pulling speed and no jumping;
- Note that the liquid level in the copper pipe should not be too low to avoid leakage;
- When pouring steel, it is required to add a small amount of protective slag several times, and the amount of oil should not be too large, just a small column flow;
- When pouring steel, the residual steel on the mold cover should be disposed of in time to avoid hanging steel;
- If crusts appear during pouring and during pouring, the groove should be placed in time, and the pulling speed should be reset to zero, and the pulling speed can only be increased after the billet shell in the copper tube is pulled away;
- Steel connection treatment method: add a proper amount of cold steel to the copper tube of the mold, pass through several swing troughs to make the joint and the steel condense, and then speed up.
06 Safe operation of crystallizer replacement
- Use a good hoisting chain, wire rope or triangle belt to lift the crystallizer, and the commander should direct the crane to lift it under safe conditions, and the crystallizer is forbidden to hurt people;
- Clean up the sundries of the water tank and the vibration spring plate;
- Padded the sealing ring to avoid the occurrence of “water leakage”;
- The crystallizer is accurately aligned, the screws are pressed tightly, and the surroundings are covered with asbestos cloth;
- Cover the crystallizer cover.
07 Billet stripping
- Before pouring, check whether the air pressure meets the standard and whether the spindle button switch is normal;
- After the billet is at least leveled by the tension leveler, press the stripping switch to separate the billet from the starter head. If the billet cannot be automatically stripped, the steel puller must be notified to stop the trough, and then use the cutting gun to move the starter head. The connection with the billet is cut, and the caster is notified to continue pouring the steel.
08 Billet Shearing
- Before pouring, switch on the power of the shearing machine and check the operation of the shearing machine;
- Check whether the blade is loose and whether the blade edge is defective, replace the blade in advance and tighten it;
- Check whether the hydraulic system of the shearing machine is normal and whether it is leaking oil, and deal with it in advance;
- When the billet passes through the shearing machine, one person controls the switch, and one person observes the cut length of the billet. Observers must instruct the operator to press the cutting button to manually operate the cut billet, and the billet head should be pulled away in time;
- Set the cutting program to automatic, and the billet will be automatically cut when it reaches the infrared induction point through the shearing machine;
- In case of sunlight reflection, the infrared probe should be covered to prevent “light leakage”, shearing machine random cutting, and blockage;
- After pouring and during pouring, if “explosive steel” occurs, spare water should be used to flush the billet exploded in time, and forced cooling.
09 billet delivery
- Check the quality of the billet when the billet is sent for rolling in accordance with the rolling instruction. If there is rotten steel, out of square, black steel, joints, and bulging billets, they should be sent to the pusher and cannot be sent for rolling;
- The billet that cannot be rolled should be cut to the specified size (4.8 meters);
- Send rolling according to the specified size of the new and old rolling lines, and shall not be sent by mistake to prevent the steel billet from being stuck in the rolling place due to the long billet;
- Pay close attention to the temperature of the two-strand billet and keep the temperature of the two-strand roughly the same. If the temperature deviation between the two streams is greater than 15°C, the chief control engineer or the captain should be notified in time to adjust the correction coefficient of the secondary cold water.
10 water transfer
Observe the temperature of the two-strand billet. When the temperature is low, the correction coefficient of the secondary cooling water should be adjusted small, and when the temperature is too high, the correction coefficient of the secondary cooling water should be adjusted large to meet the billet rolling requirements.
11 Lifting and stacking of billets
- Check the condition of the crane spreader;
- The waste blank should be cut short, with a length of 30-40cm;
- The steel billet that can enter the heating furnace should be cut at 4.8 meters, and the short billet should be cut at 2 meters or more;
- For the lifting of billets, each lifting shall not exceed 6 pieces;
- No more than 6 pieces of steel can be pushed each time;
- The foundation of billet stacking should be level and firm;
- The billet stacking requirements are neat and consistent in length;
- The problematic billets shall not be mixed in the good billets.
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